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trunk/paper/notes.tex
r502 r508 123 123 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. 124 124 125 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 126 preselection. 125 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 preselection. Even if \textsc{Delphes} has been developped for the simulation of general-purpose detectors at the \textsc{lhc} (namely, \textsc{cms} and \textsc{atlas}), the input cards allow a flexible parametrisation for other cases, e.g.\ at future linear colliders. 127 126 128 127 … … 167 166 168 167 \subsubsection*{Magnetic field} 169 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 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. The field extension is limited to the tracker volume and is in particular not applied for muon chambers. Howerver, this is not a limiting factor as the resolution applied for muon reconstruction is the one expected by the experiment, which consequently includes the effects of the magnetic field within the muon system. 170 169 171 170 … … 187 186 188 187 189 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.}.188 The particle four-momentum $p^\mu$ are smeared with a parametrisation directly derived from typical detector technical designs\footnote{\texttt{[code] } The response of the detector is applied to the electromagnetic and the hadronic particles through the \texttt{SmearElectron} and \texttt{SmearHadron} functions.} \cite{bib:cmsjetresolution,bib:ATLASresolution}. 190 189 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. 191 190 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.}. … … 575 574 \textsc{Delphes} performs a fast simulation of a collider experiment. 576 575 Its performances in terms of computing time and data size are directly proportional to the number of simulated events and on the considered physics process. As an example, $10,000$ $pp \rightarrow t \bar t X$ events are processed in $110~\textrm{s}$ on a regular laptop and use less than $250~\textrm{MB}$ of disk space. 577 The quality and validity of the output are assessed by comparing to resolution of the reconstructed data to the \textsc{cms} detector expectations. 578 579 Electrons and muons are by construction equal to the experiment designs, as the Gaussian smearing of their kinematics properties is defined according to their resolutions. 580 Similarly, the $b$-tagging efficiency (for real $b$-jets) and misidentification rates (for fake $b$-jets) are taken from the expected values of the experiment. 576 The quality and validity of the output are assessed by comparing the resolutions on the reconstructed data to the expectations of both \textsc{cms}~\cite{bib:cmsjetresolution} and \textsc{atlas}~\cite{bib:ATLASresolution} detectors. 577 578 Electrons and muons are by construction equal to the experiment designs, as the Gaussian smearing of their kinematics properties is defined according to 579 the detector specifications. 580 Similarly, the $b$-tagging efficiency (for real $b$-jets) and misidentification rates (for fake $b$-jets) are taken directly from the expected values of the experiment. 581 581 Unlike these simple objects, jets and missing transverse energy should be carefully cross-checked. 582 582 … … 586 586 This validation is based on $pp \rightarrow gg$ events produced with \textsc{MadGraph/MadEvent} and hadronised using \textsc{Pythia}~\cite{bib:mgme,bib:pythia}. 587 587 588 For a \textsc{cms}-like detector, a similar procedure as the one explained in publi cresults is applied here.588 For a \textsc{cms}-like detector, a similar procedure as the one explained in published results is applied here. 589 589 The events were arranged in $14$ bins of gluon transverse momentum $\hat{p}_T$. In each $\hat{p}_T$ bin, every jet in \textsc{Delphes} is matched to the closest jet of generator-level particles, using the spatial separation between the two jet axes 590 590 \begin{equation} 591 591 \Delta R = \sqrt{ \big(\eta^\textrm{rec} - \eta^\textrm{MC} \big)^2 + \big(\phi^\textrm{rec} - \phi^\textrm{MC} \big)^2}<0.25. 592 592 \end{equation} 593 The jets made of generator-level particles, here referred as \textit{MC jets}, are obtained by applying the algorithm to all particles considered as stable after hadronisation .593 The jets made of generator-level particles, here referred as \textit{MC jets}, are obtained by applying the algorithm to all particles considered as stable after hadronisation (i.e.\ including muons). 594 594 Jets produced by \textsc{Delphes} and satisfying the matching criterion are called hereafter \textit{reconstructed jets}. 595 595 All jets are computed with the clustering algorithm (\textsc{jetclu}) with a cone radius $R$ of $0.7$. … … 794 794 \section*{Acknowledgements} 795 795 \addcontentsline{toc}{section}{Acknowledgements} 796 The authors would like to thank very warmly Vincent Lema ître 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.796 The authors would like to thank very warmly Vincent Lema\^itre 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. 797 797 Part of this work was supported by the Belgian Federal Office for Scientific, Technical and Cultural Affairs through the Interuniversity Attraction Pole P6/11. 798 798 … … 810 810 \bibitem{bib:ExRootAnalysis} %\textit{The} \textsc{ExRootAnalysis} \textit{analysis steering utility}, 811 811 P. Demin, (2006), unpublished. Now part of \textsc{MadGraph/MadEvent}. 812 \bibitem{bib:cmsjetresolution} The CMSCollaboration, \textbf{CERN/LHCC} \\ \href{http://documents.cern.ch/cgi-bin/setlink?base=lhcc&categ=public&id=lhcc-2006-001}{2006-001}.813 \bibitem{bib:ATLASresolution} The ATLASCollaboration, \textbf{CERN-OPEN} 2008-020, arXiv:\href{http://arxiv.org/abs/arxiv:0901.0512}{0901.0512v1}[hep-ex].812 \bibitem{bib:cmsjetresolution} The \textsc{cms} Collaboration, \textbf{CERN/LHCC} \\ \href{http://documents.cern.ch/cgi-bin/setlink?base=lhcc&categ=public&id=lhcc-2006-001}{2006-001}. 813 \bibitem{bib:ATLASresolution} The \textsc{atlas} Collaboration, \textbf{CERN-OPEN} 2008-020, arXiv:\href{http://arxiv.org/abs/arxiv:0901.0512}{0901.0512v1}[hep-ex]. 814 814 \bibitem{bib:Hector} %\textsc{Hector}, \textit{a fast simulator for the transport of particles in beamlines}, 815 815 X. Rouby, J. de Favereau, K. Piotrzkowski, \textbf{JINST} \href{http://www.iop.org/EJ/abstract/1748-0221/2/09/P09005}{2 P09005 (2007)}.
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