Fork me on GitHub

Changeset 441 in svn for trunk/paper


Ignore:
Timestamp:
Jun 17, 2009, 11:57:53 PM (15 years ago)
Author:
Xavier Rouby
Message:

update

Location:
trunk/paper
Files:
3 edited

Legend:

Unmodified
Added
Removed
  • trunk/paper/CommPhysComp/notes.tex

    r426 r441  
    274274%\includegraphics[width=\columnwidth]{calosegmentation}
    275275\includegraphics[width=\columnwidth]{fig4}
    276 \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 expressend in radians.}
     276\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.}
    277277\label{fig:calosegmentation}
    278278\end{center}
     
    10701070# In case FROG event display allowed
    10711071NEvents_Frog      100
     1072# Number of events to process
     1073NEvents           -1                    // -1 means 'all'
    10721074
    10731075# input PDG tables
     
    10771079
    10781080In general, energies, momenta and masses are expressed in GeV, GeV$/c$, GeV$/c^2$ respectively, and  magnetic fields in T.
    1079 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 will also be included in the detector card (\texttt{NEvents}).
     1081Geometrical extension are often referred in terms of pseudorapidity $\eta$, as the detectors are supposed to be symmetric in $\phi$. The number of events to run is also included in the detector card (\texttt{NEvents}).
    10801082 
    10811083\item{\bf The trigger card }
  • trunk/paper/notes.tex

    r343 r441  
    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.
    65 The framework is interfaced to standard file formats (e.g. Les Houches Event File) and outputs observable objects for analysis, like missing transverse energy and collections of electrons or jets.
     65The 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.
    6666The 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.
    6767An overview of \textsc{Delphes} is given as well as a few \textsc{lhc} use-cases for illustration.
     
    8181\section{Introduction}
    8282
    83 Experiments 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.
     83Experiments 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.
    8484
    8585This 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.
     
    115115Although 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.
    116116
    117 Three dataformat files can be used as input in \textsc{Delphes}\footnote{\texttt{[code] }See the \texttt{HEPEVTConverter}, \texttt{LHEFConverter} and \texttt{STDHEPConverter} classes.}. In order to process events from many different generators, the standard Monte Carlo event structure \texttt{StdHEP}~\cite{bib:stdhep} can be used as an input. Besides, \textsc{Delphes} can also provide detector response for events read in ``Les Houches Event Format'' (\textsc{lhef}~\cite{bib:lhe}) and \textsc{root} files obtained from \textsc{.hbook} using the \texttt{h2root} utility from the \textsc{root} framework~\cite{bib:Root}.
     117Four 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 structure \texttt{StdHEP}~\cite{bib:stdhep} can be used as an input. Besides, \textsc{Delphes} can also provide detector response for events read in ``Les Houches Event Format'' (\textsc{lhef}~\cite{bib:lhe}) and \textsc{root} files obtained from \textsc{.hbook} using the \texttt{h2root} utility from the \textsc{root} framework~\cite{bib:Root}.
    118118%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.
    119119
     
    143143\textsc{tracker}        & {\verb CEN_max_tracker }      & $[-2.5; 2.5]$         & $[-\pi ; \pi]$\\
    144144\textsc{ecal}, \textsc{hcal} & {\verb CEN_max_calo_cen }& $[-3.0 ; 3.0]$        & $[-\pi ; \pi]$\\
    145 \textsc{fcal}           & {\verb CEN_max_calo_fwd }     & $[-5 ; 3]$ \& $[3 ;5]$     & $[-\pi ; \pi]$\\
     145\textsc{fcal}           & {\verb CEN_max_calo_fwd }     & $[-5 ; -3]$ \& $[3 ;5]$     & $[-\pi ; \pi]$\\
    146146\textsc{muon}           & {\verb CEN_max_mu }           & $[-2.4 ; 2.4]$        & $[-\pi ; \pi]$\\ \hline
    147147\end{tabular}
     
    165165
    166166\subsubsection*{Magnetic field}
    167 In 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.
     167In addition to the subdetectors, the effects of a solenoidal magnetic field are 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.
    168168
    169169
     
    174174
    175175
    176 \subsection{Simulation of calorimeters}
     176\subsection{Simulation of central calorimeters}
    177177
    178178The 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.
     
    211211 \multicolumn{4}{l}{\textsc{fcal}, hadronic part} \\
    212212        & $S$ (GeV$^{1/2}$)& {\verb HAD_Shf }   & $2.7$\\
    213         & $N$ (GeV)& {\verb HAD_Nhf }   & $0$. \\
     213        & $N$ (GeV)& {\verb HAD_Nhf }   & $0$ \\
    214214        & $C$ & {\verb HAD_Chf }   & $0.13$\\
    215215\hline
     
    235235
    236236The 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}.
    237 As 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 segmentation of the $(\eta,\phi)$ plane.
     237As 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 segmentation of the $(\eta,\phi)$ plane.
    238238
    239239\begin{figure}[!h]
    240240\begin{center}
    241241\includegraphics[width=\columnwidth]{calosegmentation}
    242 \caption{Default segmentation of the calorimeters in the $(\eta,\phi)$ plane. Only the central detectors (\textsc{ecal}, \textsc{hcal}) and \textsc{fcal} are considered.}
     242\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.}
    243243\label{fig:calosegmentation}
    244244\end{center}
     
    250250
    251251Most 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.
    252 Zero Degree Calorimeters (\textsc{zdc}) are located at zero angle, i.e. are aligned with the beamline axis at the interaction point, and placed beyond the point where the paths of incoming and outgoing beams separate (Fig.~\ref{fig:fdets}). 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}).
     252Zero Degree Calorimeters (\textsc{zdc}) are located at zero angle, i.e.\ are aligned with the beamline axis at the interaction point, and placed beyond the point where the paths of incoming and outgoing beams separate (Fig.~\ref{fig:fdets}). 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}).
    253253Forward 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. To be able to reach these detectors, such particles must have a charge identical to the beam particles, and a momentum very close to the nominal value for 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}).
    254254
     
    288288 t = t_0 + \frac{1}{v} \times \Big( \frac{s-z}{\cos \theta}\Big),
    289289\end{equation}
    290 where $t$ is the time of flight, $t_0$ is 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 from which the particle comes from, $\theta$ is the particle emission angle. This assumes 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 $1 - \cos \theta < 10^{-4}$.
     290where $t$ is the time of flight, $t_0$ is 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 from which the particle comes from, $\theta$ is the particle emission angle. This assumes 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 $1 - \cos \theta < 10^{-4}$.
    291291The formula then reduces to
    292292\begin{equation}
    293293 t = \frac{1}{c} \times (s-z)
    294294\end{equation}
    295 For example, a photon takes $0.47~\mu\textrm{s}$ to reach a \textsc{zdc} located at $s=140~\textrm{m}$, neglecting $z$ and $\theta$, and assuming that $v=c$. Only neutrons and photons are currently assumed to be able to reach the \textsc{zdc}. All other particles are neglected in the \textsc{zdc}.
     295For example, a photon takes $0.47~\mu\textrm{s}$ to reach a \textsc{zdc} located at $s=140~\textrm{m}$, neglecting $z$ and $\theta$, and assuming that $v=c$. Only neutrons and photons are currently assumed to be able to reach the \textsc{zdc}. All other particles are neglected in the \textsc{zdc}. 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 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.
     296
     297\begin{table}[!h]
     298\begin{center}
     299\caption{Default values for the resolution of the zero degree calorimeters. Resolution is parametrised by the \textit{stochastic} ($S$), \textit{noise} ($N$) and \textit{constant} ($C$) terms (Eq.~\ref{eq:caloresolution}).
     300 The corresponding parameter name, in the detector card, is given. \vspace{0.5cm}}
     301\begin{tabular}[!h]{lllc}
     302 \hline
     303 \multicolumn{2}{c}{Resolution Term}   & Card flag & Value\\\hline
     304 \multicolumn{4}{l}{\textsc{zdc}, electromagnetic part} \\
     305         & $S$ (GeV$^{1/2}$)& {\verb ELG_Szdc }  & $0.7$ \\
     306         & $N$ (GeV)& {\verb ELG_Nzdc }  & $0.0$ \\
     307         & $C$ & {\verb ELG_Czdc }  & $0.08$ \\
     308 \multicolumn{4}{l}{\textsc{zdc}, hadronic part} \\
     309         & $S$ (GeV$^{1/2}$)& {\verb HAD_Szdc }   & $1.38$\\
     310         & $N$ (GeV)& {\verb HAD_Nzdc }   & $0$ \\
     311         & $C$ & {\verb HAD_Czdc }   & $0.13$\\
     312 \hline
     313\end{tabular}
     314\label{tab:defResolZdc}
     315\end{center}
     316\end{table}
     317
    296318
    297319\section{High-level object reconstruction}
     
    321343
    322344To 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.
    323 The result (i.e. \textit{isolated} or \textit{not}) is added to the charged lepton measured properties.
     345The result (i.e.\ \textit{isolated} or \textit{not}) is added to the charged lepton measured properties.
    324346In addition, the sum $P_T$ of the transverse momenta of all tracks but the lepton one within the isolation cone is
    325347provided\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.}:
     
    330352$$ \rho_\mu = \frac{\Sigma_i E_T(i)}{p_T(\mu)}~,~ i\textrm{ in }N \times N \textrm { grid centred on }\mu.$$
    331353
    332 
    333 
    334 
     354\subsubsection*{Forward neutrals}
     355
     356The 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).
    335357
    336358
     
    349371This so-called \textsc{Jetclu} cone jet algorithm is used by the \textsc{cdf} experiment in Run II.
    350372All 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.
    351 The existing \textsc{FastJet} code has been modified to allow easy modification of the tower pattern in $\eta$, $\phi$ space.
    352 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 detector card.}.
    353  
    354 \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.
     373The existing \textsc{FastJet} code has been modified to allow easy modification of the tower pattern in ($\eta$, $\phi$) space.
     374In 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.}.
     375 
     376\item {\it CDF MidPoint}~\cite{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.
    355377 
    356378\item {\it Seedless Infrared Safe Cone}~\cite{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.
     
    391413\end{enumerate}
    392414 
    393 
     415\subsubsection*{Energy flow}
     416
     417In 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.
    394418 
    395419\subsection{$b$-tagging}
    396420
    397 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{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.}.
    398 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 $0.7$).
     421A 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.}.
     422The (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.
    399423
    400424\subsection{\texorpdfstring{$\tau$}{\texttau} identification}
    401425
    402 Jets originating from $\tau$-decays are identified using an identification procedure consistent with the one applied in a full detector simulation~\cite{bib:cmsjetresolution}.
     426Jets originating from $\tau$-decays are identified using a procedure consistent with the one applied in a full detector simulation~\cite{bib:cmsjetresolution}.
    403427The tagging relies on two properties of the $\tau$ lepton. First, $77\%$ of the $\tau$ hadronic decays contain only one charged hadron associated to a few neutrals (Tab.~\ref{tab:taudecay}). Tracks are useful for this criterion. Secondly, the particles arisen from the $\tau$ lepton produce narrow jets in the calorimeter (this is defined as the jet \textit{collimation}).
    404428
     
    406430\begin{table}[!h]
    407431\begin{center}
    408 \caption{ Branching rations for $\tau^-$ lepton~\cite{bib:pdg}. $h^\pm$ and $h^0$ refer to charged and neutral hadrons, respectively. $n \geq 0$ and $m \geq 0$ are integers.
     432\caption{ Branching ratios for $\tau^-$ lepton~\cite{bib:pdg}. $h^\pm$ and $h^0$ refer to charged and neutral hadrons, respectively. $n \geq 0$ and $m \geq 0$ are integers.
    409433\vspace{0.5cm}  }
    410434\begin{tabular}[!h]{ll}
     
    426450\begin{center}
    427451\includegraphics[width=0.6\columnwidth]{Tau}
    428 \caption{Illustration of the identification of $\tau$-jets. The jet cone is narrow and contains only one track. The small cone shown as the red one is used for the \textit{electromagnetic collimation}, while the green cone is the cone radius used to reconstruct the jet originating from the $\tau$-decay.}
     452\caption{Illustration of the identification of $\tau$-jets ($1-$prong). The jet cone is narrow and contains only one track. The small cone shown as the red one is used for the \textit{electromagnetic collimation}, while the green cone is the cone radius used to reconstruct the jet originating from the $\tau$-decay.}
    429453\label{h_WW_ss_cut1}
    430454\end{center}
     
    445469\multicolumn{3}{l}{\textbf{Tracking isolation}} \\
    446470$R^\textrm{tracks}$ & \texttt{TAU\_track\_scone} & $0.4$\\
    447 min $p_T^{tracks}$      & \texttt{PTAU\_track\_pt } & $2$ GeV$/c$\\
     471min $p_T^\textrm{tracks}$      & \texttt{PTAU\_track\_pt } & $2$ GeV$/c$\\
    448472\multicolumn{3}{l}{\textbf{$\tau$-jet candidate}} \\
    449473$\min p_T$ & \texttt{TAUJET\_pt} & $10$ GeV$/c$\\
     
    457481\subsubsection*{Electromagnetic collimation}
    458482
    459 To use the narrowness of the $\tau$-jet, the \textit{electromagnetic collimation} $C_{\tau}^{em}$ is defined as the sum of the energy of towers in a small cone of radius $R^\textrm{em}$ around the jet axis, divided by the energy of the reconstructed jet.
     483To use the narrowness of the $\tau$-jet, the \textit{electromagnetic collimation} $C_{\tau}$ is defined as the sum of the energy of towers in a small cone of radius $R^\textrm{em}$ around the jet axis, divided by the energy of the reconstructed jet.
    460484To be taken into account, a calorimeter tower should have a transverse energy $E_T^\textrm{tower}$ above a given threshold.
    461 A large fraction of the jet energy is expected in this small cone. This fraction, or collimation factor, is represented in Fig.~\ref{fig:tau2} for the default values (see Tab.~\ref{tab:tauRef}).
     485A large fraction of the jet energy is expected in this small cone. This fraction, or \textit{collimation factor}, is represented in Fig.~\ref{fig:tau2} for the default values (see Tab.~\ref{tab:tauRef}).
    462486
    463487\begin{figure}[!h]
     
    474498\subsubsection*{Tracking isolation}
    475499
    476 The tracking isolation for the $\tau$ identification requires that the number of tracks associated to a particle with a significant transverse momentum is one and only one in a cone of radius $R^\textrm{tracks}$ (3-prong $\tau$s are dropped).
     500The tracking isolation for the $\tau$ identification requires that the number of tracks associated to particles with significant transverse momenta is one and only one in a cone of radius $R^\textrm{tracks}$ (3-prong $\tau$s are dropped).
    477501This cone should be entirely incorporated into the tracker to be taken into account. Default values of these parameters are given in Tab.~\ref{tab:tauRef}.
    478502
     
    509533\right.
    510534\end{equation}
    511 The \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.
    512 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:
     535The \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.
     536In 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 }:
    513537\begin{equation}
    514538\overrightarrow{E_T}^\textrm{miss} = - \sum^\textrm{towers}_i \overrightarrow{E_T}(i)
     
    520544New 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 $2 \times 10^{-3}~\textrm{nb}$ ($pp \rightarrow WH$, $m_H=115~\textrm{GeV}/c^2$).
    521545
    522 %High statistics are required for data analyses, consequently imposing high luminosity, i.e. a high collision rate.
     546%High statistics are required for data analyses, consequently imposing high luminosity, i.e.\ a high collision rate.
    523547As 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.
    524548This 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.}.
    525549Dedicated 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.
    526550
    527 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 $p_T^e > 50~\textrm{GeV}/c$.
     551Most 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 $p_T^e > 50~\textrm{GeV}/c$.
    528552
    529553A 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.
     
    739763\section*{Acknowledgements}
    740764\addcontentsline{toc}{section}{Acknowledgements}
    741 The 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.
     765The authors would like to thank very warmly Vincent Lemaître 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.
    742766Part of this work was supported by the Belgian Federal Office for Scientific, Technical and Cultural Affairs through the Interuniversity Attraction Pole P6/11.
    743767
     
    749773%hepforge:
    750774\bibitem{bib:stdhep} L.A. Garren, M. Fischler, \\ \href{http://cepa.fnal.gov/psm/stdhep/c++}{cepa.fnal.gov/psm/stdhep/c++}
     775\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}.
    751776\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}.
    752777\bibitem{bib:Root} %\textsc{Root}, \textit{An Object Oriented Data Analysis Framework},
     
    796821\section{User manual}
    797822 
    798 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}~\cite{bib:ExRootAnalysis}, \textsc{Hector}~\cite{bib:Hector}, \textsc{FastJet}~\cite{bib:FastJet}, and \textsc{Frog}~\cite{bib:Frog}, as well as the conversion codes to read standard \mbox{\textsc{s}td\textsc{hep}} input files (\texttt{mcfio} and \texttt{stdhep})~\cite{bib:mcfio}.
     823The 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}~\cite{bib:ExRootAnalysis}, \textsc{Hector}~\cite{bib:Hector}, \textsc{FastJet}~\cite{bib:FastJet}, and \textsc{Frog}~\cite{bib:Frog}, as well as the conversion codes to read standard \mbox{\textsc{s}td\textsc{hep}} input files (\texttt{mcfio} and \texttt{stdhep})~\cite{bib:mcfio} and \textsc{HepMC}~\cite{bib:hepmc}.
    799824In 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/}.
    800825 
     
    803828In order to run \textsc{Delphes} on your system, first download its sources and compile them:\\
    804829\texttt{wget http://www.fynu.ucl.ac.be/users/s.ovyn/Delphes/files/Delphes\_V\_*.tar.gz}\\
    805 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}.}.
     830Replace 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 1.7 (May 2009)}.
    806831
    807832\begin{quote}
     
    823848\subsection{Running \textsc{Delphes} on your events}
    824849 
    825 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} 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).
     850In 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).
    826851 
    827852\begin{quote}
     
    833858\subsubsection{Setting up the configuration}
    834859 
    835 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.
     860The 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.
    836861 
    837862\begin{enumerate}
     
    858883ELG_Ccen          0.005    // C term for central ECAL
    859884ELG_Sfwd          2.084    // S term for FCAL
    860 ELG_Nfwd          0.0      // N term for FCAL
     885ELG_Nfwd          0.       // N term for FCAL
    861886ELG_Cfwd          0.107    // C term for FCAL
     887ELG_Szdc          0.70     // S term for ZDC
     888ELG_Nzdc          0.       // N term for ZDC
     889ELG_Czdc          0.08     // C term for ZDC
     890
    862891
    863892# Energy resolution for hadrons in ecal/hcal/hf
     
    869898HAD_Nhf           0.       // N term for FCAL
    870899HAD_Chf           0.13     // C term for FCAL
     900HAD_Szdc          1.38     // S term for ZDC
     901HAD_Nzdc          0.       // N term for ZDC
     902HAD_Czdc          0.13     // C term for ZDC
     903
     904# Time resolution for ZDC/RP220/RP420
     905ZDC_T_resolution   0       // in s
     906RP220_T_resolution 0       // in s
     907RP420_T_resolution 0       // in s
     908
    871909 
    872910# Muon smearing
     
    888926### the list ends with the higher edged of the most forward tower
    889927### there should be NTOWER+1 values
    890 TOWER_eta_edges 0.    0.087 0.174 0.261 0.348 0.435 0.522 0.609 0.696 0.783
     928TOWER_eta_edges 0. 0.087 0.174 0.261 0.348 0.435 0.522 0.609 0.696 0.783
    891929               0.870 0.957 1.044 1.131 1.218 1.305 1.392 1.479 1.566 1.653
    892930               1.740 1.830 1.930 2.043 2.172 2.322 2.500 2.650 2.868 2.950
     
    909947PTCUT_taujet     10.0
    910948
     949# Thresholds for reconstructed objects in ZDC, E in GeV
     950ZDC_gamma_E      20
     951ZDC_n_E          50
     952
    911953# Charged lepton isolation. Pt and Et in GeV
    912954ISOL_PT          2.0  //minimal pt of tracks for isolation criteria
    913955ISOL_Cone        0.5  //Cone  for isolation criteria
    914956ISOL_Calo_ET     2.0  //minimal tower E_T for isolation criteria. 1E99 means "off"
    915 ISOL_Calo_Cone   0.4  //Cone for calorimetric isolation
    916957ISOL_Calo_Grid   3    //Grid size (N x N) for calorimetric isolation
    917958
     
    925966                        // 6 for anti-kt algorithm
    926967JET_seed         1.0    // minimum seed to start jet reconstruction, in GeV
     968JET_Eflow        1      // Energy flow: perfect energy assumed in the tracker coverage.
     969                        // 1 is 'on' ; 0 is 'off'
    927970\end{verbatim}
    928971\end{quote}
     
    952995# Very forward detector extension, in pseudorapidity
    953996# if allowed
    954 VFD_min_calo_vfd  5.2     // very forward calorimeter (if any) like CASTOR
    955 VFD_max_calo_vfd  6.6
    956997VFD_min_zdc       8.3     // Zero-Degree neutral Calorimeter
    957998VFD_s_zdc         140     // distance of the ZDC, from the IP, in [m]
     
    9651006RP_beam2Card      data/LHCB2IR5_v6.500.tfs // beam optics file, beam 2
    9661007RP_IP_name        IP5     // tag for IP in Hector ; 'IP1' for ATLAS
     1008RP_offsetEl_x     0.097   // horizontal separation between both beam, in meters
     1009RP_offsetEl_y     0       // vertical separation between both beam, in meters
     1010RP_offsetEl_s     120     // distance of beam separation point, from IP
     1011RP_cross_x        -500    // IP offset in horizontal plane, in micrometers
     1012RP_cross_y        0       // IP offset in vertical plane, in micrometers
     1013RP_cross_ang_x    142.5   // half-crossing angle in horizontal plane, in microrad
     1014RP_cross_ang_y    0       // half-crossing angle in vertical plane, in microrad
     1015
    9671016
    9681017# In case FROG event display allowed
    9691018NEvents_Frog      100
    970  
     1019# Number of events to process
     1020NEvents           -1                    // -1 means 'all'
     1021
     1022# input PDG tables
     1023PdgTableFilename  data/particle.tbl     // table with particle pid,mass,charge,...
    9711024\end{verbatim}
    9721025\end{quote}
    9731026In general, energies, momenta and masses are expressed in GeV, GeV$/c$, GeV$/c^2$ respectively, and  magnetic fields in T.
    974 Geometrical extension are often referred in terms of pseudorapidity $\eta$, as the detectors are supposed to be symmetric in $\phi$.
     1027Geometrical extension are often referred in terms of pseudorapidity $\eta$, as the detectors are supposed to be symmetric in $\phi$. The number of events to run is also included in the detector card (\texttt{NEvents}).
    9751028 
    9761029\item{\bf The trigger card }
     
    9941047 
    9951048Each line in the trigger datacard is allocated to exactly one trigger-bit and starts with the name of the corresponding trigger.
    996 Logical 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. Finally, the different requirements on the objects must be separated by a {\verb && } flag.
    997 The default trigger card can be found in the data repository of \textsc{Delphes} (\texttt{data/TriggerCard.dat}).
     1049Logical 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.
     1050The 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}.
    9981051An example of trigger table consistent with the previous rules is given here:
    9991052\begin{quote}
     
    10091062 
    10101063First, create the detector and trigger cards (\texttt{data/DetectorCard.dat} and \texttt{data/TriggerCard.dat}). \\
    1011 Then, create a text file containing the list of input files that will be used by \textsc{Delphes} (with extension \texttt{*.lhe}, \texttt{*.root} or \texttt{*.hep}).
     1064Then, 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}).
    10121065To run the code, type the following command (in one line)
    10131066\begin{quote}
     
    10231076me@mylaptop:~$ ./Delphes
    10241077 Usage: ./Delphes input_file output_file [detector_card] [trigger_card]
    1025  input_list - list of files in Ntpl, StdHep of LHEF format,
     1078 input_list - list of files in Ntpl, StdHep, HepMC or LHEF format,
    10261079 output_file - output file.
    10271080 detector_card - Card containing resolution variables for detector simulation (optional)
     
    10371090The \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.
    10381091
    1039 Here is the exhaustive list of \textit{branches} availables in these \textit{trees}, together with their corresponding physical objet and \texttt{ExRootAnalysis} class:
     1092Here is the exhaustive list of \textit{branches} availables in these \textit{trees}, together with their corresponding physical objet and \texttt{ExRootAnalysis} C++ class name:
    10401093\begin{quote}
    10411094\begin{tabular}{lll}
     
    10431096~~~Particle & generator particles from \textsc{hepevt}     & {\verb GenParticle }\\
    10441097\multicolumn{3}{l}{}\\
    1045 {\bf Trigger } & &\\
     1098{\bf Trigger tree } & &\\
    10461099~~~TrigResult & Acceptance of different trigger-bits       & {\verb TRootTrigger }\\
    10471100\multicolumn{3}{l}{}\\
     
    10611114\end{quote}
    10621115The third column shows the names of the corresponding classes to be written in a \textsc{root} tree.
    1063 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}):
     1116The 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.
     1117In \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}):
    10641118\begin{quote}
    10651119\begin{tabular}{ll}
     
    10781132\begin{quote}
    10791133\begin{tabular}{ll}
    1080 \multicolumn{2}{l}{{\bf Leaves in the \texttt{Particle} branch}} \\   
     1134\multicolumn{2}{l}{{\bf Leaves in the \texttt{Particle} branch (\texttt{GEN} tree)}} \\   
    10811135   \texttt{~~~int PID;      }&\texttt{ // particle HEP ID number }\\
    10821136   \texttt{~~~int Status;   }&\texttt{ // particle status }\\
     
    10951149\begin{quote}
    10961150\begin{tabular}{ll}
    1097 \multicolumn{2}{l}{\textbf{Additional leaves in \texttt{Electron} and \texttt{Muon} branches}} \\
     1151\multicolumn{2}{l}{\textbf{Additional leaves in \texttt{Electron} and \texttt{Muon} branches (\texttt{Analysis} tree)}} \\
    10981152   \texttt{~~~int Charge }    &\texttt{ // particle Charge }\\
    10991153   \texttt{~~~bool IsolFlag } &\texttt{ // stores the result of the tracking isolation test }\\
     
    11021156   \texttt{~~~float EHoverEE }&\texttt{ // hadronic energy over electromagnetic energy }\\
    11031157   \texttt{~~~float EtRatio } &\texttt{ // calo Et in NxN-tower grid around the muon over the muon Et }\\
     1158   \texttt{~~~float IsolPt } &\texttt{  // sum of all track pt in isolation cone (GeV/c) }\\
    11041159\end{tabular}
    11051160\end{quote}
    11061161\begin{quote}
    11071162\begin{tabular}{ll}
    1108 \multicolumn{2}{l}{\textbf{Additional leaf in the \texttt{Jet} branch}}  \\
     1163\multicolumn{2}{l}{\textbf{Additional leaf in the \texttt{Jet} branch (\texttt{Analysis} tree)}}  \\
    11091164   \texttt{~~~bool Btag }  &\texttt{ // stores the result of the b-tagging }\\
    11101165   \texttt{~~~int NTracks }&\texttt{ // number of tracks associated to the jet }\\
     
    11141169\begin{quote}
    11151170\begin{tabular}{ll}
    1116 \multicolumn{2}{l}{\textbf{Additional leaves in the \texttt{ZDChits} branch}}\\
    1117    \texttt{~~~float T } &\texttt{ // time of flight  in s }\\
    1118    \texttt{~~~int side }&\texttt{ // -1 or +1 }
    1119 \end{tabular}
    1120 \end{quote}
    1121 \begin{quote}
    1122 \begin{tabular}{ll}
    1123 \multicolumn{2}{l}{\textbf{Leaves in the \texttt{Tracks} branch}}\\
     1171\multicolumn{2}{l}{\textbf{Leaves in the \texttt{Tracks} branch (\texttt{Analysis} tree)}}\\
    11241172    \texttt{~~~float Eta }     &\texttt{ // pseudorapidity at the beginning of the track }\\
    11251173    \texttt{~~~float Phi }     &\texttt{ // azimuthal angle at the beginning of the track }\\
     
    11311179    \texttt{~~~float Py }      &\texttt{ // track momentum vector (x component) in GeV$/c$ }\\
    11321180    \texttt{~~~float Pz }      &\texttt{ // track momentum vector (x component) in GeV$/c$ }\\
    1133     \texttt{~~~float Charge }  &\texttt{ // track charge }\\
     1181    \texttt{~~~float Charge }  &\texttt{ // track charge in units of $e$ }\\
    11341182\end{tabular}
    11351183\end{quote}
    11361184\begin{quote}
    11371185\begin{tabular}{ll}
    1138 \multicolumn{2}{l}{\textbf{Leaves in the \texttt{CaloTower} branch}}\\
     1186\multicolumn{2}{l}{\textbf{Leaves in the \texttt{CaloTower} branch (\texttt{Analysis} tree)}}\\
    11391187    \texttt{~~~float Eta }     &\texttt{ // pseudorapidity of the tower }\\
    11401188    \texttt{~~~float Phi }     &\texttt{ // azimuthal angle of the tower in rad }\\
     
    11441192    \texttt{~~~float ET }      &\texttt{ // tower transverse energy in GeV }\\
    11451193& \\
    1146 \multicolumn{2}{l}{\textbf{Leaves in the \texttt{ETmis} branch}}\\
     1194\multicolumn{2}{l}{\textbf{Leaves in the \texttt{ETmis} branch (\texttt{Analysis} tree)}}\\
    11471195    \texttt{~~~float Phi }     &\texttt{ // azimuthal angle of the transverse missing energy in rad }\\
    11481196    \texttt{~~~float ET }      &\texttt{ // transverse missing energy in GeV }\\
     
    11511199\end{tabular}
    11521200\end{quote}
     1201
     1202The 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).
     1203
     1204\begin{quote}
     1205\begin{tabular}{ll}
     1206\multicolumn{2}{l}{\textbf{Common leaves for ZDC, RP220, FP420}}\\
     1207   \texttt{~~~float T } &\texttt{ // time of flight  in s }\\
     1208   \texttt{~~~float E } &\texttt{ // measured/smeared energy in GeV }\\
     1209   \texttt{~~~int side }&\texttt{ // -1 or +1 }\\
     1210\multicolumn{2}{l}{Generator level data}\\
     1211   \texttt{~~~int pid;     }&\texttt{ // particle ID }\\
     1212   \texttt{~~~float genPx;    }&\texttt{ // particle momentum vector (x component) in GeV$/c$ }\\
     1213   \texttt{~~~float genPy;    }&\texttt{ // particle momentum vector (y component) in GeV$/c$ }\\
     1214   \texttt{~~~float genPz;    }&\texttt{ // particle momentum vector (z component) in GeV$/c$ }\\
     1215   \texttt{~~~float genPT;    }&\texttt{ // particle transverse momentum in GeV$/c$ }\\
     1216   \texttt{~~~float genEta;   }&\texttt{ // particle pseudorapidity   }\\
     1217   \texttt{~~~float genPhi;   }&\texttt{ // particle azimuthal angle in rad }\\
     1218\end{tabular}
     1219\end{quote}
     1220
     1221\begin{quote}
     1222\begin{tabular}{ll}
     1223\multicolumn{2}{l}{\textbf{Additional leaves in the \texttt{ZDChits} branch (\texttt{Analysis} tree)}}\\
     1224   \texttt{~~~int hadronic\_hit } &\texttt{ // 0(is not hadronic) or 1(is hadronic) }
     1225\end{tabular}
     1226\end{quote}
     1227
     1228\begin{quote}
     1229\begin{tabular}{ll}
     1230\multicolumn{2}{l}{\textbf{Additional leaves in the \texttt{RP220hits} and \texttt{FP420hits} branches (\texttt{Analysis} tree)}}\\
     1231   \texttt{~~~flaot S } &\texttt{ // detector position from IP in m } \\
     1232   \texttt{~~~float X } &\texttt{ // hit horizontal position in m } \\
     1233   \texttt{~~~float Y } &\texttt{ // hit vertical position in m }   \\
     1234   \texttt{~~~float TX } &\texttt{ // hit horizontal angle in rad } \\
     1235   \texttt{~~~float TY } &\texttt{ // hit vertical angle in rad } \\
     1236   \texttt{~~~float q2 } &\texttt{ // reconstructed momentum transfer in GeV$^2$ }
     1237\end{tabular}
     1238\end{quote}
     1239The hit position is computed from the center of the beam position, not from the edge of the detector.
     1240
    11531241 
    11541242\subsection{Running an analysis on your \textsc{Delphes} events}
     
    12061294\end{verbatim}
    12071295\end{quote}
    1208 Mathematical operations on several \textit{leaves} are possible within a given \textit{tree}:
     1296Mathematical operations on several \textit{leaves} are possible within a given \textit{tree}, following the C++ syntax:
    12091297\begin{quote}
    12101298\begin{verbatim}
     
    12131301\end{verbatim}
    12141302\end{quote}
    1215 Finally, to prepare an deeper analysis, the \texttt{MakeClass} method is useful:
     1303Finally, to prepare an deeper analysis, the \texttt{MakeClass} method is useful. It creates two files (\texttt{*.h} and \texttt{*.C}) with automatically generated code that allows the access to all branches and leaves of the corresponding tree:
    12161304\begin{quote}
    12171305\begin{verbatim}
     
    12211309\end{verbatim}
    12221310\end{quote}
     1311For more information, refer to ROOT documentation. Moreover, an example of code (based on the output of \begin{verbatim}MakeClass\end{verbatim}) is provided in the \texttt{Examples/} directory.
    12231312
    12241313To 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.
     
    12281317\end{verbatim}
    12291318 \end{quote}
     1319One can easily edit, modify and compile (\begin{verbatim}make\end{verbatim}) changes in this file.
    12301320 
    12311321\subsubsection{Adding the trigger information}
     
    12421332\begin{itemize}
    12431333\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}.
    1244 \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).
     1334\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).
    12451335\item Go back into the main directory and type
    12461336\begin{quote}
     
    12641354  7   6   0.000   0.845  62.574   0.000   0.000   0.000   0.000   0.000  0.000
    12651355\end{verbatim}
    1266 Each row in an event starts with a unique number (i.e. in first column).
     1356Each row in an event starts with a unique number (i.e.\ in first column).
    12671357Row \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}.).
    12681358Subsequent rows list the reconstructed high-level objects.
Note: See TracChangeset for help on using the changeset viewer.