MEzCalculator Class Reference

#include <MEzCalculator.h>

Public Member Functions
double	Calculate (int type=1)
	member functions More...
bool	IsComplex () const
	check for complex root More...
	MEzCalculator ()
	constructor More...
void	Print ()
	verbose More...
void	SetLepton (const pat::Particle &lepton, bool isMuon=true)
	Set lepton. More...
void	SetLepton (const TLorentzVector &lepton)
void	SetMET (const pat::MET &MET)
	Set MET. More...
void	SetMET (const TLorentzVector &MET)
	~MEzCalculator ()
	destructor More...

Private Attributes
bool	isComplex_
bool	isMuon_
pat::Particle	lepton_
pat::MET	MET_

Detailed Description

---

class: MEzCalculator.h

author: Francisco Yumiceva, Fermilab (yumic.nosp@m.eva@.nosp@m.fnal..nosp@m.gov)

version

Id:

MEzCalculator.h,v 1.4 2009/02/18 21:31:15 yumiceva Exp

---

Definition at line 18 of file MEzCalculator.h.

Constructor & Destructor Documentation

MEzCalculator::MEzCalculator

(

)

constructor

Definition at line 5 of file MEzCalculator.cc.

References isComplex_, and isMuon_.

{
  isComplex_ = false;
  isMuon_ = true;
}

MEzCalculator::~MEzCalculator

(

)

destructor

Definition at line 12 of file MEzCalculator.cc.

{
}

Member Function Documentation

double MEzCalculator::Calculate

(

int

type = 1

)

member functions

Calculate MEz options to choose roots from quadratic equation: type = 0 : if real roots, pick the one nearest to the lepton Pz except when the Pz so chosen is greater than 300 GeV in which case pick the most central root. type = 1 (default): if real roots, choose the one closest to the lepton Pz if complex roots, use only the real part. type = 2: if real roots, choose the most central solution. if complex roots, use only the real part.

Definition at line 18 of file MEzCalculator.cc.

References funct::A, a, Abs(), funct::C, reco::LeafCandidate::energy(), edm::hlt::Exception, isComplex_, isMuon_, lepton_, MET_, reco::LeafCandidate::px(), reco::LeafCandidate::py(), and reco::LeafCandidate::pz().

Referenced by TtSemiLRSignalSelObservables::operator()(), and TtSemiLepJetCombWMassDeltaTopMass::produce().

{
  if(type<0 || type>3)
    throw cms::Exception("UnimplementedFeature") << "Type " << type << " not supported in MEzCalculator.\n";

  double M_W  = 80.4;
  double M_mu =  0.10566;
  double M_e = 0.511e-3;
  double M_lepton = M_mu;
  if (! isMuon_ ) M_lepton = M_e;
  
  double emu = lepton_.energy();
  double pxmu = lepton_.px();
  double pymu = lepton_.py();
  double pzmu = lepton_.pz();
  double pxnu = MET_.px();
  double pynu = MET_.py();
  double pznu = 0.;

  // use pznu = - B/2*A +/- sqrt(B*B-4*A*C)/(2*A)
  
  double a = M_W*M_W - M_lepton*M_lepton + 2.0*(pxmu*pxnu + pymu*pynu);
  double A = 4.0*(emu*emu - pzmu*pzmu);
  double B = -4.0*a*pzmu;
  double C = 4.0*emu*emu*(pxnu*pxnu + pynu*pynu) - a*a;
  
  double tmproot = B*B - 4.0*A*C;
  
  if (tmproot<0) {
    isComplex_= true;
    pznu = - B/(2*A); // take real part of complex roots
  }
  else {
    isComplex_ = false;
    double tmpsol1 = (-B + TMath::Sqrt(tmproot))/(2.0*A);
    double tmpsol2 = (-B - TMath::Sqrt(tmproot))/(2.0*A);
    
    if (type == 0 ) {
      // two real roots, pick the one closest to pz of muon
      if (TMath::Abs(tmpsol2-pzmu) < TMath::Abs(tmpsol1-pzmu)) { pznu = tmpsol2;}
      else pznu = tmpsol1;
      // if pznu is > 300 pick the most central root
      if ( pznu > 300. ) {
    if (TMath::Abs(tmpsol1)<TMath::Abs(tmpsol2) ) pznu = tmpsol1;
    else pznu = tmpsol2;
      }
    }
    if (type == 1 ) {
      // two real roots, pick the one closest to pz of muon
      if (TMath::Abs(tmpsol2-pzmu) < TMath::Abs(tmpsol1-pzmu)) { pznu = tmpsol2;}
      else pznu = tmpsol1;
    }
    if (type == 2 ) {
      // pick the most central root.
      if (TMath::Abs(tmpsol1)<TMath::Abs(tmpsol2) ) pznu = tmpsol1;
      else pznu = tmpsol2;
    }
    if (type == 3 ) {
      // pick the largest value of the cosine
      TVector3 p3w, p3mu;
      p3w.SetXYZ(pxmu+pxnu, pymu+pynu, pzmu+ tmpsol1);
      p3mu.SetXYZ(pxmu, pymu, pzmu );
      
      double sinthcm1 = 2.*(p3mu.Perp(p3w))/M_W;
      p3w.SetXYZ(pxmu+pxnu, pymu+pynu, pzmu+ tmpsol2);
      double sinthcm2 = 2.*(p3mu.Perp(p3w))/M_W;
      
      double costhcm1 = TMath::Sqrt(1. - sinthcm1*sinthcm1);
      double costhcm2 = TMath::Sqrt(1. - sinthcm2*sinthcm2);
      
      if ( costhcm1 > costhcm2 ) pznu = tmpsol1;
      else pznu = tmpsol2;
    }   

  }
  
  //Particle neutrino;
  //neutrino.setP4( LorentzVector(pxnu, pynu, pznu, TMath::Sqrt(pxnu*pxnu + pynu*pynu + pznu*pznu ))) ;
  
  return pznu;
}

bool MEzCalculator::IsComplex ( ) const

inline

check for complex root

Definition at line 52 of file MEzCalculator.h.

References isComplex_.

{ return isComplex_; };

void MEzCalculator::Print ( void  )

inline

verbose

Definition at line 54 of file MEzCalculator.h.

References gather_cfg::cout, lepton_, MET_, reco::LeafCandidate::px(), reco::LeafCandidate::py(), and reco::LeafCandidate::pz().

               {
      std::cout << " METzCalculator: pxmu = " << lepton_.px() << " pzmu= " << lepton_.pz() << std::endl;
      std::cout << " METzCalculator: pxnu = " << MET_.px() << " pynu= " << MET_.py() << std::endl;
  }

void MEzCalculator::SetLepton ( const pat::Particle &  lepton, bool  isMuon = true  )

inline

Set lepton.

Definition at line 32 of file MEzCalculator.h.

References reco::isMuon(), isMuon_, and lepton_.

Referenced by TtSemiLRSignalSelObservables::operator()(), and TtSemiLepJetCombWMassDeltaTopMass::produce().

                                                                {
      lepton_ = lepton;
      isMuon_ = isMuon;
  };

void MEzCalculator::SetLepton ( const TLorentzVector &  lepton )

inline

Definition at line 36 of file MEzCalculator.h.

References lepton_, AlCaHLTBitMon_ParallelJobs::p, and reco::LeafCandidate::setP4().

                                               {
      pat::Particle::LorentzVector p(lepton.Px(), lepton.Py(), lepton.Pz(), lepton.E() );
      lepton_.setP4(p);
  }

void MEzCalculator::SetMET ( const pat::MET &  MET )

inline

Set MET.

Definition at line 26 of file MEzCalculator.h.

References MET_.

Referenced by TtSemiLRSignalSelObservables::operator()(), and TtSemiLepJetCombWMassDeltaTopMass::produce().

{ MET_ = MET; } ;

void MEzCalculator::SetMET ( const TLorentzVector &  MET )

inline

Definition at line 27 of file MEzCalculator.h.

References MET_, AlCaHLTBitMon_ParallelJobs::p, and reco::LeafCandidate::setP4().

                                         {
      pat::Particle::LorentzVector p(MET.Px(),MET.Py(),MET.Pz(),MET.E());
      MET_.setP4(p);
  }

Member Data Documentation

bool MEzCalculator::isComplex_

private

Definition at line 61 of file MEzCalculator.h.

Referenced by Calculate(), IsComplex(), and MEzCalculator().

bool MEzCalculator::isMuon_

private

Definition at line 64 of file MEzCalculator.h.

Referenced by Calculate(), MEzCalculator(), and SetLepton().

pat::Particle MEzCalculator::lepton_

private

Definition at line 62 of file MEzCalculator.h.

Referenced by Calculate(), Print(), and SetLepton().

pat::MET MEzCalculator::MET_

private

Definition at line 63 of file MEzCalculator.h.

Referenced by Calculate(), Print(), and SetMET().