Kalanand's May 2011 Log

May 4th

To access trigger object 4-vectors

May 19th

Re-running trigger lists on MC

May 26th

Jet color coherence: pull angle variable

pat::Jet *leadingJet;

pat::Jet *secondLeadingJet;

leadingDeltaTheta = TMath::Abs( getDeltaTheta( leadingJet ,
secondLeadingJet ) );

where

//the pull vector is going to be calculated using j1

double ZH_channel::getDeltaTheta( pat::Jet* j1, pat::Jet* j2 ){

 double deltaTheta = 1e10;
 TLorentzVector pi(0,0,0,0);
 TLorentzVector v_j1(0,0,0,0);
 TLorentzVector v_j2(0,0,0,0);

//re-reconstruct the jet direction with the charged tracks

 std::vector< reco::PFCandidatePtr>
   j1pfc = j1->getPFConstituents();
 for(size_t idx = 0; idx < j1pfc.size(); idx++){
   if( j1pfc.at(idx)->charge() != 0 ){
     pi.SetPtEtaPhiE( j1pfc.at(idx)->pt(), j1pfc.at(idx)->eta(),
j1pfc.at(idx)->phi(), j1pfc.at(idx)->energy() );
     v_j1 += pi;
   }
 }

//re-reconstruct the jet direction with the charged tracks

 std::vector< reco::PFCandidatePtr>
   j2pfc = j2->getPFConstituents();
 for(size_t idx = 0; idx < j2pfc.size(); idx++){
   if( j2pfc.at(idx)->charge() != 0 ){
     pi.SetPtEtaPhiE( j2pfc.at(idx)->pt(), j2pfc.at(idx)->eta(),
j2pfc.at(idx)->phi(), j2pfc.at(idx)->energy() );
     v_j2 += pi;
   }
 }

 if( v_j2.Mag() < == 0
     or v_j1.Mag() < == 0 )
   return deltaTheta = 1e10;

 TVector2 v2_j1( v_j1.Rapidity(), v_j1.Phi());
 TVector2 v2_j2( v_j2.Rapidity(), v_j2.Phi());
//use j1 to calculate the pull vector

 TVector2 t = getTvect(j1);

 if( t.Mod() == 0 )
   return deltaTheta = 1e10;

 Double_t deltaphi = Geom::deltaPhi( v_j2.Phi(), v_j1.Phi() );
 Double_t deltaeta = v_j2.Rapidity() - v_j1.Rapidity();
 TVector2 BBdir( deltaeta, deltaphi );

 deltaTheta = t.DeltaPhi(BBdir);

 return deltaTheta;

}

which needs

TVector2 ZH_channel::getTvect( pat::Jet* patJet ){

 TVector2 t_Vect(0,0);
 TVector2 null(0,0);
 TVector2 ci(0,0);
 TLorentzVector pi(0,0,0,0);
 TLorentzVector J(0,0,0,0);
 TVector2 r(0,0);
 double patJetpfcPt = 1e10;
 double r_mag = 1e10;
 unsigned int nOfconst = 0;

//re-reconstruct the jet direction with the charged tracks
 std::vector< reco::PFCandidatePtr>
   patJetpfc = patJet->getPFConstituents();
 for(size_t idx = 0; idx < patJetpfc.size(); idx++){
   if( patJetpfc.at(idx)->charge() != 0 ){
     pi.SetPtEtaPhiE( patJetpfc.at(idx)->pt(),
patJetpfc.at(idx)->eta(), patJetpfc.at(idx)->phi(),
patJetpfc.at(idx)->energy() );
     J += pi;
     nOfconst++;
   }
 }

// if there are less than two charged tracks do not calculate the pull
(there is not enough info). It returns a null vector

 if( nOfconst < 2 )
   return null;

 TVector2 v_J( J.Rapidity(), J.Phi() );
//calculate TVector using only charged tracks
 for(size_t idx = 0; idx < patJetpfc.size(); idx++){
   if( patJetpfc.at(idx)->charge() != 0  ){
     patJetpfcPt = patJetpfc.at(idx)->pt();
     pi.SetPtEtaPhiE( patJetpfc.at(idx)->pt(),
patJetpfc.at(idx)->eta(), patJetpfc.at(idx)->phi(),
patJetpfc.at(idx)->energy() );
     r.Set( pi.Rapidity() - J.Rapidity(), Geom::deltaPhi(
patJetpfc.at(idx)->phi(), J.Phi() ) );
     r_mag = r.Mod();
     t_Vect += ( patJetpfcPt / J.Pt() ) * r_mag * r;
   }
 }

 return t_Vect;

}

The code for cos(theta*) is:

TVector3 higgsBoost;
 higgsBoost = higgsP4.BoostVector();
 leading_higgsHelicity = getHelicity( leadingJet, higgsBoost );
 secondLeading_higgsHelicity = getHelicity( secondLeadingJet, higgsBoost );

double ZH_channel::getHelicity( pat::Jet* jet , TVector3 boost ){
 double hel = 1e10;
 TLorentzVector j;
 j.SetPtEtaPhiE( jet->pt(), jet->eta(), jet->phi(), jet->energy() );
 j.Boost( -boost );
 hel = TMath::Cos( j.Vect().Angle( boost ) );
 return hel;
}

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