AliAnalysisTaskEmcalJetHUtils.cxx

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//
// Utilities class for Jet-Hadron correlation analysis
//

#include "AliAnalysisTaskEmcalJetHUtils.h"

// Require to use AliLog streams with some types
#include <iostream>

#include <TMath.h>

#include <AliLog.h>

#include "AliEmcalJet.h"
#include "AliEmcalParticleJetConstituent.h"
#include "AliEmcalClusterJetConstituent.h"

namespace PWGJE {
namespace EMCALJetTasks {

const std::map<std::string, AliAnalysisTaskEmcalJetHUtils::ELeadingHadronBiasType_t> AliAnalysisTaskEmcalJetHUtils::fgkLeadingHadronBiasMap = {
  { "kCharged", AliAnalysisTaskEmcalJetHUtils::kCharged},
  { "kNeutral", AliAnalysisTaskEmcalJetHUtils::kNeutral},
  { "kBoth", AliAnalysisTaskEmcalJetHUtils::kBoth}
};

double AliAnalysisTaskEmcalJetHUtils::GetLeadingHadronPt(AliEmcalJet * jet, AliAnalysisTaskEmcalJetHUtils::ELeadingHadronBiasType_t leadingHadronType)
{
  double maxTrackPt = 0;
  double maxClusterPt = 0;

  if (leadingHadronType == kCharged || leadingHadronType == kBoth) {
    auto particle = jet->GetLeadingParticleConstituent();
    if (particle) {
      maxTrackPt = particle->Pt();
    }
  }
  if (leadingHadronType == kNeutral || leadingHadronType == kBoth) {
    // NOTE: We don't want to use jet->MaxNeutralPt() because this uses energy
    //       from the neutral particles at the particle level. While this is not
    //       strictly wrong, it can be rather misleading to have a leading neutral
    //       particle value when we are really interested in the cluster pt that is
    //       only meaningful at detector level.
    auto cluster = jet->GetLeadingClusterConstituent();
    if (cluster) {
      // Uses the energy definition that was used when the constituent was created
      // to calculate the Pt(). Usually, this would be the hadronic corrected energy
      maxClusterPt = cluster->Pt();
    }
  }

  // The max value will be 0 unless it was filled. Thus, it will only be greater if
  // it was requested.
  return (maxTrackPt > maxClusterPt) ? maxTrackPt : maxClusterPt;
}

double AliAnalysisTaskEmcalJetHUtils::RelativeEPAngle(double jetAngle, double epAngle)
{
  double dphi = (epAngle - jetAngle);

  // ran into trouble with a few dEP<-Pi so trying this...
  if( dphi<-1*TMath::Pi() ) {
    dphi = dphi + 1*TMath::Pi();
  } // this assumes we are doing full jets currently

  if( (dphi>0) && (dphi<1*TMath::Pi()/2) ) {
    // Do nothing! we are in quadrant 1
  } else if ( (dphi>1*TMath::Pi()/2) && (dphi<1*TMath::Pi()) ) {
    dphi = 1*TMath::Pi() - dphi;
  } else if ( (dphi<0) && (dphi>-1*TMath::Pi()/2) ) {
    dphi = std::abs(dphi);
  } else if ( (dphi<-1*TMath::Pi()/2) && (dphi>-1*TMath::Pi()) ) {
    dphi = dphi + 1*TMath::Pi();
  }

  // Warn if we are not in the proper range
  if ( dphi < 0 || dphi > TMath::Pi()/2 ) {
    AliWarningGeneralStream("AliAnalysisTaskEmcalJetHUtils") << ": dPHI not in range [0, 0.5*Pi]!\n";
  }

  return dphi;   // dphi in [0, Pi/2]
}

} /* namespace EMCALJetTasks */
} /* namespace PWGJE */