GenFilters/plugins/PythiaFilterGammaJetWithOutBg.cc

0001 /** \class PythiaFilterGammaJet
0002  *
0003  *  PythiaFilterGammaJet filter implements generator-level preselections
0004  *  for photon+jet like events to be used in jet energy calibration.
0005  *  Ported from fortran code written by V.Konoplianikov.
0006  *
0007  * \author A.Ulyanov, ITEP
0008  *
0009  ************************************************************/
0010
0011 #include "DataFormats/Common/interface/Handle.h"
0012 #include "FWCore/Framework/interface/Event.h"
0013 #include "FWCore/Framework/interface/EventSetup.h"
0014 #include "FWCore/Framework/interface/Frameworkfwd.h"
0015 #include "FWCore/Framework/interface/global/EDFilter.h"
0016 #include "FWCore/Framework/interface/MakerMacros.h"
0017 #include "FWCore/ParameterSet/interface/ParameterSet.h"
0018 #include "FWCore/Utilities/interface/EDGetToken.h"
0019 #include "FWCore/Utilities/interface/ESGetToken.h"
0020 #include "FWCore/Utilities/interface/InputTag.h"
0021 #include "SimDataFormats/GeneratorProducts/interface/HepMCProduct.h"
0022 #include "SimGeneral/HepPDTRecord/interface/ParticleDataTable.h"
0023 #include "SimGeneral/HepPDTRecord/interface/PDTRecord.h"
0024
0025 #include <cmath>
0026 #include <cstdlib>
0027 #include <list>
0028 #include <string>
0029
0030 class PythiaFilterGammaJetWithOutBg : public edm::global::EDFilter<> {
0031 public:
0032   explicit PythiaFilterGammaJetWithOutBg(const edm::ParameterSet&);
0033
0034   bool filter(edm::StreamID, edm::Event&, const edm::EventSetup&) const override;
0035
0036 private:
0037   const edm::EDGetTokenT<edm::HepMCProduct> token_;
0038   const edm::ESGetToken<ParticleDataTable, PDTRecord> particleDataTableToken_;
0039
0040   const double etaMax;
0041   const double ptSeed;
0042   const double ptMin;
0043   const double ptMax;
0044   const double dphiMin;
0045   const double detaMax;
0046   const double etaPhotonCut2;
0047
0048   const double cone;
0049   const double ebEtaMax;
0050   const double deltaEB;
0051   const double deltaEE;
0052 };
0053
0054 namespace {
0055
0056   double deltaR2(double eta0, double phi0, double eta, double phi) {
0057     double dphi = phi - phi0;
0058     if (dphi > M_PI)
0059       dphi -= 2 * M_PI;
0060     else if (dphi <= -M_PI)
0061       dphi += 2 * M_PI;
0062     return dphi * dphi + (eta - eta0) * (eta - eta0);
0063   }
0064
0065   double deltaPhi(double phi0, double phi) {
0066     double dphi = phi - phi0;
0067     if (dphi > M_PI)
0068       dphi -= 2 * M_PI;
0069     else if (dphi <= -M_PI)
0070       dphi += 2 * M_PI;
0071     return dphi;
0072   }
0073
0074   class ParticlePtGreater {
0075   public:
0076     int operator()(const HepMC::GenParticle* p1, const HepMC::GenParticle* p2) const {
0077       return p1->momentum().perp() > p2->momentum().perp();
0078     }
0079   };
0080 }  // namespace
0081
0082 PythiaFilterGammaJetWithOutBg::PythiaFilterGammaJetWithOutBg(const edm::ParameterSet& iConfig)
0083     : token_(consumes<edm::HepMCProduct>(
0084           edm::InputTag(iConfig.getUntrackedParameter("moduleLabel", std::string("generator")), "unsmeared"))),
0085       particleDataTableToken_(esConsumes<ParticleDataTable, PDTRecord>()),
0086       etaMax(iConfig.getUntrackedParameter<double>("MaxPhotonEta", 2.8)),
0087       ptSeed(iConfig.getUntrackedParameter<double>("PhotonSeedPt", 5.)),
0088       ptMin(iConfig.getUntrackedParameter<double>("MinPhotonPt")),
0089       ptMax(iConfig.getUntrackedParameter<double>("MaxPhotonPt")),
0090       dphiMin(iConfig.getUntrackedParameter<double>("MinDeltaPhi", -1) / 180 * M_PI),
0091       detaMax(iConfig.getUntrackedParameter<double>("MaxDeltaEta", 10.)),
0092       etaPhotonCut2(iConfig.getUntrackedParameter<double>("MinPhotonEtaForwardJet", 1.3)),
0093       cone(0.5),
0094       ebEtaMax(1.479),
0095       deltaEB(0.01745 / 2 * 5),       // delta_eta, delta_phi
0096       deltaEE(2.93 / 317 / 2 * 5) {}  // delta_x/z, delta_y/z
0097
0098 bool PythiaFilterGammaJetWithOutBg::filter(edm::StreamID, edm::Event& iEvent, const edm::EventSetup& iSetup) const {
0099   bool accepted = false;
0100   edm::Handle<edm::HepMCProduct> evt;
0101   iEvent.getByToken(token_, evt);
0102
0103   std::list<const HepMC::GenParticle*> seeds;
0104   const HepMC::GenEvent* myGenEvent = evt->GetEvent();
0105
0106   for (HepMC::GenEvent::particle_const_iterator p = myGenEvent->particles_begin(); p != myGenEvent->particles_end();
0107        ++p) {
0108     if ((*p)->pdg_id() == 22 && (*p)->status() == 1 && (*p)->momentum().perp() > ptSeed &&
0109         std::abs((*p)->momentum().eta()) < etaMax)
0110       seeds.push_back(*p);
0111   }
0112
0113   seeds.sort(ParticlePtGreater());
0114
0115   for (std::list<const HepMC::GenParticle*>::const_iterator is = seeds.begin(); is != seeds.end(); is++) {
0116     double etaPhoton = (*is)->momentum().eta();
0117     double phiPhoton = (*is)->momentum().phi();
0118
0119     HepMC::GenEvent::particle_const_iterator ppp = myGenEvent->particles_begin();
0120     for (int i = 0; i < 6; ++i)
0121       ppp++;
0122     HepMC::GenParticle* particle7 = (*ppp);
0123     ppp++;
0124     HepMC::GenParticle* particle8 = (*ppp);
0125
0126     double dphi7 = std::abs(deltaPhi(phiPhoton, particle7->momentum().phi()));
0127     double dphi8 = std::abs(deltaPhi(phiPhoton, particle8->momentum().phi()));
0128
0129     double etaJet = dphi7 > dphi8 ? particle7->momentum().eta() : particle8->momentum().eta();
0130
0131     double eta1 = etaJet - detaMax;
0132     double eta2 = etaJet + detaMax;
0133     if (eta1 > etaPhotonCut2)
0134       eta1 = etaPhotonCut2;
0135     if (eta2 < -etaPhotonCut2)
0136       eta2 = -etaPhotonCut2;
0137
0138     if (etaPhoton < eta1 || etaPhoton > eta2) {
0139       continue;
0140     }
0141     bool inEB(false);
0142     double tgx(0);
0143     double tgy(0);
0144     if (std::abs(etaPhoton) < ebEtaMax)
0145       inEB = true;
0146     else {
0147       tgx = (*is)->momentum().px() / (*is)->momentum().pz();
0148       tgy = (*is)->momentum().py() / (*is)->momentum().pz();
0149     }
0150
0151     double etPhoton = 0;
0152     double ptMaxHadron = 0;
0153
0154     for (HepMC::GenEvent::particle_const_iterator p = myGenEvent->particles_begin(); p != myGenEvent->particles_end();
0155          ++p) {
0156       if ((*p)->status() != 1)
0157         continue;
0158       int apid = std::abs((*p)->pdg_id());
0159       if (apid > 11 && apid < 21)
0160         continue;  //get rid of muons and neutrinos
0161       double eta = (*p)->momentum().eta();
0162       double phi = (*p)->momentum().phi();
0163       if (deltaR2(etaPhoton, phiPhoton, eta, phi) > cone * cone)
0164         continue;
0165       double pt = (*p)->momentum().perp();
0166
0167       //select particles matching a crystal array centered on photon
0168       if (inEB) {
0169         if (std::abs(eta - etaPhoton) > deltaEB || std::abs(deltaPhi(phi, phiPhoton)) > deltaEB)
0170           continue;
0171       } else if (std::abs((*p)->momentum().px() / (*p)->momentum().pz() - tgx) > deltaEE ||
0172                  std::abs((*p)->momentum().py() / (*p)->momentum().pz() - tgy) > deltaEE)
0173         continue;
0174
0175       etPhoton += pt;
0176       if (apid > 100 && apid != 310 && pt > ptMaxHadron)
0177         ptMaxHadron = pt;
0178     }
0179
0180     if (etPhoton < ptMin || etPhoton > ptMax) {
0181       continue;
0182     }
0183
0184     accepted = true;
0185     break;
0186
0187   }  //loop over seeds
0188   return accepted;
0189 }
0190
0191 DEFINE_FWK_MODULE(PythiaFilterGammaJetWithOutBg);