                                                   {
     double pigaga = 0.;
 
     // Leptonic contribution (just one loop, precise at < 0.3% level)
     const double alphapi = 1 / 137.036 / M_PI;
     const double mass_e = 0.0005;
     const double mass_mu = 0.106;
     const double mass_tau = 1.777;
     const double mass_Z = 91.2;
     if (pt > mass_e)
       pigaga += alphapi * (2 * log(pt / mass_e) / 3. - 5. / 9.);
     if (pt > mass_mu)
       pigaga += alphapi * (2 * log(pt / mass_mu) / 3. - 5. / 9.);
     if (pt > mass_tau)
       pigaga += alphapi * (2 * log(pt / mass_tau) / 3. - 5. / 9.);
 
     // Hadronic vaccum contribution
     // Using simple effective parametrization from Physics Letters B 513 (2001) 46.
     // Top contribution neglected
     double A = 0.;
     double B = 0.;
     double C = 0.;
     if (pt < 0.7) {
       A = 0.0;
       B = 0.0023092;
       C = 3.9925370;
     } else if (pt < 2.0) {
       A = 0.0;
       B = 0.0022333;
       C = 4.2191779;
     } else if (pt < 4.0) {
       A = 0.0;
       B = 0.0024402;
       C = 3.2496684;
     } else if (pt < 10.0) {
       A = 0.0;
       B = 0.0027340;
       C = 2.0995092;
     } else if (pt < mass_Z) {
       A = 0.0010485;
       B = 0.0029431;
       C = 1.0;
     } else if (pt < 10000.) {
       A = 0.0012234;
       B = 0.0029237;
       C = 1.0;
     } else {
       A = 0.0016894;
       B = 0.0028984;
       C = 1.0;
     }
     pigaga += A + B * log(1. + C * pt * pt);
 
     // Done
     return 1. / (1. - pigaga);
   }

◆ clear()

void heppy::FSRWeightAlgo::clear ( void )

inline

Definition at line 13 of file FSRWeightAlgo.h.

References genParticles_.

13 { genParticles_.clear(); }

heppy::FSRWeightAlgo::genParticles_

std::vector< reco::GenParticle > genParticles_

Definition: FSRWeightAlgo.h:19

◆ weight()

double heppy::FSRWeightAlgo::weight ( ) const

Definition at line 10 of file FSRWeightAlgo.cc.

References funct::abs(), alphaRatio(), funct::cos(), reco::CompositeRefCandidateT< D >::daughter(), reco::CompositeRefCandidateT< D >::daughterRef(), dumpMFGeometry_cfg::delta, reco::LeafCandidate::energy(), genParticles_, mps_fire::i, dqmiolumiharvest::j, HLT_2024v13_cff::leptonId, reco::Candidate::mass(), reco::LeafCandidate::mass(), reco::CompositeRefCandidateT< D >::mother(), reco::CompositeRefCandidateT< D >::numberOfDaughters(), reco::CompositeRefCandidateT< D >::numberOfMothers(), reco::Candidate::pdgId(), reco::LeafCandidate::pdgId(), reco::LeafCandidate::phi(), displacedMuons_cfi::photon, MaterialEffects_cfi::photonEnergy, HLTObjectMonitor_cfi::photonPhi, funct::pow(), funct::sin(), mathSSE::sqrt(), reco::LeafCandidate::status(), and reco::LeafCandidate::theta().

                                      {
     double weight = 1.;
 
     unsigned int gensize = genParticles_.size();
     for (unsigned int i = 0; i < gensize; ++i) {
       const reco::GenParticle& lepton = genParticles_[i];
       if (lepton.status() != 3)
         continue;
       int leptonId = lepton.pdgId();
       if (abs(leptonId) != 11 && abs(leptonId) != 13 && abs(leptonId) != 15)
         continue;
       if (lepton.numberOfMothers() != 1)
         continue;
       const reco::Candidate* boson = lepton.mother();
       int bosonId = abs(boson->pdgId());
       if (bosonId != 23 && bosonId != 24)
         continue;
       double bosonMass = boson->mass();
       double leptonMass = lepton.mass();
       double leptonEnergy = lepton.energy();
       double cosLeptonTheta = cos(lepton.theta());
       double sinLeptonTheta = sin(lepton.theta());
       double leptonPhi = lepton.phi();
 
       int trueKey = i;
       if (lepton.numberOfDaughters() == 0) {
         continue;
       } else if (lepton.numberOfDaughters() == 1) {
         int otherleptonKey = lepton.daughterRef(0).key();
         const reco::GenParticle& otherlepton = genParticles_[otherleptonKey];
         if (otherlepton.pdgId() != leptonId)
           continue;
         if (otherlepton.numberOfDaughters() <= 1)
           continue;
         trueKey = otherleptonKey;
       }
 
       const reco::GenParticle& trueLepton = genParticles_[trueKey];
       unsigned int nDaughters = trueLepton.numberOfDaughters();
 
       for (unsigned int j = 0; j < nDaughters; ++j) {
         const reco::Candidate* photon = trueLepton.daughter(j);
         if (photon->pdgId() != 22)
           continue;
         double photonEnergy = photon->energy();
         double cosPhotonTheta = cos(photon->theta());
         double sinPhotonTheta = sin(photon->theta());
         double photonPhi = photon->phi();
         double costheta =
             sinLeptonTheta * sinPhotonTheta * cos(leptonPhi - photonPhi) + cosLeptonTheta * cosPhotonTheta;
         // Missing O(alpha) terms in soft-collinear approach
         // Only for W, from hep-ph/0303260
         if (bosonId == 24) {
           double betaLepton = sqrt(1 - pow(leptonMass / leptonEnergy, 2));
           double delta = -8 * photonEnergy * (1 - betaLepton * costheta) / pow(bosonMass, 3) /
                          (1 - pow(leptonMass / bosonMass, 2)) / (4 - pow(leptonMass / bosonMass, 2)) * leptonEnergy *
                          (pow(leptonMass, 2) / bosonMass + 2 * photonEnergy);
           weight *= (1 + delta);
         }
         // Missing NLO QED orders in QED parton shower approach
         // Change coupling scale from 0 to kT to estimate this effect
         weight *= alphaRatio(photonEnergy * sqrt(1 - pow(costheta, 2)));
       }
     }
 
     return weight;
   }

Member Data Documentation

◆ genParticles_

std::vector<reco::GenParticle> heppy::FSRWeightAlgo::genParticles_

private

Definition at line 19 of file FSRWeightAlgo.h.

Referenced by addGenParticle(), clear(), and weight().

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ FSRWeightAlgo()

◆ ~FSRWeightAlgo()

Member Function Documentation

◆ addGenParticle()

◆ alphaRatio()

◆ clear()

◆ weight()

Member Data Documentation

◆ genParticles_