ParticleLevelElectronObjectSelector.cxx

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/*
   Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
// Filename: ParticleLevelElectronObjectSelector.cxx
// Description:
// Author: Fabian Wilk
// Created: Sun Feb 22 15:18:45 2015
 
#include "TopParticleLevel/ParticleLevelElectronObjectSelector.h"
 
#include "MCTruthClassifier/MCTruthClassifierDefs.h"
#include "TopParticleLevel/TruthTools.h"
 
namespace top {
  ParticleLevelElectronObjectSelector::ParticleLevelElectronObjectSelector(Options opt /* = Options() */)
    : m_opt(opt) { /* Deliberately Empty */}
 
  /* virtual */ bool
  ParticleLevelElectronObjectSelector::apply(const xAOD::TruthParticle& truthParticle) {
    // Obtain the particle type and particle origin from the decoration
    // created by the MCTruthClassifier. For legacy reasons, try both
    // decoration names.
    unsigned int type;
 
    if (truthParticle.isAvailable<unsigned int>("particleType")) {
      type = truthParticle.auxdata<unsigned int>("particleType");
    } else if (truthParticle.isAvailable<unsigned int>("classifierParticleType")) {
      type = truthParticle.auxdata<unsigned int>("classifierParticleType");
    } else {
      throw std::runtime_error("ParticleLevelElectronObjectSelector::apply: "
          "Could not obtain MCTruthClassifier result decoration.");
    }
 
    // --------------------------------------------------
    // Accept electrons iff they do not come from a hadron
    using namespace MCTruthPartClassifier;
    if (m_opt.not_from_hadron &&
        type != ParticleType::IsoElectron) {
      return false;
    }
 
    // If it is requested that tauons are hadrons, perform a check of the
    // ancestry: It shall not contain a single tauon.
    if (m_opt.tau_is_hadron) {
      auto truthProxy = truthParticle.auxdata<ElementLink<xAOD::TruthParticleContainer> >("originalTruthParticle");
      if (not truthProxy.isValid()) {
        throw std::runtime_error("ParticleLevelElectronObjectSelector::apply: "
            "Could not obtain 'originalTruthParticle' reference.");
      }
      if (truth::isLeptonFromTau(*truthProxy)) {
        return false;
      }
    }
 
    // --------------------------------------------------
    // Apply kinematic cut on the dressed pT:
    //     must exceed 25 GeV
    if (truthParticle.auxdata<float>("pt_dressed") < m_opt.pt_min) {
      return false;
    }
 
    // --------------------------------------------------
    // Apply kinematic cut on the dressed eta:
    //     must be less than or equal to 2.5
    if (std::abs(truthParticle.auxdata<float>("eta_dressed")) > m_opt.eta_max) {
      return false;
    }
 
 
    // --------------------------------------------------
    // Everything that reaches this point has passed the selection
    return true;
  }
}