CbmLmvmUtils.h

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#ifndef CBM_LMVM_UTILS_H
#define CBM_LMVM_UTILS_H
 
#include "CbmKFVertex.h"
#include "CbmL1PFFitter.h"
#include "CbmLmvmCandidate.h"
#include "CbmMCTrack.h"
#include "CbmStsTrack.h"
#include "TMCProcess.h"
 
class CbmLmvmUtils {
public:
  /*
         * Calculates and set track parameters to CbmLmvmCandidate.
         * The following parameters are set: fChi2sts, fChi2Prim, fPosition, fMomentum, fMass, fCharge, fEnergy, fRapidity
         */
  static void CalculateAndSetTrackParamsToCandidate(CbmLmvmCandidate* cand,
                                                    CbmStsTrack* stsTrack,
                                                    CbmKFVertex& kfVertex) {
    CbmL1PFFitter fPFFitter;
    vector<CbmStsTrack> stsTracks;
    stsTracks.resize(1);
    stsTracks[0] = *stsTrack;
    vector<L1FieldRegion> vField;
    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()));
  }
 
  /*
         * Armenteros - Podolansky plot
         */
  static void CalculateArmPodParams(CbmLmvmCandidate* cand1,
                                    CbmLmvmCandidate* cand2,
                                    Double_t& alpha,
                                    Double_t& ptt) {
    alpha = ptt  = 0.;
    Double_t spx = cand1->fMomentum.X() + cand2->fMomentum.X();
    Double_t spy = cand1->fMomentum.Y() + cand2->fMomentum.Y();
    Double_t spz = cand1->fMomentum.Z() + cand2->fMomentum.Z();
    Double_t sp  = sqrt(spx * spx + spy * spy + spz * spz);
 
    if (sp == 0.0) return;
    Double_t pn, /*pp,*/ pln, plp;
    if (cand1->fCharge < 0.) {
      pn = cand1->fMomentum.Mag();
      //pp = cand2->fMomentum.Mag();
      pln = (cand1->fMomentum.X() * spx + cand1->fMomentum.Y() * spy
             + cand1->fMomentum.Z() * spz)
            / sp;
      plp = (cand2->fMomentum.X() * spx + cand2->fMomentum.Y() * spy
             + cand2->fMomentum.Z() * spz)
            / sp;
    } else {
      pn = cand2->fMomentum.Mag();
      //pp = cand1->fMomentum.Mag();
      pln = (cand2->fMomentum.X() * spx + cand2->fMomentum.Y() * spy
             + cand2->fMomentum.Z() * spz)
            / sp;
      plp = (cand1->fMomentum.X() * spx + cand1->fMomentum.Y() * spy
             + cand1->fMomentum.Z() * spz)
            / sp;
    }
    if (pn == 0.0) return;
    Double_t ptm = (1. - ((pln / pn) * (pln / pn)));
    ptt          = (ptm >= 0.) ? pn * sqrt(ptm) : 0;
    alpha        = (plp - pln) / (plp + pln);
  }
 
  /*
         * \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
          && mctrack->GetGeantProcessId() != kPPrimary) {
        return true;
      }
    }
    return false;
  }
 
  /*
         * \brief Return true if MC track is electron from Eta decay.
         */
  static Bool_t IsMcEtaElectron(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 == 221 && pdg == 11) { return true; }
    }
    return false;
  }
};
 
#endif