#acl EditorsGroup:read,write All:read

= Safe Variables in tauRec =
This page desribes the cut-based discriminant in tauRec with so-called Safe Variables<<BR>>
Current results can be found here: [[http://www.desy.de/~gosdzik/SafeVarOpt/FinalPlots/|Safe Variables]]

== Cut-based approach ==
There are two approaches available, one using only calorimeter information one combining calorimeter and tracking information.

=== Calo-approach ===
More safe approach, calorimeter will be well understood at very early stage (hopefully ;) ).<<BR>>
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'''Variable desription:'''
 * EMRadius (Radius in EM Calorimeter)<<BR>><<latex(\Large $R_{em}=\frac{\sum_{i=1}^{n}E_{T,i}\sqrt{\left(\eta_i-\eta_{cluster}\right)^2+\left(\phi_i-\phi_{cluster}\right)^2}}{\sum_{i=1}^{n}E_{T,i}}$)>><<BR>>{{{#!wiki blue/solid
Runs over all cells in the EM Calorimeter in a cluster with dR<0.4
}}}

 * !IsoFrac (Isolation Fraction)<<BR>><<latex(\Large $\Delta E_T^{12}=\frac{\sum_i E_{T,i}}{\sum_j E_{T,j}}$)>><<BR>>{{{#!wiki blue/solid
Ring of 0.1<dR<0.2 as islolation region, i and j run over all EM cells in a cone with 0.1<dR<0.2 and dR<0.4
}}}

 * stripWidth2 (Width in strip layer)<<BR>><<latex(\Large $\Delta\eta=\sqrt{\frac{\sum_{i=1}^n E_{T,i}^{strip}\left(\eta_i-\eta_{cluster}\right)^2}{\sum_{i=1}^n E_{T,i}^{strip}}}$)>><<BR>>{{{#!wiki blue/solid
Transverse energy width in strip layer (fist layer of EM barrel)
}}}

 * EtEMEt (Fraction of transverse energy in the EM Calorimeter and total Et)<<BR>><<latex(\Large $\Delta E_T^{EM/tot}=\frac{E_T^{EM}}{E_T^{total}}$)>><<BR>>{{{#!wiki blue/solid
Fraction of transverse energy in the EM calorimeter and the total transverse energy
}}}
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'''Histograms for Calo-approach:'''<<BR>>
 * [[Projects/SimRec/TauID/SafeVariables/CaloOnlyDist|Distribution plots]] <<BR>>
 * [[Projects/SimRec/TauID/SafeVariables/CaloOnlyPerf|Performance plots]] <<BR>>
 * Correlation plots
  * [[Projects/SimRec/TauID/SafeVariables/CaloOnlyCorrelationSignal|Signal]] <<BR>>
  * [[Projects/SimRec/TauID/SafeVariables/CaloOnlyCorrelationBackground|Background]]

=== Calo+Track-approach ===
More aggressive approach with better rejection power.<<BR>>
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'''Variable description:'''
 * RWidth2Trk3 (Width of track momenta)<<BR>><<latex(\Large $W_{track}^{\tau}=\frac{\sum\left(\Delta\eta^{\tau,track}\right)^2\cdot p_T^{track}}{\sum p_T^{track}}-\frac{\sum\left(\Delta\eta^{\tau,track}\cdot p_T^{track}\right)^2}{\left(\sum p_T^{track}\right)^2}$)>><<BR>>{{{#!wiki blue/solid
Width of tracks, weighted with their transverse momenta
}}}

 * etOverPtLeadTrack (Fraction of pT and Et of leading track)<<BR>><<latex(\Large $\Delta E_T^{p_{T,1}}\frac{E_T^{total}}{p_{T,1}}$)>><<BR>>{{{#!wiki blue/solid
Large fraction of tau energy is expected to be carried by the leading track
}}}

 * EtEMsumpT<<BR>><<latex(\Large $\Delta E_T^{EM/p_T}=\frac{E_T^{EM}}{p_T^{total}}$)>><<BR>>{{{#!wiki blue/solid
Fraction of transverse energy in the EM Calorimeter and total pT
}}}

 * EtEMsumpT<<BR>><<latex(\Large $\Delta E_T^{Had/p_T}=\frac{E_T^{Had}}{p_T^{total}}$)>><<BR>>{{{#!wiki blue/solid
Fraction of transverse energy in the EM Calorimeter and total pT
}}}

 * sumpTEt<<BR>><<latex(\Large $\Delta p_T^{E_T}=\frac{p_T^{total}}{E_T^{total}}$)>><<BR>>{{{#!wiki blue/solid
Fraction of total transverse momenta and total transverse energy
}}}

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'''Histograms for Calo+Track-approach:'''<<BR>>
 * [[Projects/SimRec/TauID/SafeVariables/CaloTrackDist|Distribution plots]] <<BR>>
 * [[Projects/SimRec/TauID/SafeVariables/CaloTrackPerf|Performance plots]] <<BR>>
 * Correlation plots
  * [[Projects/SimRec/TauID/SafeVariables/CaloTrackCorrelationSignal|Signal]] <<BR>>
  * [[Projects/SimRec/TauID/SafeVariables/CaloTrackCorrelationBackground|Background]]

== Data samples ==
Several signal and background data samples from release 14.2.0 production were used for the optimization of the safe variables. The tables below give the number of events and cross-section for these samples.

 * Signal:
||<#8080FF> Dataset ID||<#8080FF> channel||<#8080FF> number events||<#8080FF> x-section||
||005188||Z->tautau||131500||<<latex($\rm 1.64\cdot10^{3}$ pb)>>||
||005862||bbA(800)->tautau||66750||<<latex($\rm 0.0152$ pb)>>||

 * Background:
||<#8080FF> Dataset ID||<#8080FF> channel||<#8080FF> number events||<#8080FF> x-section||
||005010||Di-jet J1 (17-35 GeV)||78500||<<latex($\rm 1.38\cdot10^{9}$ pb)>>||
||005011||Di-jet J2 (35-70 GeV)||141000||<<latex($\rm 93.3\cdot10^{6}$ pb)>>||
||005012||Di-jet J3 (70-140 GeV)||123950||<<latex($\rm 5.88\cdot10^{6}$ pb)>>||
||005014||Di-jet J5 (280-560 GeV)||116200||<<latex($\rm 12.5\cdot10^{3}$ pb)>>||

For the distribution and performance plots the J5 was excluded and the samples were weighted to <<latex($\rm 1 pb^{-1}$)>>

== PUB Note ==
[[Projects/SimRec/TauID/SafeVariables/PUBNoteDist|Distribution plots]] <<BR>>
[[Projects/SimRec/TauID/SafeVariables/PUBNotePerf|Performance plots]] <<BR>>
[[Projects/SimRec/TauID/SafeVariables/PUBNoteTables|Performance tables]] <<BR>>
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If you have questions please contact [[BjoernGosdzik|Björn Gosdzik]]