DataFormats/HepMCCandidate/interface/GenParticle.h - master - githubmirror/cmssw

DataFormats/HepMCCandidate/interface/GenParticle.h
121 строка5 KB
Matti Kortelainen
Move stored types in io_v1 namespace, reset class versions to 3
22 май 2026, 18:18
22 май 2026, 18:18909f324
#ifndef HepMCCandidate_GenParticle_h
#define HepMCCandidate_GenParticle_h
/** \class reco::GenParticle
 *
 * particle candidate with information from HepMC::GenParticle
 *
 * \author: Luca Lista, INFN
 *
 */
#include "DataFormats/Candidate/interface/CompositeRefCandidateT.h"
#include "DataFormats/HepMCCandidate/interface/GenParticleFwd.h"
#include "DataFormats/HepMCCandidate/interface/GenStatusFlags.h"
#include <vector>

namespace HepMC {
  class GenParticle;
}

namespace reco {
  namespace io_v1 {

    class GenParticle : public CompositeRefCandidateT<GenParticleRefVector> {
    public:
      /// default constructor
      GenParticle() {}
      /// default constructor
      GenParticle(const LeafCandidate &c) : CompositeRefCandidateT<GenParticleRefVector>(c) {}
      /// constrocturo from values
      GenParticle(Charge q, const LorentzVector &p4, const Point &vtx, int pdgId, int status, bool integerCharge);
      /// constrocturo from values
      GenParticle(Charge q, const PolarLorentzVector &p4, const Point &vtx, int pdgId, int status, bool integerCharge);
      /// destructor
      ~GenParticle() override;
      /// return a clone
      GenParticle *clone() const override;
      void setCollisionId(int s) { collisionId_ = s; }
      int collisionId() const { return collisionId_; }

      const GenStatusFlags &statusFlags() const { return statusFlags_; }
      GenStatusFlags &statusFlags() { return statusFlags_; }

      /////////////////////////////////////////////////////////////////////////////
      //basic set of gen status flags accessible directly here
      //the rest accessible through statusFlags()
      //(see GenStatusFlags.h for their meaning)

      /////////////////////////////////////////////////////////////////////////////
      //these are robust, generator-independent functions for categorizing
      //mainly final state particles, but also intermediate hadrons/taus

      //is particle prompt (not from hadron, muon, or tau decay) and final state
      bool isPromptFinalState() const { return status() == 1 && statusFlags_.isPrompt(); }

      //is particle prompt (not from hadron, muon, or tau decay) and decayed
      //such as a prompt tau
      bool isPromptDecayed() const { return statusFlags_.isDecayedLeptonHadron() && statusFlags_.isPrompt(); }

      //this particle is a direct decay product of a prompt tau and is final state
      //(eg an electron or muon from a leptonic decay of a prompt tau)
      bool isDirectPromptTauDecayProductFinalState() const {
        return status() == 1 && statusFlags_.isDirectPromptTauDecayProduct();
      }

      /////////////////////////////////////////////////////////////////////////////
      //these are generator history-dependent functions for tagging particles
      //associated with the hard process
      //Currently implemented for Pythia 6 and Pythia 8 status codes and history
      //and may not have 100% consistent meaning across all types of processes
      //Users are strongly encouraged to stick to the more robust flags above,
      //as well as the expanded set available in GenStatusFlags.h

      //this particle is part of the hard process
      bool isHardProcess() const { return statusFlags_.isHardProcess(); }

      //this particle is the final state direct descendant of a hard process particle
      bool fromHardProcessFinalState() const { return status() == 1 && statusFlags_.fromHardProcess(); }

      //this particle is the decayed direct descendant of a hard process particle
      //such as a tau from the hard process
      bool fromHardProcessDecayed() const {
        return statusFlags_.isDecayedLeptonHadron() && statusFlags_.fromHardProcess();
      }

      //this particle is a direct decay product of a hardprocess tau and is final state
      //(eg an electron or muon from a leptonic decay of a tau from the hard process)
      bool isDirectHardProcessTauDecayProductFinalState() const {
        return status() == 1 && statusFlags_.isDirectHardProcessTauDecayProduct();
      }

      //this particle is the direct descendant of a hard process particle of the same pdg id.
      //For outgoing particles the kinematics are those before QCD or QED FSR
      //This corresponds roughly to status code 3 in pythia 6
      //This is the most complex and error prone of all the flags and you are strongly encouraged
      //to consider using the others to fill your needs.
      bool fromHardProcessBeforeFSR() const { return statusFlags_.fromHardProcessBeforeFSR(); }

      //provided for convenience.  Use this one if you were using status 3 before and didn't know or care what it exactly meant
      bool isMostlyLikePythia6Status3() { return fromHardProcessBeforeFSR(); }

      //this particle is the last copy of the particle in the chain  with the same pdg id
      //(and therefore is more likely, but not guaranteed, to carry the final physical momentum)
      bool isLastCopy() const { return statusFlags_.isLastCopy(); }

      //this particle is the last copy of the particle in the chain with the same pdg id
      //before QED or QCD FSR
      //(and therefore is more likely, but not guaranteed, to carry the momentum after ISR)
      bool isLastCopyBeforeFSR() const { return statusFlags_.isLastCopyBeforeFSR(); }

    private:
      /// checp overlap with another candidate
      bool overlap(const Candidate &) const override;
      int collisionId_;
      GenStatusFlags statusFlags_;
    };

  }  // namespace io_v1
  using GenParticle = io_v1::GenParticle;

}  // namespace reco

#endif