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0001 # INTRODUCTION
0003 This brief README file is meant to explain the usage of the
0004 RecoMaterial tools that are present in the
0005 Validation/Geometry/test directory.
0007 # GOALS
0009 The main goal is to provide the users with the necessary
0010 tools to assess the goodness of the material description
0011 used during the reconstruction process (compared to the one
0012 used in the Monte Carlo simulation). In order to do that,
0013 two main ingredients are necessary:
0015 * the material map as derived from the Monte Carlo
0017 * the material description as "derived" during the
0018 reconstruction phase
0020 The procedure to derive the former is extensively documented
0021 in a TWiki page
0023 In the rest of the documentation we will assume that the
0024 user has already followed those instructions and produced
0025 all the required ROOT files.
0027 **NOTA BENE**: it will also be implied that the samples used
0028 to derive the material profile from the Simulation have been
0029 produced **without** any vertex smearing.
0031 The procedure to derive the latter is the subject of the
0032 next few sections.
0034 **REMINDER**: it is a user's responsibility to carefully
0035 check which geometry is loaded (either via GT or via files)
0036 in all the scripts used to derive the material description
0037 from the simulation. As of this PR the default is to use the
0038 PhaseI geometry, while the scripts that are explained below
0039 use the Run2 geometry.
0041 ## Material Map used during track reconstruction.
0043 Energy loss and multiple scattering are taken into account
0044 during the patter recognition. In order to have a somewhat
0045 better understanding of the mechanism put in place to do
0046 that, you can read the following [slides](://indico.cern.ch/event/512686/contributions/2182630/attachments/1280489/1901936/TrackerDPG_POG_20160527_MR.pdf)
0048 The main idea to derive the reco-material map effectively
0049 used during the patter-recognition is to ask to each layer
0050 traversed by the particle, what are its material properties
0051 (as injected by XML files or DB) and simply integrate these
0052 values in eta.
0054 A simple EDAnalyzer (*TrackingRecoMaterialAnalyser*) has
0055 been put in place. The Analyzer will re-fit the tracks that
0056 have been reconstructed during the main reconstruction
0057 phase. The refit is mandatory in order to derive the proper
0058 TSOS at each detector and correct the "effective material"
0059 that the track sees while traversing the detector. The
0060 analyzer can be safely coupled with the standard
0061 reconstruction step.
0063 ### Procedure
0065 The steps to be followed in order to derive the
0066 reco-material map are included in few shell scripts, that
0067 automatically take care of issuing the correct cmsDriver command for
0068 the different scenarios. The files to be used are:
0076 Each script accept two command line options, that could be useful for
0077 quick testing:
0080 -n XXX
0083 to generate only XXX events in place of the default 5K.
0086 -g GEOMETRY
0089 to select a geometry different from the default one included in the
0090 shell script itself.