TtSemiSimpleBestJetComb Class Reference

Simple method to get the correct jet combination in semileptonic ttbar events. More...

#include "TopQuarkAnalysis/TopLeptonSelection/interface/TtSemiSimpleBestJetComb.h"

Public Member Functions
int	operator() (std::vector< TtSemiEvtSolution > &)
	TtSemiSimpleBestJetComb ()
	~TtSemiSimpleBestJetComb ()

Detailed Description

Simple method to get the correct jet combination in semileptonic ttbar events.

This method starts from a vector of fitted TtSemiEvtSolutions. This class returns the solution with the highest probChi^2 value. In case that there are more possibilities (eg when only a hadrW constraint was applied), the correct hadronic b is assumed to be the one with the smallest DR angle wrt the Whadr direction.

Author

Jan Heyninck

Version

Id:

TtSemiSimpleBestJetComb.h,v 1.3 2007/09/20 18:03:21 lowette Exp

Definition at line 32 of file TtSemiSimpleBestJetComb.h.

Constructor & Destructor Documentation

TtSemiSimpleBestJetComb::TtSemiSimpleBestJetComb

(

)

Definition at line 6 of file TtSemiSimpleBestJetComb.cc.

{
}

TtSemiSimpleBestJetComb::~TtSemiSimpleBestJetComb

(

)

Definition at line 10 of file TtSemiSimpleBestJetComb.cc.

{
}

Member Function Documentation

int TtSemiSimpleBestJetComb::operator()

(

std::vector< TtSemiEvtSolution > &

sols

)

Definition at line 14 of file TtSemiSimpleBestJetComb.cc.

References max(), phi, and alignCSCRings::s.

{ 
  // search the highest probChi^2 value in the among the different jet combination solutions   
  double maxProbChi2 = 0;
  for(unsigned int s=0; s<sols.size(); s++)  maxProbChi2 = std::max(maxProbChi2,sols[s].getProbChi2());
  
  //search indices of original solutions with highest probChi2 value
  std::vector<unsigned int> indices;
  indices.clear();
  for(unsigned int s=0; s<sols.size(); s++){
    if(fabs(sols[s].getProbChi2()-maxProbChi2) < 0.0001) indices.push_back(s);
  }
     
  int bestSol = -999;
  if(maxProbChi2 > 0.){
    if(indices.size() == 1) bestSol = indices[0];
    if(indices.size() == 2) {
      //typically only light jets constraints applied, so still b-jet ambiguity to resolve 
      // -> look at DPhi(Whadr,bhadr) and choose smallest value
      double DPhi_Wb0 = fabs(sols[indices[0]].getFitHadW().phi()-sols[indices[0]].getFitHadb().phi());
      double DPhi_Wb1 = fabs(sols[indices[1]].getFitHadW().phi()-sols[indices[1]].getFitHadb().phi());
      if(DPhi_Wb0>3.1415) DPhi_Wb0 = 2.*3.1415-DPhi_Wb0;
      if(DPhi_Wb1>3.1415) DPhi_Wb1 = 2.*3.1415-DPhi_Wb1;
      if(DPhi_Wb0 < DPhi_Wb1){
         bestSol = indices[0];
      }
      else{
        bestSol = indices[1];
      }
    }
  }
  return bestSol;
}