CbmAnaJpsiUtils.h

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/* Copyright (C) 2015-2016 UGiessen, JINR-LIT
   SPDX-License-Identifier: GPL-3.0-only
   Authors: Semen Lebedev [committer] */
 
#ifndef CBM_ANA_JPSI_UTILS_H
#define CBM_ANA_JPSI_UTILS_H
 
#include "CbmAnaJpsiCandidate.h"
#include "CbmKFVertex.h"
#include "CbmL1PFFitter.h"
#include "CbmMCTrack.h"
#include "CbmStsTrack.h"
 
#include "TClonesArray.h"
#include "TDatabasePDG.h"
#include "TMCProcess.h"
 
#include <vector>
 
 
class CbmAnaJpsiUtils {
public:
  /*
         * Calculates and set track parameters to CbmAnaJpsiCandidate.
         * The following parameters are set: fChi2sts, fChi2Prim, fPosition, fMomentum, fMass, fCharge, fEnergy, fRapidity
         */
  static void CalculateAndSetTrackParamsToCandidate(CbmAnaJpsiCandidate* cand, CbmStsTrack* stsTrack,
                                                    CbmKFVertex& kfVertex)
  {
    CbmL1PFFitter fPFFitter;
    std::vector<CbmStsTrack> stsTracks;
    stsTracks.resize(1);
    stsTracks[0] = *stsTrack;
    std::vector<CbmL1PFFitter::PFFieldRegion> vField;
    std::vector<float> chiPrim;
    fPFFitter.GetChiToVertex(stsTracks, vField, chiPrim, kfVertex, 3e6);
    cand->fChi2sts  = stsTracks[0].GetChiSq() / stsTracks[0].GetNDF();
    cand->fChi2Prim = chiPrim[0];
 
    const FairTrackParam* vtxTrack = stsTracks[0].GetParamFirst();
 
    vtxTrack->Position(cand->fPosition);
    vtxTrack->Momentum(cand->fMomentum);
 
    cand->fMass     = TDatabasePDG::Instance()->GetParticle(11)->Mass();
    cand->fCharge   = (vtxTrack->GetQp() > 0) ? 1 : -1;
    cand->fEnergy   = sqrt(cand->fMomentum.Mag2() + cand->fMass * cand->fMass);
    cand->fRapidity = 0.5 * TMath::Log((cand->fEnergy + cand->fMomentum.Z()) / (cand->fEnergy - cand->fMomentum.Z()));
  }
 
  /*
         * \brief Return true if MC track is signal primary electron.
         */
  static Bool_t IsMcSignalElectron(CbmMCTrack* mctrack)
  {
    if (mctrack == NULL) return false;
    Int_t pdg = TMath::Abs(mctrack->GetPdgCode());
    if (mctrack->GetGeantProcessId() == kPPrimary && pdg == 11) return true;
    return false;
  }
 
  /*
     * \brief Return true if MC track is electron from gamma conversion.
     */
  static Bool_t IsMcGammaElectron(CbmMCTrack* mctrack, TClonesArray* mcTracks)
  {
    if (mctrack == NULL) return false;
    Int_t pdg = TMath::Abs(mctrack->GetPdgCode());
    if (pdg != 11) return false;
    Int_t motherId = mctrack->GetMotherId();
    if (motherId < 0) { return false; }
    else {
      CbmMCTrack* mct1 = static_cast<CbmMCTrack*>(mcTracks->At(motherId));
      Int_t motherPdg  = mct1->GetPdgCode();
      if (mct1 != NULL && motherPdg == 22 && pdg == 11) { return true; }
    }
    return false;
  }
 
  /*
     * \brief Return true if MC track is electron from Pi0 dalitz decay.
     */
  static Bool_t IsMcPi0Electron(CbmMCTrack* mctrack, TClonesArray* mcTracks)
  {
    if (mctrack == NULL) return false;
    Int_t pdg = TMath::Abs(mctrack->GetPdgCode());
    if (pdg != 11) return false;
    Int_t motherId = mctrack->GetMotherId();
    if (motherId < 0) { return false; }
    else {
      CbmMCTrack* mct1 = static_cast<CbmMCTrack*>(mcTracks->At(motherId));
      Int_t motherPdg  = mct1->GetPdgCode();
      if (mct1 != NULL && motherPdg == 111 && pdg == 11) { return true; }
    }
    return false;
  }
};
 
#endif