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Aug 14, 2009, 2:18:25 PM (15 years ago)
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Xavier Rouby
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  • trunk/paper/CommPhysComp/notes.tex

    r523 r525  
    1 %\documentclass[a4paper,11pt,oneside,twocolumn]{article}
    21\documentclass[preprint,times,5p,twocolumn]{elsarticle}
    3 %\usepackage[english]{babel}
    42\usepackage[ansinew]{inputenc}
    5 %\usepackage{abstract}
    63
    74\usepackage{amsmath}
    … …  
    3431\begin{frontmatter}
    3532
    36 \title{\textsc{Delphes}, a framework for fast simulation of a generic collider experiment}
     33\title{Delphes, a framework for fast simulation of a generic collider experiment}
    3734\author{S. Ovyn\corref{cor1}}
    3835\ead{severine.ovyn@uclouvain.be}
    3936
    40 %\author{X. Rouby\fnref{freiburg}}
    41 %\fntext[freiburg]{Now in Physikalisches Institut, Albert-Ludwigs-Universit\"at Freiburg}
     37\author{X. Rouby\fnref{freiburg}}
     38\fntext[freiburg]{Now in Physikalisches Institut, Albert-Ludwigs-Universit\"at Freiburg}
    4239%\ead{xavier.rouby@cern.ch}
    4340
    44 \address{Center for Particle Physics and Phenomenology (CP3),
    45         Universit\'e catholique de Louvain,
     41\author{V. Lema\^itre}
     42
     43\address{Center for Particle Physics and Phenomenology (CP3),\\
     44        Universit\'e catholique de Louvain,\\
    4645        B-1348 Louvain-la-Neuve, Belgium}
    4746
    48 \author{X. Rouby}
    49 \ead{xavier.rouby@cern.ch}
    50 
    51 \address{Physikalisches Institut,
    52         Albert-Ludwigs-Universit\"at Freiburg,
    53         D-79104 Freiburg-im-Breisgau, Germany}
     47%\author{X. Rouby}
     48%\ead{xavier.rouby@cern.ch}
     49
     50%\address{Physikalisches Institut,
     51%       Albert-Ludwigs-Universit\"at Freiburg,
     52%       D-79104 Freiburg-im-Breisgau, Germany}
    5453
    5554\begin{abstract}
    5655It is always delicate to  know whether theoretical predictions are visible and measurable in a high energy collider experiment due to the complexity of the related detectors, data acquisition chain and software.
    57 We introduce here a new \texttt{C++}-based framework, \textsc{Delphes}, for fast simulation of
     56We introduce here a new \texttt{C++}-based framework, \textit{Delphes}, for fast simulation of
    5857a general-purpose experiment. The simulation includes a tracking system, embedded into a magnetic field, calorimetry and a muon
    5958system, and possible very forward detectors arranged along the beamline.
    6059The framework is interfaced to standard file formats (e.g.\ Les Houches Event File or \texttt{HepMC}) and outputs observable objects for analysis, like missing transverse energy and collections of electrons or jets.
    61 The simulation of detector response takes into account the detector resolution, and usual reconstruction algorithms, such as \textsc{FastJet}. A simplified preselection can also be applied on processed data for trigger emulation. Detection of very forward scattered particles relies on the transport in beamlines with the \textsc{Hector} software. Finally, the \textsc{Frog} 2D/3D event display is used for visualisation of the collision final states.
    62 An overview of \textsc{Delphes} is given as well as a few \textsc{lhc} use-cases for illustration.\\ \\
     60The simulation of detector response takes into account the detector resolution, and usual reconstruction algorithms, such as FastJet. A simplified preselection can also be applied on processed data for trigger emulation. Detection of very forward scattered particles relies on the transport in beamlines with the \textit{Hector} software. Finally, the \textsc{FROG} 2D/3D event display is used for visualisation of the collision final states.
     61An overview of \textit{Delphes} is given as well as a few \textsc{LHC} use-cases for illustration.\\ \\
    6362\textit{Preprint:} \texttt{CP3-09-01}, \texttt{arXiv:0903.2225 [hep-ph]}\\ \\
    64 %\includegraphics[scale=0.8]{DelphesLogoSml}\\
     63%\includegraphics[scale=0.8]{DELPHESLogoSml}\\
    6564\includegraphics[scale=0.8]{fig0}\\
    6665{\bf PROGRAM SUMMARY}\\
    … …  
    9695{\em External routines/libraries:} ROOT environment \\
    9796  % Fill in if necessary, otherwise leave out.
    98 {\em Subprograms used:} HepMC, STDHEP, FastJet, Hector, FROG. All provided within DELPHES distribution.  \\
     97{\em Subprograms used:} HepMC, StdHEP, FASTJET, \textit{Hector}, FROG. All provided within \textit{Delphes} distribution.  \\
    9998{\em URL:}\href{http://www.fynu.ucl.ac.be/delphes.html}{http://www.fynu.ucl.ac.be/delphes.html}\\
    10099%{\em References:}
    … …  
    108107
    109108\begin{keyword}
    110 \textsc{Delphes} \sep fast simulation \sep trigger \sep event display \sep \textsc{lhc} \sep \textsc{FastJet} \sep \textsc{Hector} \sep \textsc{Frog} \sep Les Houches Event File \sep HepMC \sep \textsc{root}
     109\textit{Delphes} \sep fast simulation \sep trigger \sep event display \sep \textsc{LHC} \sep FastJet \sep \textit{Hector} \sep \textsc{FROG} \sep Les Houches Event File \sep HepMC \sep \textsc{ROOT}
    111110\PACS 29.85.-c \sep 07.05.Tp \sep 29.90.+r \sep 29.50.+v
    112111\end{keyword}
    … …  
    122121This complexity is handled by large collaborations of thousands of people, but the data and the expertise are only available to their members. Real data analyses require a full detector simulation, including transport of the primary and secondary particles through the detector material accounting for the various detector inefficiencies, the dead material, the imperfections and the geometrical details. Moreover, control of the detector calibration and alignment are crucial. Such simulation is very complicated, technical and requires a large \texttt{CPU} power. On the other hand, phenomenological studies, looking for the observability of given signals, may require only fast but realistic estimates of the expected signals and associated backgrounds.
    123122
    124 A new framework, called \textsc{Delphes}~\citep{bib:Delphes}, is introduced here, for the fast simulation of a general-purpose collider experiment.
     123A new framework, called \textit{Delphes}~\citep{bib:delphes}, is introduced here, for the fast simulation of a general-purpose collider experiment.
    125124Using the framework, observables can be estimated for specific signal and background channels, as well as their production and measurement rates.
    126125Starting from the output of event generators, the simulation of the detector response takes into account the subdetector resolutions, by smearing the kinematic properties of the final-state particles\footnote{Throughout the paper, final-state particles refer as particles considered as stable by the event generator.}. Tracks of charged particles and deposits of energy in calorimetric cells (or \textit{calotowers}) are then created.
    127126
    128 \textsc{Delphes} includes the most crucial experimental features, such as (Fig.~\ref{fig:FlowChart}):
     127\textit{Delphes} includes the most crucial experimental features, such as (Fig.~\ref{fig:FlowChart}):
    129128\begin{enumerate}
    130129\item the geometry of both central and forward detectors,
    … …  
    138137\begin{figure*}[!ht]
    139138\begin{center}
    140 %\includegraphics[scale=0.78]{FlowDelphes}
     139%\includegraphics[scale=0.78]{FlowDELPHES}
    141140\includegraphics[scale=0.78]{fig1}
    142 \caption{Flow chart describing the principles behind \textsc{Delphes}. Event files coming from external Monte Carlo generators are read by a converter stage (top).
     141\caption{Flow chart describing the principles behind \textit{Delphes}. Event files coming from external Monte Carlo generators are read by a converter stage (top).
    143142The kinematics variables of the final-state particles are then smeared according to the tunable subdetector resolutions.
    144143Tracks are reconstructed in a simulated solenoidal magnetic field and calorimetric towers sample the energy deposits. Based on these low-level objects, dedicated algorithms are applied for particle identification, isolation and reconstruction.
    … …  
    153152Although this kind of approach yields much realistic results than a simple ``parton-level" analysis, a fast simulation comes with some limitations. Detector geometry is idealised, being uniform, symmetric around the beam axis, and having no cracks nor dead material. Secondary interactions, multiple scatterings, photon conversion and bremsstrahlung are also neglected.
    154153
    155 Four datafile formats can be used as input in \textsc{Delphes}\footnote{\texttt{[code] }See the \texttt{HEPEVTConverter}, \texttt{HepMCConverter}, \texttt{LHEFConverter} and \texttt{STDHEPConverter} classes.}. In order to process events from many different generators, the standard Monte Carlo event structures \texttt{StdHEP}~\citep{bib:stdhep} and \texttt{HepMC}~\citep{bib:hepmc} can be used as an input. Besides, \textsc{Delphes} can also provide detector response for events read in ``Les Houches Event Format'' (\textsc{lhef}~\citep{bib:lhe}) and \textsc{root} files obtained from \textsc{.hbook} using the \texttt{h2root} utility from the \textsc{root} framework~\citep{bib:Root}.
    156 %Afterwards, \textsc{Delphes} performs a simple trigger simulation and reconstruct "high-level objects". These informations are organised in classes and each objects are ordered with respect to the transverse momentum.
    157 
    158 \textsc{Delphes} uses the \texttt{ExRootAnalysis} utility~\citep{bib:ExRootAnalysis} to create output data in a \texttt{*.root} ntuple.
    159 This output contains a copy of the generator-level data (\textsc{gen} tree), the analysis data objects after reconstruction (\mbox{\textsc{A}nalysis} tree), and possibly the results of the trigger emulation (\mbox{\textsc{T}rigger} tree).
    160 In option\footnote{\texttt{[code]} See the \texttt{FLAG\_lhco} variable in the detector datacard. This text file format is shortly described in the user manual.}, \textsc{Delphes} can produce a reduced output file in \texttt{*.lhco} text format, which is limited to the list of the reconstructed high-level objects in the final states.
    161 
    162 The program is driven by input cards. The detector card (\texttt{data/DetectorCard.dat}) allows a large spectrum of running conditions by modifying basic detector parameters, including calorimeter and tracking coverage and resolution, thresholds or jet algorithm parameters. The trigger card (\texttt{data/TriggerCard.dat}) lists the user algorithms for the simplified online preselection. Even if \textsc{Delphes} has been developped for the simulation of general-purpose detectors at the \textsc{lhc} (namely, \textsc{cms} and \textsc{atlas}), the input cards allow a flexible parametrisation for other cases, e.g.\ at future linear colliders.
     154Four datafile formats can be used as input in \textit{Delphes}\footnote{\texttt{[code] }See the \texttt{HEPEVTConverter}, \texttt{HepMCConverter}, \texttt{LHEFConverter} and \texttt{STDHEPConverter} classes.}. In order to process events from many different generators, the standard Monte Carlo event structures \texttt{StdHEP}~\citep{bib:stdhep} and \texttt{HepMC}~\citep{bib:hepmc} can be used as an input. Besides, \textit{Delphes} can also provide detector response for events read in ``Les Houches Event Format'' (\textsc{LHEF}~\citep{bib:lhe}) and \texttt{*.root} files obtained from \texttt{*.hbook} using the \texttt{h2root} utility from the \textsc{ROOT} framework~\citep{bib:Root}.
     155%Afterwards, \textit{Delphes} performs a simple trigger simulation and reconstruct "high-level objects". These informations are organised in classes and each objects are ordered with respect to the transverse momentum.
     156
     157\textit{Delphes} uses the \texttt{ExRootAnalysis} utility~\citep{bib:ExRootAnalysis} to create output data in a \texttt{*.root} ntuple.
     158This output contains a copy of the generator-level data (\texttt{GEN} tree), the analysis data objects after reconstruction (\texttt{Analysis} tree), and possibly the results of the trigger emulation (\texttt{Trigger} tree).
     159In option\footnote{\texttt{[code]} See the \texttt{FLAG\_LHCO} variable in the detector datacard. This text file format is shortly described in the user manual.}, \textit{Delphes} can produce a reduced output file in \texttt{*.LHCO} text format, which is limited to the list of the reconstructed high-level objects in the final states.
     160
     161The program is driven by input cards. The detector card (\texttt{data/DetectorCard.dat}) allows a large spectrum of running conditions by modifying basic detector parameters, including calorimeter and tracking coverage and resolution, thresholds or jet algorithm parameters. The trigger card (\texttt{data/TriggerCard.dat}) lists the user algorithms for the simplified online preselection. Even if \textit{Delphes} has been developped for the simulation of general-purpose detectors at the \textsc{LHC} (namely, \textsc{CMS} and \textsc{ATLAS}), the input cards allow a flexible parametrisation for other cases, e.g.\ at future linear colliders.
    163162
    164163
    165164\section{Detector simulation}
    166165
    167 The overall layout of the general-purpose detector simulated by \textsc{Delphes} is shown in Fig.~\ref{fig:GenDet3}.
    168 A central tracking system (\textsc{tracker}) is surrounded by an electromagnetic and a hadron calorimeters (\textsc{ecal} and \textsc{hcal}, resp., each with a central region and two endcaps). Two forward calorimeters (\textsc{fcal}) ensure a larger geometric coverage for the measurement of the missing transverse energy. Finally, a muon system (\textsc{muon}) encloses the central detector volume
     166The overall layout of the general-purpose detector simulated by \textit{Delphes} is shown in Fig.~\ref{fig:GenDet3}.
     167A central tracking system (\textsc{TRACKER}) is surrounded by an electromagnetic and a hadron calorimeters (\textsc{ECAL} and \textsc{HCAL}, resp., each with a central region and two endcaps). Two forward calorimeters (\textsc{FCAL}) ensure a larger geometric coverage for the measurement of the missing transverse energy. Finally, a muon system (\textsc{MUON}) encloses the central detector volume
    169168The fast simulation of the detector response takes into account geometrical acceptance of sub-detectors and their finite resolution, as defined in the detector data card\footnote{\texttt{[code] }See the \texttt{RESOLution} class.}.
    170 If no such file is provided, predefined values based on ``typical'' \textsc{cms} acceptances and resolutions are used\footnote{\texttt{[code] }Detector and trigger cards for the \textsc{atlas} and \textsc{cms} experiments are also provided in \texttt{data/} directory.}. The geometrical coverage of the various subsystems used in the default configuration are summarised in Tab.~\ref{tab:defEta}.
     169If no such file is provided, predefined values based on ``typical'' \textsc{CMS} acceptances and resolutions are used\footnote{\texttt{[code] }Detector and trigger cards for the \textsc{ATLAS} and \textsc{CMS} experiments are also provided in \texttt{data/} directory.}. The geometrical coverage of the various subsystems used in the default configuration are summarised in Tab.~\ref{tab:defEta}.
    171170
    172171\begin{table*}[t]
    … …  
    178177\hline
    179178Subdetector & & $\eta$ & $\phi$ \\
    180 \textsc{tracker}        & {\verb CEN_max_tracker }      & $[-2.5; 2.5]$         & $[-\pi ; \pi]$\\
    181 \textsc{ecal}, \textsc{hcal} & {\verb CEN_max_calo_cen }& $[-1.7 ; 1.7]$        & $[-\pi ; \pi]$\\
    182 \textsc{ecal}, \textsc{hcal} endcaps & {\verb CEN_max_calo_ec }& $[-3 ; -1.7] \& [1.7 ; 3]$     & $[-\pi ; \pi]$\\
    183 \textsc{fcal}           & {\verb CEN_max_calo_fwd }     & $[-5 ; -3]$ \& $[3 ;5]$     & $[-\pi ; \pi]$\\
    184 \textsc{muon}           & {\verb CEN_max_mu }           & $[-2.4 ; 2.4]$        & $[-\pi ; \pi]$\\ \hline
     179\textsc{TRACKER}        & {\verb CEN_max_tracker }      & $[-2.5; 2.5]$         & $[-\pi ; \pi]$\\
     180\textsc{ECAL}, \textsc{HCAL} & {\verb CEN_max_calo_cen }& $[-1.7 ; 1.7]$        & $[-\pi ; \pi]$\\
     181\textsc{ECAL}, \textsc{HCAL} endcaps & {\verb CEN_max_calo_ec }& $[-3 ; -1.7] \& [1.7 ; 3]$     & $[-\pi ; \pi]$\\
     182\textsc{FCAL}           & {\verb CEN_max_calo_fwd }     & $[-5 ; -3]$ \& $[3 ;5]$     & $[-\pi ; \pi]$\\
     183\textsc{MUON}           & {\verb CEN_max_mu }           & $[-2.4 ; 2.4]$        & $[-\pi ; \pi]$\\ \hline
    185184\end{tabular}
    186185\label{tab:defEta}
    … …  
    190189\begin{figure}[!ht]
    191190\begin{center}
    192 %\includegraphics[width=\columnwidth]{Detector_Delphes_3}
     191%\includegraphics[width=\columnwidth]{Detector_DELPHES_3}
    193192\includegraphics[width=\columnwidth]{fig2}
    194193\caption{
    195 Profile of layout of the generic detector geometry assumed in \textsc{Delphes}. The innermost layer, close to the interaction point, is a central tracking system (pink).
     194Profile of layout of the generic detector geometry assumed in \textit{Delphes}. The innermost layer, close to the interaction point, is a central tracking system (pink).
    196195It is surrounded by a central calorimeter volume (green) with both electromagnetic and hadronic sections.
    197196The outer layer of the central system (red) consist of a muon system. In addition, two end-cap calorimeters (blue) extend the pseudorapidity coverage of the central detector.
    … …  
    215214\subsection{Simulation of central calorimeters}
    216215
    217 The energy of each particle considered as stable in the generator particle list is smeared, with a Gaussian distribution depending on the calorimeter resolution. This resolution varies with the sub-calorimeter (\textsc{ecal}, \textsc{hcal}, \textsc{fcal}) measuring the particle.
     216The energy of each particle considered as stable in the generator particle list is smeared, with a Gaussian distribution depending on the calorimeter resolution. This resolution varies with the sub-calorimeter (\textsc{ECAL}, \textsc{HCAL}, \textsc{FCAL}) measuring the particle.
    218217The response of each sub-calorimeter is parametrised as a function of the energy:
    219218\begin{equation}
    … …  
    226225The particle four-momentum $p^\mu$ are smeared with a parametrisation directly derived from typical detector technical designs\footnote{\texttt{[code] } The response of the detector is applied to the electromagnetic and the hadronic particles through the \texttt{SmearElectron} and \texttt{SmearHadron} functions.} \citep{bib:cmsjetresolution,bib:ATLASresolution}.
    227226In the default parametrisation, the calorimeter is assumed to cover the pseudorapidity range $|\eta|<3$ and consists in an electromagnetic and hadronic parts. Coverage between pseudorapidities of $3.0$ and $5.0$ is provided by forward calorimeters, with different response to electromagnetic objects ($e^\pm, \gamma$) or hadrons.
    228 Muons and neutrinos are assumed not to interact with the calorimeters\footnote{In the current \textsc{Delphes} version, particles other than electrons ($e^\pm$), photons ($\gamma$), muons ($\mu^\pm$) and neutrinos ($\nu_e$, $\nu_\mu$ and $\nu_\tau$) are simulated as hadrons for their interactions with the calorimeters. The simulation of stable particles beyond the Standard Model should therefore be handled with care.}.
     227Muons and neutrinos are assumed not to interact with the calorimeters\footnote{In the current \textit{Delphes} version, particles other than electrons ($e^\pm$), photons ($\gamma$), muons ($\mu^\pm$) and neutrinos ($\nu_e$, $\nu_\mu$ and $\nu_\tau$) are simulated as hadrons for their interactions with the calorimeters. The simulation of stable particles beyond the Standard Model should therefore be handled with care.}.
    229228The default values of the stochastic, noise and constant terms are given in Tab.~\ref{tab:defResol}.\\
    230229
    … …  
    236235\hline
    237236\multicolumn{2}{c}{Resolution Term}   & Card flag & Value\\\hline
    238  \multicolumn{4}{l}{\textsc{ecal}} \\
     237 \multicolumn{4}{l}{\textsc{ECAL}} \\
    239238        & $S$ (GeV$^{1/2}$) & {\verb ELG_Scen }  & $0.05$ \\
    240239        & $N$ (GeV)& {\verb ELG_Ncen }  & $0.25$ \\
    241240        & $C$ & {\verb ELG_Ccen }  & $0.0055$ \\
    242  \multicolumn{4}{l}{\textsc{ecal}, end caps} \\
     241 \multicolumn{4}{l}{\textsc{ECAL}, end caps} \\
    243242        & $S$ (GeV$^{1/2}$) & {\verb ELG_Sec }  & $0.05$ \\
    244243        & $N$ (GeV)& {\verb ELG_Nec }  & $0.25$ \\
    245244        & $C$ & {\verb ELG_Cec }  & $0.0055$ \\
    246  \multicolumn{4}{l}{\textsc{fcal}, electromagnetic part} \\
     245 \multicolumn{4}{l}{\textsc{FCAL}, electromagnetic part} \\
    247246        & $S$ (GeV$^{1/2}$)& {\verb ELG_Sfwd }  & $2.084$ \\
    248247        & $N$ (GeV)& {\verb ELG_Nfwd }  & $0$ \\
    249248        & $C$ & {\verb ELG_Cfwd }  & $0.107$ \\
    250  \multicolumn{4}{l}{\textsc{hcal}} \\
     249 \multicolumn{4}{l}{\textsc{HCAL}} \\
    251250        & $S$ (GeV$^{1/2}$)& {\verb HAD_Scen } & $1.5$ \\
    252251        & $N$ (GeV)& {\verb HAD_Ncen } & $0$\\
    253252        & $C$ & {\verb HAD_Ccen } & $0.05$\\
    254  \multicolumn{4}{l}{\textsc{hcal}, end caps} \\
     253 \multicolumn{4}{l}{\textsc{HCAL}, end caps} \\
    255254        & $S$ (GeV$^{1/2}$)& {\verb HAD_Sec } & $1.5$ \\
    256255        & $N$ (GeV)& {\verb HAD_Nec } & $0$\\
    257256        & $C$ & {\verb HAD_Cec } & $0.05$\\
    258  \multicolumn{4}{l}{\textsc{fcal}, hadronic part} \\
     257 \multicolumn{4}{l}{\textsc{FCAL}, hadronic part} \\
    259258        & $S$ (GeV$^{1/2}$)& {\verb HAD_Sfwd }   & $2.7$\\
    260259        & $N$ (GeV)& {\verb HAD_Nfwd }   & $0$ \\
    … …  
    266265\end{table}
    267266
    268 The energy of electrons and photons found in the particle list are smeared using the \textsc{ecal} resolution terms. Charged and neutral final-state hadrons interact with the \textsc{ecal}, \textsc{hcal} and \textsc{fcal}.
    269 Some long-living particles, such as the $K^0_s$ and $\Lambda$'s, with lifetime $c\tau$ smaller than $10~\textrm{mm}$ are considered as stable particles although they decay before the calorimeters. The energy smearing of such particles is performed using the expected fraction of the energy, determined according to their decay products, that would be deposited into the \textsc{ecal} ($E_{\textsc{ecal}}$) and into the \textsc{hcal} ($E_{\textsc{hcal}}$). Defining $F$ as the fraction of the energy leading to a \textsc{hcal} deposit, the two energy values are given by
     267The energy of electrons and photons found in the particle list are smeared using the \textsc{ECAL} resolution terms. Charged and neutral final-state hadrons interact with the \textsc{ECAL}, \textsc{HCAL} and \textsc{FCAL}.
     268Some long-living particles, such as the $K^0_s$ and $\Lambda$'s, with lifetime $c\tau$ smaller than $10~\textrm{mm}$ are considered as stable particles although they decay before the calorimeters. The energy smearing of such particles is performed using the expected fraction of the energy, determined according to their decay products, that would be deposited into the \textsc{ECAL} ($E_{\textsc{ECAL}}$) and into the \textsc{HCAL} ($E_{\textsc{HCAL}}$). Defining $F$ as the fraction of the energy leading to a \textsc{HCAL} deposit, the two energy values are given by
    270269\begin{equation}
    271270\left\{
    272271\begin{array}{l}
    273 E_{\textsc{hcal}} = E \times F \\
    274 E_{\textsc{ecal}} = E \times (1-F) \\
     272E_{\textsc{HCAL}} = E \times F \\
     273E_{\textsc{ECAL}} = E \times (1-F) \\
    275274\end{array}
    276275\right.
    277276\end{equation}
    278277where $0 \leq F \leq 1$. The electromagnetic part is handled the same way for the electrons and photons.
    279 The resulting calorimetry energy measurement given after the application of the smearing is then $E = E_{\textsc{hcal}} + E_{\textsc{ecal}}$. For $K_S^0$ and $\Lambda$ hadrons\footnote{\texttt{[code]} To implement different ratios for other particles, see the \texttt{BlockClasses} class.}, the energy fraction is $F$ is assumed to be $0.7$.\\
     278The resulting calorimetry energy measurement given after the application of the smearing is then $E = E_{\textsc{HCAL}} + E_{\textsc{ECAL}}$. For $K_S^0$ and $\Lambda$ hadrons\footnote{\texttt{[code]} To implement different ratios for other particles, see the \texttt{BlockClasses} class.}, the energy fraction is $F$ is assumed to be $0.7$.\\
    280279
    281280\subsection{Calorimetric towers}
    282281
    283 The smallest unit for geometrical sampling of the calorimeters is a \textit{tower}; it segments the $(\eta,\phi)$ plane for the energy measurement. No longitudinal segmentation is available in the simulated calorimeters. All undecayed particles, except muons and neutrinos deposit energy in a calorimetric tower, either in \textsc{ecal}, in \textsc{hcal} or \textsc{fcal}.
     282The smallest unit for geometrical sampling of the calorimeters is a \textit{tower}; it segments the $(\eta,\phi)$ plane for the energy measurement. No longitudinal segmentation is available in the simulated calorimeters. All undecayed particles, except muons and neutrinos deposit energy in a calorimetric tower, either in \textsc{ECAL}, in \textsc{HCAL} or \textsc{FCAL}.
    284283As the detector is assumed to be cylindrical (e.g.\ symmetric in $\phi$ and with respect to the $\eta=0$ plane), the detector card stores the number of calorimetric towers with $\phi=0$ and $\eta>0$ (default: $40$ towers). For a given $\eta$, the size of the $\phi$ segmentation is also specified. Fig.~\ref{fig:calosegmentation} illustrates the default calorimeter segmentation, which is common for the electromagnetic and hadronic sections at a given $(\eta,\phi)$.
    285284
    … …  
    288287%\includegraphics[width=\columnwidth]{calosegmentation}
    289288\includegraphics[width=\columnwidth]{fig3}
    290 \caption{Default segmentation of the calorimeters in the $(\eta,\phi)$ plane. Only the central detectors (\textsc{ecal}, \textsc{hcal}) and \textsc{fcal} are considered. $\phi$ angles are expressed in radians.}
     289\caption{Default segmentation of the calorimeters in the $(\eta,\phi)$ plane. Only the central detectors (\textsc{ECAL}, \textsc{HCAL}) and \textsc{FCAL} are considered. $\phi$ angles are expressed in radians.}
    291290\label{fig:calosegmentation}
    292291\end{center}
    293292\end{figure}
    294293
    295 The calorimetric towers directly enter in the calculation of the missing transverse energy (\textsc{met}), and as input for the jet reconstruction algorithms. No sharing between neighbouring towers is implemented when particles enter a tower very close to its geometrical edge. Smearing is applied directly on the accumulated electromagnetic and hadronic energies of each calorimetric tower.
     294The calorimetric towers directly enter in the calculation of the missing transverse energy (\textsc{MET}), and as input for the jet reconstruction algorithms. No sharing between neighbouring towers is implemented when particles enter a tower very close to its geometrical edge. Smearing is applied directly on the accumulated electromagnetic and hadronic energies of each calorimetric tower.
    296295
    297296\subsection{Very forward detector simulation}
    298297
    299 Most of the recent experiments in beam colliders have additional instrumentation along the beamline. These extend the $\eta$ coverage to higher values, for the detection of very forward final-state particles. In \textsc{Delphes}, Zero Degree Calorimeters, roman pots and forward taggers have been implemented (Fig.~\ref{fig:fdets}).
     298Most of the recent experiments in beam colliders have additional instrumentation along the beamline. These extend the $\eta$ coverage to higher values, for the detection of very forward final-state particles. In \textit{Delphes}, Zero Degree Calorimeters, roman pots and forward taggers have been implemented (Fig.~\ref{fig:fdets}).
    300299
    301300\begin{figure}[!ht]
    … …  
    303302%\includegraphics[width=\columnwidth]{fdets}
    304303\includegraphics[width=\columnwidth]{fig4}
    305 \caption{Default location of the very forward detectors, including \textsc{zdc}, \textsc{rp220} and \textsc{fp420} in the \textsc{lhc} beamline.
    306 Incoming (beam 1, red) and outgoing (beam 2, black) beams on one side of the fifth interaction point (\textsc{ip}5, $s=0~\textrm{m}$ on the plot).
    307 The Zero Degree Calorimeter is located in perfect alignment with the beamline axis at the interaction point, at $140~\textrm{m}$, the beam paths are separated. The forward taggers are near-beam detectors located at $220~\textrm{m}$ and $420~\textrm{m}$. Beamline simulation with \textsc{Hector}~\citep{bib:Hector}. All very forward detectors are located symmetrically around the interaction point. }
     304\caption{Default location of the very forward detectors, including \textsc{ZDC}, \textsc{RP220} and \textsc{FP420} in the \textsc{LHC} beamline.
     305Incoming (beam 1, red) and outgoing (beam 2, black) beams on one side of the fifth interaction point (\textsc{IP5}, $s=0~\textrm{m}$ on the plot).
     306The Zero Degree Calorimeter is located in perfect alignment with the beamline axis at the interaction point, at $140~\textrm{m}$, the beam paths are separated. The forward taggers are near-beam detectors located at $220~\textrm{m}$ and $420~\textrm{m}$. Beamline simulation with \textit{Hector}~\citep{bib:hector}. All very forward detectors are located symmetrically around the interaction point. }
    308307\label{fig:fdets}
    309308\end{center}
    … …  
    312311\begin{table*}[t]
    313312\begin{center}
    314 \caption{Default parameters for the forward detectors: distance from the interaction point and detector acceptance. The \textsc{lhc} beamline is assumed around the fifth \textsc{lhc} interaction point (\textsc{ip}). For the \textsc{zdc}, the acceptance depends only on the pseudorapidity $\eta$ of the particle, which should be neutral and stable.
    315 The tagger acceptance is fully determined by the distance in the transverse plane of the detector to the real beam position~\citep{bib:Hector}. It is expressed in terms of the particle energy ($E$).
     313\caption{Default parameters for the forward detectors: distance from the interaction point and detector acceptance. The \textsc{LHC} beamline is assumed around the fifth \textsc{LHC} interaction point (\textsc{IP}). For the \textsc{ZDC}, the acceptance depends only on the pseudorapidity $\eta$ of the particle, which should be neutral and stable.
     314The tagger acceptance is fully determined by the distance in the transverse plane of the detector to the real beam position~\citep{bib:hector}. It is expressed in terms of the particle energy ($E$).
    316315All detectors are located on both sides of the interaction point.
    317316\vspace{0.5cm}}
    318317\begin{tabular}{llcl}
    319318\hline
    320 Detector & Distance from \textsc{ip}& Acceptance & \\ \hline
    321 \textsc{zdc}   & $\pm 140$ m & $|\eta|> 8.3$       & for $n$ and $\gamma$\\
    322 \textsc{rp220} & $\pm 220$ m & $E \in [6100 ; 6880]$ (GeV) & at $2~\textrm{mm}$\\
    323 \textsc{fp420} & $\pm 420$ m & $E \in [6880 ; 6980]$ (GeV) & at $4~\textrm{mm}$\\
     319Detector & Distance from \textsc{IP}& Acceptance & \\ \hline
     320\textsc{ZDC}   & $\pm 140$ m & $|\eta|> 8.3$       & for $n$ and $\gamma$\\
     321\textsc{RP220} & $\pm 220$ m & $E \in [6100 ; 6880]$ (GeV) & at $2~\textrm{mm}$\\
     322\textsc{FP420} & $\pm 420$ m & $E \in [6880 ; 6980]$ (GeV) & at $4~\textrm{mm}$\\
    324323\hline
    325324\end{tabular}
    … …  
    331330\subsubsection*{Zero Degree Calorimeters}
    332331
    333 In direct sight of the interaction point, on both sides of the central detector, the Zero Degree Calorimeters (\textsc{zdc}s) are located at zero angle, i.e.\ are aligned with the beamline axis at the interaction point. They are placed beyond the point where the paths of incoming and outgoing beams separate. These allow the measurement of stable neutral particles ($\gamma$ and $n$) coming from the interaction point, with large pseudorapidities (e.g.\ $|\eta_{\textrm{n,}\gamma}| > 8.3$ in \textsc{atlas} and \textsc{cms}).
    334 
    335 The trajectory of the neutrals observed in the \textsc{zdc}s is a straight line, while charged particles are deflected away from their acceptance window by the powerful magnets located in front of them. The fact that additional charged particles may enter the \textsc{zdc} acceptance is neglected here.
    336 
    337 The \textsc{zdc}s have the ability to measure the time-of-flight of the particle.
     332In direct sight of the interaction point, on both sides of the central detector, the Zero Degree Calorimeters (\textsc{ZDC}s) are located at zero angle, i.e.\ are aligned with the beamline axis at the interaction point. They are placed beyond the point where the paths of incoming and outgoing beams separate. These allow the measurement of stable neutral particles ($\gamma$ and $n$) coming from the interaction point, with large pseudorapidities (e.g.\ $|\eta_{\textrm{n,}\gamma}| > 8.3$ in \textsc{ATLAS} and \textsc{CMS}).
     333
     334The trajectory of the neutrals observed in the \textsc{ZDC}s is a straight line, while charged particles are deflected away from their acceptance window by the powerful magnets located in front of them. The fact that additional charged particles may enter the \textsc{ZDC} acceptance is neglected here.
     335
     336The \textsc{ZDC}s have the ability to measure the time-of-flight of the particle.
    338337This corresponds to the delay after which the particle is observed in the detector, with respect to the bunch crossing reference time at the interaction point ($t_0$). The measured time-of-flight $t$ is simply given by:
    339338\begin{equation}
    340339 t = t_0 + \frac{1}{v} \times \Big( \frac{s-z}{\cos \theta}\Big),
    341340\end{equation}
    342 where $t_0$ is thus the true time coordinate of the vertex from which the particle originates, $v$ the particle velocity, $s$ is the \textsc{zdc} distance to the interaction point, $z$ is the longitudinal coordinate of the vertex, $\theta$ is the particle emission angle. It is then assumed that the neutral particle observed in the \textsc{zdc} is highly relativistic, i.e.\ travelling at the speed of light $c$. We also assume that $\cos \theta = 1$, i.e.\ $\theta \approx 0$ or equivalently $\eta$ is large. As an example, $\eta = 5$ leads to $\theta = 0.013$ and $1 - \cos \theta < 10^{-4}$.
     341where $t_0$ is thus the true time coordinate of the vertex from which the particle originates, $v$ the particle velocity, $s$ is the \textsc{ZDC} distance to the interaction point, $z$ is the longitudinal coordinate of the vertex, $\theta$ is the particle emission angle. It is then assumed that the neutral particle observed in the \textsc{ZDC} is highly relativistic, i.e.\ travelling at the speed of light $c$. We also assume that $\cos \theta = 1$, i.e.\ $\theta \approx 0$ or equivalently $\eta$ is large. As an example, $\eta = 5$ leads to $\theta = 0.013$ and $1 - \cos \theta < 10^{-4}$.
    343342The formula then reduces to
    344343\begin{equation}
    345344 t = \frac{1}{c} \times (s-z).
    346345\end{equation}
    347 For example, a photon takes $0.47~\mu\textrm{s}$ to reach a \textsc{zdc} located at $s=140~\textrm{m}$, neglecting $z$ and $\theta$. For the time-of-flight measurement, a Gaussian smearing can be applied according to the detector resolution (Tab.~\ref{tab:defResolZdc}). In the current version of \textsc{Delphes}, only neutrons, antineutrons and photons are assumed to be able to reach the \textsc{zdc}s, all other particles being neglected.
    348 
    349 The \textsc{zdc}s are composed of an electromagnetic and a hadronic sections, for the measurement of photons and neutrons, respectively. The energy of the observed neutral is smeared according to Eq.~\ref{eq:caloresolution} and the corresponding section resolutions (Tab.~\ref{tab:defResolZdc}). The \textsc{zdc} hits do not enter in the calorimeter tower list used for reconstruction of jets and missing transverse energy.
     346For example, a photon takes $0.47~\mu\textrm{s}$ to reach a \textsc{ZDC} located at $s=140~\textrm{m}$, neglecting $z$ and $\theta$. For the time-of-flight measurement, a Gaussian smearing can be applied according to the detector resolution (Tab.~\ref{tab:defResolZdc}). In the current version of \textit{Delphes}, only neutrons, antineutrons and photons are assumed to be able to reach the \textsc{ZDC}s, all other particles being neglected.
     347
     348The \textsc{ZDC}s are composed of an electromagnetic and a hadronic sections, for the measurement of photons and neutrons, respectively. The energy of the observed neutral is smeared according to Eq.~\ref{eq:caloresolution} and the corresponding section resolutions (Tab.~\ref{tab:defResolZdc}). The \textsc{ZDC} hits do not enter in the calorimeter tower list used for reconstruction of jets and missing transverse energy.
    350349
    351350\begin{table}[!h]
    … …  
    356355\hline
    357356\multicolumn{2}{c}{Resolution Term}   & Card flag & Value\\\hline
    358  \multicolumn{4}{l}{\textsc{zdc}, electromagnetic part} \\
     357 \multicolumn{4}{l}{\textsc{ZDC}, electromagnetic part} \\
    359358        & $S$ (GeV$^{1/2}$)& \texttt{ELG\_Szdc}  & $0.7$ \\
    360359        & $N$ (GeV)& \texttt{ELG\_Nzdc}  & $0.0$ \\
    361360        & $C$ & \texttt{ELG\_Czdc}  & $0.08$ \\
    362  \multicolumn{4}{l}{\textsc{zdc}, hadronic part} \\
     361 \multicolumn{4}{l}{\textsc{ZDC}, hadronic part} \\
    363362        & $S$ (GeV$^{1/2}$)& \texttt{HAD\_Szdc}   & $1.38$\\
    364363        & $N$ (GeV)& \texttt{HAD\_Nzdc}   & $0$ \\
    365364        & $C$ & \texttt{HAD\_Czdc}   & $0.13$\\
    366  \multicolumn{4}{l}{\textsc{zdc}, timing resolution} \\
     365 \multicolumn{4}{l}{\textsc{ZDC}, timing resolution} \\
    367366        & $\sigma_t$ (s) & \texttt{ZDC\_T\_resolution} & $0$ \\
    368367\hline
    … …  
    374373\subsubsection*{Forward taggers}
    375374
    376 Forward taggers (called here \textsc{rp220}, for ``roman pots at $220~\textrm{m}$'' and \textsc{fp420} ``for forward proton taggers at $420~\textrm{m}$'', as at the \textsc{lhc}) are meant for the measurement of particles following very closely the beam path. Such devices, also used at \textsc{hera} and \textsc{Tevratron}, are located very far away from the interaction point (further than $150$~m in the \textsc{lhc} case).
     375Forward taggers (called here \textsc{RP220}, for ``roman pots at $220~\textrm{m}$'' and \textsc{FP420} ``for forward proton taggers at $420~\textrm{m}$'', as at the \textsc{LHC}) are meant for the measurement of particles following very closely the beam path. Such devices, also used at \textsc{HERA} and Tevatron, are located very far away from the interaction point (further than $150$~m in the \textsc{LHC} case).
    377376
    378377To be able to reach these detectors, particles must have a charge identical to the beam particles, and a momentum very close to the nominal value of the beam. These taggers are near-beam detectors located a few millimetres from the true beam trajectory and this distance defines their acceptance (Tab.~\ref{tab:fdetacceptance}).
    379 For instance, roman pots at $220~\textrm{m}$ from the  \textsc{ip} and $2~\textrm{mm}$ from the beam will detect all forward protons with an energy between $120$ and $900~\textrm{GeV}$~\citep{bib:Hector}.
    380 In practice, in the \textsc{lhc}, only positively charged muons ($\mu^+$) and protons can reach the forward taggers as other particles with a single positive charge coming from the interaction points will decay before their possible tagging. In \textsc{Delphes}, extra hits coming from the beam-gas events or secondary particles hitting the beampipe in front of the detectors are not taken into account.
    381 
    382 While neutral particles propagate along a straight line to the \textsc{zdc}, a dedicated simulation of the transport of charged particles is needed for \textsc{rp220} and \textsc{fp420}. This fast simulation uses the \textsc{Hector} software~\citep{bib:Hector}, which includes the chromaticity effects and the geometrical aperture of the beamline elements of any arbitrary collider.
    383 
    384 Forward taggers are able to measure the hit positions ($x,y$) and angles ($\theta_x,\theta_y$) in the transverse plane at the location of the detector ($s$ meters away from the \textsc{ip}), as well as the time-of-flight\footnote{It should be noted that for both \textsc{cms} and \textsc{atlas} experiments, the taggers located at $220$~m are not able to measure the time-of-flight, contrary to \textsc{fp}420 detectors.} ($t$). Out of these the particle energy ($E$) and the momentum transfer it underwent during the interaction ($q^2$) can be reconstructed\footnote{The reconstruction of $E$ and $q^2$ are not implemeted in \textsc{Delphes} but can be performed at the analysis level.}. The time-of-flight measurement can be smeared with a Gaussian distribution (default value\footnote{\texttt{[code] } The resolution is defined by the \texttt{RP220\_T\_resolution} and \texttt{RP420\_T\_resolution} parameters in the detector card.} $\sigma_t = 0~\textrm{s}$).
     378For instance, roman pots at $220~\textrm{m}$ from the  \textsc{IP} and $2~\textrm{mm}$ from the beam will detect all forward protons with an energy between $120$ and $900~\textrm{GeV}$~\citep{bib:hector}.
     379In practice, in the \textsc{LHC}, only positively charged muons ($\mu^+$) and protons can reach the forward taggers as other particles with a single positive charge coming from the interaction points will decay before their possible tagging. In \textit{Delphes}, extra hits coming from the beam-gas events or secondary particles hitting the beampipe in front of the detectors are not taken into account.
     380
     381While neutral particles propagate along a straight line to the \textsc{ZDC}, a dedicated simulation of the transport of charged particles is needed for \textsc{RP220} and \textsc{FP420}. This fast simulation uses the \textit{Hector} software~\citep{bib:hector}, which includes the chromaticity effects and the geometrical aperture of the beamline elements of any arbitrary collider.
     382
     383Forward taggers are able to measure the hit positions ($x,y$) and angles ($\theta_x,\theta_y$) in the transverse plane at the location of the detector ($s$ meters away from the \textsc{IP}), as well as the time-of-flight\footnote{It should be noted that for both \textsc{CMS} and \textsc{ATLAS} experiments, the taggers located at $220$~m are not able to measure the time-of-flight, contrary to \textsc{FP420} detectors.} ($t$). Out of these the particle energy ($E$) and the momentum transfer it underwent during the interaction ($q^2$) can be reconstructed\footnote{The reconstruction of $E$ and $q^2$ are not implemeted in \textit{Delphes} but can be performed at the analysis level.}. The time-of-flight measurement can be smeared with a Gaussian distribution (default value\footnote{\texttt{[code] } The resolution is defined by the \texttt{RP220\_T\_resolution} and \texttt{RP420\_T\_resolution} parameters in the detector card.} $\sigma_t = 0~\textrm{s}$).
    385384
    386385
    … …  
    388387\section{High-level object reconstruction}
    389388
    390 Analysis object data contain the final collections of particles ($e^\pm$, $\mu^\pm$, $\gamma$) or objects (light jets, $b$-jets, $\tau$-jets, $E_T^\textrm{miss}$) and are stored\footnote{\texttt{[code] }All these processed data are located under the \texttt{Analysis} tree.} in the output file created by \textsc{Delphes}.
    391 In addition, some detector data are added: tracks, calorimetric towers and hits in \textsc{zdc}, \textsc{rp220} and \textsc{fp420}.
     389Analysis object data contain the final collections of particles ($e^\pm$, $\mu^\pm$, $\gamma$) or objects (light jets, $b$-jets, $\tau$-jets, $E_T^\textrm{miss}$) and are stored\footnote{\texttt{[code] }All these processed data are located under the \texttt{Analysis} tree.} in the output file created by \textit{Delphes}.
     390In addition, some detector data are added: tracks, calorimetric towers and hits in \textsc{ZDC}, \textsc{RP220} and \textsc{FP420}.
    392391While electrons, muons and photons are easily identified, some other objects are more difficult to measure, like jets or missing energy due to invisible particles.
    393392
    394 For most of these objects, their four-momentum and related quantities are directly accessible in \textsc{Delphes} output ($E$, $\vec{p}$, $p_T$, $\eta$ and $\phi$). Additional properties are available for specific objects (like the charge and the isolation status for $e^\pm$ and $\mu^\pm$, the result of application of $b$-tag for jets and time-of-flight for some detector hits).
     393For most of these objects, their four-momentum and related quantities are directly accessible in \textit{Delphes} output ($E$, $\vec{p}$, $p_T$, $\eta$ and $\phi$). Additional properties are available for specific objects (like the charge and the isolation status for $e^\pm$ and $\mu^\pm$, the result of application of $b$-tag for jets and time-of-flight for some detector hits).
    395394 
    396395
    … …  
    401400\subsubsection*{Electrons and photons}
    402401Electron ($e^\pm$) and photon candidates are reconstructed if they fall into the acceptance of the tracking system and have a transverse momentum above a threshold (default $p_T > 10~\textrm{GeV}/c$). A calorimetric tower will be seen in the detector, as electrons will leave in addition a track. Subsequently, electrons and photons create a candidate in the jet collection.
    403 Assuming a good measurement of the track parameters in the real experiment, the electron energy can be reasonably recovered. In \textsc{Delphes}, electron energy is smeared according to the resolution of the calorimetric tower where it points to, but independently from any other deposited energy is this tower. This approach is still conservative as the calorimeter resolution is worse than the tracker one.
     402Assuming a good measurement of the track parameters in the real experiment, the electron energy can be reasonably recovered. In \textit{Delphes}, electron energy is smeared according to the resolution of the calorimetric tower where it points to, but independently from any other deposited energy is this tower. This approach is still conservative as the calorimeter resolution is worse than the tracker one.
    404403
    405404\subsubsection*{Muons}
    406405Generator-level muons entering the detector acceptance are considered as candidates for the analysis level.
    407406The acceptance is defined in terms of a transverse momentum threshold to be overpassed that should be computed using the chosen geometry of the detector and the magnetic field considered (default : $p_T > 10~\textrm{GeV}/c$) and of the pseudorapidity coverage of the muon system (default: $-2.4 \leq \eta \leq 2.4$).
    408 The application of the detector resolution on the muon momentum depends on a Gaussian smearing of the $p_T$ variable\footnote{\texttt{[code]} See the \texttt{SmearMuon} method.}. Neither $\eta$ nor $\phi$ variables are modified beyond the calorimeters: no additional magnetic field is applied. Multiple scattering is neglected. This implies that low energy muons have in \textsc{Delphes} a better resolution than in a real detector. Furthermore, muons leave no deposit in calorimeters. At last, the particles which might leak out of the calorimeters into the muon systems (\textit{punch-through}) will not be see
    409 n as muon candidates in \textsc{Delphes}.
     407The application of the detector resolution on the muon momentum depends on a Gaussian smearing of the $p_T$ variable\footnote{\texttt{[code]} See the \texttt{SmearMuon} method.}. Neither $\eta$ nor $\phi$ variables are modified beyond the calorimeters: no additional magnetic field is applied. Multiple scattering is neglected. This implies that low energy muons have in \textit{Delphes} a better resolution than in a real detector. Furthermore, muons leave no deposit in calorimeters. At last, the particles which might leak out of the calorimeters into the muon systems (\textit{punch-through}) will not be see
     408n as muon candidates in \textit{Delphes}.
    410409
    411410\subsubsection*{Charged lepton isolation}
    412411\label{sec:isolation}
    413412
    414 To improve the quality of the contents of the charged lepton collections, additional criteria can be applied such as isolation. This requires that electron or muon candidates are isolated in the detector from any other particle, within a small cone. In \textsc{Delphes}, charged lepton isolation demands that there is no other charged particle with $p_T>2~\textrm{GeV}/c$ within a cone of $\Delta R = \sqrt{\Delta \eta^2 + \Delta \phi^2} <0.5$ around the lepton.
     413To improve the quality of the contents of the charged lepton collections, additional criteria can be applied such as isolation. This requires that electron or muon candidates are isolated in the detector from any other particle, within a small cone. In \textit{Delphes}, charged lepton isolation demands that there is no other charged particle with $p_T>2~\textrm{GeV}/c$ within a cone of $\Delta R = \sqrt{\Delta \eta^2 + \Delta \phi^2} <0.5$ around the lepton.
    415414The result (i.e.\ \textit{isolated} or \textit{not}) is added to the charged lepton measured properties.
    416415In addition, the sum $P_T$ of the transverse momenta of all tracks but the lepton one within the isolation cone is
    … …  
    425424\subsubsection*{Forward neutrals}
    426425
    427 The zero degree calorimeter hits correspond to neutral particles with a lifetime long enough to reach these detectors (default: $c \tau \geq 140~\textrm{m}$) and very large pseudorapidities (default: $|\eta|>8.3$). In current versions of \textsc{Delphes}, only photons and neutrons are considered. Photons are identified thanks to the electromagnetic section of the calorimeter, and if their energy overpasses a given threshold (def. $20$~GeV). Similarly, neutrons are reconstructed according to the resolution of the hadronic section, if their energy exceeds a threshold\footnote{\texttt{[code]} These thresholds are defined by the \texttt{ZDC\_gamma\_E} and \texttt{ZDC\_n\_E} variables in the detector card.} (def. $50$~GeV).
     426The zero degree calorimeter hits correspond to neutral particles with a lifetime long enough to reach these detectors (default: $c \tau \geq 140~\textrm{m}$) and very large pseudorapidities (default: $|\eta|>8.3$). In current versions of \textit{Delphes}, only photons and neutrons are considered. Photons are identified thanks to the electromagnetic section of the calorimeter, and if their energy overpasses a given threshold (def. $20$~GeV). Similarly, neutrons are reconstructed according to the resolution of the hadronic section, if their energy exceeds a threshold\footnote{\texttt{[code]} These thresholds are defined by the \texttt{ZDC\_gamma\_E} and \texttt{ZDC\_n\_E} variables in the detector card.} (def. $50$~GeV).
    428427
    429428
    … …  
    431430\subsection{Jet reconstruction}
    432431
    433 A realistic analysis requires a correct treatment of particles which have hadronised. Therefore, the most widely currently used jet algorithms have been integrated into the \textsc{Delphes} framework using the \textsc{FastJet} tools~\citep{bib:FastJet}.
     432A realistic analysis requires a correct treatment of particles which have hadronised. Therefore, the most widely currently used jet algorithms have been integrated into the \textit{Delphes} framework using the FastJet tools~\citep{bib:FASTJET}.
    434433Six different jet reconstruction schemes are available\footnote{\texttt{[code] }The choice is done by allocating the \texttt{JET\_jetalgo } input parameter in the detector card.}. The first three belong to the cone algorithm class while the last three are using a sequential recombination scheme. For all of them, the towers are used as input for the jet clustering. Jet algorithms differ in their sensitivity to soft particles or collinear splittings, and in their computing speed performances.
    435434By default, reconstruction uses a cone algorithm with $\Delta R=0.7$.
    … …  
    441440 
    442441\item {\it CDF Jet Clusters}~\citep{bib:jetclu}: Algorithm forming jets by associating together towers lying within a circle (default radius $\Delta R=0.7$) in the $(\eta$, $\phi)$ space.
    443 This so-called \textsc{Jetclu} cone jet algorithm is used by the \textsc{cdf} experiment in Run II.
     442This so-called JetCLU cone jet algorithm is used by the \textsc{CDF} experiment in Run II.
    444443All towers with a transverse energy $E_T$ higher than a given threshold (default: $E_T > 1~\textrm{GeV}$) are used to seed the jet candidates.
    445 The existing \textsc{FastJet} code has been modified to allow easy modification of the tower pattern in $(\eta, \phi)$ space.
    446 In following versions of \textsc{Delphes}, a new dedicated plug-in will be created on this purpose\footnote{\texttt{[code] }\texttt{JET\_coneradius} and \texttt{JET\_seed} variables in the detector card.}.
    447  
    448 \item {\it CDF MidPoint}~\citep{bib:midpoint}: Algorithm developed for the \textsc{cdf} Run II to reduce infrared and collinear sensitivities compared to purely seed-based cone by adding `midpoints' (energy barycentres) in the list of cone seeds.
    449  
    450 \item {\it Seedless Infrared Safe Cone}~\citep{bib:SIScone}: The \textsc{SISCone} algorithm is simultaneously insensitive to additional soft particles and collinear splittings, and fast enough to be used in experimental analysis.
     444The existing FastJet code has been modified to allow easy modification of the tower pattern in $(\eta, \phi)$ space.
     445In following versions of \textit{Delphes}, a new dedicated plug-in will be created on this purpose\footnote{\texttt{[code] }\texttt{JET\_coneradius} and \texttt{JET\_seed} variables in the detector card.}.
     446 
     447\item {\it CDF MidPoint}~\citep{bib:midpoint}: Algorithm developed for the \textsc{CDF} Run II to reduce infrared and collinear sensitivities compared to purely seed-based cone by adding `midpoints' (energy barycentres) in the list of cone seeds.
     448 
     449\item {\it Seedless Infrared Safe Cone}~\citep{bib:SIScone}: The \textsc{SISC}one algorithm is simultaneously insensitive to additional soft particles and collinear splittings, and fast enough to be used in experimental analysis.
    451450 
    452451\end{enumerate}
    … …  
    487486\subsubsection*{Energy flow}
    488487
    489 In jets, several particle can leave their energy into a given calorimetric tower, which broadens the jet energy resolution. However, the energy of charged particles associated to jets can be deduced from their reconstructed track, thus providing a way to identify some of the components of towers with multiple hits. When the \textit{energy flow} is switched on in \textsc{Delphes}\footnote{\texttt{[code]} Set \texttt{JET\_Eflow} to $1$ or $0$ in the detector card in order to switch on or off the energy flow for jet reconstruction.}, the energy of tracks pointing to calotowers is extracted and smeared separately, before running the chosen jet reconstruction algorithm. This option allows a better jet $E$ reconstruction.
     488In jets, several particle can leave their energy into a given calorimetric tower, which broadens the jet energy resolution. However, the energy of charged particles associated to jets can be deduced from their reconstructed track, thus providing a way to identify some of the components of towers with multiple hits. When the \textit{energy flow} is switched on in \textit{Delphes}\footnote{\texttt{[code]} Set \texttt{JET\_Eflow} to $1$ or $0$ in the detector card in order to switch on or off the energy flow for jet reconstruction.}, the energy of tracks pointing to calotowers is extracted and smeared separately, before running the chosen jet reconstruction algorithm. This option allows a better jet $E$ reconstruction.
    490489 
    491490\subsection{$b$-tagging}
    … …  
    493492
    494493A jet is tagged as $b$-jets if its direction lies in the acceptance of the tracker and if it is associated to a parent $b$-quark. By default, a $b$-tagging efficiency of $40\%$ is assumed if the jet has a parent $b$ quark. For $c$-jets and light jets (i.e.\ originating in $u$, $d$, $s$ quarks or in gluons), a fake $b$-tagging efficiency of $10 \%$ and $1 \%$ respectively is assumed\footnote{\texttt{[code] }Corresponding to the \texttt{BTAG\_b}, \texttt{BTAG\_mistag\_c} and \texttt{BTAG\_mistag\_l} constants, for (respectively) the efficiency of tagging of a $b$-jet, the efficiency of mistagging a $c$-jet as a $b$-jet, and the efficiency of mistagging a light jet ($u$,$d$,$s$,$g$) as a $b$-jet.}.
    495 The (mis)tagging relies on the true particle identity (\textsc{pid}) of the most energetic particle within a cone around the observed $(\eta,\phi)$ region, with a radius equal to the one used to reconstruct the jet (default: $\Delta R$ of $0.7$). In current version of \textsc{Delphes}, the displacement of secondary vertices is not simulated.
     494The (mis)tagging relies on the true particle identity (\textsc{PID}) of the most energetic particle within a cone around the observed $(\eta,\phi)$ region, with a radius equal to the one used to reconstruct the jet (default: $\Delta R$ of $0.7$). In current version of \textit{Delphes}, the displacement of secondary vertices is not simulated.
    496495
    497496\subsection{\texorpdfstring{$\tau$}{\texttau} identification}
    … …  
    564563\includegraphics[width=\columnwidth]{fig6}
    565564\caption{Distribution of the electromagnetic collimation $C_\tau$ variable for true $\tau$-jets, normalised to unity. This distribution is shown for associated $WH$ photoproduction~\citep{bib:whphotoproduction}, where the Higgs boson decays into a $W^+ W^-$ pair. Each $W$ boson decays into a $\ell \nu_\ell$ pair, where $\ell = e, \mu, \tau$.
    566 Events generated with \textsc{MadGraph/MadEvent}~\citep{bib:mgme}.
    567 Final state hadronisation is performed by \textsc{Pythia}~\citep{bib:pythia}.
     565Events generated with MadGraph/MadEvent~\citep{bib:mgme}.
     566Final state hadronisation is performed by \textit{Pythia}~\citep{bib:pythia}.
    568567Histogram entries correspond to true $\tau$-jets, matched with generator-level data. }
    569568\label{fig:tau2}
    … …  
    610609\end{equation}
    611610The \textit{true} missing transverse energy, i.e.\ at generator-level, is calculated as the opposite of the vector sum of the transverse momenta of all visible particles -- or equivalently, to the vector sum of invisible particle transverse momenta.
    612 In a real experiment, calorimeters measure energy and not momentum. Any problem affecting the detector (dead channels, misalignment, noisy towers, cracks) worsens directly the measured missing transverse energy $\overrightarrow {E_T}^\textrm{miss}$. In this document, \textsc{met} is based on the calorimetric towers and only muons and neutrinos are not taken into account for its evaluation\footnote{However, as tracks and calorimetric towers are available in the output file, the missing transverse energy can always be reprocessed a posteriori. }:
     611In a real experiment, calorimeters measure energy and not momentum. Any problem affecting the detector (dead channels, misalignment, noisy towers, cracks) worsens directly the measured missing transverse energy $\overrightarrow {E_T}^\textrm{miss}$. In this document, \textsc{MET} is based on the calorimetric towers and only muons and neutrinos are not taken into account for its evaluation\footnote{However, as tracks and calorimetric towers are available in the output file, the missing transverse energy can always be reprocessed a posteriori. }:
    613612\begin{equation}
    614613\overrightarrow{E_T}^\textrm{miss} = - \sum^\textrm{towers}_i \overrightarrow{E_T}(i)
    … …  
    618617\section{Trigger emulation}
    619618
    620 New physics in collider experiment are often characterised in phenomenology by low cross-section values, compared to the Standard Model (\textsc{sm}) processes. %For instance at the \textsc{lhc} ($\sqrt{s}=14~\textrm{TeV}$), the cross-section of inclusive production of $b \bar b$ pairs is expected to be $10^7~\textrm{nb}$, or inclusive jets at $100~\textrm{nb}$ ($p_T > 200~\textrm{GeV}/c$), while Higgs boson cross-section within the \textsc{sm} can be as small as $2 \times 10^{-3}~\textrm{nb}$ ($pp \rightarrow WH$, $m_H=115~\textrm{GeV}/c^2$).
     619New physics in collider experiment are often characterised in phenomenology by low cross-section values, compared to the Standard Model (\textsc{SM}) processes. %For instance at the \textsc{LHC} ($\sqrt{s}=14~\textrm{TeV}$), the cross-section of inclusive production of $b \bar b$ pairs is expected to be $10^7~\textrm{nb}$, or inclusive jets at $100~\textrm{nb}$ ($p_T > 200~\textrm{GeV}/c$), while Higgs boson cross-section within the \textsc{SM} can be as small as $2 \times 10^{-3}~\textrm{nb}$ ($pp \rightarrow WH$, $m_H=115~\textrm{GeV}/c^2$).
    621620
    622621%High statistics are required for data analyses, consequently imposing high luminosity, i.e.\ a high collision rate.
    623622As only a tiny fraction of the observed events can be stored for subsequent \textit{offline} analyses, a very large data rejection factor should be applied directly as the events are produced.
    624 This data selection is supposed to reject only well-known \textsc{sm} events\footnote{However, some bandwidth is allocated to minimum-bias and/or zero-bias (``random'') triggers that stores a small fraction of the events without any selection criteria.}.
     623This data selection is supposed to reject only well-known \textsc{SM} events\footnote{However, some bandwidth is allocated to minimum-bias and/or zero-bias (``random'') triggers that stores a small fraction of the events without any selection criteria.}.
    625624Dedicated algorithms of this \textit{online} selection, or \textit{trigger}, should be fast and very efficient for data rejection, in order to preserve the experiment output bandwidth. They must also be as inclusive as possible to avoid loosing interesting events.
    626625
    627 Most of the usual trigger algorithms select events containing objects (i.e.\ jets, particles, \textsc{met}) with an energy scale above some threshold. This is often expressed in terms of a cut on the transverse momentum of one or several objects of the measured event. Logical combinations of several conditions are also possible. For instance, a trigger path could select events containing at least one jet and one electron such as $p_T^\textrm{jet} > 100~\textrm{GeV}/c$ and $p_T^e > 50~\textrm{GeV}/c$.
    628 
    629 A trigger emulation is included in \textsc{Delphes}, using a fully parametrisable \textit{trigger table}\footnote{\texttt{[code] }The trigger card is the \texttt{data/TriggerCard.dat} file.}. When enabled, this trigger is applied on analysis-object data.
     626Most of the usual trigger algorithms select events containing objects (i.e.\ jets, particles, \textsc{MET}) with an energy scale above some threshold. This is often expressed in terms of a cut on the transverse momentum of one or several objects of the measured event. Logical combinations of several conditions are also possible. For instance, a trigger path could select events containing at least one jet and one electron such as $p_T^\textrm{jet} > 100~\textrm{GeV}/c$ and $p_T^e > 50~\textrm{GeV}/c$.
     627
     628A trigger emulation is included in \textit{Delphes}, using a fully parametrisable \textit{trigger table}\footnote{\texttt{[code] }The trigger card is the \texttt{data/TriggerCard.dat} file.}. When enabled, this trigger is applied on analysis-object data.
    630629In a real experiment, the online selection is often divided into several steps (or \textit{levels}).
    631630This splits the overall reduction factor into a product of smaller factors, corresponding to the different trigger levels.
    … …  
    635634
    636635Real triggers are thus intrinsically based on reconstructed data with a worse resolution than final analysis data.
    637 On the contrary, same data are used in \textsc{Delphes} for trigger emulation and for final analyses.
     636On the contrary, same data are used in \textit{Delphes} for trigger emulation and for final analyses.
    638637
    639638\section{Validation}
    640639
    641 \textsc{Delphes} performs a fast simulation of a collider experiment.
     640\textit{Delphes} performs a fast simulation of a collider experiment.
    642641Its performances in terms of computing time and data size are directly proportional to the number of simulated events and on the considered physics process. As an example, $10,000$ $pp \rightarrow t \bar t X$ events are processed in $110~\textrm{s}$ on a regular laptop and use less than $250~\textrm{MB}$ of disk space.
    643 The quality and validity of the output are assessed by comparing the resolutions on the reconstructed data to the expectations of both \textsc{cms}~\citep{bib:cmsjetresolution} and \textsc{atlas}~\citep{bib:ATLASresolution} detectors.
     642The quality and validity of the output are assessed by comparing the resolutions on the reconstructed data to the expectations of both \textsc{CMS}~\citep{bib:cmsjetresolution} and \textsc{ATLAS}~\citep{bib:ATLASresolution} detectors.
    644643
    645644Electrons and muons are by construction equal to the experiment designs, as the Gaussian smearing of their kinematics properties is defined according to the detector specifications.
    … …  
    649648\subsection{Jet resolution}
    650649 
    651 The majority of interesting processes at the \textsc{lhc} contain jets in the final state. The jet resolution obtained using \textsc{Delphes} is therefore a crucial point for its validation, both for \textsc{cms}- and \textsc{atlas}-like detectors.
    652 This validation is based on $pp \rightarrow gg$ events produced with \textsc{MadGraph/MadEvent} and hadronised using \textsc{Pythia}~\citep{bib:mgme,bib:pythia}.
    653 
    654 For a \textsc{cms}-like detector, a similar procedure as the one explained in published results is applied here.
    655 The events were arranged in $14$ bins of gluon transverse momentum $\hat{p}_T$. In each $\hat{p}_T$ bin, every jet in \textsc{Delphes} is matched to the closest jet of generator-level particles, using the spatial separation between the two jet axes
     650The majority of interesting processes at the \textsc{LHC} contain jets in the final state. The jet resolution obtained using \textit{Delphes} is therefore a crucial point for its validation, both for \textsc{CMS}- and \textsc{ATLAS}-like detectors.
     651This validation is based on $pp \rightarrow gg$ events produced with MadGraph/MadEvent and hadronised using \textit{Pythia}~\citep{bib:mgme,bib:pythia}.
     652
     653For a \textsc{CMS}-like detector, a similar procedure as the one explained in published results is applied here.
     654The events were arranged in $14$ bins of gluon transverse momentum $\hat{p}_T$. In each $\hat{p}_T$ bin, every jet in \textit{Delphes} is matched to the closest jet of generator-level particles, using the spatial separation between the two jet axes
    656655\begin{equation}
    657656\Delta R = \sqrt{ \big(\eta^\textrm{rec} - \eta^\textrm{MC} \big)^2 +  \big(\phi^\textrm{rec} - \phi^\textrm{MC} \big)^2}<0.25.
    658657\end{equation}
    659658The jets made of generator-level particles, here referred as \textit{MC jets}, are obtained by applying the algorithm to all particles considered as stable after hadronisation (i.e.\ including muons).
    660 Jets produced by \textsc{Delphes} and satisfying the matching criterion are called hereafter \textit{reconstructed jets}.
    661 All jets are computed with the clustering algorithm (\textsc{jetclu}) with a cone radius $R$ of $0.7$.
    662 
    663 The ratio of the transverse energies of every reconstructed jet $E_T^\textrm{rec}$ to its corresponding \textsc{mc} jet $E_T^\textrm{MC}$ is calculated in each $\hat{p}_T$ bin.
    664 The $E_T^\textrm{rec}/E_T^\textrm{MC}$ histogram is fitted with a Gaussian distribution in the interval \mbox{$\pm 2$~\textsc{rms}} centred around the mean value.
     659Jets produced by \textit{Delphes} and satisfying the matching criterion are called hereafter \textit{reconstructed jets}.
     660All jets are computed with the clustering algorithm (JetCLU) with a cone radius $R$ of $0.7$.
     661
     662The ratio of the transverse energies of every reconstructed jet $E_T^\textrm{rec}$ to its corresponding \textsc{MC} jet $E_T^\textrm{MC}$ is calculated in each $\hat{p}_T$ bin.
     663The $E_T^\textrm{rec}/E_T^\textrm{MC}$ histogram is fitted with a Gaussian distribution in the interval \mbox{$\pm 2$~\textsc{RMS}} centred around the mean value.
    665664The resolution in each $\hat{p}_T$ bin is obtained by the fit mean $\langle x \rangle$ and variance $\sigma^2(x)$:
    666665\begin{equation}
    … …  
    674673%\includegraphics[width=\columnwidth]{resolutionJet}
    675674\includegraphics[width=\columnwidth]{fig8}
    676 \caption{Resolution of the transverse energy of reconstructed jets $E_T^\textrm{rec}$ as a function of the transverse energy of the closest jet of generator-level particles $E_T^\textrm{MC}$, in a \textsc{cms}-like detector. The jets events are reconstructed with the \textsc{jetclu} clustering algorithm with a cone radius of $0.7$. The maximum separation between the reconstructed and \textsc{mc}-jets is $\Delta R= 0.25$. Dotted line is the fit result for comparison to the \textsc{cms} resolution~\citep{bib:cmsjetresolution}, in blue. The $pp \rightarrow gg$ dijet events have been generated with \textsc{MadGraph/MadEvent} and hadronised with \textsc{Pythia}.}
     675\caption{Resolution of the transverse energy of reconstructed jets $E_T^\textrm{rec}$ as a function of the transverse energy of the closest jet of generator-level particles $E_T^\textrm{MC}$, in a \textsc{CMS}-like detector. The jets events are reconstructed with the JetCLU clustering algorithm with a cone radius of $0.7$. The maximum separation between the reconstructed and \textsc{MC}-jets is $\Delta R= 0.25$. Dotted line is the fit result for comparison to the \textsc{CMS} resolution~\citep{bib:cmsjetresolution}, in blue. The $pp \rightarrow gg$ dijet events have been generated with MadGraph/MadEvent and hadronised with \textit{Pythia}.}
    677676\label{fig:jetresolcms}
    678677\end{center}
    … …  
    686685\end{equation}
    687686where $a$, $b$ and $c$ are the fit parameters.
    688 It is then compared to the resolution published by the \textsc{cms} collaboration~\citep{bib:cmsjetresolution}. The resolution curves from \textsc{Delphes} and \textsc{cms} are in good agreement.
    689 
    690 Similarly, the jet resolution is evaluated for an \textsc{atlas}-like detector. The $pp \rightarrow gg$ events are here arranged in $8$ adjacent bins in $p_T$. A $k_T$ reconstruction algorithm with $R=0.6$ is chosen and the maximal matching distance between the \textsc{mc}-jets and the reconstructed jets is set to $\Delta R=0.2$. The relative energy resolution is evaluated in each bin by:
     687It is then compared to the resolution published by the \textsc{CMS} collaboration~\citep{bib:cmsjetresolution}. The resolution curves from \textit{Delphes} and \textsc{CMS} are in good agreement.
     688
     689Similarly, the jet resolution is evaluated for an \textsc{ATLAS}-like detector. The $pp \rightarrow gg$ events are here arranged in $8$ adjacent bins in $p_T$. A $k_T$ reconstruction algorithm with $R=0.6$ is chosen and the maximal matching distance between the \textsc{MC}-jets and the reconstructed jets is set to $\Delta R=0.2$. The relative energy resolution is evaluated in each bin by:
    691690\begin{equation}
    692691\frac{\sigma(E)}{E} = \sqrt{~~ \Bigg \langle ~\Bigg( \frac{E^\textrm{rec} - E^\textrm{MC}}{E^\textrm{rec}} \Bigg)^2 ~ \Bigg \rangle ~ - ~ \Bigg \langle \frac{E^\textrm{rec} - E^\textrm{MC}}{ E^\textrm{rec} } \Bigg \rangle^2}.
    693692\end{equation}
    694693
    695 Figure~\ref{fig:jetresolatlas} shows a good agreement between the resolution obtained with \textsc{Delphes}, the result of the fit with Equation~\ref{eq:fitresolution} and the corresponding curve provided by the \textsc{atlas} collaboration~\citep{bib:ATLASresolution}.
     694Figure~\ref{fig:jetresolatlas} shows a good agreement between the resolution obtained with \textit{Delphes}, the result of the fit with Equation~\ref{eq:fitresolution} and the corresponding curve provided by the \textsc{ATLAS} collaboration~\citep{bib:ATLASresolution}.
    696695
    697696\begin{figure}[!ht]
    698697\begin{center}
    699698\includegraphics[width=\columnwidth]{fig9}
    700 \caption{Relative energy resolution of reconstructed jets as a function of the energy of the closest jet of generator-level particles $E^\textrm{MC}$, in an \textsc{atlas}-like detector. The jets are reconstructed with the $k_T$ algorithm with a radius $R=0.6$. The maximal matching distance between \textsc{mc}- and reconstructed jets is $\Delta R=0.2$. Only central jets are considered ($|\eta|<0.5$). Dotted line is the fit result for comparison to the \textsc{atlas} resolution~\citep{bib:ATLASresolution}, in blue. The $pp \rightarrow gg$ di-jet events have been generated with \textsc{MadGraph/MadEvent} and hadronised with \textsc{Pythia}.}
     699\caption{Relative energy resolution of reconstructed jets as a function of the energy of the closest jet of generator-level particles $E^\textrm{MC}$, in an \textsc{ATLAS}-like detector. The jets are reconstructed with the $k_T$ algorithm with a radius $R=0.6$. The maximal matching distance between \textsc{MC}- and reconstructed jets is $\Delta R=0.2$. Only central jets are considered ($|\eta|<0.5$). Dotted line is the fit result for comparison to the \textsc{ATLAS} resolution~\citep{bib:ATLASresolution}, in blue. The $pp \rightarrow gg$ di-jet events have been generated with MadGraph/MadEvent and hadronised with \textit{Pythia}.}
    701700\label{fig:jetresolatlas}
    702701\end{center}
    … …  
    707706 
    708707All major detectors at hadron colliders have been designed to be as much hermetic as possible in order to detect the presence of one or more neutrinos and/or new weakly interacting particles through apparent missing transverse energy.
    709 The resolution of the $\overrightarrow{E_T}^\textrm{miss}$ variable, as obtained with \textsc{Delphes}, is then crucial.
    710 
    711 The samples used to study the \textsc{met} performance are identical to those used for the jet validation.
     708The resolution of the $\overrightarrow{E_T}^\textrm{miss}$ variable, as obtained with \textit{Delphes}, is then crucial.
     709
     710The samples used to study the \textsc{MET} performance are identical to those used for the jet validation.
    712711It is worth noting that the contribution to $E_T^\textrm{miss}$ from muons is negligible in the studied sample.
    713712The input samples are divided in five bins of scalar $E_T$ sums $(\Sigma E_T)$. This sum, called \textit{total visible transverse energy}, is defined as the scalar sum of transverse energy in all towers.
    714 The quality of the \textsc{met} reconstruction is checked via the resolution on its horizontal component $E_x^\textrm{miss}$.
     713The quality of the \textsc{MET} reconstruction is checked via the resolution on its horizontal component $E_x^\textrm{miss}$.
    715714
    716715The $E_x^\textrm{miss}$ resolution is evaluated in the following way.
    717 The distribution of the difference between $E_x^\textrm{miss}$ in \textsc{Delphes} and at generator-level is fitted with a Gaussian function in each $(\Sigma E_T)$ bin. The fit \textsc{rms} gives the \textsc{met} resolution in each bin.
     716The distribution of the difference between $E_x^\textrm{miss}$ in \textit{Delphes} and at generator-level is fitted with a Gaussian function in each $(\Sigma E_T)$ bin. The fit \textsc{RMS} gives the \textsc{MET} resolution in each bin.
    718717The resulting value is plotted in Fig.~\ref{fig:resolETmis} as a function of the total visible transverse
    719 energy, for \textsc{cms}- and \textsc{atlas}-like detectors.
     718energy, for \textsc{CMS}- and \textsc{ATLAS}-like detectors.
    720719 
    721720\begin{figure}[!ht]
    … …  
    724723\includegraphics[width=\columnwidth]{fig10}
    725724\includegraphics[width=\columnwidth]{fig10b}
    726 \caption{$\sigma(E^\textrm{mis}_{x})$ as a function on the scalar sum of all towers ($\Sigma E_T$) for $pp \rightarrow gg$ events, for a \textsc{cms}-like detector (top) and an \textsc{atlas}-like detector (bottom), for di-jet events produced with \textsc{MadGraph/MadEvent} and hadronised with \textsc{Pythia}.}
     725\caption{$\sigma(E^\textrm{mis}_{x})$ as a function on the scalar sum of all towers ($\Sigma E_T$) for $pp \rightarrow gg$ events, for a \textsc{CMS}-like detector (top) and an \textsc{ATLAS}-like detector (bottom), for di-jet events produced with MadGraph/MadEvent and hadronised with \textit{Pythia}.}
    727726\label{fig:resolETmis}
    728727\end{center}
    729728\end{figure}
    730729 
    731 The resolution $\sigma_x$ of the horizontal component of \textsc{met} is observed to behave like
     730The resolution $\sigma_x$ of the horizontal component of \textsc{MET} is observed to behave like
    732731\begin{equation}
    733732\sigma_x = \alpha ~\sqrt{E_T}~~~(\mathrm{GeV}^{1/2}),
    … …  
    735734where the $\alpha$ parameter depends on the resolution of the calorimeters.
    736735
    737 The \textsc{met} resolution expected for the \textsc{cms} detector for similar events is $\sigma_x = (0.6-0.7) ~ \sqrt{E_T} ~ \mathrm{GeV}^{1/2}$ with no pile-up\footnote{\textit{Pile-up} events are extra simultaneous $pp$ collision occurring at high-luminosity in the same bunch crossing.}~\citep{bib:cmsjetresolution}, which compares very well with the $\alpha = 0.63$ obtained with \textsc{Delphes}. Similarly, for an \textsc{atlas}-like detector, a value of $0.53$ is obtained by \textsc{Delphes} for the $\alpha$ parameter, while the experiment expects it in the range $[0.53~ ;~0.57]$~\citep{bib:ATLASresolution}.
     736The \textsc{MET} resolution expected for the \textsc{CMS} detector for similar events is $\sigma_x = (0.6-0.7) ~ \sqrt{E_T} ~ \mathrm{GeV}^{1/2}$ with no pile-up\footnote{\textit{Pile-up} events are extra simultaneous $pp$ collision occurring at high-luminosity in the same bunch crossing.}~\citep{bib:cmsjetresolution}, which compares very well with the $\alpha = 0.63$ obtained with \textit{Delphes}. Similarly, for an \textsc{ATLAS}-like detector, a value of $0.53$ is obtained by \textit{Delphes} for the $\alpha$ parameter, while the experiment expects it in the range $[0.53~ ;~0.57]$~\citep{bib:ATLASresolution}.
    738737
    739738\subsection{\texorpdfstring{$\tau$}{\texttau}-jet efficiency}
    740739Due to the complexity of their reconstruction algorithm, $\tau$-jets have also to be checked.
    741 Table~\ref{tab:taurecoefficiency} lists the reconstruction efficiencies in \textsc{Delphes} for the hadronic $\tau$-jets from $H,Z \rightarrow \tau^+ \tau^-$. The mass of the Higgs boson is set successively to $140$ and $300~\textrm{GeV}/c^2$. The inclusive gauge boson productions  ($pp \rightarrow HX$ and $pp \rightarrow ZX$) are performed with \textsc{MadGraph/MadEvent} and the $\tau$ lepton decay and further hadronisation are handled by \textsc{Pythia/Tauola}. All reconstructed $\tau$-jets are $1-$prong, and follow the definition described in section~\ref{btagging}, which is very close to an algorithm of the \textsc{cms} experiment~\citep{bib:cmstauresolution}. At last, corresponding efficiencies published by the \textsc{cms} and \textsc{atlas} experiments are quoted for comparison. The agreement is good enough at this level to validate the $\tau-$reconstruction.
     740Table~\ref{tab:taurecoefficiency} lists the reconstruction efficiencies in \textit{Delphes} for the hadronic $\tau$-jets from $H,Z \rightarrow \tau^+ \tau^-$. The mass of the Higgs boson is set successively to $140$ and $300~\textrm{GeV}/c^2$. The inclusive gauge boson productions  ($pp \rightarrow HX$ and $pp \rightarrow ZX$) are performed with MadGraph/MadEvent and the $\tau$ lepton decay and further hadronisation are handled by \textit{Pythia/Tauola}. All reconstructed $\tau$-jets are $1-$prong, and follow the definition described in section~\ref{btagging}, which is very close to an algorithm of the \textsc{CMS} experiment~\citep{bib:cmstauresolution}. At last, corresponding efficiencies published by the \textsc{CMS} and \textsc{ATLAS} experiments are quoted for comparison. The agreement is good enough at this level to validate the $\tau-$reconstruction.
    742741
    743742\begin{table}[!h]
    744743\begin{center}
    745 \caption{Reconstruction efficiencies of $\tau$-jets in $\tau^+ \tau^-$ decays from $Z$ or $H$ bosons, in \textsc{Delphes}, \textsc{cms} and \textsc{atlas} experiments~\citep{bib:cmstauresolution,bib:ATLASresolution}. Two scenarios for the mass of the Higgs boson are investigated. Events generated with \textsc{MadGraph/MadEvent} and hadronised with \textsc{Pythia}. The decays of $\tau$ leptons is handled by the \textsc{Tauola} version embedded in \textsc{Pythia}.\vspace{0.5cm}}
     744\caption{Reconstruction efficiencies of $\tau$-jets in $\tau^+ \tau^-$ decays from $Z$ or $H$ bosons, in \textit{Delphes}, \textsc{CMS} and \textsc{ATLAS} experiments~\citep{bib:cmstauresolution,bib:ATLASresolution}. Two scenarios for the mass of the Higgs boson are investigated. Events generated with MadGraph/MadEvent and hadronised with \textit{Pythia}. The decays of $\tau$ leptons is handled by the \textit{Tauola} version embedded in \textit{Pythia}.\vspace{0.5cm}}
    746745%\begin{tabular}{lll}
    747746%\hline
    748 %\multicolumn{2}{c}{\textsc{cms}} & \\
     747%\multicolumn{2}{c}{\textsc{CMS}} & \\
    749748%$Z \rightarrow \tau^+ \tau^-$                   & $38 \%$ &  \\
    750749%$H \rightarrow \tau^+ \tau^-$ & $36 \%$ & $m_H = 150~\textrm{GeV}/c^2$ \\
    751750%$H \rightarrow \tau^+ \tau^-$ & $47 \%$ & $m_H = 300~\textrm{GeV}/c^2$ \\
    752 %\multicolumn{2}{c}{\textsc{Delphes}} & \\
     751%\multicolumn{2}{c}{Delphes} & \\
    753752%$H \rightarrow \tau^+ \tau^-$ &$42 \%$  & $m_H = 140~\textrm{GeV}/c^2$ \\
    754753%\hline
    … …  
    757756\begin{tabular}{lrlrl}
    758757\hline
    759                                 & \textsc{cms}&\textsc{Delphes} & \textsc{atlas}&\textsc{Delphes}       \\
     758                                & \textsc{CMS}&Delphes & \textsc{ATLAS}&Delphes         \\
    760759$Z \rightarrow \tau^+ \tau^-$   & $38.2\%$ & $32.4\pm1.8\%$     & $33\%$ & $28.6\pm 1.9\%$              \\
    761760$H(140) \rightarrow \tau^+ \tau^-$      & $36.3\%$ & $39.9\pm1.6\%$     & & $32.8\pm 1.8\%$             \\
    … …  
    771770\section{Visualisation}
    772771
    773 When performing an event analysis, a visualisation tool is useful to convey information about the detector layout and the event topology in a simple way. The \textit{Fast and Realistic OpenGL Displayer} \textsc{frog}~\citep{bib:Frog} has been interfaced in \textsc{Delphes}, allowing an easy display of the defined detector configuration\footnote{\texttt{[code] } To prepare the visualisation, the \texttt{FLAG\_frog} parameter should be equal to $1$.}.
     772When performing an event analysis, a visualisation tool is useful to convey information about the detector layout and the event topology in a simple way. The \textit{Fast and Realistic OpenGL Displayer} \textsc{FROG}~\citep{bib:FROG} has been interfaced in \textit{Delphes}, allowing an easy display of the defined detector configuration\footnote{\texttt{[code] } To prepare the visualisation, the \texttt{FLAG\_FROG} parameter should be equal to $1$.}.
    774773 
    775774% \begin{figure}[!ht]
    776775% \begin{center}
    777 % \includegraphics[width=\columnwidth]{Detector_Delphes_1}
    778 % \caption{Layout of the generic detector geometry assumed in \textsc{Delphes}. The innermost layer, close to the interaction point, is a central tracking system (pink), embedded into a solenoidal magnetic field.
     776% \includegraphics[width=\columnwidth]{Detector_DELPHES_1}
     777% \caption{Layout of the generic detector geometry assumed in Delphes. The innermost layer, close to the interaction point, is a central tracking system (pink), embedded into a solenoidal magnetic field.
    779778% It is surrounded by a central calorimeter volume (green) with both electromagnetic and hadronic sections.
    780779% The outer layer of the central system (red) consist of a muon system.
    … …  
    796795\begin{figure}[!ht]
    797796\begin{center}
    798 %\includegraphics[width=\columnwidth]{Detector_Delphes_2b}
     797%\includegraphics[width=\columnwidth]{Detector_DELPHES_2b}
    799798\includegraphics[width=\columnwidth]{fig11}
    800 \caption{Layout of the generic detector geometry assumed in \textsc{Delphes}. Open 3D-view of the detector with solid volumes. Same colour codes as for Fig.~\ref{fig:GenDet3} are applied. Additional forward detectors are not depicted.}
     799\caption{Layout of the generic detector geometry assumed in \textit{Delphes}. Open 3D-view of the detector with solid volumes. Same colour codes as for Fig.~\ref{fig:GenDet3} are applied. Additional forward detectors are not depicted.}
    801800\label{fig:GenDet2}
    802801\end{center}
    … …  
    817816\begin{figure}[!ht]
    818817\begin{center}
    819 %%\includegraphics[width=\columnwidth]{Events_Delphes_1}
     818%%\includegraphics[width=\columnwidth]{Events_DELPHES_1}
    820819%\includegraphics[width=\columnwidth]{DisplayWt}
    821820\includegraphics[width=\columnwidth]{fig12}
    … …  
    834833\begin{figure}[!ht]
    835834\begin{center}
    836 %%\includegraphics[width=\columnwidth]{Events_Delphes_1}
     835%%\includegraphics[width=\columnwidth]{Events_DELPHES_1}
    837836%\includegraphics[width=\columnwidth]{Displayppgg}
    838837\includegraphics[width=\columnwidth]{fig13}
    … …  
    846845
    847846% \subsection{version 1}
    848 % We have described here the major features of the \textsc{Delphes} framework, introduced for the fast simulation of a collider experiment.
    849 % It has already been used for several phenomenological studies, in particular in photon interactions at the \textsc{lhc}.
     847% We have described here the major features of the \textit{Delphes} framework, introduced for the fast simulation of a collider experiment.
     848% It has already been used for several phenomenological studies, in particular in photon interactions at the \textsc{LHC}.
    850849%
    851 % \textsc{Delphes} takes the output of event generators, in various formats, and yields analysis-object data.
     850% \textit{Delphes} takes the output of event generators, in various formats, and yields analysis-object data.
    852851% The simulation applies the resolutions of central and forward detectors by smearing the kinematical properties of final state particles.
    853852% It yields tracks in a solenoidal magnetic field and calorimetric towers.
    854 % Realistic reconstruction algorithms are run, including the \textsc{FastJet} package, to produce collections of $e^\pm$, $\mu^\pm$, jets and $\tau$-jets. $b$-tag and missing transverse energy are also evaluated.
    855 % The output is validated by comparing to the \textsc{cms} expected performances.
     853% Realistic reconstruction algorithms are run, including the FastJet package, to produce collections of $e^\pm$, $\mu^\pm$, jets and $\tau$-jets. $b$-tag and missing transverse energy are also evaluated.
     854% The output is validated by comparing to the \textsc{CMS} expected performances.
    856855% A trigger stage can be emulated on the output data.
    857 % At last, event visualisation is possible through the \textsc{Frog} 3D event display.
     856% At last, event visualisation is possible through the \textsc{FROG} 3D event display.
    858857%
    859858%
    860 % \textsc{Delphes} has been developped using the parameters of the \textsc{cms} experiment but can be easily extended to \textsc{atlas} and other non-\textsc{lhc} experiments, as at Tevatron or at the \textsc{ilc}. Further developments include a more flexible design for the subdetector assembly and possibly the implementation of an event mixing module for pile-up event simulation.
     859% \textit{Delphes} has been developped using the parameters of the \textsc{CMS} experiment but can be easily extended to \textsc{ATLAS} and other non-\textsc{LHC} experiments, as at Tevatron or at the \textsc{ILC}. Further developments include a more flexible design for the subdetector assembly and possibly the implementation of an event mixing module for pile-up event simulation.
    861860%
    862861%
    863862% \subsection{version 2}
    864 We have described here the major features of the \textsc{Delphes} framework, introduced for the fast simulation of a collider experiment. This framework is a tool meant for feasibility studies in phenomenology, gauging the observability of model predictions in collider experiments.
    865 
    866 \textsc{Delphes} takes as an input the output of event-generators and yields analysis-object data in the form of \texttt{TTree} in a \textsc{root} file.
     863We have described here the major features of the \textit{Delphes} framework, introduced for the fast simulation of a collider experiment. This framework is a tool meant for feasibility studies in phenomenology, gauging the observability of model predictions in collider experiments.
     864
     865\textit{Delphes} takes as an input the output of event-generators and yields analysis-object data in the form of \texttt{TTree} in a \texttt{*.root} file.
    867866The simulation includes central and forward detectors to produce realistic observables using standard reconstruction algorithms.
    868867Moreover, the framework allows trigger emulation and 3D event visualisation.
    869868
    870 \textsc{Delphes} has been developed using the parameters of the \textsc{cms} experiment but can be easily extended to \textsc{atlas} and other non-\textsc{lhc} experiments, as at Tevatron or at the \textsc{ilc}. Further developments include a more flexible design for the subdetector assembly and possibly the implementation of an event mixing module for pile-up event simulation.
    871 
    872 This framework has already been used for several analyses, in particular in photon-induced interactions at the \textsc{lhc}~\citep{bib:wtphotoproduction, bib:papierquisortirajamais, bib:papiersimon}.
     869\textit{Delphes} has been developed using the parameters of the \textsc{CMS} experiment but can be easily extended to \textsc{ATLAS} and other non-\textsc{LHC} experiments, as at Tevatron or at the \textsc{ILC}. Further developments include a more flexible design for the subdetector assembly and possibly the implementation of an event mixing module for pile-up event simulation.
     870
     871This framework has already been used for several analyses, in particular in photon-induced interactions at the \textsc{LHC}~\citep{bib:wtphotoproduction, bib:papierquisortirajamais, bib:papiersimon}.
    873872
    874873
    875874\section*{Acknowledgements}
    876875\addcontentsline{toc}{section}{Acknowledgements}
    877 The authors would like to thank very warmly Vincent Lema\^itre for the interesting suggestions during the development of the software, as well as Jer\^ome de Favereau, Christophe Delaere, Muriel Vander Donckt and David d'Enterria for useful discussions and comments, and Loic Quertenmont for support in interfacing \textsc{Frog}. We are also really grateful to Alice Dechambre and Simon de Visscher for being beta testers of the complete package.
     876The authors would like to thank Jer\^ome de Favereau, Christophe Delaere, Muriel Vander Donckt and David d'Enterria for useful discussions and comments, and Loic Quertenmont for support in interfacing \textsc{FROG}. We are also really grateful to Alice Dechambre and Simon de Visscher for being beta testers of the complete package.
    878877Part of this work was supported by the Belgian Federal Office for Scientific, Technical and Cultural Affairs through the Interuniversity Attraction Pole P6/11.
    879878
    … …  
    882881\addcontentsline{toc}{section}{References}
    883882 
    884 \bibitem{bib:Delphes} \textsc{Delphes}, \href{http://www.fynu.ucl.ac.be/delphes.html}{www.fynu.ucl.ac.be/delphes.html}
     883\bibitem{bib:delphes} \textit{Delphes}, \href{http://www.fynu.ucl.ac.be/delphes.html}{www.fynu.ucl.ac.be/delphes.html}
    885884%hepforge:
    886885\bibitem{bib:stdhep} L.A. Garren, M. Fischler, \href{http://cepa.fnal.gov/psm/stdhep/c++}{cepa.fnal.gov/psm/stdhep/c++}
    887886\bibitem{bib:hepmc} M. Dobbs and J.B. Hansen, \textbf{Comput. Phys. Commun.} \href{http://dx.doi.org/10.1016/S0010-4655(00)00189-2}{134 (2001) 41}.
    888887\bibitem{bib:lhe} J. Alwall, et al., \textbf{Comput. Phys. Commun.} \href{http://dx.doi.org/10.1016/j.cpc.2006.11.010}{176:300-304,2007}.
    889 \bibitem{bib:Root} %\textsc{Root}, \textit{An Object Oriented Data Analysis Framework},
     888\bibitem{bib:Root} %\textsc{ROOT}, \textit{An Object Oriented Data Analysis Framework},
    890889R. Brun, F. Rademakers, Nucl. Inst. \& Meth. in \textbf{Phys. Res. A} \href{http://dx.doi.org/10.1016/S0168-9002(97)00048-X}{389 (1997) 81-86}.
    891890\bibitem{bib:ExRootAnalysis} %\textit{The} \textsc{ExRootAnalysis} \textit{analysis steering utility},
    892 P. Demin, (2006), unpublished. Now part of \textsc{MadGraph/MadEvent}.
    893 \bibitem{bib:cmsjetresolution} The \textsc{cms} Collaboration, \textbf{CERN/LHCC} \href{http://documents.cern.ch/cgi-bin/setlink?base=lhcc&categ=public&id=lhcc-2006-001}{2006-001}.
    894 \bibitem{bib:ATLASresolution} The \textsc{atlas} Collaboration, \textbf{CERN-OPEN} 2008-020, \\arXiv:\href{http://arxiv.org/abs/arxiv:0901.0512}{0901.0512v1}[hep-ex].
    895 \bibitem{bib:Hector} %\textsc{Hector}, \textit{a fast simulator for the transport of particles in beamlines},
     891P. Demin, (2006), unpublished. Now part of MadGraph/MadEvent.
     892\bibitem{bib:cmsjetresolution} The \textsc{CMS} Collaboration, \textbf{CERN/LHCC} \href{http://documents.cern.ch/cgi-bin/setlink?base=LHCc&categ=public&id=LHCc-2006-001}{2006-001}.
     893\bibitem{bib:ATLASresolution} The \textsc{ATLAS} Collaboration, \textbf{CERN-OPEN} 2008-020, \\arXiv:\href{http://arxiv.org/abs/arxiv:0901.0512}{0901.0512v1}[hep-ex].
     894\bibitem{bib:hector} %\textit{Hector}, \textit{a fast simulator for the transport of particles in beamlines},
    896895X. Rouby, J. de Favereau, K. Piotrzkowski, \textbf{JINST} \href{http://www.iop.org/EJ/abstract/1748-0221/2/09/P09005}{2 P09005 (2007)}.
    897 \bibitem{bib:FastJet} %\textit{The} \textsc{FastJet} \textit{package},
     896\bibitem{bib:FASTJET} %\textit{The} FastJet \textit{package},
    898897M. Cacciari, G.P. Salam, \textbf{Phys. Lett. B} \href{http://dx.doi.org/10.1016/j.physletb.2006.08.037}{641 (2006) 57}.
    899 \bibitem{bib:jetclu} %\textsc{cdf} Run I legacy algorithm,
     898\bibitem{bib:jetclu} %\textsc{CDF} Run I legacy algorithm,
    900899F. Abe et al. (CDF Coll.), \textbf{Phys. Rev. D} \href{http://link.aps.org/doi/10.1103/PhysRevD.45.1448}{45 (1992) 1448}.
    901900\bibitem{bib:midpoint} %Run II Jet Physics: Proceedings of the Run II QCD and Weak Boson Physics Workshop,
    902901G.C. Blazey, et al., arXiv:\href{http://arxiv.org/abs/hep-ex/0005012}{0005012}[hep-ex].
    903 \bibitem{bib:SIScone} %\textsc{SIScone}, \textit{A practical Seedless Infrared-Safe Cone jet algorithm},
     902\bibitem{bib:SIScone} %\textsc{SISC}one, \textit{A practical Seedless Infrared-Safe Cone jet algorithm},
    904903G.P. Salam, G. Soyez, \textbf{JHEP} \href{http://dx.doi.org/10.1088/1126-6708/2007/05/086}{05 (2007) 086}.
    905904\bibitem{bib:ktjet} S. Catani, Y.L. Dokshitzer, M.H. Seymour, B.R. Webber, \textbf{Nucl. Phys. B} \href{http://dx.doi.org/10.1016/0550-3213(93)90166-M}{406 (1993) 187}; S.D. Ellis, D.E. Soper, \textbf{Phys. Rev. D} \href{http://link.aps.org/doi/10.1103/PhysRevD.48.3160}{48 (1993) 3160}.
    … …  
    915914\bibitem{bib:cmstauresolution} %\textit{Study of $\tau$-jet identification in CMS},
    916915R. Kinnunen, A.N. Nikitenko, \textbf{CMS NOTE} \href{http://cdsweb.cern.ch/record/687274}{1997/002}.
    917 \bibitem{bib:Frog} L. Quertenmont, V. Roberfroid, \textbf{CMS CR} \href{http://cms.cern.ch/iCMS/jsp/openfile.jsp?type=CR&year=2009&files=CR2009_028.pdf}{2009/028}, arXiv:\href{http://arxiv.org/abs/0901.2718}{0901.2718v1}[hep-ex].
     916\bibitem{bib:FROG} L. Quertenmont, V. Roberfroid, \textbf{CMS CR} \href{http://cms.cern.ch/iCMS/jsp/openfile.jsp?type=CR&year=2009&files=CR2009_028.pdf}{2009/028}, arXiv:\href{http://arxiv.org/abs/0901.2718}{0901.2718v1}[hep-ex].
    918917\bibitem{bib:wtphotoproduction} J. de Favereau de Jeneret, S. Ovyn, \textbf{Nucl. Phys. Proc. Suppl.} \href{http://dx.doi.org/10.1016/j.nuclphysbps.2008.07.040}{179-180 (2008)} \href{http://dx.doi.org/10.1016/j.nuclphysbps.2008.07.040}{277-284}; S. Ovyn, J. de Favereau de Jeneret, \href{http://dx.doi.org/10.1393/ncb/i2008-10684-5}{Nuovo Cimento B}, arXiv:0806.4841[hep-ph].
    919918
    … …  
    933932\section{User manual}
    934933 
    935 The available \texttt{C++}-code is compressed in a zipped tar file which contains everything needed to run the \textsc{Delphes} package, assuming a running \textsc{root} installation. The package includes \texttt{ExRootAnalysis}~\citep{bib:ExRootAnalysis}, \textsc{Hector}~\citep{bib:Hector}, \textsc{FastJet}~\citep{bib:FastJet}, and \textsc{Frog}~\citep{bib:Frog}, as well as the conversion codes to read standard \mbox{\textsc{s}td\textsc{hep}} input files (\texttt{mcfio} and \texttt{stdhep})~\citep{bib:mcfio} and \textsc{HepMC}~\citep{bib:hepmc}.
    936 In order to visualise the events with the \textsc{Frog} software, a few additional external libraries may be required, as explained in \href{http://projects.hepforge.org/frog/}{http://projects.hepforge.org/frog/}.
     934The available \texttt{C++}-code is compressed in a zipped tar file which contains everything needed to run the \textit{Delphes} package, assuming a running \textsc{ROOT} installation. The package includes \texttt{ExRootAnalysis}~\citep{bib:ExRootAnalysis}, \textit{Hector}~\citep{bib:hector}, FastJet~\citep{bib:FASTJET}, and \textsc{FROG}~\citep{bib:FROG}, as well as the conversion codes to read standard \mbox{StdHEP} input files (\texttt{mcfio} and \texttt{stdhep})~\citep{bib:mcfio} and HepMC~\citep{bib:hepmc}.
     935In order to visualise the events with the \textsc{FROG} software, a few additional external libraries may be required, as explained in \href{http://projects.hepforge.org/FROG/}{http://projects.hepforge.org/FROG/}.
    937936 
    938937\subsection{Getting started}
    939938 
    940 In order to run \textsc{Delphes} on your system, first download its sources and compile them:\\
     939In order to run \textit{Delphes} on your system, first download its sources and compile them:\\
    941940\texttt{wget http://www.fynu.ucl.ac.be/users/s.ovyn/Delphes/files/Delphes\_V\_*.tar.gz}\\
    942 Replace the \texttt{*} symbol by the proper version number\footnote{Refer to the download page on the \textsc{Delphes} website \href{http://www.fynu.ucl.ac.be/users/s.ovyn/Delphes/download.html}{http://www.fynu.ucl.ac.be/users/s.ovyn/Delphes/download.html}. Current version of \textsc{Delphes} for this manual is V 1.8 (July 2009)}.
    943 
    944 \begin{quote}
    945 \begin{verbatim}
    946 me@mylaptop:~$ tar -xvf Delphes_V_*.tar.gz 
     941Replace the \texttt{*} symbol by the proper version number\footnote{Refer to the download page on the \textit{Delphes} website \href{http://www.fynu.ucl.ac.be/users/s.ovyn/Delphes/download.html}{http://www.fynu.ucl.ac.be/users/s.ovyn/Delphes/download.html}. Current version of Delphes for this manual is V 1.8 (July 2009)}.
     942
     943\begin{quote}
     944\begin{verbatim}
     945me@mylaptop:~$ tar -xvf Delphes_V_*.tar.gz
    947946me@mylaptop:~$ cd Delphes_V_*.*
    948947me@mylaptop:~$ ./genMakefile.tcl > Makefile
    … …  
    950949\end{verbatim}
    951950\end{quote}
    952 Due to the large number of external utilities, the number of printed lines during the compilation can be high. The user should not pay attention to possible warning messages, which are due to the external packages used by \textsc{Delphes}. When compilation is completed, the following message is printed:
     951Due to the large number of external utilities, the number of printed lines during the compilation can be high. The user should not pay attention to possible warning messages, which are due to the external packages used by \textit{Delphes}. When compilation is completed, the following message is printed:
    953952\begin{quote}
    954953\begin{verbatim}
    … …  
    958957\end{quote}
    959958
    960 \subsection{Running \textsc{Delphes} on your events}
    961  
    962 In this sub-appendix, we will explain how to use \textsc{Delphes} to perform a fast simulation of a general-purpose detector on your event files. The first step to use \textsc{Delphes} is to create the list of input event files (e.g.\ {\verb inputlist.list }). It is important to notice that all the files comprised in the list file should have the same of extension (\texttt{*.hep}, \texttt{*.lhe}, \texttt{*.hepmc} or \texttt{*.root}). In the simplest way to run \textsc{Delphes}, you need this input file and you need to specify the name of the output file that will contain the generator-level data (\texttt{GEN} tree), the analysis data objects after reconstruction (\texttt{Analysis} tree), and the results of the trigger emulation (\texttt{Trigger} tree).
     959\subsection{Running \textit{Delphes} on your events}
     960 
     961In this sub-appendix, we will explain how to use \textit{Delphes} to perform a fast simulation of a general-purpose detector on your event files. The first step to use \textit{Delphes} is to create the list of input event files (e.g.\ {\verb inputlist.list }). It is important to notice that all the files comprised in the list file should have the same of extension (\texttt{*.hep}, \texttt{*.lhe}, \texttt{*.hepmc} or \texttt{*.root}). In the simplest way to run \textit{Delphes}, you need this input file and you need to specify the name of the output file that will contain the generator-level data (\texttt{GEN} tree), the analysis data objects after reconstruction (\texttt{Analysis} tree), and the results of the trigger emulation (\texttt{Trigger} tree).
    963962 
    964963\begin{quote}
    … …  
    970969\subsubsection{Setting up the configuration}
    971970 
    972 The program is driven by two datacards (default cards are {\verb data/DetectorCard.dat } and {\verb data/TriggerCard.dat }) which allow the user to choose among a large spectrum of running conditions. Please note that if the user does not provide these datacards, the running will be done using the default parameters defined in the constructor of the class \texttt{RESOLution} (see next). If you choose a different detector or running configuration, you will need to edit the datacards accordingly. Detector and trigger cards are provided in the \texttt{data/} subdirectory for the \textsc{cms} and \textsc{atlas} experiments.
     971The program is driven by two datacards (default cards are {\verb data/DetectorCard.dat } and {\verb data/TriggerCard.dat }) which allow the user to choose among a large spectrum of running conditions. Please note that if the user does not provide these datacards, the running will be done using the default parameters defined in the constructor of the class \texttt{RESOLution} (see next). If you choose a different detector or running configuration, you will need to edit the datacards accordingly. Detector and trigger cards are provided in the \texttt{data/} subdirectory for the \textsc{CMS} and \textsc{ATLAS} experiments.
    973972 
    974973\begin{enumerate}
    975974\item{\bf The detector card }
    976 It contains all pieces of information needed to run \textsc{Delphes}:
     975It contains all pieces of information needed to run \textit{Delphes}:
    977976\begin{itemize}
    978977 \item detector parameters, including calorimeter and tracking coverage and resolutions, transverse energy thresholds for object reconstruction and jet algorithm parameters.
    979  \item six flags ({\verb FLAG_bfield }, {\verb FLAG_vfd }, {\verb FLAG_RP }, {\verb FLAG_trigger }, {\verb FLAG_frog } and {\verb FLAG_lhco }), should be set in order to configure the magnetic field propagation, the very forward detectors simulation, the use of very forward taggers, the trigger selection, the preparation for \textsc{Frog} display and the creation of an output file in \texttt{*.lhco} text format (respectively).
     978 \item six flags ({\verb FLAG_bfield }, {\verb FLAG_vfd }, {\verb FLAG_RP }, {\verb FLAG_trigger }, {\verb FLAG_FROG } and {\verb FLAG_LHCO }), should be set in order to configure the magnetic field propagation, the very forward detectors simulation, the use of very forward taggers, the trigger selection, the preparation for \textsc{FROG} display and the creation of an output file in \texttt{*.LHCO} text format (respectively).
    980979 \end{itemize}
    981980 
    … …  
    11051104FLAG_RP          1     //1 to run the very forward detectors else 0
    11061105FLAG_trigger     1     //1 to run the trigger selection else 0
    1107 FLAG_frog        1     //1 to run the FROG event display
    1108 FLAG_lhco        1     //1 to run the LHCO
     1106FLAG_FROG        1     //1 to run the FROG event display
     1107FLAG_LHCO        1     //1 to run the LHCO
    11091108
    11101109# In case BField propagation allowed
    … …  
    11251124\begin{quote}
    11261125\begin{verbatim}
    1127 #Hector parameters
     1126#\textit{Hector} parameters
    11281127RP_220_s          220     // distance of the RP to the IP, in meters
    11291128RP_220_x          0.002   // distance of the RP to the beam, in meters
    … …  
    11321131RP_beam1Card      data/LHCB1IR5_v6.500.tfs // beam optics file, beam 1
    11331132RP_beam2Card      data/LHCB2IR5_v6.500.tfs // beam optics file, beam 2
    1134 RP_IP_name        IP5     // tag for IP in Hector ; 'IP1' for ATLAS
     1133RP_IP_name        IP5     // tag for IP in \textit{Hector} ; 'IP1' for ATLAS
    11351134RP_offsetEl_x     0.097   // horizontal separation between both beam, in meters
    11361135RP_offsetEl_y     0       // vertical separation between both beam, in meters
    … …  
    11431142
    11441143# In case FROG event display allowed
    1145 NEvents_Frog      100
     1144NEvents_FROG      100
    11461145# Number of events to process
    11471146NEvents           -1                    // -1 means 'all'
    … …  
    11541153
    11551154In general, energies, momenta and masses are expressed in GeV, GeV$/c$, GeV$/c^2$ respectively, and  magnetic fields in T.
    1156 Geometrical extension are often referred in terms of pseudorapidity $\eta$, as the detectors are supposed to be symmetric in $\phi$. From version 1.8 onwards, the number of events to run is also be included in the detector card (\texttt{NEvents}). For version 1.7 and earlier, the parameters related to the calorimeter endcaps (\texttt{CEN\_max\_calo\_ec}, \texttt{ELG\_Sec}, \texttt{ELG\_Nec}, \texttt{ELG\_Cec}, \texttt{HAD\_Sec}, \texttt{HAD\_Nec} and \texttt{HAD\_Cec}) did not exist in the detector cards; in addition, some other variables had different names (\texttt{HAD\_Scen} was \texttt{HAD\_Sfcal}, \texttt{HAD\_Ncen} was \texttt{HAD\_Nfcal}, \texttt{HAD\_Ccen} was \texttt{HAD\_Cfcal}, \texttt{HAD\_Sfwd} was \texttt{HAD\_Shf}, \texttt{HAD\_Nfwd} was \texttt{HAD\_Nhf}, \texttt{HAD\_Cfwd} was \texttt{HAD\_Chf}). However, these cards are still completely compatible with new versions of \textsc{Delphes}. In such a case, the calorimeter endcaps are simply assumed to be located at the edge of the central calorimeter volumes, with the same resolution values.
     1155Geometrical extension are often referred in terms of pseudorapidity $\eta$, as the detectors are supposed to be symmetric in $\phi$. From version 1.8 onwards, the number of events to run is also be included in the detector card (\texttt{NEvents}). For version 1.7 and earlier, the parameters related to the calorimeter endcaps (\texttt{CEN\_max\_calo\_ec}, \texttt{ELG\_Sec}, \texttt{ELG\_Nec}, \texttt{ELG\_Cec}, \texttt{HAD\_Sec}, \texttt{HAD\_Nec} and \texttt{HAD\_Cec}) did not exist in the detector cards; in addition, some other variables had different names (\texttt{HAD\_Scen} was \texttt{HAD\_Sfcal}, \texttt{HAD\_Ncen} was \texttt{HAD\_Nfcal}, \texttt{HAD\_Ccen} was \texttt{HAD\_Cfcal}, \texttt{HAD\_Sfwd} was \texttt{HAD\_Shf}, \texttt{HAD\_Nfwd} was \texttt{HAD\_Nhf}, \texttt{HAD\_Cfwd} was \texttt{HAD\_Chf}). However, these cards are still completely compatible with new versions of \textit{Delphes}. In such a case, the calorimeter endcaps are simply assumed to be located at the edge of the central calorimeter volumes, with the same resolution values.
    11571156 
    11581157\item{\bf The trigger card }
    11591158 
    1160 This card contains the definitions of all trigger-bits. Cuts can be applied on the transverse momentum $p_T$ of electrons, muons, jets, $\tau$-jets, photons and the missing transverse energy. The following codes should be used so that \textsc{Delphes} can correctly translate the input list of trigger-bits into selection algorithms:
     1159This card contains the definitions of all trigger-bits. Cuts can be applied on the transverse momentum $p_T$ of electrons, muons, jets, $\tau$-jets, photons and the missing transverse energy. The following codes should be used so that \textit{Delphes} can correctly translate the input list of trigger-bits into selection algorithms:
    11611160
    11621161\begin{quote}
    … …  
    11771176Each line in the trigger datacard is allocated to exactly one trigger-bit and starts with the name of the corresponding trigger.
    11781177Logical combination of several conditions is also possible. If the trigger-bit requires the presence of multiple identical objects, the order of their $p_T$ thresholds is very important: they must be defined in \textit{decreasing} order. The transverse momentum $p_T$ is expressed in \mbox{GeV/$c$}. Finally, the different requirements on the objects must be separated by a {\verb && } flag.
    1179 The default trigger card can be found in the data repository of \textsc{Delphes} (\texttt{data/TriggerCard.dat}), as well as for both \textsc{cms} and \textsc{atlas} experiments at the \textsc{lhc}.
     1178The default trigger card can be found in the data repository of \textit{Delphes} (\texttt{data/TriggerCard.dat}), as well as for both \textsc{CMS} and \textsc{ATLAS} experiments at the \textsc{LHC}.
    11801179An example of trigger table consistent with the previous rules is given here:
    11811180\begin{quote}
    … …  
    11911190 
    11921191First, create the detector and trigger cards (\texttt{data/DetectorCard.dat} and \texttt{data/TriggerCard.dat}). \\
    1193 Then, create a text file containing the list of input files that will be used by \textsc{Delphes} (with extension \texttt{*.lhe}, \texttt{*.hepmc}, \texttt{*.root} or \texttt{*.hep}).
     1192Then, create a text file containing the list of input files that will be used by \textit{Delphes} (with extension \texttt{*.lhe}, \texttt{*.hepmc}, \texttt{*.root} or \texttt{*.hep}).
    11941193To run the code, type the following command (in one line)
    11951194\begin{quote}
    11961195\begin{verbatim}
    1197 me@mylaptop:~$ ./Delphes inputlist.list OutputRootFileName.root 
     1196me@mylaptop:~$ ./Delphes inputlist.list OutputRootFileName.root
    11981197                         data/DetectorCard.dat data/TriggerCard.dat
    11991198\end{verbatim}
    … …  
    12131212 
    12141213 
    1215 \subsection{Getting the \textsc{Delphes} information}
    1216  
    1217 \subsubsection{Contents of the \textsc{Delphes} ROOT trees}
    1218  
    1219 The \textsc{Delphes} output file (\texttt{*.root}) is subdivided into three \textit{trees}, corresponding to generator-level data, analysis-object data and trigger output. These \textit{trees} are structures that organise the output data into \textit{branches} containing data (or \textit{leaves}) related with each others, like the kinematics properties ($E$, $p_x$, $\eta$, $\ldots$) of a given particle.
     1214\subsection{Getting the \textit{Delphes} information}
     1215 
     1216\subsubsection{Contents of the \textit{Delphes} ROOT trees}
     1217 
     1218The \textit{Delphes} output file (\texttt{*.root}) is subdivided into three \textit{trees}, corresponding to generator-level data, analysis-object data and trigger output. These \textit{trees} are structures that organise the output data into \textit{branches} containing data (or \textit{leaves}) related with each others, like the kinematics properties ($E$, $p_x$, $\eta$, $\ldots$) of a given particle.
    12201219
    12211220Here is the exhaustive list of \textit{branches} availables in these \textit{trees}, together with their corresponding physical objet and \texttt{ExRootAnalysis} C++ class name:
    12221221\begin{quote}
    12231222\begin{tabular}{lll}
    1224 {\bf GEN \textsc{tree}} & &\\
     1223\textbf{GEN \texttt{Tree}} & &\\
    12251224~~~Particle & generator particles from \textsc{hepevt}     & {\verb GenParticle }\\
    12261225\multicolumn{3}{l}{}\\
    1227 {\bf Trigger  \textsc{tree}} & &\\
     1226\textbf{Trigger  \texttt{Tree}} & &\\
    12281227~~~TrigResult & Acceptance of different trigger-bits       & {\verb TRootTrigger }\\
    12291228\multicolumn{3}{l}{}\\
    1230 {\bf Analysis \textsc{tree}} & & \\
     1229\textbf{Analysis \texttt{Tree}} & & \\
    12311230~~~Tracks     & Collection of tracks                       & {\verb TRootTracks }\\
    12321231~~~CaloTower  & Calorimetric towers                        & {\verb TRootCalo }\\
    … …  
    12421241\end{tabular}
    12431242\end{quote}
    1244 The third column shows the names of the corresponding classes to be written in a \textsc{root} tree.
     1243The third column shows the names of the corresponding classes to be written in a \textsc{ROOT} tree.
    12451244The bin number in the unique leaf in the \texttt{trigger} tree (namely, \texttt{TrigResult.Accepted}) corresponds to the trigger number in the provided list. In addition, the result of the global trigger decision upon each event (i.e.\ the logical \texttt{OR} of all trigger conditions) is stored in the first bin (number 0) of this leaf.
    12461245In \texttt{Analysis} tree, all classes except \texttt{TRootTracks}, \texttt{TRootCalo}, \texttt{TRootTrigger}, \texttt{TRootETmis} and \texttt{TRootRomanPotHits} inherit from the class \texttt{TRootParticle} which includes the following data members (stored as \textit{leaves} in \textit{branches} of the \textit{trees}):
    … …  
    13291328\end{quote}
    13301329
    1331 The hits in very forward detector (\textsc{zdc, rp220, fp420}) have some common data. In particular, the \texttt{side} variable tells in which detector (left:-1 or right:+1 of the interaction point) the hit has been seen. Moreover, some generator level data is provided for information, as the correspondance with the contents of the \texttt{GEN} tree is not possible. These generator-level data correspond to the particle kinematics (energy, momentum, angle) and identification (pid).
     1330The hits in very forward detector (\textsc{ZDC, RP220, FP420}) have some common data. In particular, the \texttt{side} variable tells in which detector (left:-1 or right:+1 of the interaction point) the hit has been seen. Moreover, some generator level data is provided for information, as the correspondance with the contents of the \texttt{GEN} tree is not possible. These generator-level data correspond to the particle kinematics (energy, momentum, angle) and identification (pid).
    13321331
    13331332\begin{quote}
    … …  
    13691368
    13701369 
    1371 \subsection{Running an analysis on your \textsc{Delphes} events}
    1372  
    1373 To analyse the \textsc{root} ntuple produced by \textsc{Delphes}, the simplest way is to use the {\verb Analysis_Ex.cpp } code which is coming in the {\verb Examples } repository of \textsc{Delphes}. Note that all of this is optional and done to facilitate the analyses, as the output from \textsc{Delphes} is viewable with the standard \textsc{root} \texttt{TBrowser} and can be analysed using the \texttt{MakeClass} facility.
    1374 As an example, here is a simple overview of a \texttt{myoutput.root} file created by \textsc{Delphes}:
     1370\subsection{Running an analysis on your \textit{Delphes} events}
     1371 
     1372To analyse the \textsc{ROOT} ntuple produced by \textit{Delphes}, the simplest way is to use the {\verb Analysis_Ex.cpp } code which is coming in the {\verb Examples } repository of \textit{Delphes}. Note that all of this is optional and done to facilitate the analyses, as the output from \textit{Delphes} is viewable with the standard \textsc{ROOT} \texttt{TBrowser} and can be analysed using the \texttt{MakeClass} facility.
     1373As an example, here is a simple overview of a \texttt{myoutput.root} file created by \textit{Delphes}:
    13751374\begin{quote}
    13761375\begin{verbatim}
    … …  
    14401439For more information, refer to ROOT documentation. Moreover, an example of code (based on the output of \texttt{MakeClass}) is provided in the \texttt{Examples/} directory.
    14411440
    1442 To run the \texttt{Examples/Analysis\_Ex.cpp} code, the two following arguments are required: a text file containing the input \textsc{Delphes} \textsc{root} files to run, and the name of the output \textsc{root} file.
     1441To run the \texttt{Examples/Analysis\_Ex.cpp} code, the two following arguments are required: a text file containing the input \textit{Delphes} \texttt{root} files to run, and the name of the output \texttt{root} file.
    14431442 \begin{quote}
    14441443\begin{verbatim}
    … …  
    14491448
    14501449\subsubsection{Adding the trigger information}
    1451 The \texttt{Examples/Trigger\_Only.cpp} code permits to run the trigger selection separately from the general detector simulation on output \textsc{Delphes} root files. A \textsc{Delphes} root file is mandatory as an input argument for the \texttt{Trigger\_Only} routine. The new \textit{tree} containing the trigger result data will be appended to this file.
     1450The \texttt{Examples/Trigger\_Only.cpp} code permits to run the trigger selection separately from the general detector simulation on output \textit{Delphes} root files. A \textit{Delphes} \texttt{root} file is mandatory as an input argument for the \texttt{Trigger\_Only} routine. The new \textit{tree} containing the trigger result data will be appended to this file.
    14521451The trigger datacard is also necessary. To run the code:
    14531452 \begin{quote}
    … …  
    14601459 
    14611460\begin{itemize}
    1462 \item If the { \verb FLAG_frog } was switched on in the smearing card, two files have been created during the running of \textsc{Delphes}: {\verb DelphesToFrog.vis } and {\verb DelphesToFrog.geom }. They contain all the needed pieces of information to run \textsc{frog}.
    1463 \item To display the events and the geometry, you first need to compile \textsc{Frog}. Go to the {\verb Utilities/FROG } and type {\verb make }. This compilation is done once for all, with this geometry (i.e.\ as long as the \texttt{*vis} and \texttt{*geom} files do not change).
     1461\item If the { \verb FLAG_FROG } was switched on in the smearing card, two files have been created during the running of \textit{Delphes}: \texttt{DelphesToFROG.vis} and \texttt{DelphesToFROG.geom }. They contain all the needed pieces of information to run \textsc{FROG}.
     1462\item To display the events and the geometry, you first need to compile \textsc{FROG}. Go to the {\verb Utilities/FROG } and type {\verb make }. This compilation is done once for all, with this geometry (i.e.\ as long as the \texttt{*vis} and \texttt{*geom} files do not change).
    14641463\item Go back into the main directory and type
    14651464\begin{quote}
    1466 \texttt{me@mylaptop:~\$ ./Utilities/FROG/frog}
     1465\texttt{me@mylaptop:~\$ ./Utilities/FROG/FROG}
    14671466\end{quote}
    14681467\end{itemize}
    14691468
    14701469\subsection{LHCO file format}
    1471  The \texttt{*lhco} file format is a text-\textsc{ascii} data format briefly discussed here. An exhaustive description is provided on \href{http://v1.jthaler.net/olympicswiki}{http://v1.jthaler.net/olympicswiki}. This section is based on this webpage.
    1472 Only final high-level objects are available in the \texttt{lhco} format, and their properties are arranged in columns. Each row corresponds to an object in the event and all events are written after each other. Comment-lines starts with a hash \texttt{\#} symbol.
     1470 The \texttt{*LHCO} file format is a text-\textsc{ASCII} data format briefly discussed here. An exhaustive description is provided on \href{http://v1.jthaler.net/olympicswiki}{http://v1.jthaler.net/olympicswiki}. This section is based on this webpage.
     1471Only final high-level objects are available in the \texttt{LHCO} format, and their properties are arranged in columns. Each row corresponds to an object in the event and all events are written after each other. Comment-lines starts with a hash \texttt{\#} symbol.
    14731472
    14741473\begin{verbatim}
    … …  
    14841483\end{verbatim}
    14851484Each row in an event starts with a unique number (i.e.\ in first column).
    1486 Row \texttt{0} contains the event number (here: \texttt{57}) and some trigger information (here: \texttt{0}. This very particular trigger encoding is not implemented in \textsc{Delphes}.).
     1485Row \texttt{0} contains the event number (here: \texttt{57}) and some trigger information (here: \texttt{0}. This very particular trigger encoding is not implemented in \textit{Delphes}.).
    14871486Subsequent rows list the reconstructed high-level objects.
    14881487Each row is organised in columns, which details the object kinematics as well as more specific information, such as isolation criteria or $b$-tagging.
    … …  
    15281527
    15291528\paragraph{Warning}
    1530 Inherently to the data format itself, the \texttt{*lhco} output contains only a fraction of the available data. Moreover, dealing with text file may have various drawbacks, such as the output file size and the time needed for its creation. Whenever possible, working on the \texttt{*root} output file should be preferred.
     1529Inherently to the data format itself, the \texttt{*LHCO} output contains only a fraction of the available data. Moreover, dealing with text file may have various drawbacks, such as the output file size and the time needed for its creation. Whenever possible, working on the \texttt{*root} output file should be preferred.
    15311530
    15321531\end{document}
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