Changeset 441 in svn
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- Jun 17, 2009, 11:57:53 PM (15 years ago)
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trunk/paper/CommPhysComp/notes.tex
r426 r441 274 274 %\includegraphics[width=\columnwidth]{calosegmentation} 275 275 \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 expresse nd 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.} 277 277 \label{fig:calosegmentation} 278 278 \end{center} … … 1070 1070 # In case FROG event display allowed 1071 1071 NEvents_Frog 100 1072 # Number of events to process 1073 NEvents -1 // -1 means 'all' 1072 1074 1073 1075 # input PDG tables … … 1077 1079 1078 1080 In 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 beincluded in the detector card (\texttt{NEvents}).1081 Geometrical 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}). 1080 1082 1081 1083 \item{\bf The trigger card } -
trunk/paper/notes.tex
r343 r441 63 63 a general-purpose experiment. The simulation includes a tracking system, embedded into a magnetic field, calorimetry and a muon 64 64 system, 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.65 The 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. 66 66 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. 67 67 An overview of \textsc{Delphes} is given as well as a few \textsc{lhc} use-cases for illustration. … … 81 81 \section{Introduction} 82 82 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.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. 84 84 85 85 This 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. … … 115 115 Although 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. 116 116 117 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}.117 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 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}. 118 118 %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. 119 119 … … 143 143 \textsc{tracker} & {\verb CEN_max_tracker } & $[-2.5; 2.5]$ & $[-\pi ; \pi]$\\ 144 144 \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 } & $[-5 ; -3]$ \& $[3 ;5]$ & $[-\pi ; \pi]$\\ 146 146 \textsc{muon} & {\verb CEN_max_mu } & $[-2.4 ; 2.4]$ & $[-\pi ; \pi]$\\ \hline 147 147 \end{tabular} … … 165 165 166 166 \subsubsection*{Magnetic field} 167 In addition to the subdetectors, the effects of a solenoidal magnetic field issimulated 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.167 In 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. 168 168 169 169 … … 174 174 175 175 176 \subsection{Simulation of c alorimeters}176 \subsection{Simulation of central calorimeters} 177 177 178 178 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. … … 211 211 \multicolumn{4}{l}{\textsc{fcal}, hadronic part} \\ 212 212 & $S$ (GeV$^{1/2}$)& {\verb HAD_Shf } & $2.7$\\ 213 & $N$ (GeV)& {\verb HAD_Nhf } & $0$ .\\213 & $N$ (GeV)& {\verb HAD_Nhf } & $0$ \\ 214 214 & $C$ & {\verb HAD_Chf } & $0.13$\\ 215 215 \hline … … 235 235 236 236 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}. 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.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. 238 238 239 239 \begin{figure}[!h] 240 240 \begin{center} 241 241 \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.} 243 243 \label{fig:calosegmentation} 244 244 \end{center} … … 250 250 251 251 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. 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}).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}). 253 253 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. 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}). 254 254 … … 288 288 t = t_0 + \frac{1}{v} \times \Big( \frac{s-z}{\cos \theta}\Big), 289 289 \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 $1 - \cos \theta < 10^{-4}$.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 $1 - \cos \theta < 10^{-4}$. 291 291 The formula then reduces to 292 292 \begin{equation} 293 293 t = \frac{1}{c} \times (s-z) 294 294 \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}. 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}. 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} 317 296 318 297 319 \section{High-level object reconstruction} … … 321 343 322 344 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. 323 The result (i.e. \textit{isolated} or \textit{not}) is added to the charged lepton measured properties.345 The result (i.e.\ \textit{isolated} or \textit{not}) is added to the charged lepton measured properties. 324 346 In addition, the sum $P_T$ of the transverse momenta of all tracks but the lepton one within the isolation cone is 325 347 provided\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.}: … … 330 352 $$ \rho_\mu = \frac{\Sigma_i E_T(i)}{p_T(\mu)}~,~ i\textrm{ in }N \times N \textrm { grid centred on }\mu.$$ 331 353 332 333 334 354 \subsubsection*{Forward neutrals} 355 356 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). 335 357 336 358 … … 349 371 This so-called \textsc{Jetclu} cone jet algorithm is used by the \textsc{cdf} experiment in Run II. 350 372 All 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 thefollowing 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 sensitivit ycompared to purely seed-based cone by adding `midpoints' (energy barycentres) in the list of cone seeds.373 The existing \textsc{FastJet} code has been modified to allow easy modification of the tower pattern in ($\eta$, $\phi$) space. 374 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.}. 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. 355 377 356 378 \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. … … 391 413 \end{enumerate} 392 414 393 415 \subsubsection*{Energy flow} 416 417 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. 394 418 395 419 \subsection{$b$-tagging} 396 420 397 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 $0.7$). 421 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.}. 422 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. 399 423 400 424 \subsection{\texorpdfstring{$\tau$}{\texttau} identification} 401 425 402 Jets originating from $\tau$-decays are identified using a n identificationprocedure consistent with the one applied in a full detector simulation~\cite{bib:cmsjetresolution}.426 Jets originating from $\tau$-decays are identified using a procedure consistent with the one applied in a full detector simulation~\cite{bib:cmsjetresolution}. 403 427 The 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}). 404 428 … … 406 430 \begin{table}[!h] 407 431 \begin{center} 408 \caption{ Branching ratio ns 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. 409 433 \vspace{0.5cm} } 410 434 \begin{tabular}[!h]{ll} … … 426 450 \begin{center} 427 451 \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.} 429 453 \label{h_WW_ss_cut1} 430 454 \end{center} … … 445 469 \multicolumn{3}{l}{\textbf{Tracking isolation}} \\ 446 470 $R^\textrm{tracks}$ & \texttt{TAU\_track\_scone} & $0.4$\\ 447 min $p_T^ {tracks}$ & \texttt{PTAU\_track\_pt } & $2$ GeV$/c$\\471 min $p_T^\textrm{tracks}$ & \texttt{PTAU\_track\_pt } & $2$ GeV$/c$\\ 448 472 \multicolumn{3}{l}{\textbf{$\tau$-jet candidate}} \\ 449 473 $\min p_T$ & \texttt{TAUJET\_pt} & $10$ GeV$/c$\\ … … 457 481 \subsubsection*{Electromagnetic collimation} 458 482 459 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.483 To 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. 460 484 To 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}).485 A 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}). 462 486 463 487 \begin{figure}[!h] … … 474 498 \subsubsection*{Tracking isolation} 475 499 476 The tracking isolation for the $\tau$ identification requires that the number of tracks associated to a particle with a significant transverse momentumis one and only one in a cone of radius $R^\textrm{tracks}$ (3-prong $\tau$s are dropped).500 The 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). 477 501 This 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}. 478 502 … … 509 533 \right. 510 534 \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 :535 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. 536 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 }: 513 537 \begin{equation} 514 538 \overrightarrow{E_T}^\textrm{miss} = - \sum^\textrm{towers}_i \overrightarrow{E_T}(i) … … 520 544 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 $2 \times 10^{-3}~\textrm{nb}$ ($pp \rightarrow WH$, $m_H=115~\textrm{GeV}/c^2$). 521 545 522 %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. 523 547 As 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. 524 548 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.}. 525 549 Dedicated 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. 526 550 527 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 $p_T^e > 50~\textrm{GeV}/c$.551 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 $p_T^e > 50~\textrm{GeV}/c$. 528 552 529 553 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. … … 739 763 \section*{Acknowledgements} 740 764 \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.765 The 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. 742 766 Part of this work was supported by the Belgian Federal Office for Scientific, Technical and Cultural Affairs through the Interuniversity Attraction Pole P6/11. 743 767 … … 749 773 %hepforge: 750 774 \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}. 751 776 \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}. 752 777 \bibitem{bib:Root} %\textsc{Root}, \textit{An Object Oriented Data Analysis Framework}, … … 796 821 \section{User manual} 797 822 798 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} .823 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} and \textsc{HepMC}~\cite{bib:hepmc}. 799 824 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/}. 800 825 … … 803 828 In order to run \textsc{Delphes} on your system, first download its sources and compile them:\\ 804 829 \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}. }.830 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 1.7 (May 2009)}. 806 831 807 832 \begin{quote} … … 823 848 \subsection{Running \textsc{Delphes} on your events} 824 849 825 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).850 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). 826 851 827 852 \begin{quote} … … 833 858 \subsubsection{Setting up the configuration} 834 859 835 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. 860 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. 836 861 837 862 \begin{enumerate} … … 858 883 ELG_Ccen 0.005 // C term for central ECAL 859 884 ELG_Sfwd 2.084 // S term for FCAL 860 ELG_Nfwd 0. 0// N term for FCAL885 ELG_Nfwd 0. // N term for FCAL 861 886 ELG_Cfwd 0.107 // C term for FCAL 887 ELG_Szdc 0.70 // S term for ZDC 888 ELG_Nzdc 0. // N term for ZDC 889 ELG_Czdc 0.08 // C term for ZDC 890 862 891 863 892 # Energy resolution for hadrons in ecal/hcal/hf … … 869 898 HAD_Nhf 0. // N term for FCAL 870 899 HAD_Chf 0.13 // C term for FCAL 900 HAD_Szdc 1.38 // S term for ZDC 901 HAD_Nzdc 0. // N term for ZDC 902 HAD_Czdc 0.13 // C term for ZDC 903 904 # Time resolution for ZDC/RP220/RP420 905 ZDC_T_resolution 0 // in s 906 RP220_T_resolution 0 // in s 907 RP420_T_resolution 0 // in s 908 871 909 872 910 # Muon smearing … … 888 926 ### the list ends with the higher edged of the most forward tower 889 927 ### there should be NTOWER+1 values 890 TOWER_eta_edges 0. 928 TOWER_eta_edges 0. 0.087 0.174 0.261 0.348 0.435 0.522 0.609 0.696 0.783 891 929 0.870 0.957 1.044 1.131 1.218 1.305 1.392 1.479 1.566 1.653 892 930 1.740 1.830 1.930 2.043 2.172 2.322 2.500 2.650 2.868 2.950 … … 909 947 PTCUT_taujet 10.0 910 948 949 # Thresholds for reconstructed objects in ZDC, E in GeV 950 ZDC_gamma_E 20 951 ZDC_n_E 50 952 911 953 # Charged lepton isolation. Pt and Et in GeV 912 954 ISOL_PT 2.0 //minimal pt of tracks for isolation criteria 913 955 ISOL_Cone 0.5 //Cone for isolation criteria 914 956 ISOL_Calo_ET 2.0 //minimal tower E_T for isolation criteria. 1E99 means "off" 915 ISOL_Calo_Cone 0.4 //Cone for calorimetric isolation916 957 ISOL_Calo_Grid 3 //Grid size (N x N) for calorimetric isolation 917 958 … … 925 966 // 6 for anti-kt algorithm 926 967 JET_seed 1.0 // minimum seed to start jet reconstruction, in GeV 968 JET_Eflow 1 // Energy flow: perfect energy assumed in the tracker coverage. 969 // 1 is 'on' ; 0 is 'off' 927 970 \end{verbatim} 928 971 \end{quote} … … 952 995 # Very forward detector extension, in pseudorapidity 953 996 # if allowed 954 VFD_min_calo_vfd 5.2 // very forward calorimeter (if any) like CASTOR955 VFD_max_calo_vfd 6.6956 997 VFD_min_zdc 8.3 // Zero-Degree neutral Calorimeter 957 998 VFD_s_zdc 140 // distance of the ZDC, from the IP, in [m] … … 965 1006 RP_beam2Card data/LHCB2IR5_v6.500.tfs // beam optics file, beam 2 966 1007 RP_IP_name IP5 // tag for IP in Hector ; 'IP1' for ATLAS 1008 RP_offsetEl_x 0.097 // horizontal separation between both beam, in meters 1009 RP_offsetEl_y 0 // vertical separation between both beam, in meters 1010 RP_offsetEl_s 120 // distance of beam separation point, from IP 1011 RP_cross_x -500 // IP offset in horizontal plane, in micrometers 1012 RP_cross_y 0 // IP offset in vertical plane, in micrometers 1013 RP_cross_ang_x 142.5 // half-crossing angle in horizontal plane, in microrad 1014 RP_cross_ang_y 0 // half-crossing angle in vertical plane, in microrad 1015 967 1016 968 1017 # In case FROG event display allowed 969 1018 NEvents_Frog 100 970 1019 # Number of events to process 1020 NEvents -1 // -1 means 'all' 1021 1022 # input PDG tables 1023 PdgTableFilename data/particle.tbl // table with particle pid,mass,charge,... 971 1024 \end{verbatim} 972 1025 \end{quote} 973 1026 In 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 $\phi$. 1027 Geometrical 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}). 975 1028 976 1029 \item{\bf The trigger card } … … 994 1047 995 1048 Each 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}) .1049 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. 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. 1050 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}. 998 1051 An example of trigger table consistent with the previous rules is given here: 999 1052 \begin{quote} … … 1009 1062 1010 1063 First, 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}).1064 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}). 1012 1065 To run the code, type the following command (in one line) 1013 1066 \begin{quote} … … 1023 1076 me@mylaptop:~$ ./Delphes 1024 1077 Usage: ./Delphes input_file output_file [detector_card] [trigger_card] 1025 input_list - list of files in Ntpl, StdHep ofLHEF format,1078 input_list - list of files in Ntpl, StdHep, HepMC or LHEF format, 1026 1079 output_file - output file. 1027 1080 detector_card - Card containing resolution variables for detector simulation (optional) … … 1037 1090 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. 1038 1091 1039 Here is the exhaustive list of \textit{branches} availables in these \textit{trees}, together with their corresponding physical objet and \texttt{ExRootAnalysis} class:1092 Here is the exhaustive list of \textit{branches} availables in these \textit{trees}, together with their corresponding physical objet and \texttt{ExRootAnalysis} C++ class name: 1040 1093 \begin{quote} 1041 1094 \begin{tabular}{lll} … … 1043 1096 ~~~Particle & generator particles from \textsc{hepevt} & {\verb GenParticle }\\ 1044 1097 \multicolumn{3}{l}{}\\ 1045 {\bf Trigger } & &\\1098 {\bf Trigger tree } & &\\ 1046 1099 ~~~TrigResult & Acceptance of different trigger-bits & {\verb TRootTrigger }\\ 1047 1100 \multicolumn{3}{l}{}\\ … … 1061 1114 \end{quote} 1062 1115 The 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}): 1116 The 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. 1117 In \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}): 1064 1118 \begin{quote} 1065 1119 \begin{tabular}{ll} … … 1078 1132 \begin{quote} 1079 1133 \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)}} \\ 1081 1135 \texttt{~~~int PID; }&\texttt{ // particle HEP ID number }\\ 1082 1136 \texttt{~~~int Status; }&\texttt{ // particle status }\\ … … 1095 1149 \begin{quote} 1096 1150 \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)}} \\ 1098 1152 \texttt{~~~int Charge } &\texttt{ // particle Charge }\\ 1099 1153 \texttt{~~~bool IsolFlag } &\texttt{ // stores the result of the tracking isolation test }\\ … … 1102 1156 \texttt{~~~float EHoverEE }&\texttt{ // hadronic energy over electromagnetic energy }\\ 1103 1157 \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) }\\ 1104 1159 \end{tabular} 1105 1160 \end{quote} 1106 1161 \begin{quote} 1107 1162 \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)}} \\ 1109 1164 \texttt{~~~bool Btag } &\texttt{ // stores the result of the b-tagging }\\ 1110 1165 \texttt{~~~int NTracks }&\texttt{ // number of tracks associated to the jet }\\ … … 1114 1169 \begin{quote} 1115 1170 \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)}}\\ 1124 1172 \texttt{~~~float Eta } &\texttt{ // pseudorapidity at the beginning of the track }\\ 1125 1173 \texttt{~~~float Phi } &\texttt{ // azimuthal angle at the beginning of the track }\\ … … 1131 1179 \texttt{~~~float Py } &\texttt{ // track momentum vector (x component) in GeV$/c$ }\\ 1132 1180 \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 $e$ }\\ 1134 1182 \end{tabular} 1135 1183 \end{quote} 1136 1184 \begin{quote} 1137 1185 \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)}}\\ 1139 1187 \texttt{~~~float Eta } &\texttt{ // pseudorapidity of the tower }\\ 1140 1188 \texttt{~~~float Phi } &\texttt{ // azimuthal angle of the tower in rad }\\ … … 1144 1192 \texttt{~~~float ET } &\texttt{ // tower transverse energy in GeV }\\ 1145 1193 & \\ 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)}}\\ 1147 1195 \texttt{~~~float Phi } &\texttt{ // azimuthal angle of the transverse missing energy in rad }\\ 1148 1196 \texttt{~~~float ET } &\texttt{ // transverse missing energy in GeV }\\ … … 1151 1199 \end{tabular} 1152 1200 \end{quote} 1201 1202 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). 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} 1239 The hit position is computed from the center of the beam position, not from the edge of the detector. 1240 1153 1241 1154 1242 \subsection{Running an analysis on your \textsc{Delphes} events} … … 1206 1294 \end{verbatim} 1207 1295 \end{quote} 1208 Mathematical operations on several \textit{leaves} are possible within a given \textit{tree} :1296 Mathematical operations on several \textit{leaves} are possible within a given \textit{tree}, following the C++ syntax: 1209 1297 \begin{quote} 1210 1298 \begin{verbatim} … … 1213 1301 \end{verbatim} 1214 1302 \end{quote} 1215 Finally, to prepare an deeper analysis, the \texttt{MakeClass} method is useful :1303 Finally, 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: 1216 1304 \begin{quote} 1217 1305 \begin{verbatim} … … 1221 1309 \end{verbatim} 1222 1310 \end{quote} 1311 For 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. 1223 1312 1224 1313 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. … … 1228 1317 \end{verbatim} 1229 1318 \end{quote} 1319 One can easily edit, modify and compile (\begin{verbatim}make\end{verbatim}) changes in this file. 1230 1320 1231 1321 \subsubsection{Adding the trigger information} … … 1242 1332 \begin{itemize} 1243 1333 \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). 1245 1335 \item Go back into the main directory and type 1246 1336 \begin{quote} … … 1264 1354 7 6 0.000 0.845 62.574 0.000 0.000 0.000 0.000 0.000 0.000 1265 1355 \end{verbatim} 1266 Each row in an event starts with a unique number (i.e. in first column).1356 Each row in an event starts with a unique number (i.e.\ in first column). 1267 1357 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}.). 1268 1358 Subsequent rows list the reconstructed high-level objects.
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