Maintenance script: Created page with " == Top Jet Combination == This study is actually done with sisCone05 jets calibrated at L2L3 level.
The selection of jets happens in different steps: === 0. Jet c..."

2015-08-26T12:29:08Z

Created page with " == Top Jet Combination == This study is actually done with sisCone05 jets calibrated at L2L3 level. <br> The selection of jets happens in different steps: === 0. Jet c..."

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== Top Jet Combination ==
This study is actually done with sisCone05 jets calibrated at L2L3 level. <br>
The selection of jets happens in different steps:

=== 0. Jet cleaning ===
electron removal done in PAT-L0

=== 1. Jet rejection ===
use of the [https://twiki.cern.ch/twiki/bin/view/CMS/JetRejectorTool JetRejectorTool] (ported in CMSSW_2_2_3 by Ilaria)

=== 2. Selection of a collection of 4 jets ===
tools & study performed by Gregory

=== 3. Selection of a combination in a 4 jets collection: MVA package ===
==== Tuning of variables for MVA package (Joris) ====
*A list of >80 variables is implemented and can be found in (code is compatible with TQAF tag V04-07-01)
<pre>
/user/jmmaes/CMSSW/CMSSW_2_2_4_v1/CMSSW_2_2_4/src/TopQuarkAnalysis/TopTools/interface/TtSemiLepJetComb.h
</pre>
Due to Recent changes in TQAF this file became incompatible

*For this list the MVA trainer is used to make the distributions for signal and background in two cases
**'''case1''': The 4 top jet candidates are selected from the 6 jets with highest pt. The 4 jets are chosen according the ''chi square'' method in the jet selection tool of gregory (see previous section)
**'''case2''': The 4 top jet candidated are the 4 highest pt jets
in the following locations you can find the complete cfg file used to produce the root files containing signal and background plots
<pre>
/user/jmmaes/CMSSW/CMSSW_2_2_4_v1/CMSSW_2_2_4/src/TopQuarkAnalysis/TopJetCombination/test/caseX/ttSemiLepJetCombMVATrainer_muons_cfg.py
</pre>
*The root files created are in
<pre>
/msa1/TopGroup/Results/TopJetCombination/SValues/root/train_monitoring_caseX.root
</pre>

*For the list of all variables a '''separation''' power is calculated, two definitions are used to calculated '''S''':
**The overlapping area of the (normalized) signal and background histograms ''(surface)''
**The maximum value of the scan of the multiplication of efficiency for signal times 1-efficiency for background ''(pte)''
The code for calculating S can be found in
<pre>
/user/jmmaes/CMSSW/CMSSW_2_2_4_v1/CMSSW_2_2_4/src/Svalue/DistributionAnalyzer.C
</pre>
The list of S values for the 2 cases X times the 2 definitions Y is located in
<pre>
/msa1/TopGroup/Results/TopJetCombination/SValues/table/caseX_Y.txt
</pre>
The main conclusion is that the ordering of the variables doesn't change significantly when using another definition. Also when selecting the 4 jets from the 6 highest pt jets the relative ranking of the variables w.r.t. separation power stays the same
*To make a selection of O(5) variables we have to take into account the correlation between them. This list is also in the former text file.
*The list of 5 variables looks like this (numbering comes from the 81 variables)
**1. mass of hadronic W (massHadW)
**80. sum of b-tag discriminant value of leptonic b and hadronic b (sumBTag1HadBLepB)
**78. relative pt of the hadronic top (relPtHadTop)
**53. delta theta between leptonic b and hadronic top (deltaThetaLepBHadTop)
**50. delta theta between leptonic b and muon (deltaThetaLepBLepton)
*The plots of the variables Z can be found in
<pre>
/msa1/TopGroup/Results/TopJetCombination/SValues/image/varZ_caseX.png
</pre>
*The correlation between these 5 variables is made from the train_monitoring.root files of petra. The numbering of the variables is different from the previous section. The plots for both cases X can be found in
<pre>
/msa1/TopGroup/Results/TopJetCombination/SValues/image/ProcMatrix_rot_caseX.png
</pre>
*The numbering of the variables is (1:"massHadW",2:"deltaThetaLepBLepton",3:"deltaThetaLepBHadTop",4:"relPtHadTop",5:"sumBTag1HadBLepB")
*in the txt files you can find explicitly the value of the correlation
<pre>
/msa1/TopGroup/Results/TopJetCombination/SValues/table/caseX_corr.txt
</pre>

==== Study of MVA tool (Petra) ====
*MVA tools: NN & LR are performed by Petra

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TopJetCombination - Revision history

Maintenance script: Created page with " == Top Jet Combination == This study is actually done with sisCone05 jets calibrated at L2L3 level. The selection of jets happens in different steps: === 0. Jet c..."

Maintenance script: Created page with " == Top Jet Combination == This study is actually done with sisCone05 jets calibrated at L2L3 level.
The selection of jets happens in different steps: === 0. Jet c..."