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trunk/paper/CommPhysComp/notes.tex
r560 r561 49 49 calorimeters and a muon system, and possible very forward detectors arranged 50 50 along the beamline. 51 The framework is interfaced to standard file formats (e.g.\ Les Houches Event File or \texttt{HepMC}) and outputs observables such as isolated leptons, missing transverse energy and collection of jets which can be used for dedicated analyses. 52 The simulation of the detector response takes into account the effect of magnetic field, the granularity of the calorimeters and subdetector resolutions. 53 A simplified preselection can also be applied on processed events for trigger emulation. Detection of very forward scattered particles relies on the transport in beamlines with the \textit{Hector} software. Finally, the \textsc{FROG} 2D/3D event display is used for visualisation of the collision final states. 51 The framework is interfaced to standard file formats (e.g.\ Les Houches Event 52 File or \texttt{HepMC}) and outputs observables such as isolated leptons, 53 missing transverse energy and collection of jets which can be used for dedicated 54 analyses. The simulation of the detector response takes into account the effect 55 of magnetic field, the granularity of the calorimeters and subdetector 56 resolutions. 57 A simplified preselection can also be applied on processed events for trigger 58 emulation. Detection of very forward scattered particles relies on the transport 59 in beamlines with the \textit{Hector} software. Finally, the \textsc{FROG} 2D/3D 60 event display is used for visualisation of the collision final states. 54 61 \\ \\ 55 62 … … 116 123 117 124 118 This complexity can only be handled by large collaborations. Such simulation is 119 very complicated, technical and requires a large \texttt{CPU} power. 125 This complexity can only be handled by large collaborations. 120 126 Phenomenological studies, looking for the observability of given signals, 121 127 require in general only fast but realistic estimates of the expected signal … … 210 216 \textsc{ATLAS}), this input parameter file interfaces a flexible parametrisation 211 217 for other cases, e.g.\ at future linear colliders~\citep{qr:datacards}. 212 If no detector card is provided, predefined values based on ``typical'' 213 \textsc{CMS} acceptances and resolutions are used. The geometrical coverage of 214 the various subsystems used in the default configuration are summarised in 215 Tab.~\ref{tab:defEta}. The detector is assumed to be strictly symmetric around 216 the beam axis. 218 The geometrical coverage of the various subsystems used in the default 219 configuration are summarised in Tab.~\ref{tab:defEta}. 217 220 218 221 \begin{table}[t] … … 257 260 position at which charged particles enter the calorimeters and their 258 261 corresponding tracks. The field extension is limited to the tracker volume and 259 is in particular not applied for muon chambers. Howerver, this is not a limiting 260 factor as the resolution applied for muon reconstruction is the one expected by 261 the experiment, which consequently includes the effects of the magnetic field 262 within the muon system. 262 is in particular not applied for muon chambers. This is not a limiting 263 factor since the magnetic field is not used for the muon momentum smearing. 263 264 264 265 265 266 \subsection{Tracks reconstruction} 266 Every stable charged particle with a transverse momentum above some threshold and lying inside the detector volume covered by the tracker provides a track. 267 Every stable charged particle with a transverse momentum above some threshold 268 and lying inside the detector volume covered by the tracker provides a track. 267 269 By default, a track is assumed to be reconstructed with $90\%$ probability if 268 270 its transverse momentum $p_T$ is higher than $0.9~\textrm{GeV}/c$ and if its 269 271 pseudorapidity $|\eta| \leq 2.5$~\citep{qr:tracks}. No smearing is currently 270 applied on tracks. 272 applied on track parameters. For each track, the positions at vertex 273 $(\eta,\phi)$ and at the entry point in the calorimeter layers 274 $(\eta,\phi)_{calo}$ are available. 271 275 272 276 … … 280 284 regions~\citep{bib:cmsjetresolution,bib:ATLASresolution}. It is thus very 281 285 important to compute the exact coordinates of the entry point of the particles 282 into the calorimeters, via the magnetic field calculations.286 into the calorimeters, in taking the magnetic field effect into account. 283 287 284 288 The smallest unit for geometrical sampling of the calorimeters is a … … 308 312 where $S$, $N$ and $C$ are the \textit{stochastic}, \textit{noise} and \textit{constant} terms, respectively, and $\oplus$ stands for quadratic additions~\citep{qr:energysmearing}.\\ 309 313 310 In the default parametrisation, ECAL and HCAL are assumed to cover the pseudorapidity range $|\eta|<3$, and FCAL between $3.0$ and $5.0$, with different response to electromagnetic objects ($e^\pm, \gamma$) or hadrons. 311 Muons and neutrinos are assumed not to interact with the calorimeters~\citep{qr:invisibleparticles}. 312 The default values of the stochastic, noise and constant terms are given in Tab.~\ref{tab:defResol}.\\ 314 In the default parametrisation, ECAL and HCAL are assumed to cover the 315 pseudorapidity range $|\eta|<3$, and FCAL between $3.0$ and $5.0$, with 316 different response to electrons and photons, or to hadrons. 317 Muons and neutrinos are assumed not to interact with the 318 calorimeters~\citep{qr:invisibleparticles}. The default values of the 319 stochastic, noise and constant terms are given in Tab.~\ref{tab:defResol}.\\ 313 320 314 321 \begin{table}[!h] … … 336 343 337 344 338 Electrons and photons leave their energy in the electromagnetic parts of the339 calorimeters (\textsc{ECAL} and \textsc{FCAL}, e.m.), while charged and neutral 340 final-state hadrons interact with the hadronic parts (\textsc{HCAL} and 341 \textsc{FCAL}, had.).345 Electrons and photons are assumed to leave their energy in the electromagnetic 346 parts of the calorimeters (\textsc{ECAL} and \textsc{FCAL}, e.m.), while charged 347 and neutral final-state hadrons are assumed to leave their entire energy 348 interactin the hadronic parts (\textsc{HCAL} and \textsc{FCAL}, had.). 342 349 Some long-living particles, such as the $K^0_s$ and $\Lambda$'s, with lifetime 343 350 $c\tau$ smaller than $10~\textrm{mm}$ are considered as stable particles by the 344 generators although they may decay before the calorimeters. The energy smearing345 of such particles is therefore performed using the expected fraction of the 346 energy, determined according to their decay products, that would be deposited 347 into the \textsc{ECAL} ($E_{\textsc{ECAL}}$) and into the \textsc{HCAL} 348 ($E_{\textsc{HCAL}}$). Defining $F$ as the fraction of the energy leading to a 349 \textsc{HCAL} deposit, the two energy values are given by351 generators although they may decay before reaching the calorimeters. The energy 352 smearing of such particles is therefore performed using the expected fraction of 353 the energy, determined according to their decay products, that would be 354 deposited into the \textsc{ECAL} ($E_{\textsc{ECAL}}$) and into the 355 \textsc{HCAL} ($E_{\textsc{HCAL}}$). Defining $F$ as the fraction of the energy 356 leading to a \textsc{HCAL} deposit, the two energy values are given by 350 357 \begin{equation} 351 358 \left\{ … … 356 363 \right. 357 364 \end{equation} 358 where $0 \leq F \leq 1$. The electromagnetic part is handled similarly as for 359 electrons and photons. The resulting calorimetry energy measurement given after 360 the application of the smearing is then $E = E_{\textsc{HCAL}} + 365 where $0 \leq F \leq 1$. The resulting calorimetry energy measurement given 366 after the application of the smearing is then $E = E_{\textsc{HCAL}} + 361 367 E_{\textsc{ECAL}}$. For $K_S^0$ and $\Lambda$ hadrons, the energy fraction is 362 368 $F$ is assumed to be $0.7$~\citep{qr:emhadratios}.\\ … … 370 376 (\textsc{MET}), and are used as input for the jet reconstruction algorithms. 371 377 372 373 374 375 \section{High-level object reconstruction}376 377 378 The output file created by \textit{Delphes}~\citep{qr:analysistree} stores the 378 379 final collections of particles ($e^\pm$, $\mu^\pm$, $\gamma$) and objects (light 379 jets, $b$-jets, $\tau$-jets, $E_T^\textrm{miss}$). In addition, some detector 380 data are added, such as tracks, calorimetric cells and hits in the very forward 381 detectors (\textsc{ZDC}, \textsc{RP220} and \textsc{FP420}, see 382 Sec.~\ref{sec:vfd}). While electrons, muons and photons are easily identified, 383 other quantities are more difficult to evaluate as they rely on sophisticated 384 algorithms (e.g. jets or missing energy). 380 jets, $b$-jets, $\tau$-jets, $E_T^\textrm{miss}$). In addition, collections of 381 tracks, calorimetric cells and hits in the very forward detectors (\textsc{ZDC}, 382 \textsc{RP220} and \textsc{FP420}, see Sec.~\ref{sec:vfd}) are added. 383 384 \section{High-level reconstruction} 385 386 While electrons, 387 muons and photons are easily identified, other quantities are more difficult to 388 evaluate as they rely on sophisticated algorithms (e.g. jets or missing energy). 385 389 386 390 For most of these objects, their four-momentum and related quantities are … … 411 415 collections if they fall into the acceptance of the tracking system and have a 412 416 transverse momentum above some threshold (default: $p_T > 10~\textrm{GeV}/c$). 413 Assuming a good measurement of the track parameters in the real experiment, the 414 electron energy can be reasonably recovered. \textit{Delphes} assumes a perfect 417 \textit{Delphes} assumes a perfect 415 418 algorithm for clustering and Brehmstrahlung recovery. Electron energy is smeared 416 419 according to the resolution of the calorimetric cell where it points to, but 417 independently from any other deposited energy is this cell. 418 Electrons and photons may create a candidate in the jet collection. 420 independently from any other deposited energy in this cell. 421 Electrons and photons may create a candidate in the jet collection. The $(\eta, 422 \phi)$ position at vertex corresponds to corresponding track vertex. 419 423 420 424 \subsubsection*{Muons} 421 425 Generator-level muons entering the muon detector acceptance (default: $-2.4 422 \leq \eta \leq 2.4$) and overpassing some threshold (default 426 \leq \eta \leq 2.4$) and overpassing some threshold (default: $p_T > 423 427 10~\textrm{GeV}/c$) are considered as good candidates for analyses. 424 428 The application of the detector resolution on the muon momentum depends on a 425 429 Gaussian smearing of the $p_T$~\citep{qr:muonsmearing}. 426 Neither $\eta$ nor $\phi$ variables are modified beyond the calorimeters : no427 additional magnetic field is applied. Multiple scattering is neglected. This 428 implies that low energy muons have in \textit{Delphes} a better resolution than 429 in a real detector. At last, the particles which might leak out of the 430 calorimeters into the muon systems (\textit{punch-through}) are not considered 431 as muon candidates in\textit{Delphes}.430 Neither $\eta$ nor $\phi$ variables are modified beyond the calorimeters. 431 Multiple scattering is neglected. This implies that low energy muons have in 432 \textit{Delphes} a better resolution than in a real detector. At last, the 433 particles which might leak out of the calorimeters into the muon systems 434 (\textit{punch-through}) are not considered as muon candidates in 435 \textit{Delphes}. 432 436 433 437 \subsubsection*{Charged lepton isolation} … … 437 441 isolation criteria can be applied. This requires that electron or muon 438 442 candidates are isolated in the detector from any other particle, within a small 439 cone. In \textit{Delphes}, charged lepton isolation demands that there is no 440 other charged particle with $p_T>2~\textrm{GeV}/c$ within a cone of $\Delta R = 441 \sqrt{\Delta \eta^2 + \Delta \phi^2} <0.5$ centered on the cell associated to 442 the charged lepton $\ell$, obviously taking the magnetic field into account. 443 cone. In \textit{Delphes}, charged lepton isolation demands by default that 444 there is no other charged particle with $p_T>2~\textrm{GeV}/c$ within a cone of 445 $\Delta R = \sqrt{\Delta \eta^2 + \Delta \phi^2} <0.5$ centered on the cell 446 associated to the charged lepton $\ell$, obviously taking the magnetic field 447 into account. 443 448 444 449 The result (i.e.\ \textit{isolated} or \textit{not}) is added to the charged lepton measured properties. … … 509 514 In jets, several particle can leave their energy into a given calorimetric cell, 510 515 which broadens the jet energy resolution. However, the energy of charged 511 particles associated to jets can be deduced from their reconstructed track, thus516 particles associated to jets can be deduced from their associated track, thus 512 517 providing a way to identify some of the components of cells with multiple hits. 513 518 When the \textit{energy flow} is switched on in \textit{Delphes}, the energy of 514 519 tracks pointing to calorimetric cells is subtracted and smeared separately, 515 520 before running the chosen jet reconstruction algorithm. This option allows a 516 better jet $E$reconstruction~\citep{qr:energyflow}.521 better jet energy reconstruction~\citep{qr:energyflow}. 517 522 518 523 \subsection{$b$-tagging} … … 520 525 521 526 A jet is tagged as $b$-jets if its direction lies in the acceptance of the 522 tracker and if it is associated to a parent $b$-quark. By default, a $b$-tagging 523 efficiency of $40\%$ is assumed if the jet has a parent $b$ quark. For $c$-jets 524 and light jets (i.e.\ originating in $u$, $d$, $s$ quarks or in gluons), a fake 525 $b$-tagging efficiency of $10 \%$ and $1 \%$ respectively is 526 assumed~\citep{qr:btag}. The (mis)tagging relies on the identity of 527 tracker and if it is associated to a parent $b$-quark. 528 The (mis)tagging relies on the identity of 527 529 the most energetic parton within a cone around the jet axis, with a 528 530 radius equal to the one used to reconstruct the jet (default: $\Delta R$ of 529 $0.7$). In current version of \textit{Delphes}, the displacement of secondary 530 vertices is not simulated. 531 532 \subsection{\texorpdfstring{$\tau$}{\texttau} identification} 531 $0.7$). 532 By default, a $b$-tagging efficiency of $40\%$ is assumed if the jet has a 533 parent $b$ quark. For $c$-jets and light jets (i.e.\ originating in $u$, $d$, 534 $s$ quarks or in gluons), a fake $b$-tagging efficiency of $10 \%$ and $1 \%$ 535 is assumed respectively~\citep{qr:btag}. Therefore, in current version of 536 \textit{Delphes}, the displacement of secondary vertices is not taken into 537 account. As such, the $b$-tagging efficiency is below the expected $40\%$. 538 539 \subsection{Identification of hadronic \texorpdfstring{$\tau$}{\texttau} decays} 533 540 534 541 Jets originating from $\tau$-decays are identified using a procedure consistent … … 536 543 The tagging relies on two properties of the $\tau$ lepton. First, $77\%$ of the 537 544 $\tau$ hadronic decays contain only one charged hadron associated to a few 538 neutrals ( Tab.~\ref{tab:taudecay}). Secondly, the particles arisen from the545 neutrals (\textit{1-prong}). Secondly, the particles arisen from the 539 546 $\tau$ lepton produce narrow jets in the calorimeter (this is defined as the jet 540 547 \textit{collimation}). 541 542 543 \begin{table}[!h]544 \begin{center}545 \caption{ Branching ratios for $\tau^-$ lepton~\citep{bib:pdg}. $h^\pm$ and546 $h^0$ refer to charged and neutral hadrons, respectively. $n \geq 0$ and $m \geq547 0$ are integers.548 \vspace{0.5cm} }549 \begin{tabular}[!h]{lll}550 \hline551 \multicolumn{3}{l}{\textbf{Leptonic decays}}\\552 & $ \tau^- \rightarrow e^- \ \bar \nu_e \ \nu_\tau$ & $17.9\% $ \\553 & $ \tau^- \rightarrow \mu^- \ \bar \nu_\mu \ \nu_\tau$ & $17.4\%$ \\554 \multicolumn{3}{l}{\textbf{Hadronic decays}}\\555 & $ \tau^- \rightarrow h^-\ (n\times h^\pm) \ (m\times h^0) \ \nu_\tau$ & $64.7\%$ \\556 & $ \tau^- \rightarrow h^-\ (m\times h^0) \ \nu_\tau$ & $50.1\%$ \\557 & $ \tau^- \rightarrow h^-\ h^+ h^- (m\times h^0) \ \nu_\tau$ & $14.6\%$ \\558 \hline559 \end{tabular}560 \label{tab:taudecay}561 \end{center}562 \end{table}563 548 564 549 \begin{figure}[!ht] … … 622 607 of tracks associated to particles with significant transverse momenta is one and 623 608 only one in a cone of radius $R^\textrm{tracks}$ ($3-$prong $\tau$-jets are 624 dropped). This cone should be entirely incorporated into the tracker to be taken 625 into account. Default values of these parameters are given in609 rejected). This cone should be entirely incorporated into the tracker to be 610 taken into account. Default values of these parameters are given in 626 611 Tab.~\ref{tab:tauRef}. 627 612 … … 658 643 worsens directly the measured missing transverse energy $\overrightarrow 659 644 {E_T}^\textrm{miss}$. In \textit{Delphes}, \textsc{MET} is based on the 660 calorimetric cells only. Muons and neutrinos are therefore not taken into661 account for its evaluation:645 calorimetric cells only. Muons and neutrinos are therefore 646 not taken into account for its evaluation: 662 647 \begin{equation} 663 648 \overrightarrow{E_T}^\textrm{miss} = - \sum^\textrm{cells}_i \overrightarrow{E_T}(i) … … 694 679 \section{\label{sec:vfd}Very forward detector simulation} 695 680 696 Most of the recent experiments in beam colliders have additional 697 instrumentation along the beamline. These extend the $\eta$ coverage to higher 698 values, for the detection of very forward final-state particles. In 699 \textit{Delphes}, Zero Degree Calorimeters, roman pots and forward taggers have 700 been implemented (Fig.~\ref{fig:fdets}), similarly as for CMS and 701 ATLAS collaborations~\citep{bib:cmsjetresolution,bib:ATLASresolution}.681 Collider experiments often have additional instrumentation along the beamline. 682 These extend the $\eta$ coverage to higher values, for the detection of very 683 forward final-state particles. In \textit{Delphes}, Zero Degree Calorimeters, 684 roman pots and forward taggers have been implemented (Fig.~\ref{fig:fdets}), 685 similarly as for CMS and ATLAS collaborations~\citep{bib:cmsjetresolution, 686 bib:ATLASresolution}. 702 687 703 688 \begin{figure}[!ht] … … 822 807 823 808 To be able to reach these detectors, particles must have a charge identical to 824 the beam particles, and a momentum very close to the nominal value of the beam .825 These taggers are near-beam detectors located a few millimetres from the true 826 beam trajectory and this distance defines their acceptance809 the beam particles, and a momentum very close to the nominal value of the beam 810 particules. These taggers are near-beam detectors located a few millimetres from 811 the true beam trajectory and this distance defines their acceptance 827 812 (Tab.~\ref{tab:fdetacceptance}). For instance, roman pots at $220~\textrm{m}$ 828 813 from the \textsc{IP} and $2~\textrm{mm}$ from the beam will detect all forward 829 814 protons with an energy between $120$ and $900~\textrm{GeV}$~\citep{bib:hector}. 830 In practice, in the \textsc{LHC}, only positively charged muons ($\mu^+$) and 831 protons can reach the forward taggers as other particles with a single positive 832 charge coming from the interaction points will decay before their possible 833 tagging. In \textit{Delphes}, extra hits coming from the beam-gas events or 815 In \textit{Delphes}, extra hits coming from the beam-gas events or 834 816 secondary particles hitting the beampipe in front of the detectors are not taken 835 817 into account. … … 849 831 these the particle energy ($E$) and the momentum transfer it underwent during 850 832 the interaction ($q^2$) can be reconstructed at the analysis level (it is not 851 implemented in the current versions of \textit{Delphes} . The time-of-flight833 implemented in the current versions of \textit{Delphes}). The time-of-flight 852 834 measurement can be smeared with a Gaussian distribution (default value 853 835 $\sigma_t = 0~\textrm{s}$)~\citep{qr:protontaggers}. … … 868 850 \textsc{ATLAS}~\citep{bib:ATLASresolution} detectors. 869 851 870 Electrons and muons are by construction equal to the experiment designs, as the 871 Gaussian smearing of their kinematics properties is defined according to the 872 detector specifications. Similarly, the $b$-tagging efficiency (for real 873 $b$-jets) and misidentification rates (for fake $b$-jets) are taken directly 874 from the expected values of the experiment. Unlike these simple objects, jets 875 and missing transverse energy should be carefully cross-checked. 852 Electrons and muons resolutions in \textit{Delphes} match by construction the 853 experiment designs, as the Gaussian smearing of their kinematics properties is 854 defined according to the detector specifications. Similarly, the $b$-tagging 855 efficiency (for real $b$-jets) and misidentification rates (for fake $b$-jets) 856 are taken directly from the expected values of the experiment. Unlike these 857 simple objects, jets and missing transverse energy should be carefully 858 cross-checked. 876 859 877 860 \subsection{Jet resolution} … … 895 878 The jets made of generator-level particles, here referred as \textit{MC jets}, 896 879 are obtained by applying the algorithm to all particles considered as stable 897 after hadronisation (i.e.\ including muons). Jets produced by \textit{Delphes}880 after hadronisation. Jets produced by \textit{Delphes} 898 881 and satisfying the matching criterion are called hereafter \textit{reconstructed 899 882 jets}. All jets are computed with the clustering algorithm (JetCLU) with a cone … … 918 901 %\includegraphics[width=\columnwidth]{resolutionJet} 919 902 \includegraphics[width=\columnwidth]{fig8} 920 \caption{Resolution of the transverse energy of reconstructed jets $E_T^\textrm{rec}$ as a function of the transverse energy of the closest jet of generator-level particles $E_T^\textrm{MC}$, in a \textsc{CMS}-like detector. The jets events are reconstructed with the JetCLU clustering algorithm with a cone radius of $0.7$. The maximum separation between the reconstructed and \textsc{MC}-jets is $\Delta R= 0.25$. Dotted line is the fit result for comparison to the \textsc{CMS} resolution~\citep{bib:cmsjetresolution}, in blue. The $pp \rightarrow gg$ dijet events have been generated with MadGraph/MadEvent and hadronised with \textit{Pythia}.} 903 \caption{Resolution of the transverse energy of reconstructed jets 904 $E_T^\textrm{rec}$ as a function of the transverse energy of the closest jet of 905 generator-level particles $E_T^\textrm{MC}$, in a \textsc{CMS}-like detector. 906 The jets events are reconstructed with the JetCLU clustering algorithm with a 907 cone radius of $0.7$. The maximum separation between the reconstructed and 908 \textsc{MC}-jets is $\Delta R= 0.25$. Dotted line is the fit result for 909 comparison to the \textsc{CMS} resolution~\citep{bib:cmsjetresolution}, in blue. 910 The $pp \rightarrow gg$ dijet events have been generated with MadGraph/MadEvent 911 and hadronised with \textit{Pythia}.} 921 912 \label{fig:jetresolcms} 922 913 \end{center} 923 914 \end{figure} 924 915 925 The resulting jet resolution as a function of $E_T^\textrm{MC}$ is shown in Fig.~\ref{fig:jetresolcms}. 916 The resulting jet resolution as a function of $E_T^\textrm{MC}$ is shown in 917 Fig.~\ref{fig:jetresolcms}. 926 918 This distribution is fitted with a function of the following form: 927 919 \begin{equation} … … 930 922 \end{equation} 931 923 where $a$, $b$ and $c$ are the fit parameters. 932 It is then compared to the resolution published by the \textsc{CMS} collaboration~\citep{bib:cmsjetresolution}. The resolution curves from \textit{Delphes} and \textsc{CMS} are in good agreement. 933 934 Similarly, the jet resolution is evaluated for an \textsc{ATLAS}-like detector. The $pp \rightarrow gg$ events are here arranged in $8$ adjacent bins in $p_T$. A $k_T$ reconstruction algorithm with $R=0.6$ is chosen and the maximal matching distance between the \textsc{MC}-jets and the reconstructed jets is set to $\Delta R=0.2$. The relative energy resolution is evaluated in each bin by: 924 It is then compared to the resolution published by the \textsc{CMS} 925 collaboration~\citep{bib:cmsjetresolution}. The resolution curves from 926 \textit{Delphes} and \textsc{CMS} are in good agreement. 927 928 Similarly, the jet resolution is evaluated for an \textsc{ATLAS}-like detector. 929 The $pp \rightarrow gg$ events are here arranged in $8$ adjacent bins in $p_T$. 930 A $k_T$ reconstruction algorithm with $R=0.6$ is chosen and the maximal matching 931 distance between the \textsc{MC}-jets and the reconstructed jets is set to 932 $\Delta R=0.2$. The relative energy resolution is evaluated in each bin by: 935 933 \begin{equation} 936 \frac{\sigma(E)}{E} = \sqrt{~~ \Bigg \langle ~\Bigg( \frac{E^\textrm{rec} - E^\textrm{MC}}{E^\textrm{rec}} \Bigg)^2 ~ \Bigg \rangle ~ - ~ \Bigg \langle \frac{E^\textrm{rec} - E^\textrm{MC}}{ E^\textrm{rec} } \Bigg \rangle^2}. 934 \frac{\sigma(E)}{E} = \sqrt{~~ \Bigg \langle ~\Bigg( \frac{E^\textrm{rec} - 935 E^\textrm{MC}}{E^\textrm{rec}} \Bigg)^2 ~ \Bigg \rangle ~ - ~ \Bigg \langle 936 \frac{E^\textrm{rec} - E^\textrm{MC}}{ E^\textrm{rec} } \Bigg \rangle^2}. 937 937 \end{equation} 938 938 939 Figure~\ref{fig:jetresolatlas} shows a good agreement between the resolution obtained with \textit{Delphes}, the result of the fit with Equation~\ref{eq:fitresolution} and the corresponding curve provided by the \textsc{ATLAS} collaboration~\citep{bib:ATLASresolution}. 939 Figure~\ref{fig:jetresolatlas} shows a good agreement between the resolution 940 obtained with \textit{Delphes}, the result of the fit with 941 Equation~\ref{eq:fitresolution} and the corresponding curve provided by the 942 \textsc{ATLAS} collaboration~\citep{bib:ATLASresolution}. 940 943 941 944 \begin{figure}[!ht] 942 945 \begin{center} 943 946 \includegraphics[width=\columnwidth]{fig9} 944 \caption{Relative energy resolution of reconstructed jets as a function of the energy of the closest jet of generator-level particles $E^\textrm{MC}$, in an \textsc{ATLAS}-like detector. The jets are reconstructed with the $k_T$ algorithm with a radius $R=0.6$. The maximal matching distance between \textsc{MC}- and reconstructed jets is $\Delta R=0.2$. Only central jets are considered ($|\eta|<0.5$). Dotted line is the fit result for comparison to the \textsc{ATLAS} resolution~\citep{bib:ATLASresolution}, in blue. The $pp \rightarrow gg$ di-jet events have been generated with MadGraph/MadEvent and hadronised with \textit{Pythia}.} 947 \caption{Relative energy resolution of reconstructed jets as a function of the 948 energy of the closest jet of generator-level particles $E^\textrm{MC}$, in an 949 \textsc{ATLAS}-like detector. The jets are reconstructed with the $k_T$ 950 algorithm with a radius $R=0.6$. The maximal matching distance between 951 \textsc{MC}- and reconstructed jets is $\Delta R=0.2$. Only central jets are 952 considered ($|\eta|<0.5$). Dotted line is the fit result for comparison to the 953 \textsc{ATLAS} resolution~\citep{bib:ATLASresolution}, in blue. The $pp 954 \rightarrow gg$ di-jet events have been generated with MadGraph/MadEvent and 955 hadronised with \textit{Pythia}.} 945 956 \label{fig:jetresolatlas} 946 957 \end{center} … … 950 961 \subsection{MET resolution} 951 962 952 All major detectors at hadron colliders have been designed to be as much hermetic as possible in order to detect the presence of one or more neutrinos and/or new weakly interacting particles through apparent missing transverse energy. 953 The resolution of the $\overrightarrow{E_T}^\textrm{miss}$ variable, as obtained with \textit{Delphes}, is then crucial. 954 955 The samples used to study the \textsc{MET} performance are identical to those used for the jet validation. 956 It is worth noting that the contribution to $E_T^\textrm{miss}$ from muons is negligible in the studied sample. 957 The input samples are divided in five bins of scalar $E_T$ sums $(\Sigma E_T)$. This sum, called \textit{total visible transverse energy}, is defined as the scalar sum of transverse energy in all cells. 958 The quality of the \textsc{MET} reconstruction is checked via the resolution on its horizontal component $E_x^\textrm{miss}$. 959 960 The $E_x^\textrm{miss}$ resolution is evaluated in the following way. 961 The distribution of the difference between $E_x^\textrm{miss}$ in \textit{Delphes} and at generator-level is fitted with a Gaussian function in each $(\Sigma E_T)$ bin. The fit \textsc{RMS} gives the \textsc{MET} resolution in each bin. 962 The resulting value is plotted in Fig.~\ref{fig:resolETmis} as a function of the total visible transverse 963 All major detectors at hadron colliders have been designed to be as hermetic as 964 possible in order to detect the presence of one or more neutrinos and/or new 965 weakly interacting particles through apparent missing transverse energy. 966 The resolution of the $\overrightarrow{E_T}^\textrm{miss}$ variable, as 967 obtained with \textit{Delphes}, is then crucial. 968 969 The samples used to study the \textsc{MET} performance are identical to those 970 used for the jet validation. It is worth noting that the contribution to 971 $E_T^\textrm{miss}$ from muons is negligible in the studied sample. 972 The input samples are divided in five bins of scalar $E_T$ sums $(\Sigma E_T)$. 973 This sum, called \textit{total visible transverse energy}, is defined as the 974 scalar sum of transverse energy in all cells. The quality of the \textsc{MET} 975 reconstruction is checked via the resolution on its horizontal component 976 $E_x^\textrm{miss}$. 977 978 The $E_x^\textrm{miss}$ resolution is evaluated in the following way. The 979 distribution of the difference between $E_x^\textrm{miss}$ in \textit{Delphes} 980 and at generator-level is fitted with a Gaussian function in each $(\Sigma E_T)$ 981 bin. The fit \textsc{RMS} gives the \textsc{MET} resolution in each bin. 982 The resulting value is presented in Fig.~\ref{fig:resolETmis} as a function of 983 the total visible transverse 963 984 energy, for \textsc{CMS}- and \textsc{ATLAS}-like detectors. 964 985 … … 968 989 \includegraphics[width=\columnwidth]{fig10} 969 990 \includegraphics[width=\columnwidth]{fig10b} 970 \caption{$\sigma(E^\textrm{mis}_{x})$ as a function on the scalar sum of all cells ($\Sigma E_T$) for $pp \rightarrow gg$ events, for a \textsc{CMS}-like detector (top) and an \textsc{ATLAS}-like detector (bottom), for di-jet events produced with MadGraph/MadEvent and hadronised with \textit{Pythia}.} 991 \caption{$\sigma(E^\textrm{mis}_{x})$ as a function on the scalar sum of all 992 cells ($\Sigma E_T$) for $pp \rightarrow gg$ events, for a \textsc{CMS}-like 993 detector (top) and an \textsc{ATLAS}-like detector (bottom), for di-jet events 994 produced with MadGraph/MadEvent and hadronised with \textit{Pythia}.} 971 995 \label{fig:resolETmis} 972 996 \end{center} 973 997 \end{figure} 974 998 975 The resolution $\sigma_x$ of the horizontal component of \textsc{MET} is observed to behave like 999 The resolution $\sigma_x$ of the horizontal component of \textsc{MET} is 1000 observed to behave like 976 1001 \begin{equation} 977 1002 \sigma_x = \alpha ~\sqrt{E_T}~~~(\mathrm{GeV}^{1/2}), … … 979 1004 where the $\alpha$ parameter depends on the resolution of the calorimeters. 980 1005 981 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 (i.e. extra simultaneous $pp$ collision occurring at high-luminosity in the same bunch crossing)~\citep{bib:cmsjetresolution}, which compares very well with the $\alpha = 0.63$ obtained with \textit{Delphes}. Similarly, for an \textsc{ATLAS}-like detector, a value of $0.53$ is obtained by \textit{Delphes} for the $\alpha$ parameter, while the experiment expects it in the range $[0.53~ ;~0.57]$~\citep{bib:ATLASresolution}. 1006 The \textsc{MET} resolution expected for the \textsc{CMS} detector for similar 1007 events is $\sigma_x = (0.6-0.7) ~ \sqrt{E_T} ~ \mathrm{GeV}^{1/2}$ with no 1008 pile-up (i.e. extra simultaneous $pp$ collision occurring at high-luminosity in 1009 the same bunch crossing)~\citep{bib:cmsjetresolution}, which compares very well 1010 with the $\alpha = 0.63$ obtained with \textit{Delphes}. Similarly, for an 1011 \textsc{ATLAS}-like detector, a value of $0.53$ is obtained by \textit{Delphes} 1012 for the $\alpha$ parameter, while the experiment expects it in the range $[0.53~ 1013 ;~0.57]$~\citep{bib:ATLASresolution}. 982 1014 983 1015 \subsection{\texorpdfstring{$\tau$}{\texttau}-jet efficiency} 984 Due to the complexity of their reconstruction algorithm, $\tau$-jets have also to be checked. 985 Table~\ref{tab:taurecoefficiency} lists the reconstruction efficiencies in \textit{Delphes} for the hadronic $\tau$-jets from $H,Z \rightarrow \tau^+ \tau^-$. The mass of the Higgs boson is set successively to $140$ and $300~\textrm{GeV}/c^2$. The inclusive gauge boson productions ($pp \rightarrow HX$ and $pp \rightarrow ZX$) are performed with MadGraph/MadEvent and the $\tau$ lepton decay and further hadronisation are handled by \textit{Pythia/Tauola}. All reconstructed $\tau$-jets are $1-$prong, and follow the definition described in section~\ref{btagging}, which is very close to an algorithm of the \textsc{CMS} experiment~\citep{bib:cmstauresolution}. At last, corresponding efficiencies published by the \textsc{CMS} and \textsc{ATLAS} experiments are quoted for comparison. The agreement is good enough at this level to validate the $\tau-$reconstruction. 1016 Table~\ref{tab:taurecoefficiency} lists the reconstruction efficiencies in 1017 \textit{Delphes} for the hadronic $\tau$-jets from $H,Z \rightarrow \tau^+ 1018 \tau^-$. The mass of the Higgs boson is set successively to $140$ and 1019 $300~\textrm{GeV}/c^2$. The inclusive gauge boson productions ($pp \rightarrow 1020 HX$ and $pp \rightarrow ZX$) are performed with MadGraph/MadEvent and the $\tau$ 1021 lepton decay and further hadronisation are handled by \textit{Pythia/Tauola}. 1022 All reconstructed $\tau$-jets are $1-$prong, and follow the definition described 1023 in section~\ref{btagging}, which is very close to an algorithm of the 1024 \textsc{CMS} experiment~\citep{bib:cmstauresolution}. At last, corresponding 1025 efficiencies published by the \textsc{CMS} and \textsc{ATLAS} experiments are 1026 quoted for comparison. The level of agreement is satisfactory provided possible 1027 differences due to the event generation chain and the detail of reconstruction 1028 algorithms. 986 1029 987 1030 \begin{table}[!h] 988 1031 \begin{center} 989 \caption{Reconstruction efficiencies of $\tau$-jets in $\tau^+ \tau^-$ decays from $Z$ or $H$ bosons, in \textit{Delphes}, \textsc{CMS} and \textsc{ATLAS} experiments~\citep{bib:cmstauresolution,bib:ATLASresolution}. Two scenarios for the mass of the Higgs boson are investigated. Events generated with MadGraph/MadEvent and hadronised with \textit{Pythia}. The decays of $\tau$ leptons is handled by the \textit{Tauola} version embedded in \textit{Pythia}.\vspace{0.5cm}} 990 %\begin{tabular}{lll} 991 %\hline 992 %\multicolumn{2}{c}{\textsc{CMS}} & \\ 993 %$Z \rightarrow \tau^+ \tau^-$ & $38 \%$ & \\ 994 %$H \rightarrow \tau^+ \tau^-$ & $36 \%$ & $m_H = 150~\textrm{GeV}/c^2$ \\ 995 %$H \rightarrow \tau^+ \tau^-$ & $47 \%$ & $m_H = 300~\textrm{GeV}/c^2$ \\ 996 %\multicolumn{2}{c}{Delphes} & \\ 997 %$H \rightarrow \tau^+ \tau^-$ &$42 \%$ & $m_H = 140~\textrm{GeV}/c^2$ \\ 998 %\hline 999 %\end{tabular} 1000 1032 \caption{Reconstruction efficiencies of $\tau$-jets in $\tau^+ \tau^-$ decays 1033 from $Z$ or $H$ bosons, in \textit{Delphes}, \textsc{CMS} and \textsc{ATLAS} 1034 experiments~\citep{bib:cmstauresolution,bib:ATLASresolution}. Two scenarios for 1035 the mass of the Higgs boson are investigated. Events generated with 1036 MadGraph/MadEvent and hadronised with \textit{Pythia}. The decays of $\tau$ 1037 leptons is handled by the \textit{Tauola} version embedded in 1038 \textit{Pythia}.\vspace{0.5cm}} 1001 1039 \begin{tabular}{lrlrl} 1002 1040 \hline 1003 & \textsc{CMS}&Delphes & \textsc{ATLAS}&Delphes \\ 1041 & \textsc{CMS}&Delphes & \textsc{ATLAS}&Delphes 1042 \\ 1004 1043 $Z \rightarrow \tau^+ \tau^-$ & $38.2\%$ & $32.4\pm1.8\%$ & $33\%$ & $28.6\pm 1.9\%$ \\ 1005 1044 $H(140) \rightarrow \tau^+ \tau^-$ & $36.3\%$ & $39.9\pm1.6\%$ & & $32.8\pm 1.8\%$ \\ … … 1015 1054 \section{Visualisation} 1016 1055 1017 When performing an event analysis, a visualisation tool is useful to convey information about the detector layout and the event topology in a simple way. The \textit{Fast and Realistic OpenGL Displayer} \textsc{FROG}~\citep{bib:FROG} has been interfaced in \textit{Delphes}, allowing an easy display of the defined detector configuration~\citep{qr:frog}. 1018 %\footnote{\texttt{[code] } To prepare the visualisation, the \texttt{FLAG\_FROG} parameter should be equal to $1$.}. 1019 1020 % \begin{figure}[!ht] 1021 % \begin{center} 1022 % \includegraphics[width=\columnwidth]{Detector_DELPHES_1} 1023 % \caption{Layout of the generic detector geometry assumed in Delphes. The innermost layer, close to the interaction point, is a central tracking system (pink), embedded into a solenoidal magnetic field. 1024 % It is surrounded by a central calorimeter volume (green) with both electromagnetic and hadronic sections. 1025 % The outer layer of the central system (red) consist of a muon system. 1026 % In addition, two end-cap calorimeters (blue) extend the pseudorapidity coverage of the central detector. 1027 % The actual detector granularity and extension is defined in the detector card. 1028 % The detector is assumed to be strictly symmetric around the beam axis (black line). 1029 % Additional forward detectors are not depicted.} 1030 % \label{fig:GenDet} 1031 % \end{center} 1032 % \end{figure} 1033 1034 Two and three-dimensional representations of the detector configuration can be used for communication purposes, as they clearly illustrate the geometric coverage of the different detector subsystems. 1035 As an example, the generic detector geometry assumed in this paper is shown in Fig.~\ref{fig:GenDet3} 1036 %, \ref{fig:GenDet} 1037 and~\ref{fig:GenDet2}. 1038 The extensions of the central tracking system, the central calorimeters and both forward calorimeters are visible. 1039 Note that only the geometrical coverage is depicted and that the calorimeter segmentation is not taken into account in the drawing of the detector. Moreover, both the radius and the length of each sub-detectors are just display parameters and are not relevant for the physics simulation. 1056 When performing an analysis, a visualisation tool is useful to convey 1057 information about the detector layout and the event topology in a simple way. 1058 The \textit{Fast and Realistic OpenGL Displayer} \textsc{FROG}~\citep{bib:FROG} 1059 has been interfaced in \textit{Delphes}, allowing an easy display of the defined 1060 detector configuration~\citep{qr:frog}. 1061 1062 Two and three-dimensional representations of the detector configuration can be 1063 used for communication purposes, as they clearly illustrate the geometric 1064 coverage of the different detector subsystems. 1065 As an example, the generic detector geometry assumed in this paper is shown in 1066 Fig.~\ref{fig:GenDet3} and~\ref{fig:GenDet2}. The extensions of the central 1067 tracking system, the central calorimeters and both forward calorimeters are 1068 visible. Note that only the geometrical coverage is depicted and that the 1069 calorimeter segmentation is not taken into account in the drawing of the 1070 detector. 1040 1071 1041 1072 \begin{figure}[!ht] … … 1043 1074 %\includegraphics[width=\columnwidth]{Detector_DELPHES_2b} 1044 1075 \includegraphics[width=\columnwidth]{fig11} 1045 \caption{Layout of the generic detector geometry assumed in \textit{Delphes}. Open 3D-view of the detector with solid volumes. Same colour codes as for Fig.~\ref{fig:GenDet3} are applied. Additional forward detectors are not depicted.} 1076 \caption{Layout of the generic detector geometry assumed in \textit{Delphes}. 1077 Open 3D-view of the detector with solid volumes. Same colour codes as for 1078 Fig.~\ref{fig:GenDet3} are applied. Additional forward detectors are not 1079 depicted.} 1046 1080 \label{fig:GenDet2} 1047 1081 \end{center} 1048 1082 \end{figure} 1049 1083 1050 Deeper understanding of interesting physics processes is possible by displaying the events themselves. 1051 The visibility of each set of objects ($e^\pm$, $\mu^\pm$, $\tau^\pm$, jets, transverse missing energy) is enhanced by a colour coding. 1052 Moreover, kinematics information of each object is visible by a simple mouse action. 1053 As an illustration, an associated photoproduction of a $W$ boson and a $t$ quark is shown in Fig.~\ref{fig:wt}. 1054 This corresponds to a $pp(\gamma p \rightarrow Wt)pX$ process, where the $Wt$ couple is induced by an incoming photon emitted by one of the colliding proton~\citep{bib:wtphotoproduction}. 1055 This leading proton survives after photon emission and is present in the final state. 1056 As the energy and virtuality of the emitted photon are low, the surviving proton does not leave the beam and escapes from the central detector without being detected. 1057 The experimental signature is a lack of hadronic activity in the forward hemisphere where the surviving proton escapes. 1058 The $t$ quark decays into a $W$ boson and a $b$ quark. 1059 Both $W$ bosons decay into leptons ($W \rightarrow \mu \nu_\mu$ and $W \rightarrow e \nu_e$). 1060 The balance between the missing transverse energy and the charged lepton pair is clear, as well as the presence of an empty forward region. It is interesting to notice that the reconstruction algorithms build a fake $\tau$-jet around the electron. 1084 Deeper understanding of interesting physics processes is possible by displaying 1085 the events themselves. The visibility of each set of objects ($e^\pm$, 1086 $\mu^\pm$, $\tau^\pm$, jets, transverse missing energy) is enhanced by a colour 1087 coding. Moreover, kinematics information of each object is visible by a simple 1088 mouse action. As an illustration, an associated photoproduction of a $W$ boson 1089 and a $t$ quark~\citep{bib:wtphotoproduction} is shown in Fig.~\ref{fig:wt}. 1090 1091 % This corresponds to a $pp(\gamma p \rightarrow Wt)pX$ process, where the $Wt$ 1092 % couple is induced by an incoming photon emitted by one of the colliding 1093 % proton. This leading proton survives after photon emission and is present in 1094 % the final state. As the energy and virtuality of the emitted photon are low, 1095 % the surviving proton does not leave the beam and escapes from the central 1096 % detector without being detected. The experimental signature is a lack of 1097 % hadronic activity in the forward hemisphere where the surviving proton 1098 % escapes. 1099 % The $t$ quark decays into a $W$ boson and a $b$ quark. Both $W$ bosons decay 1100 % into leptons ($W \rightarrow \mu \nu_\mu$ and $W \rightarrow e \nu_e$). The 1101 % balance between the missing transverse energy and the charged lepton pair is 1102 % clear, as well as the presence of an empty forward region. It is interesting 1103 % to notice that the reconstruction algorithms build a fake $\tau$-jet around 1104 % the electron. 1061 1105 1062 1106 \begin{figure}[!ht] … … 1064 1108 %%\includegraphics[width=\columnwidth]{Events_DELPHES_1} 1065 1109 %\includegraphics[width=\columnwidth]{DisplayWt} 1066 \includegraphics[width=\columnwidth]{fig12} 1067 \caption{Example of $pp(\gamma p \rightarrow Wt)pY$ event display in different orientations, with $t \rightarrow Wb$. 1068 One $W$ boson decays into a $\mu \nu_\mu$ pair and the second one into a $e \nu_e$ pair. 1069 The surviving proton leaves a forward hemisphere with no hadronic activity. 1070 The isolated muon is shown as the dark blue vector. 1071 Around the electron, in red, is reconstructed a fake $\tau$-jet (green vector surrounded by a blue cone), while the reconstructed missing energy (in grey) is very small. One jet is visible in one forward region, along the beamline axis, opposite to the direction of the escaping proton.} 1110 \includegraphics[width=0.6\columnwidth]{fig12} 1111 \caption{Example of $pp(\gamma p \rightarrow Wt)pY$ event display in 1112 transverse view, with $t \rightarrow Wb$. One 1113 $W$ boson decays into a $\mu \nu_\mu$ pair and the second one into a $e \nu_e$ 1114 pair. The surviving proton leaves a forward hemisphere with no hadronic 1115 activity. The isolated muon is shown as the dark blue vector. Around the 1116 electron, in red, is reconstructed a fake $\tau$-jet (blue cone surrounding a 1117 green arrow). The reconstructed missing energy is visible in grey. } 1072 1118 \label{fig:wt} 1073 1119 \end{center} 1074 1120 \end{figure} 1075 1121 1076 For comparison, Fig.~\ref{fig:gg} depicts an inclusive gluon pair production $pp \rightarrow ggX$. 1077 The event final state contains more jets, in particular along the beam axis, which is expected as the interacting protons are destroyed by the collision. Two muon candidates and large missing transverse energy are also visible. 1122 For comparison, Fig.~\ref{fig:gg} depicts an inclusive gluon pair production 1123 $pp \rightarrow ggX$. The event final state contains more jets, in particular 1124 along the beam axis, which is expected as the interacting protons are destroyed 1125 by the collision. 1078 1126 1079 1127 \begin{figure}[!ht] … … 1081 1129 %%\includegraphics[width=\columnwidth]{Events_DELPHES_1} 1082 1130 %\includegraphics[width=\columnwidth]{Displayppgg} 1083 \includegraphics[width=\columnwidth]{fig13} 1084 \caption{Example of inclusive gluon pair production $pp \rightarrow ggX$. Many jets are visible in the event, in particular along the beam axis. Two muons (in blue) are produced and the missing transverse energy is significant in this event (grey vector).} 1131 \includegraphics[width=0.6\columnwidth]{fig13} 1132 \caption{Example of inclusive gluon pair production $pp \rightarrow ggX$. Many 1133 jets are present in the event, in particular along the beam axis (black line).} 1085 1134 \label{fig:gg} 1086 1135 \end{center} … … 1090 1139 \section{Conclusion and perspectives} 1091 1140 1092 % \subsection{version 1} 1093 % We have described here the major features of the \textit{Delphes} framework, introduced for the fast simulation of a collider experiment. 1094 % It has already been used for several phenomenological studies, in particular in photon interactions at the \textsc{LHC}. 1095 % 1096 % \textit{Delphes} takes the output of event generators, in various formats, and yields analysis-object data. 1097 % The simulation applies the resolutions of central and forward detectors by smearing the kinematical properties of final state particles. 1098 % It yields tracks in a solenoidal magnetic field and calorimetric towers. 1099 % Realistic reconstruction algorithms are run, including the FastJet package, to produce collections of $e^\pm$, $\mu^\pm$, jets and $\tau$-jets. $b$-tag and missing transverse energy are also evaluated. 1100 % The output is validated by comparing to the \textsc{CMS} expected performances. 1101 % A trigger stage can be emulated on the output data. 1102 % At last, event visualisation is possible through the \textsc{FROG} 3D event display. 1103 % 1104 % 1105 % \textit{Delphes} has been developped using the parameters of the \textsc{CMS} experiment but can be easily extended to \textsc{ATLAS} and other non-\textsc{LHC} experiments, as at Tevatron or at the \textsc{ILC}. Further developments include a more flexible design for the subdetector assembly and possibly the implementation of an event mixing module for pile-up event simulation. 1106 % 1107 % 1108 % \subsection{version 2} 1109 We have described here the major features of the \textit{Delphes} framework, introduced for the fast simulation of a collider experiment. This framework is a tool meant for feasibility studies in phenomenology, gauging the observability of model predictions in collider experiments. 1110 1111 \textit{Delphes} takes as an input the output of event-generators and yields analysis-object data in the form of \texttt{TTree} in a \texttt{*.root} file. 1112 The simulation includes central and forward detectors to produce realistic observables using standard reconstruction algorithms. 1141 We have described here the major features of the \textit{Delphes} framework, 1142 introduced for the fast simulation of a collider experiment. This framework is a 1143 tool meant for feasibility studies in phenomenology, gauging the observability 1144 of model predictions in collider experiments. 1145 1146 \textit{Delphes} takes as an input the output of event-generators and yields 1147 analysis-object data in the form of \texttt{TTree} in a \texttt{*.root} file. 1148 The simulation includes central and forward detectors to produce realistic 1149 observables using standard reconstruction algorithms. 1113 1150 Moreover, the framework allows trigger emulation and 3D event visualisation. 1114 1151 1115 \textit{Delphes} has been developed using the parameters of the \textsc{CMS} experiment but can be easily extended to \textsc{ATLAS} and other non-\textsc{LHC} experiments, as at Tevatron or at the \textsc{ILC}. Further developments include a more flexible design for the subdetector assembly, a better $b$-tag description and possibly the implementation of an event mixing module for pile-up event simulation. This framework has already been used for several analyses~\citep{bib:wtphotoproduction, bib:papierquisortirajamais, bib:papiersimon}, in particular in photon-induced interactions at the \textsc{LHC}. 1152 \textit{Delphes} has been developed using the parameters of the \textsc{CMS} 1153 experiment but can be easily extended to \textsc{ATLAS} and other 1154 non-\textsc{LHC} experiments, as at Tevatron or at the \textsc{ILC}. Further 1155 developments include a more flexible design for the subdetector assembly, a 1156 better $b$-tag description and possibly the implementation of an event mixing 1157 module for pile-up event simulation. This framework has already been used for 1158 several analyses~\citep{bib:wtphotoproduction, bib:papierquisortirajamais, 1159 bib:papiersimon}, in particular in photon-induced interactions at the 1160 \textsc{LHC}. 1116 1161 1117 1162 … … 1157 1202 R. Kinnunen, A.N. Nikitenko, \textbf{CMS NOTE} \href{http://cdsweb.cern.ch/record/687274}{1997/002}. 1158 1203 \bibitem{bib:FROG} L. Quertenmont, V. Roberfroid, \textbf{CMS CR} \href{http://cms.cern.ch/iCMS/jsp/openfile.jsp?type=CR&year=2009&files=CR2009_028.pdf}{2009/028}, arXiv:\href{http://arxiv.org/abs/0901.2718}{0901.2718v1}[hep-ex]. 1159 \bibitem{bib:wtphotoproduction} J. de Favereau de Jeneret, S. Ovyn, \textbf{Nucl. Phys. Proc. Suppl.} \href{http://dx.doi.org/10.1016/j.nuclphysbps.2008.07.040}{179-180 (2008)} \href{http://dx.doi.org/10.1016/j.nuclphysbps.2008.07.040}{277-284}; S. Ovyn, J. de Favereau de Jeneret, \href{http://dx.doi.org/10.1393/ncb/i2008-10684-5}{Nuovo Cimento B}, arXiv:0806.4841[hep-ph]. 1204 \bibitem{bib:wtphotoproduction} J. de Favereau de Jeneret, S. Ovyn, 1205 \textbf{Nucl. Phys. Proc. Suppl.} 1206 \href{http://dx.doi.org/10.1016/j.nuclphysbps.2008.07.040}{179-180 (2008)} 1207 \href{http://dx.doi.org/10.1016/j.nuclphysbps.2008.07.040}{277-284}; S. Ovyn, J. 1208 de Favereau de Jeneret, \href{http://dx.doi.org/10.1393/ncb/i2008-10684-5}{Nuovo 1209 Cimento B}, arXiv:0806.4841[hep-ph]. 1160 1210 1161 1211 \bibitem{bib:papierquisortirajamais}J. de Favereau~et~al, \href{http://arxiv.org/abs/0908.2020}{arXiv:0908.2020v1} [hep-ph] (2008), to be published in EPJ. 1162 1212 1163 %\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. 1164 \bibitem{bib:papiersimon} S. de Visscher, J.M. Gerard, M. Herquet, V. Lema\^itre, F. Maltoni, arXiv:\href{http://arxiv.org/abs/0904.0705}{0904.0705}[hep-ph]. 1213 \bibitem{bib:papiersimon} S. de Visscher, J.M. Gerard, M. Herquet, V. 1214 Lema\^itre, F. Maltoni, \textbf{JHEP} 1215 \href{http://dx.doi.org/10.1088/1126-6708/2009/08/042}{08 (2009) 042}. 1165 1216 1166 1217 \bibitem{bib:mcfio} P. Lebrun, L. Garren, Copyright (c) 1994-1995 Universities Research Association, Inc.
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