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Changeset 118 in svn


Ignore:
Timestamp:
Jan 1, 2009, 8:46:02 PM (16 years ago)
Author:
Xavier Rouby
Message:

update

Location:
trunk/paper
Files:
2 added
3 edited

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  • trunk/paper/notes.tex

    r117 r118  
    22%\usepackage[english]{babel}
    33\usepackage[ansinew]{inputenc}
    4 \usepackage{abstract}
    54
    65\usepackage{amsmath}
     
    213212\subsection{Calorimetric towers}
    214213
    215 The smallest unit for geometrical sampling of the calorimeters is a \textit{tower}.
     214The smallest unit for geometrical sampling of the calorimeters is a \textit{tower}; it segments the $(\eta,\phi)$ plane for the energy measurement.
    216215All undecayed particles, except muons and neutrinos produce a calorimetric tower, either in \textsc{ecal}, in \textsc{hcal} or \textsc{fcal}.
    217 A calorimetric tower are just the smallest unit in $\eta \times \phi$ for the segmentation of the energy measurement. As the detector is assumed to be symmetric in $\phi$ and with respect to the $(x,y)$ plane, the smearing 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.
    218 The calorimeters are then segmented into towers, that directly enter in the calculation of the missing transverse energy.
    219 No longitudinal segmentation is available in the simulated calorimeters. No sharing between towers is implemented when particles enter a tower very close to its geometrical edge.
    220 
     216As the detector is assumed to be symmetric in $\phi$ and with respect to the $\eta=0$ plane, the smearing 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.
     217
     218The calorimetric towers directly enter in the calculation of the missing transverse energy, and as input for the jet reconstruction algorithms.
     219No longitudinal segmentation is available in the simulated calorimeters.
     220No sharing between neighbouring towers is implemented when particles enter a tower very close to its geometrical edge.
     221
     222\textcolor{red}{Mettre une figure avec une grille en $(\eta,\phi)$ pour illustrer la segmentation (un peu comme une feuille quadrillée).}
    221223
    222224\subsection{Muon smearing}
    223225
    224 Muons candidates are searched
    225 The smearing ot the muon 4-momentum $p^\mu$ is given by a Gaussian smearing of the $p_T$ function \texttt{SmearMuon}. Only the $p_T$ is smeared, but neither $\eta$ nor $\phi$. Multiple scattering is thus neglected, while low energy muons have a worst resolution in a real detector.
     226Generator level muons entering the detector acceptance are considered as candidates for the analysis level.
     227The acceptance is defined in terms of a transverse momentum threshold to overpass (default : $p_T > 0~\textrm{GeV}$) and of the pseudorapidity coverage of the muon system of the detector (default: $-2.4 \leq \eta \leq 2.4$).
     228
     229The application of the detector resolution on the muon 4-momentum $p^\mu$ depends on a Gaussian smearing of the $p_T$ function\footnote{\texttt{[code]} See the \texttt{SmearMuon} method.}. Neither $\eta$ nor $\phi$ variables are modified. Multiple scattering is thus neglected, while low energy muons have a worst resolution in a real detector.
    226230
    227231\subsection{Tracks reconstruction}
    228 Every stable charged particle with a transverse momentum above some threshold and lying inside the fiducial volume of the tracker provides a track. The reconstructio efficiency is defined in the smearing datacard by the {\verb TRACKING_EFF } term. By default, a track is assumed to be reconstructed with $90\%$ probability if its transverse momentum $p_T$ is higher than $0.9~\textrm{GeV}$ and if its pseudorapidity $|\eta| \leq 2.5$.
     232Every stable charged particle with a transverse momentum above some threshold and lying inside the fiducial volume of the tracker provides a track.
     233By default, a track is assumed to be reconstructed with $90\%$ probability\footnote{\texttt{[code]} The reconstruction efficiency is defined in the smearing datacard by the \texttt{TRACKING\_EFF} term.} if its transverse momentum $p_T$ is higher than $0.9~\textrm{GeV}$ and if its pseudorapidity $|\eta| \leq 2.5$.
    229234
    230235
    231236\subsection{Isolated lepton reconstruction}
    232237
    233 Photon and electron candidates are reconstructed if they fall into the acceptance of the tracking system and have a transverse momentum above the {\verb ELEC_pt } value ($10~\textrm{GeV}$ by default).
    234 %Muons candidates are searched
    235 Lepton isolation demands that there is no other charged particles with $p_T>2$~GeV within a cone of $\Delta R<0.5$ around the lepton.\\
     238Photon and electron candidates are reconstructed if they fall into the acceptance of the tracking system and have a transverse momentum above a threshold (default $p_T > 10~\textrm{GeV}$).
     239Lepton isolation (for $e^\pm$ and $\mu^\pm$) demands that there is no other charged particles with $p_T>2~\textrm{GeV}$ within a cone of $\Delta R<0.5$ around the lepton.\\
    236240
    237241\subsection{Very forward detectors simulation}
     
    251255\section{High-level object reconstruction}
    252256
    253 Hadronising final state particles or invisible ones are more difficult to measure. For instance, light jets or jets originating from $b$ quarks or $\tau$ leptons require dedicated algorithms for their measurement.
     257Final state particles which hadronise or invisible ones are more difficult to measure. For instance, light jets or jets originating from $b$ quarks or $\tau$ leptons require dedicated algorithms for their measurement.
    254258The \textsc{FastJet} tools have been integrated into the \textsc{Delphes} framework for a fast jet reconstruction, using several algorithms, like Cone or $k_T$ ones.
    255259
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