Changeset 326 in svn for trunk/paper
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r325 r326 29 29 \pdfinfo{ 30 30 /Author (S. Ovyn, X. Rouby, V. Lemaitre) 31 /Title (Delphes, a framework for fast simulation of a gener al-purpose LHC detector)31 /Title (Delphes, a framework for fast simulation of a generic collider experiment) 32 32 /Subject () 33 /Keywords (Delphes, Fast simulation, LHC, FROG, Hector, Smearing, FastJet)}33 /Keywords (Delphes, Fast simulation, smearing, reconstruction, trigger, event display, LHC, Hector, FastJet, Frog)} 34 34 \else 35 35 \usepackage[dvips]{graphicx} … … 60 60 \begin{abstract} 61 61 It is always delicate to know whether theoretical predictions are visible and measurable in a high energy collider experiment due to the complexity of the related detectors, data acquisition chain and software. 62 We introduce here a new \texttt{C++}-based framework, \textsc{Delphes}, for fast simulation of62 We introduce here a new \texttt{C++}-based framework, \textsc{Delphes}, for fast simulation of 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. … … 69 69 70 70 \noindent 71 \textit{Keywords:} \textsc{Delphes}, fast simulation, \textsc{lhc}, smearing, trigger, \textsc{FastJet}, \textsc{Hector}, \textsc{Frog}\\71 \textit{Keywords:} \textsc{Delphes}, fast simulation, trigger, event display, \textsc{lhc}, \textsc{FastJet}, \textsc{Hector}, \textsc{Frog}\\ 72 72 \href{http://www.fynu.ucl.ac.be/delphes.html}{http://www.fynu.ucl.ac.be/delphes.html}\\ 73 73 \textit{Preprint:} \texttt{CP3-09-01} … … 80 80 81 81 \section{Introduction} 82 % Motiver l'utilisation d'un simulateur rapide83 % - 1) rapide VS lent84 % - 2) relativement bonne prédiction en premiÚre approximation85 % - 3) permet de comparer86 82 87 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. … … 91 87 A new framework, called \textsc{Delphes}~\cite{bib:Delphes}, is introduced here, for the fast simulation of a general-purpose collider experiment. 92 88 Using the framework, observables can be estimated for specific signal and background channels, as well as their production and measurement rates. 93 Starting from the output of event generators, the simulation of the detector response takes into account the subdetector resolutions, by smearing the kinematic properties of the final-state particles\footnote{ throughout the paper, final-state particles refer as particles considered as stable by the event generator.}. Tracks of charged particles and deposits of energy in calorimetric cells (or \textit{calotowers}) are then created.89 Starting from the output of event generators, the simulation of the detector response takes into account the subdetector resolutions, by smearing the kinematic properties of the final-state particles\footnote{Throughout the paper, final-state particles refer as particles considered as stable by the event generator.}. Tracks of charged particles and deposits of energy in calorimetric cells (or \textit{calotowers}) are then created. 94 90 95 91 \textsc{Delphes} includes the most crucial experimental features, such as (Fig.~\ref{fig:FlowChart}): … … 108 104 \caption{Flow chart describing the principles behind \textsc{Delphes}. Event files coming from external Monte Carlo generators are read by a converter stage (top). 109 105 The kinematics variables of the final-state particles are then smeared according to the tunable subdetector resolutions. 110 Tracks are reconstructed in a simulated dipolarmagnetic field and calorimetric towers sample the energy deposits. Based on these low-level objects, dedicated algorithms are applied for particle identification, isolation and reconstruction.106 Tracks are reconstructed in a simulated solenoidal magnetic field and calorimetric towers sample the energy deposits. Based on these low-level objects, dedicated algorithms are applied for particle identification, isolation and reconstruction. 111 107 The transport of very forward particles to the near-beam detectors is also simulated. 112 Finally, an output file is written, including generator-level and analysis-object data. If requested, a fully parametrisable trigger can be emulated. Optionally, the geometry and visualisation files for the 3D event display can also be produced. 113 All user parameters are set in the \textit{Smearing Card} and the \textit{Trigger Card}. } 108 Finally, an output file is written, including generator-level and analysis-object data. 109 If requested, a fully parametrisable trigger can be emulated. Optionally, the geometry and visualisation files for the 3D event display can also be produced. 110 All user parameters are set in the \textit{Detector/Smearing Card} and the \textit{Trigger Card}. } 114 111 \label{fig:FlowChart} 115 112 \end{center} … … 122 119 123 120 \textsc{Delphes} uses the \texttt{ExRootAnalysis} utility~\cite{bib:ExRootAnalysis} to create output data in a \texttt{*.root} ntuple. 124 This output contains a copy of the generator-level data (\textsc{gen} tree), the analysis data objects after reconstruction (\mbox{\textsc{A}nalysis} tree), and possibly the results of the trigger emulation (\mbox{\textsc{T}rigger} tree). The program is driven by input cards. The detector card (\texttt{data/DataCardDet.dat}) allows a large spectrum of running conditions by modifying basic detector parameters, including calorimeter and tracking coverage and resolution, thresholds or jet algorithm parameters. The trigger card (\texttt{data/trigger.dat}) lists the user algorithms for the simplified online preselection.\\ 121 This output contains a copy of the generator-level data (\textsc{gen} tree), the analysis data objects after reconstruction (\mbox{\textsc{A}nalysis} tree), and possibly the results of the trigger emulation (\mbox{\textsc{T}rigger} tree). 122 In option\footnote{\texttt{[code]} See the \texttt{FLAG\_lhco} variable in the detector datacard. This text file format is shortly described in the user manual.}, \textsc{Delphes} can produce a reduced output file in \texttt{*.lhco} text format, which is limited to the list of the reconstructed high-level objects in the final states. 123 124 The program is driven by input cards. The detector card (\texttt{data/DetectorCard.dat}) allows a large spectrum of running conditions by modifying basic detector parameters, including calorimeter and tracking coverage and resolution, thresholds or jet algorithm parameters. The trigger card (\texttt{data/TriggerCard.dat}) lists the user algorithms for the simplified online 125 preselection. 125 126 126 127 … … 129 130 The overall layout of the general-purpose detector simulated by \textsc{Delphes} is shown in Fig.~\ref{fig:GenDet3}. 130 131 A central tracking system (\textsc{tracker}) is surrounded by an electromagnetic and a hadron calorimeters (\textsc{ecal} and \textsc{hcal}, resp.). Two forward calorimeters (\textsc{fcal}) ensure a larger geometric coverage for the measurement of the missing transverse energy. Finally, a muon system (\textsc{muon}) encloses the central detector volume 131 The fast simulation of the detector response takes into account geometrical acceptance of sub-detectors and their finite resolution, as defined in the smearingdata card\footnote{\texttt{[code] }See the \texttt{RESOLution} class.}.132 If no such file is provided, predefined values based on ``typical'' \textsc{cms} acceptances and resolutions are used . The geometrical coverage of the various subsystems used in the default configuration are summarised in Tab.~\ref{tab:defEta}.132 The fast simulation of the detector response takes into account geometrical acceptance of sub-detectors and their finite resolution, as defined in the detector data card\footnote{\texttt{[code] }See the \texttt{RESOLution} class.}. 133 If no such file is provided, predefined values based on ``typical'' \textsc{cms} acceptances and resolutions are used\footnote{\texttt{[code] }Detector and trigger cards for the \textsc{atlas} and \textsc{cms} experiments are also provided in \texttt{data/} directory.}. The geometrical coverage of the various subsystems used in the default configuration are summarised in Tab.~\ref{tab:defEta}. 133 134 134 135 \begin{table*}[t] … … 136 137 \caption{Default extension in pseudorapidity $\eta$ of the different subdetectors. 137 138 Full azimuthal ($\phi$) acceptance is assumed. 138 The corresponding parameter name, in the smearingcard, is given. \vspace{0.5cm}}139 The corresponding parameter name, in the detector card, is given. \vspace{0.5cm}} 139 140 \begin{tabular}{llcc} 140 141 \hline … … 164 165 165 166 \subsubsection*{Magnetic field} 166 In addition to the subdetectors, the effects of a dipolar magnetic field is simulated for the charged particles\footnote{\texttt{[code] }See the \texttt{TrackPropagation} class.}. This affects the position at which charged particles enter the calorimeters.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. 167 168 168 169 … … 170 171 \subsection{Tracks reconstruction} 171 172 Every stable charged particle with a transverse momentum above some threshold and lying inside the detector volume covered by the tracker provides a track. 172 By default, a track is assumed to be reconstructed with $90\%$ probability\footnote{\texttt{[code]} The reconstruction efficiency is defined in the smearingdatacard by the \texttt{TRACKING\_EFF} term.} if its transverse momentum $p_T$ is higher than $0.9~\textrm{GeV}/c$ and if its pseudorapidity $|\eta| \leq 2.5$.173 By default, a track is assumed to be reconstructed with $90\%$ probability\footnote{\texttt{[code]} The reconstruction efficiency is defined in the detector datacard by the \texttt{TRACKING\_EFF} term.} if its transverse momentum $p_T$ is higher than $0.9~\textrm{GeV}/c$ and if its pseudorapidity $|\eta| \leq 2.5$. 173 174 174 175 … … 186 187 The particle four-momentum $p^\mu$ are smeared with a parametrisation directly derived from typical detector technical designs\footnote{\texttt{[code] }~\cite{bib:cmsjetresolution,bib:ATLASresolution}. The response of the detector is applied to the electromagnetic and the hadronic particles through the \texttt{SmearElectron} and \texttt{SmearHadron} functions.}. 187 188 In the default parametrisation, the calorimeter is assumed to cover the pseudorapidity range $|\eta|<3$ and consists in an electromagnetic and hadronic parts. Coverage between pseudorapidities of $3.0$ and $5.0$ is provided by forward calorimeters, with different response to electromagnetic objects ($e^\pm, \gamma$) or hadrons. 188 Muons and neutrinos are assumed not to interact with the calorimeters\footnote{In the current \textsc{Delphes} version, particles other than electrons ($e^\pm$), photons ($\gamma$), muons ($\mu^\pm$) and neutrinos ($\nu_e$, $\nu_\mu$ and $\nu_\tau$) are simulated as hadrons for their interactions with the calorimeters. The simulation of stable particles beyond the Standard Model should therefore be handled with care.}.189 Muons and neutrinos are assumed not to interact with the calorimeters\footnote{In the current \textsc{Delphes} version, particles other thand electrons ($e^\pm$), photons ($\gamma$), muons ($\mu^\pm$) and neutrinos ($\nu_e$, $\nu_\mu$ and $\nu_\tau$) are simulated as hadrons for their interactions with the calorimeters. The simulation of stable particles beyond the Standard Model should therefore be handled with care.}. 189 190 The default values of the stochastic, noise and constant terms are given in Tab.~\ref{tab:defResol}.\\ 190 191 … … 192 193 \begin{center} 193 194 \caption{Default values for the resolution of the central and forward calorimeters. Resolution is parametrised by the \textit{stochastic} ($S$), \textit{noise} ($N$) and \textit{constant} ($C$) terms (Eq.~\ref{eq:caloresolution}). 194 The corresponding parameter name, in the smearingcard, is given. \vspace{0.5cm}}195 The corresponding parameter name, in the detector card, is given. \vspace{0.5cm}} 195 196 \begin{tabular}[!h]{lllc} 196 197 \hline … … 229 230 \end{equation} 230 231 where $0 \leq F \leq 1$. The electromagnetic part is handled the same way for the electrons and photons. 231 The resulting calorimetry energy measurement given after the application of the smearing is then $E = E_{\textsc{hcal}} + E_{\textsc{ecal}}$. For $K_S^0$ and $\Lambda$ hadrons , the energy fraction is $F$ is assumed to be $0.7$.\\232 The resulting calorimetry energy measurement given after the application of the smearing is then $E = E_{\textsc{hcal}} + E_{\textsc{ecal}}$. For $K_S^0$ and $\Lambda$ hadrons\footnote{\texttt{[code]} To implement different ratios for other particles, see the \texttt{BlockClasses} class.}, the energy fraction is $F$ is assumed to be $0.7$.\\ 232 233 233 234 \subsection{Calorimetric towers} 234 235 235 236 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}. 236 As the detector is assumed to be cylindical (e.g. symmetric in $\phi$ and with respect to the $\eta=0$ plane), the smearingcard 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 cylindical (e.g. symmetric in $\phi$ and with respect to the $\eta=0$ plane), the detector card stores the number of calorimetric towers with $\phi=0$ and $\eta>0$ (default: $40$ towers). For a given $\eta$, the size of the $\phi$ segmentation is also specified. Fig.~\ref{fig:calosegmentation} illustrates the default segmentation of the $(\eta,\phi)$ plane. 237 238 238 239 \begin{figure}[!h] … … 244 245 \end{figure} 245 246 246 The calorimetric towers directly enter in the calculation of the missing transverse energy (\textsc{met}), and as input for the jet reconstruction algorithms. No sharing between neighbouring towers is implemented when particles enter a tower very close to its geometrical edge. 247 The calorimetric towers directly enter in the calculation of the missing transverse energy (\textsc{met}), and as input for the jet reconstruction algorithms. No sharing between neighbouring towers is implemented when particles enter a tower very close to its geometrical edge. Smearing is applied directly on the accumulated electromagnetic and hadronic energies of each calorimetric tower. 247 248 248 249 \subsection{Very forward detectors simulation} … … 306 307 \subsection{Photon and charged lepton reconstruction} 307 308 From here onwards, \textit{electrons} refer to both positrons ($e^+$) and electrons ($e^-$), and $\textit{charged leptons}$ refer to electrons and muons ($\mu^\pm$), leaving out the $\tau^\pm$ leptons as they decay before being detected. 309 308 310 \subsubsection*{Electrons and photons} 309 311 Electron ($e^\pm$) and photon candidates are reconstructed if they fall into the acceptance of the tracking system and have a transverse momentum above a threshold (default $p_T > 10~\textrm{GeV}/c$). A calorimetric tower will be seen in the detector, an electrons will leave in addition a track. Subsequently, electrons and photons create a candidate in the jet collection. 312 Assuming a good measurement of the track parameters in the real experiment, the electron energy can be reasonably recovered. In \textsc{Delphes}, electron energy is smeared according to the resolution of the calorimetric tower where it points to, but independently from any other deposited energy is this tower. This approach is still conservative as the calorimeter resolution is worse than the tracker one. 310 313 311 314 \subsubsection*{Muons} 312 313 315 Generator-level muons entering the detector acceptance are considered as candidates for the analysis level. 314 316 The acceptance is defined in terms of a transverse momentum threshold to be overpassed that should be computed using the chosen geometry of the detector and the magnetic field considered (default : $p_T > 10~\textrm{GeV}/c$) and of the pseudorapidity coverage of the muon system (default: $-2.4 \leq \eta \leq 2.4$). 315 The application of the detector resolution on the muon momentum depends on a Gaussian smearing of the $p_T$ variable\footnote{\texttt{[code]} See the \texttt{SmearMuon} method.}. Neither $\eta$ nor $\phi$ variables are modified beyond the calorimeters: no additional magnetic field is applied. In addition, multiple scattering is also neglected. This implies that low energy muons have in \textsc{Delphes} a better resolution than in a real detector. Moreover, muons leave no deposit in calorimeters.317 The application of the detector resolution on the muon momentum depends on a Gaussian smearing of the $p_T$ variable\footnote{\texttt{[code]} See the \texttt{SmearMuon} method.}. Neither $\eta$ nor $\phi$ variables are modified beyond the calorimeters: no additional magnetic field is applied. Multiple scattering is neglected. This implies that low energy muons have in \textsc{Delphes} a better resolution than in a real detector. Furthermore, muons leave no deposit in calorimeters. 316 318 317 319 \subsubsection*{Charged lepton isolation} 318 320 319 To improve the quality of the contents of the charged lepton collections, additional criteria can be applied such as isolation. This requires that electron or muon candidates are isolated in the detector from any other particle, within a small cone. In \textsc{Delphes}, charged lepton isolation demands that there is no other charged particle with $p_T>2~\textrm{GeV}/c$ within a cone of $\Delta R = \sqrt{\Delta \eta^2 + \Delta \phi^2} <0.5$ around the lepton. The result (i.e. \textit{isolated} or \textit{not}) is added to the charged lepton measured properties\footnote{\texttt{[code] }See the \texttt{IsolFlag} output of the \texttt{Electron} or \texttt{Muon} collections in the \texttt{Analysis} tree.}. No calorimetric isolation is applied. \\ 320 321 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. 322 The result (i.e. \textit{isolated} or \textit{not}) is added to the charged lepton measured properties. 323 In addition, the sum $P_T$ of the transverse momenta of all tracks but the lepton one within the isolation cone is 324 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.}: 325 $$ P_T = \sum_{i \neq \mu}^\textrm{tracks} p_T(i)$$ 326 327 No calorimetric isolation is applied, but the muon collection contains also the ratio $\rho_\mu$ between (1) the sum of the transverse energies in all calotowers in a $N \times N$ grid around the muon, and (2) the muon transverse 328 momentum\footnote{\texttt{[code] }Calorimetric isolation parameters in the detector card are \texttt{ISOL\_Calo\_ET} and \texttt{ISOL\_Calo\_Grid}.}: 329 $$ \rho_\mu = \frac{\Sigma_i E_T(i)}{p_T(\mu)}~,~ i\textrm{ in }N \times N \textrm { grid centered on }\mu.$$ 321 330 322 331 … … 328 337 329 338 A realistic analysis requires a correct treatment of particles which have hadronised. Therefore, the most widely currently used jet algorithms have been integrated into the \textsc{Delphes} framework using the \textsc{FastJet} tools~\cite{bib:FastJet}. 330 Six different jet reconstruction schemes are available\footnote{\texttt{[code] }The choice is done by allocating the \texttt{JET\_jetalgo } input parameter in the smearingcard.}. The first three belong to the cone algorithm class while the last three are using a sequential recombination scheme. For all of them, the towers are used as input for the jet clustering. Jet algorithms differ in their sensitivity to soft particles or collinear splittings, and in their computing speed performances.339 Six different jet reconstruction schemes are available\footnote{\texttt{[code] }The choice is done by allocating the \texttt{JET\_jetalgo } input parameter in the detector card.}. The first three belong to the cone algorithm class while the last three are using a sequential recombination scheme. For all of them, the towers are used as input for the jet clustering. Jet algorithms differ in their sensitivity to soft particles or collinear splittings, and in their computing speed performances. 331 340 By default, reconstruction uses a cone algorithm with $\Delta R=0.7$. 332 Jets are stored if their transverse energy is higher\footnote{\texttt{[code] PTCUT\_jet }variable in the smearingcard.} than $20~\textrm{GeV}$.341 Jets are stored if their transverse energy is higher\footnote{\texttt{[code] PTCUT\_jet }variable in the detector card.} than $20~\textrm{GeV}$. 333 342 334 343 \subsubsection*{Cone algorithms} … … 340 349 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. 341 350 The existing \textsc{FastJet} code has been modified to allow easy modification of the tower pattern in $\eta$, $\phi$ space. 342 In the following versions of \textsc{Delphes}, a new dedicated plug-in will be created on this purpose\footnote{\texttt{[code] }\texttt{JET\_coneradius} and \texttt{JET\_seed} variables in the smearingcard.}.351 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.}. 343 352 344 353 \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. … … 385 394 \subsection{$b$-tagging} 386 395 387 A jet is tagged as $b$-jets if its direction lies in the acceptance of the tracker and if it is associated to a parent $b$-quark. By default, a $b$-tagging efficiency of $40\%$ is assumed if the jet has a parent $b$ quark. For $c$-jets and light jets (i.e. originating in $u$,$d$,$s$ quarks or in gluons), a fake $b$-tagging efficiency of $10 \%$ and $1 \%$ respectively is assumed\footnote{\texttt{[code] }Corresponding to the \texttt{TAGGING\_B}, \texttt{MISTAGGING\_C} and \texttt{MISTAGGING\_L} constants, for (respectively) the efficiency of tagging of a $b$-jet, the efficiency of mistagging a $c$-jet as a $b$-jet, and the efficiency of mistagging a light jet ($u$,$d$,$s$,$g$) as a $b$-jet.} 388 %(Fig.~\ref{fig:btag}) 389 . 396 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.}. 390 397 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 $0.7$). 391 392 %\begin{figure}[!h]393 %\begin{center}394 %\includegraphics[width=0.6\columnwidth]{btag}395 %\caption{Default efficiency of $b$-tag for jets coming from $b$ quarks, $c$ quarks and from other particles (jets from gluons or $u$, $d$ and $s$ quarks).}396 %\label{fig:btag}397 %\end{center}398 %\end{figure}399 400 398 401 399 \subsection{\texorpdfstring{$\tau$}{\texttau} identification} … … 528 526 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 $p_T^e > 50~\textrm{GeV}/c$. 529 527 530 A trigger emulation is included in \textsc{Delphes}, using a fully parametrisable \textit{trigger table}\footnote{\texttt{[code] }The trigger card is the \texttt{data/ trigger.dat} file.}. When enabled, this trigger is applied on analysis-object data.528 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. 531 529 In a real experiment, the online selection is often divided into several steps (or \textit{levels}). 532 530 This splits the overall reduction factor into a product of smaller factors, corresponding to the different trigger levels. … … 608 606 The resolution $\sigma_x$ of the horizontal component of \textsc{met} is observed to behave like 609 607 \begin{equation} 610 \sigma_x = \alpha ~\sqrt (E_T)~~~(\mathrm{GeV}^{1/2}),608 \sigma_x = \alpha ~\sqrt{E_T}~~~(\mathrm{GeV}^{1/2}), 611 609 \end{equation} 612 610 where the $\alpha$ parameter depends on the resolution of the calorimeters. 613 611 614 The \textsc{met} resolution expected for the \textsc{cms} detector for similar events is $\sigma_x = (0.6-0.7) ~ \sqrt (E_T)~ \mathrm{GeV}^{1/2}$ with no pile-up\footnote{\textit{Pile-up} events are extra simultaneous $pp$ collision occurring at high-luminosity in the same bunch crossing.}~\cite{bib:cmsjetresolution}, which compares very well with the $\alpha = 0.68$ obtained with \textsc{Delphes}.612 The \textsc{met} resolution expected for the \textsc{cms} detector for similar events is $\sigma_x = (0.6-0.7) ~ \sqrt{E_T} ~ \mathrm{GeV}^{1/2}$ with no pile-up\footnote{\textit{Pile-up} events are extra simultaneous $pp$ collision occurring at high-luminosity in the same bunch crossing.}~\cite{bib:cmsjetresolution}, which compares very well with the $\alpha = 0.68$ obtained with \textsc{Delphes}. 615 613 616 614 \subsection{\texorpdfstring{$\tau$}{\texttau}-jet efficiency} … … 647 645 % The outer layer of the central system (red) consist of a muon system. 648 646 % In addition, two end-cap calorimeters (blue) extend the pseudorapidity coverage of the central detector. 649 % The actual detector granularity and extension is defined in the smearingcard.647 % The actual detector granularity and extension is defined in the detector card. 650 648 % The detector is assumed to be strictly symmetric around the beam axis (black line). 651 649 % Additional forward detectors are not depicted.} … … 755 753 P. Demin, (2006), unpublished. Now part of \textsc{MadGraph/MadEvent}. 756 754 \bibitem{bib:cmsjetresolution} The CMS Collaboration, \textbf{CERN/LHCC} \\ \href{http://documents.cern.ch/cgi-bin/setlink?base=lhcc&categ=public&id=lhcc-2006-001}{2006-001}. 757 \bibitem{bib:ATLASresolution} The ATLAS Collaboration, \ \arXiv:\href{http://arxiv.org/abs/arxiv:0901.0512}{0901.0512v1}[hep-ex].755 \bibitem{bib:ATLASresolution} The ATLAS Collaboration, \textbf{CERN-OPEN} 2008-020, arXiv:\href{http://arxiv.org/abs/arxiv:0901.0512}{0901.0512v1}[hep-ex]. 758 756 \bibitem{bib:Hector} %\textsc{Hector}, \textit{a fast simulator for the transport of particles in beamlines}, 759 757 X. Rouby, J. de Favereau, K. Piotrzkowski, \textbf{JINST} \href{http://www.iop.org/EJ/abstract/1748-0221/2/09/P09005}{2 P09005 (2007)}. … … 783 781 \bibitem{bib:papierquisortirajamais}J. de Favereau~et~al, \textbf{CP3-08-04} (2008), to be published in EPJ. 784 782 785 \bibitem{bib:papiersimon} "Phenomenology of a twisted two-Higgs-doublet model", Simon de Visscher, Jean-Marc Gerard, Michel Herquet, Vincent Lemaitre, Fabio Maltoni, to be published.783 \bibitem{bib:papiersimon} ``Phenomenology of a twisted two-Higgs-doublet model'', Simon de Visscher, Jean-Marc Gerard, Michel Herquet, Vincent Lema\^itre, Fabio Maltoni, to be published. 786 784 787 785 \bibitem{bib:mcfio} P. Lebrun, L. Garren, Copyright (c) 1994-1995 Universities Research Association, Inc. … … 1237 1235 \end{quote} 1238 1236 \end{itemize} 1237 1239 1238 1240 1239 \end{document}
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