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Changeset 326 in svn


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Timestamp:
Mar 11, 2009, 11:33:20 PM (16 years ago)
Author:
Xavier Rouby
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merge versions 1.35 et 1.36

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trunk/paper
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2 edited

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  • trunk/paper/notes.tex

    r325 r326  
    2929  \pdfinfo{
    3030   /Author (S. Ovyn, X. Rouby, V. Lemaitre)
    31    /Title  (Delphes, a framework for fast simulation of a general-purpose LHC detector)
     31   /Title  (Delphes, a framework for fast simulation of a generic collider experiment)
    3232   /Subject ()
    33    /Keywords (Delphes, Fast simulation, LHC, FROG, Hector, Smearing, FastJet)}
     33   /Keywords (Delphes, Fast simulation, smearing, reconstruction, trigger, event display, LHC, Hector, FastJet, Frog)}
    3434\else
    3535   \usepackage[dvips]{graphicx}
    … …  
    6060\begin{abstract}
    6161It 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.
    62 We introduce here a new \texttt{C++}-basedframework, \textsc{Delphes}, for fast simulation of
     62We introduce here a new \texttt{C++}-based framework, \textsc{Delphes}, for fast simulation of
    6363a general-purpose experiment. The simulation includes a tracking system, embedded into a magnetic field, calorimetry and a muon
    6464system, and possible very forward detectors arranged along the beamline.
    … …  
    6969
    7070\noindent
    71 \textit{Keywords:} \textsc{Delphes}, fast simulation, \textsc{lhc}, smearing, trigger, \textsc{FastJet}, \textsc{Hector}, \textsc{Frog}\\
     71\textit{Keywords:} \textsc{Delphes}, fast simulation, trigger, event display, \textsc{lhc}, \textsc{FastJet}, \textsc{Hector}, \textsc{Frog}\\
    7272\href{http://www.fynu.ucl.ac.be/delphes.html}{http://www.fynu.ucl.ac.be/delphes.html}\\
    7373\textit{Preprint:} \texttt{CP3-09-01}
    … …  
    8080
    8181\section{Introduction}
    82 % Motiver l'utilisation d'un simulateur rapide
    83 % - 1) rapide VS lent
    84 % - 2) relativement bonne prédiction en premiÚre approximation
    85 % - 3) permet de comparer
    8682
    8783Experiments at high energy colliders are very complex systems for several reasons. Firstly, in terms of the various detector subsystems, including tracking, central calorimetry, forward calorimetry, and muon chambers. Such apparatus differ in their detection principles, technologies, geometrical acceptances, resolutions and sensitivities. Secondly, due to the requirement of a highly effective online selection (i.e. a \textit{trigger}), subdivided into several levels for an optimal reduction factor of ``uninteresting'' events, but based only on partially processed data. Finally, in terms of the experiment software, with different data formats (like \textit{raw} or \textit{reconstructed} data), many reconstruction algorithms and particle identification approaches.
    … …  
    9187A new framework, called \textsc{Delphes}~\cite{bib:Delphes}, is introduced here, for the fast simulation of a general-purpose collider experiment.
    9288Using the framework, observables can be estimated for specific signal and background channels, as well as their production and measurement rates.
    93 Starting 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.
     89Starting 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.
    9490
    9591\textsc{Delphes} includes the most crucial experimental features, such as (Fig.~\ref{fig:FlowChart}):
    … …  
    108104\caption{Flow chart describing the principles behind \textsc{Delphes}. Event files coming from external Monte Carlo generators are read by a converter stage (top).
    109105The kinematics variables of the final-state particles are then smeared according to the tunable subdetector resolutions.
    110 Tracks are reconstructed in a simulated dipolar 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.
     106Tracks 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.
    111107The transport of very forward particles to the near-beam detectors is also simulated.
    112 Finally, an output file is written, including generator-level and analysis-object data. If requested, a fully parametrisable trigger can be emulated. Optionally, the geometry and visualisation files for the 3D event display can also be produced.
    113 All user parameters are set in the \textit{Smearing Card} and the \textit{Trigger Card}. }
     108Finally, an output file is written, including generator-level and analysis-object data.
     109If requested, a fully parametrisable trigger can be emulated. Optionally, the geometry and visualisation files for the 3D event display can also be produced.
     110All user parameters are set in the \textit{Detector/Smearing Card} and the \textit{Trigger Card}. }
    114111\label{fig:FlowChart}
    115112\end{center}
    … …  
    122119
    123120\textsc{Delphes} uses the \texttt{ExRootAnalysis} utility~\cite{bib:ExRootAnalysis} to create output data in a \texttt{*.root} ntuple.
    124 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). The program is driven by input cards. The detector card (\texttt{data/DataCardDet.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/trigger.dat}) lists the user algorithms for the simplified online preselection.\\
     121This 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).
     122In 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.
     123
     124The 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
     125preselection.
    125126
    126127
    … …  
    129130The overall layout of the general-purpose detector simulated by \textsc{Delphes} is shown in Fig.~\ref{fig:GenDet3}.
    130131A central tracking system (\textsc{tracker}) is surrounded by an electromagnetic and a hadron calorimeters (\textsc{ecal} and \textsc{hcal}, resp.). 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
    131 The fast simulation of the detector response takes into account geometrical acceptance of sub-detectors and their finite resolution, as defined in the smearing data card\footnote{\texttt{[code] }See the \texttt{RESOLution} class.}.
    132 If no such file is provided, predefined values based on ``typical'' \textsc{cms} acceptances and resolutions are used. The geometrical coverage of the various subsystems used in the default configuration are summarised in Tab.~\ref{tab:defEta}.
     132The 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.}.
     133If 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}.
    133134
    134135\begin{table*}[t]
    … …  
    136137\caption{Default extension in pseudorapidity $\eta$ of the different subdetectors.
    137138Full azimuthal ($\phi$) acceptance is assumed.
    138 The corresponding parameter name, in the smearing card, is given. \vspace{0.5cm}}
     139The corresponding parameter name, in the detector card, is given. \vspace{0.5cm}}
    139140\begin{tabular}{llcc}
    140141\hline
    … …  
    164165
    165166\subsubsection*{Magnetic field}
    166 In addition to the subdetectors, the effects of a dipolar magnetic field is simulated for the charged particles\footnote{\texttt{[code] }See the \texttt{TrackPropagation} class.}. This affects the position at which charged particles enter the calorimeters.
     167In addition to the subdetectors, the effects of a solenoidal magnetic field is simulated for the charged particles\footnote{\texttt{[code] }See the \texttt{TrackPropagation} class.}. This affects the position at which charged particles enter the calorimeters and their corresponding tracks.
    167168
    168169
    … …  
    170171\subsection{Tracks reconstruction}
    171172Every stable charged particle with a transverse momentum above some threshold and lying inside the detector volume covered by the tracker provides a track.
    172 By default, a track is assumed to be reconstructed with $90\%$ probability\footnote{\texttt{[code]} The reconstruction efficiency is defined in the smearing datacard by the \texttt{TRACKING\_EFF} term.} if its transverse momentum $p_T$ is higher than $0.9~\textrm{GeV}/c$ and if its pseudorapidity $|\eta| \leq 2.5$.
     173By default, a track is assumed to be reconstructed with $90\%$ probability\footnote{\texttt{[code]} The reconstruction efficiency is defined in the detector datacard by the \texttt{TRACKING\_EFF} term.} if its transverse momentum $p_T$ is higher than $0.9~\textrm{GeV}/c$ and if its pseudorapidity $|\eta| \leq 2.5$.
    173174
    174175
    … …  
    186187The particle four-momentum $p^\mu$ are smeared with a parametrisation directly derived from typical detector technical designs\footnote{\texttt{[code] }~\cite{bib:cmsjetresolution,bib:ATLASresolution}. The response of the detector is applied to the electromagnetic and the hadronic particles through the \texttt{SmearElectron} and \texttt{SmearHadron} functions.}.
    187188In 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.
    188 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.}.
     189Muons and neutrinos are assumed not to interact with the calorimeters\footnote{In the current \textsc{Delphes} version, particles other thand 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.}.
    189190The default values of the stochastic, noise and constant terms are given in Tab.~\ref{tab:defResol}.\\
    190191
    … …  
    192193\begin{center}
    193194\caption{Default values for the resolution of the central and forward calorimeters. Resolution is parametrised by the \textit{stochastic} ($S$), \textit{noise} ($N$) and \textit{constant} ($C$) terms (Eq.~\ref{eq:caloresolution}).
    194 The corresponding parameter name, in the smearing card, is given. \vspace{0.5cm}}
     195The corresponding parameter name, in the detector card, is given. \vspace{0.5cm}}
    195196\begin{tabular}[!h]{lllc}
    196197\hline
    … …  
    229230\end{equation}
    230231where $0 \leq F \leq 1$. The electromagnetic part is handled the same way for the electrons and photons.
    231 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, the energy fraction is $F$ is assumed to be $0.7$.\\
     232The 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 $0.7$.\\
    232233
    233234\subsection{Calorimetric towers}
    234235
    235236The 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}.
    236 As the detector is assumed to be cylindical (e.g. symmetric in $\phi$ and with respect to the $\eta=0$ plane), the smearing 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 segmentation of the $(\eta,\phi)$ plane.
     237As the detector is assumed to be cylindical (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 segmentation of the $(\eta,\phi)$ plane.
    237238
    238239\begin{figure}[!h]
    … …  
    244245\end{figure}
    245246
    246 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.
     247The 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.
    247248
    248249\subsection{Very forward detectors simulation}
    … …  
    306307\subsection{Photon and charged lepton reconstruction}
    307308From here onwards, \textit{electrons} refer to both positrons ($e^+$) and electrons ($e^-$), and $\textit{charged leptons}$ refer to electrons and muons ($\mu^\pm$), leaving out the $\tau^\pm$ leptons as they decay before being detected.
     309
    308310\subsubsection*{Electrons and photons}
    309311Electron ($e^\pm$) 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, an electrons will leave in addition a track. Subsequently, electrons and photons create a candidate in the jet collection.
     312Assuming 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.
    310313
    311314\subsubsection*{Muons}
    312 
    313315Generator-level muons entering the detector acceptance are considered as candidates for the analysis level.
    314316The 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: $-2.4 \leq \eta \leq 2.4$).
    315 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. In addition, multiple scattering is also neglected. This implies that low energy muons have in \textsc{Delphes} a better resolution than in a real detector. Moreover, muons leave no deposit in calorimeters.
     317The 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.
    316318
    317319\subsubsection*{Charged lepton isolation}
    318320
    319 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. The result (i.e. \textit{isolated} or \textit{not}) is added to the charged lepton measured properties\footnote{\texttt{[code] }See the \texttt{IsolFlag} output of the \texttt{Electron} or \texttt{Muon} collections in the \texttt{Analysis} tree.}. No calorimetric isolation is applied. \\
    320 
     321To 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.
     322The result (i.e. \textit{isolated} or \textit{not}) is added to the charged lepton measured properties.
     323In addition, the sum $P_T$ of the transverse momenta of all tracks but the lepton one within the isolation cone is
     324provided\footnote{\texttt{[code] }See the \texttt{IsolFlag} and \texttt{IsolPt} values in the \texttt{Electron} or \texttt{Muon} collections in the \texttt{Analysis} tree, as well as the \texttt{ISOL\_PT} and \texttt{ISOL\_Cone} variables in the detector card.}:
     325$$ P_T = \sum_{i \neq \mu}^\textrm{tracks} p_T(i)$$
     326
     327No calorimetric isolation is applied, but the muon collection contains also the ratio $\rho_\mu$ between (1) the sum of the transverse energies in all calotowers in a $N \times N$ grid around the muon, and (2) the muon transverse
     328momentum\footnote{\texttt{[code] }Calorimetric isolation parameters in the detector card are \texttt{ISOL\_Calo\_ET} and  \texttt{ISOL\_Calo\_Grid}.}:
     329$$ \rho_\mu = \frac{\Sigma_i E_T(i)}{p_T(\mu)}~,~ i\textrm{ in }N \times N \textrm { grid centered on }\mu.$$
    321330
    322331
    … …  
    328337
    329338A 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~\cite{bib:FastJet}.
    330 Six different jet reconstruction schemes are available\footnote{\texttt{[code] }The choice is done by allocating the \texttt{JET\_jetalgo } input parameter in the smearing 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.
     339Six 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.
    331340By default, reconstruction uses a cone algorithm with $\Delta R=0.7$.
    332 Jets are stored if their transverse energy is higher\footnote{\texttt{[code] PTCUT\_jet }variable in the smearing card.} than $20~\textrm{GeV}$.
     341Jets are stored if their transverse energy is higher\footnote{\texttt{[code] PTCUT\_jet }variable in the detector card.} than $20~\textrm{GeV}$.
    333342 
    334343\subsubsection*{Cone algorithms}
    … …  
    340349All 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.
    341350The existing \textsc{FastJet} code has been modified to allow easy modification of the tower pattern in $\eta$, $\phi$ space.
    342 In the 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 smearing card.}.
     351In the 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.}.
    343352 
    344353\item {\it CDF MidPoint}~\cite{bib:midpoint}: Algorithm developed for the \textsc{cdf} Run II to reduce infrared and collinear sensitivity compared to purely seed-based cone by adding `midpoints' (energy barycentres) in the list of cone seeds.
    … …  
    385394\subsection{$b$-tagging}
    386395
    387 A 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{TAGGING\_B}, \texttt{MISTAGGING\_C} and \texttt{MISTAGGING\_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.}
    388 %(Fig.~\ref{fig:btag})
    389 .
     396A 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.}.
    390397The (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 $0.7$).
    391 
    392 %\begin{figure}[!h]
    393 %\begin{center}
    394 %\includegraphics[width=0.6\columnwidth]{btag}
    395 %\caption{Default efficiency of $b$-tag for jets coming from $b$ quarks, $c$ quarks and from other particles (jets from gluons or $u$, $d$ and $s$ quarks).}
    396 %\label{fig:btag}
    397 %\end{center}
    398 %\end{figure}
    399 
    400398
    401399\subsection{\texorpdfstring{$\tau$}{\texttau} identification}
    … …  
    528526Most 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 $p_T^e > 50~\textrm{GeV}/c$.
    529527
    530 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/trigger.dat} file.}. When enabled, this trigger is applied on analysis-object data.
     528A 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.
    531529In a real experiment, the online selection is often divided into several steps (or \textit{levels}).
    532530This splits the overall reduction factor into a product of smaller factors, corresponding to the different trigger levels.
    … …  
    608606The resolution $\sigma_x$ of the horizontal component of \textsc{met} is observed to behave like
    609607\begin{equation}
    610 \sigma_x = \alpha ~\sqrt(E_T) ~~~(\mathrm{GeV}^{1/2}),
     608\sigma_x = \alpha ~\sqrt{E_T}~~~(\mathrm{GeV}^{1/2}),
    611609\end{equation}
    612610where the $\alpha$ parameter depends on the resolution of the calorimeters.
    613611
    614 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.}~\cite{bib:cmsjetresolution}, which compares very well with the $\alpha = 0.68$ obtained with \textsc{Delphes}.
     612The \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.}~\cite{bib:cmsjetresolution}, which compares very well with the $\alpha = 0.68$ obtained with \textsc{Delphes}.
    615613
    616614\subsection{\texorpdfstring{$\tau$}{\texttau}-jet efficiency}
    … …  
    647645% The outer layer of the central system (red) consist of a muon system.
    648646% In addition, two end-cap calorimeters (blue) extend the pseudorapidity coverage of the central detector.
    649 % The actual detector granularity and extension is defined in the smearing card.
     647% The actual detector granularity and extension is defined in the detector card.
    650648% The detector is assumed to be strictly symmetric around the beam axis (black line).
    651649% Additional forward detectors are not depicted.}
    … …  
    755753P. Demin, (2006), unpublished. Now part of \textsc{MadGraph/MadEvent}.
    756754\bibitem{bib:cmsjetresolution} The CMS Collaboration, \textbf{CERN/LHCC} \\ \href{http://documents.cern.ch/cgi-bin/setlink?base=lhcc&categ=public&id=lhcc-2006-001}{2006-001}.
    757 \bibitem{bib:ATLASresolution} The ATLAS Collaboration, \\ arXiv:\href{http://arxiv.org/abs/arxiv:0901.0512}{0901.0512v1}[hep-ex].
     755\bibitem{bib:ATLASresolution} The ATLAS Collaboration, \textbf{CERN-OPEN} 2008-020, arXiv:\href{http://arxiv.org/abs/arxiv:0901.0512}{0901.0512v1}[hep-ex].
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    783781\bibitem{bib:papierquisortirajamais}J. de Favereau~et~al, \textbf{CP3-08-04} (2008), to be published in EPJ.
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    785 \bibitem{bib:papiersimon} "Phenomenology of a twisted two-Higgs-doublet model", Simon de Visscher, Jean-Marc Gerard, Michel Herquet, Vincent Lemaitre, Fabio Maltoni, to be published.
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    787785\bibitem{bib:mcfio} P. Lebrun, L. Garren, Copyright (c) 1994-1995 Universities Research Association, Inc.
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