[u/mrichter/AliRoot.git] / ANALYSIS / AliD0toKpi.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

//----------------------------------------------------------------------------
//               Implementation of the D0toKpi class
//                  for pp and PbPb interactions
// Note: the two decay tracks are labelled: 0 (positive track)
//                                          1 (negative track)
//            Origin: A. Dainese    andrea.dainese@lnl.infn.it            
//----------------------------------------------------------------------------

#include <TH1.h>
#include <TH2.h>
#include <TCanvas.h>
#include <TPaveLabel.h>
#include <TVector3.h>

#include "AliD0toKpi.h"

ClassImp(AliD0toKpi)

//----------------------------------------------------------------------------
AliD0toKpi::AliD0toKpi() {
  // Default constructor
  
  fSignal = kFALSE;

  fEvent = 0;

  fTrkNum[0] = 0;
  fTrkNum[1] = 0;

  fV1x = 0.;
  fV1y = 0.;
  fV1z = 0.;
  fV2x = 0.;
  fV2y = 0.;
  fV2z = 0.;
  fDCA = 0.;

  fPx[0] = 0.;
  fPy[0] = 0.;
  fPz[0] = 0.;
  fPx[1] = 0.;
  fPy[1] = 0.;
  fPz[1] = 0.;

  fd0[0] = 0.;
  fd0[1] = 0.;

  fPdg[0] = 0;
  fPdg[1] = 0;
  fMum[0] = 0;
  fMum[1] = 0;

  fTagPi[0] = 0.;
  fTagPi[1] = 0.;
  fTagKa[0] = 0.;
  fTagKa[1] = 0.;
  fTagNid[0] = 0.;
  fTagNid[1] = 0.;

  fWgtAD0=fWgtAD0bar=fWgtBD0=fWgtBD0bar=fWgtCD0=fWgtCD0bar=fWgtDD0=fWgtDD0bar=0;

}
//----------------------------------------------------------------------------
AliD0toKpi::AliD0toKpi(Int_t ev,Int_t trkNum[2],
		       Double_t v1[3],Double_t v2[3], 
		       Double_t dca,
		       Double_t mom[6],Double_t d0[2]) {
  // Constructor

  fSignal = kFALSE;

  fEvent = ev;
  fTrkNum[0] = trkNum[0];
  fTrkNum[1] = trkNum[1];

  fV1x = v1[0];
  fV1y = v1[1];
  fV1z = v1[2];
  fV2x = v2[0];
  fV2y = v2[1];
  fV2z = v2[2];
  fDCA = dca;

  fPx[0] = mom[0];
  fPy[0] = mom[1];
  fPz[0] = mom[2];
  fPx[1] = mom[3];
  fPy[1] = mom[4];
  fPz[1] = mom[5];

  fd0[0] = d0[0];
  fd0[1] = d0[1];

  fPdg[0] = 0;
  fPdg[1] = 0;
  fMum[0] = 0;
  fMum[1] = 0;

  fTagPi[0]  = 0.;
  fTagPi[1]  = 0.;
  fTagKa[0]  = 0.;
  fTagKa[1]  = 0.;
  fTagNid[0] = 0.;
  fTagNid[1] = 0.;

  fWgtAD0=fWgtAD0bar=fWgtBD0=fWgtBD0bar=fWgtCD0=fWgtCD0bar=fWgtDD0=fWgtDD0bar=0;
}
//----------------------------------------------------------------------------
AliD0toKpi::~AliD0toKpi() {}
//____________________________________________________________________________
AliD0toKpi::AliD0toKpi( const AliD0toKpi& d0toKpi):TObject(d0toKpi) {
  // dummy copy constructor
}
//----------------------------------------------------------------------------
void AliD0toKpi::ApplyPID(TString pidScheme) {
  // Applies particle identification

  if((!pidScheme.CompareTo("TOFparamPbPb") || !pidScheme.CompareTo("TOFparamPP")) && fPdg[0]==0) {
    printf("AliD0toKpi::ApplyPID :\n Warning: TOF parameterized PID can be used only for simulation!\n"); 
    return;
  }

  if(!pidScheme.CompareTo("TOFparamPbPb")) {
    // tagging of the positive track
    if(TMath::Abs(fPdg[0])==211 || TMath::Abs(fPdg[0])==13 
       || TMath::Abs(fPdg[0])==11) { // pion,muon,electron
      fTagPi[0]  = LinearInterpolation(PChild(0),kPiBinsPbPb,kPiBinWidthPbPb,kPiTagPiPbPb);
      fTagNid[0] = 1.-fTagPi[0];
      fTagKa[0]   = 0.;
      fTagPr[0]   = 0.;
    } 
    if(TMath::Abs(fPdg[0])==321) { // kaon
      fTagKa[0]   = LinearInterpolation(PChild(0),kKBinsPbPb,kKBinWidthPbPb,kKTagKPbPb);
      fTagNid[0] = LinearInterpolation(PChild(0),kKBinsPbPb,kKBinWidthPbPb,kKTagNidPbPb);
      if((fTagNid[0]+fTagKa[0])>1.) fTagNid[0] = 1.-fTagKa[0];
      fTagPi[0] = 1.-fTagNid[0]-fTagKa[0];
      fTagPr[0] = 0.;
    } 
    if(TMath::Abs(fPdg[0])==2212) { // proton
      fTagPr[0]  = LinearInterpolation(PChild(0),kPBinsPbPb,kPBinWidthPbPb,kPTagPPbPb);
      fTagNid[0] = LinearInterpolation(PChild(0),kPBinsPbPb,kPBinWidthPbPb,kPTagNidPbPb);
      if((fTagNid[0]+fTagPr[0])>1.) fTagNid[0] = 1.-fTagPr[0];
      fTagPi[0] = 1.-fTagNid[0]-fTagPr[0];
      fTagKa[0]   = 0.;
    } 
    // tagging of the negative track
    if(TMath::Abs(fPdg[1])==211 || TMath::Abs(fPdg[1])==13 
       || TMath::Abs(fPdg[1])==11) { // pion,muon,electron
      fTagPi[1]  = LinearInterpolation(PChild(1),kPiBinsPbPb,kPiBinWidthPbPb,kPiTagPiPbPb);
      fTagNid[1] = 1.-fTagPi[1];
      fTagKa[1]   = 0.;
      fTagPr[1]   = 0.;
    } 
    if(TMath::Abs(fPdg[1])==321) { // kaon
      fTagKa[1]   = LinearInterpolation(PChild(1),kKBinsPbPb,kKBinWidthPbPb,kKTagKPbPb);
      fTagNid[1] = LinearInterpolation(PChild(1),kKBinsPbPb,kKBinWidthPbPb,kKTagNidPbPb);
      if((fTagNid[1]+fTagKa[1])>1.) fTagNid[1] = 1.-fTagKa[1];
      fTagPi[1] = 1.-fTagNid[1]-fTagKa[1];
      fTagPr[1] = 0.;
    } 
    if(TMath::Abs(fPdg[1])==2212) { // proton
      fTagPr[1]  = LinearInterpolation(PChild(1),kPBinsPbPb,kPBinWidthPbPb,kPTagPPbPb);
      fTagNid[1] = LinearInterpolation(PChild(1),kPBinsPbPb,kPBinWidthPbPb,kPTagNidPbPb);
      if((fTagNid[1]+fTagPr[1])>1.) fTagNid[1] = 1.-fTagPr[1];
      fTagPi[1] = 1.-fTagNid[1]-fTagPr[1];
      fTagKa[1]   = 0.;
    } 
  }


  if(!pidScheme.CompareTo("TOFparamPP")) {
    // tagging of the positive track
    if(TMath::Abs(fPdg[0])==211 || TMath::Abs(fPdg[0])==13 
       || TMath::Abs(fPdg[0])==11) { // pion,muon,electron
      fTagPi[0]  = LinearInterpolation(PChild(0),kPiBinsPP,kPiBinWidthPP,kPiTagPiPP);
      fTagNid[0] = 1.-fTagPi[0];
      fTagKa[0]   = 0.;
      fTagPr[0]   = 0.;
    } 
    if(TMath::Abs(fPdg[0])==321) { // kaon
      fTagKa[0]   = LinearInterpolation(PChild(0),kKBinsPP,kKBinWidthPP,kKTagKPP);
      fTagNid[0] = LinearInterpolation(PChild(0),kKBinsPP,kKBinWidthPP,kKTagNidPP);
      if((fTagNid[0]+fTagKa[0])>1.) fTagNid[0] = 1.-fTagKa[0];
      fTagPi[0] = 1.-fTagNid[0]-fTagKa[0];
      fTagPr[0] = 0.;
    } 
    if(TMath::Abs(fPdg[0])==2212) { // proton
      fTagPr[0]  = LinearInterpolation(PChild(0),kPBinsPP,kPBinWidthPP,kPTagPPP);
      fTagNid[0] = LinearInterpolation(PChild(0),kPBinsPP,kPBinWidthPP,kPTagNidPP);
      if((fTagNid[0]+fTagPr[0])>1.) fTagNid[0] = 1.-fTagPr[0];
      fTagPi[0] = 1.-fTagNid[0]-fTagPr[0];
      fTagKa[0]   = 0.;
    } 
    // tagging of the negative track
    if(TMath::Abs(fPdg[1])==211 || TMath::Abs(fPdg[1])==13 
       || TMath::Abs(fPdg[1])==11) { // pion,muon,electron
      fTagPi[1]  = LinearInterpolation(PChild(1),kPiBinsPP,kPiBinWidthPP,kPiTagPiPP);
      fTagNid[1] = 1.-fTagPi[1];
      fTagKa[1]   = 0.;
      fTagPr[1]   = 0.;
    } 
    if(TMath::Abs(fPdg[1])==321) { // kaon
      fTagKa[1]   = LinearInterpolation(PChild(1),kKBinsPP,kKBinWidthPP,kKTagKPP);
      fTagNid[1] = LinearInterpolation(PChild(1),kKBinsPP,kKBinWidthPP,kKTagNidPP);
      if((fTagNid[1]+fTagKa[1])>1.) fTagNid[1] = 1.-fTagKa[1];
      fTagPi[1] = 1.-fTagNid[1]-fTagKa[1];
      fTagPr[1] = 0.;
    } 
    if(TMath::Abs(fPdg[1])==2212) { // proton
      fTagPr[1]  = LinearInterpolation(PChild(1),kPBinsPP,kPBinWidthPP,kPTagPPP);
      fTagNid[1] = LinearInterpolation(PChild(1),kPBinsPP,kPBinWidthPP,kPTagNidPP);
      if((fTagNid[1]+fTagPr[1])>1.) fTagNid[1] = 1.-fTagPr[1];
      fTagPi[1] = 1.-fTagNid[1]-fTagPr[1];
      fTagKa[1]   = 0.;
    } 
  }

  return;
}
//----------------------------------------------------------------------------
Double_t AliD0toKpi::ChildrenRelAngle() const {
  // relative angle between K and pi

  TVector3 mom0(fPx[0],fPy[0],fPz[0]);
  TVector3 mom1(fPx[1],fPy[1],fPz[1]);

  Double_t angle = mom0.Angle(mom1);

  return angle; 
}
//----------------------------------------------------------------------------
void AliD0toKpi::ComputeWgts() {
  // calculate the weights for PID


  // assignement of the weights from PID
  fWgtAD0    = fTagKa[1]*(fTagPi[0]+fTagNid[0]);
  fWgtAD0bar = fTagKa[0]*(fTagPi[1]+fTagNid[1]);
  fWgtBD0    = fTagPi[0]*fTagNid[1];
  fWgtBD0bar = fTagPi[1]*fTagNid[0];
  fWgtCD0    = fTagNid[0]*fTagNid[1];
  fWgtCD0bar = fTagNid[0]*fTagNid[1];
  fWgtDD0    = 1.-fWgtAD0-fWgtBD0-fWgtCD0;
  fWgtDD0bar = 1.-fWgtAD0bar-fWgtBD0bar-fWgtCD0bar;

  /*  
  cerr<<fWgtAD0<<"  "<<fWgtAD0bar<<endl;
  cerr<<fWgtBD0<<"  "<<fWgtBD0bar<<endl;
  cerr<<fWgtCD0<<"  "<<fWgtCD0bar<<endl;
  cerr<<fWgtDD0<<"  "<<fWgtDD0bar<<endl;
  */
  /*
  if(fWgtAD0<0.) cerr<<"AliD0toKpi::ComputeWgts()  Negative weight!!!\n";
  if(fWgtAD0bar<0.) cerr<<"AliD0toKpi::ComputeWgts()  Negative weight!!!\n";
  if(fWgtBD0<0.) cerr<<"AliD0toKpi::ComputeWgts()  Negative weight!!!\n";
  if(fWgtBD0bar<0.) cerr<<"AliD0toKpi::ComputeWgts()  Negative weight!!!\n";
  if(fWgtCD0<0.) cerr<<"AliD0toKpi::ComputeWgts()  Negative weight!!!\n";
  if(fWgtCD0bar<0.) cerr<<"AliD0toKpi::ComputeWgts()  Negative weight!!!\n";
  */

  return;
}
//----------------------------------------------------------------------------
void AliD0toKpi::CorrectWgt4BR(Double_t factor) {
  // correct weights of background from charm 

  fWgtAD0    *= factor;
  fWgtAD0bar *= factor;
  fWgtBD0    *= factor;
  fWgtBD0bar *= factor;
  fWgtCD0    *= factor;
  fWgtCD0bar *= factor;
  fWgtDD0    *= factor;
  fWgtDD0bar *= factor;

  return;
}
//----------------------------------------------------------------------------
Double_t AliD0toKpi::CosPointing() const {
  // cosine of pointing angle in space

  TVector3 mom(Px(),Py(),Pz());
  TVector3 flight(fV2x-fV1x,fV2y-fV1y,fV2z-fV1z);

  Double_t pta = mom.Angle(flight);

  return TMath::Cos(pta); 
}
//----------------------------------------------------------------------------
Double_t AliD0toKpi::CosPointingXY() const {
  // cosine of pointing angle in transverse plane

  TVector3 momXY(Px(),Py(),0.);
  TVector3 flightXY(fV2x-fV1x,fV2y-fV1y,0.);

  Double_t ptaXY = momXY.Angle(flightXY);

  return TMath::Cos(ptaXY); 
}
//----------------------------------------------------------------------------
void AliD0toKpi::CosThetaStar(Double_t &ctsD0,Double_t &ctsD0bar) const {
  // cosine of decay angle in the D0 rest frame

  Double_t pStar = TMath::Sqrt(TMath::Power(kMD0*kMD0-kMK*kMK-kMPi*kMPi,2.)-4.*kMK*kMK*kMPi*kMPi)/(2.*kMD0);

  Double_t beta = P()/Energy();
  Double_t gamma = Energy()/kMD0;

  ctsD0 = (Ql(1)/gamma-beta*TMath::Sqrt(pStar*pStar+kMK*kMK))/pStar;
  // if(ctsD0 > 1.)  { cerr<<"AliD0toKpi::CosThetaStar: > 1 "<<ctsD0<<"!\n"; }
  // if(ctsD0 < -1.) { cerr<<"AliD0toKpi::CosThetaStar: < -1 "<<ctsD0<<"!\n"; }

  ctsD0bar = (Ql(0)/gamma-beta*TMath::Sqrt(pStar*pStar+kMK*kMK))/pStar;
  // if(ctsD0bar > 1.)  { cerr<<"AliD0toKpi::CosThetaStar: > 1 "<<ctsD0bar<<"!\n"; }
  // if(ctsD0bar < -1.) { cerr<<"AliD0toKpi::CosThetaStar: < -1 "<<ctsD0bar<<"!\n";} 

  return;
}
//----------------------------------------------------------------------------
Double_t AliD0toKpi::Eta() const {
  // pseudorapidity of the D0

  Double_t theta = TMath::Pi()/2.-TMath::ATan2(Pz(),Pt());
  Double_t eta = -TMath::Log(TMath::Tan(theta/2.));
  return eta;
}
//----------------------------------------------------------------------------
Double_t AliD0toKpi::EtaChild(Int_t child) const {
  // pseudorapidity of the decay tracks

  Double_t theta = TMath::Pi()/2.-TMath::ATan2(fPz[child],PtChild(child));
  Double_t eta = -TMath::Log(TMath::Tan(theta/2.));
  return eta;
}
//----------------------------------------------------------------------------
void AliD0toKpi::GetWgts(Double_t &WgtD0,Double_t &WgtD0bar,TString sample) 
  const {
  // returns the weights for pid

  if(!sample.CompareTo("A")) { WgtD0 = fWgtAD0;  WgtD0bar = fWgtAD0bar; }
  if(!sample.CompareTo("B")) { WgtD0 = fWgtBD0;  WgtD0bar = fWgtBD0bar; }
  if(!sample.CompareTo("C")) { WgtD0 = fWgtCD0;  WgtD0bar = fWgtCD0bar; }
  if(!sample.CompareTo("D")) { WgtD0 = fWgtDD0;  WgtD0bar = fWgtDD0bar; }
  if(!sample.CompareTo("ABCD")) { 
    WgtD0    = fWgtAD0+fWgtBD0+fWgtCD0+fWgtDD0; 
    WgtD0bar = fWgtAD0bar+fWgtBD0bar+fWgtCD0bar+fWgtDD0bar; 
  }
  if(!sample.CompareTo("ABC")) { 
    WgtD0    = fWgtAD0+fWgtBD0+fWgtCD0; 
    WgtD0bar = fWgtAD0bar+fWgtBD0bar+fWgtCD0bar; 
  }
  if(!sample.CompareTo("BC")) { 
    WgtD0    = fWgtBD0+fWgtCD0; 
    WgtD0bar = fWgtBD0bar+fWgtCD0bar; 
  }

  return;
}
//----------------------------------------------------------------------------
Double_t AliD0toKpi::ImpPar() const {
  // D0 impact parameter in the bending plane
  
    Double_t k = -(fV2x-fV1x)*Px()-(fV2y-fV1y)*Py();
    k /= Pt()*Pt();
    Double_t dx = fV2x-fV1x+k*Px();
    Double_t dy = fV2y-fV1y+k*Py();
    Double_t absDD = TMath::Sqrt(dx*dx+dy*dy);
    TVector3 mom(Px(),Py(),Pz());
    TVector3 flight(fV2x-fV1x,fV2y-fV1y,fV2z-fV1z);
    TVector3 cross = mom.Cross(flight);
    return (cross.Z()>0. ? absDD : -absDD);
}
//----------------------------------------------------------------------------
void AliD0toKpi::InvMass(Double_t &mD0,Double_t &mD0bar) const {
  // invariant mass as D0 and as D0bar

  Double_t energy[2];

  // D0 -> K- Pi+
  energy[1] = TMath::Sqrt(kMK*kMK+PChild(1)*PChild(1));
  energy[0] = TMath::Sqrt(kMPi*kMPi+PChild(0)*PChild(0));

  mD0 = TMath::Sqrt((energy[0]+energy[1])*(energy[0]+energy[1])-P()*P());
    

  // D0bar -> K+ Pi-
  energy[0] = TMath::Sqrt(kMK*kMK+PChild(0)*PChild(0));
  energy[1] = TMath::Sqrt(kMPi*kMPi+PChild(1)*PChild(1));

  mD0bar = TMath::Sqrt((energy[0]+energy[1])*(energy[0]+energy[1])-P()*P());
    
  return;

}
//----------------------------------------------------------------------------
Double_t AliD0toKpi::Ql(Int_t child) const {
  // longitudinal momentum of decay tracks w.r.t. to D0 momentum

  Double_t qL;
  TVector3 mom(fPx[child],fPy[child],fPz[child]);
  TVector3 momD(Px(),Py(),Pz());

  qL = mom.Dot(momD)/momD.Mag();

  return qL ;
}
//----------------------------------------------------------------------------
Double_t AliD0toKpi::Qt() const {
  // transverse momentum of decay tracks w.r.t. to D0 momentum  

  TVector3 mom0(fPx[0],fPy[0],fPz[0]);
  TVector3 momD(Px(),Py(),Pz());

  return mom0.Perp(momD);
}
//----------------------------------------------------------------------------
Bool_t AliD0toKpi::Select(const Double_t* cuts,Int_t& okD0,Int_t& okD0bar) 
  const {
//
// This function compares the D0 with a set of cuts:
//
// cuts[0] = inv. mass half width [GeV]   
// cuts[1] = dca [micron]
// cuts[2] = cosThetaStar 
// cuts[3] = pTK [GeV/c]
// cuts[4] = pTPi [GeV/c]
// cuts[5] = d0K [micron]   upper limit!
// cuts[6] = d0Pi [micron]  upper limit!
// cuts[7] = d0d0 [micron^2]
// cuts[8] = cosThetaPoint
//
// If the D0/D0bar doesn't pass the cuts it sets the weights to 0
// If neither D0 nor D0bar pass the cuts return kFALSE
//
  Double_t mD0,mD0bar,ctsD0,ctsD0bar;
  okD0=1; okD0bar=1;

  if(PtChild(1) < cuts[3] || PtChild(0) < cuts[4]) okD0 = 0;
  if(PtChild(0) < cuts[3] || PtChild(1) < cuts[4]) okD0bar = 0;
  if(!okD0 && !okD0bar) return kFALSE;

  if(TMath::Abs(Getd0Child(1)) > cuts[5] || 
     TMath::Abs(Getd0Child(0)) > cuts[6]) okD0 = 0;
  if(TMath::Abs(Getd0Child(0)) > cuts[6] ||
     TMath::Abs(Getd0Child(1)) > cuts[5]) okD0bar = 0;
  if(!okD0 && !okD0bar) return kFALSE;

  if(GetDCA() > cuts[1]) { okD0 = okD0bar = 0; return kFALSE; }

  InvMass(mD0,mD0bar);
  if(TMath::Abs(mD0-kMD0)    > cuts[0]) okD0 = 0;
  if(TMath::Abs(mD0bar-kMD0) > cuts[0]) okD0bar = 0;
  if(!okD0 && !okD0bar) return kFALSE;

  CosThetaStar(ctsD0,ctsD0bar);
  if(TMath::Abs(ctsD0)    > cuts[2]) okD0 = 0;
  if(TMath::Abs(ctsD0bar) > cuts[2]) okD0bar = 0;
  if(!okD0 && !okD0bar) return kFALSE;

  if(ProdImpParams() > cuts[7]) { okD0 = okD0bar = 0; return kFALSE; }

  if(CosPointing()   < cuts[8]) { okD0 = okD0bar = 0; return kFALSE; }

  return kTRUE;
}
//-----------------------------------------------------------------------------
void AliD0toKpi::SetPIDresponse(Double_t resp0[5],Double_t resp1[5]) {
  // Set combined PID detector response probabilities

  fPIDrespEl[0] = resp0[0];
  fPIDrespEl[1] = resp1[0];
  fPIDrespMu[0] = resp0[1];
  fPIDrespMu[1] = resp1[1];
  fPIDrespPi[0] = resp0[2];
  fPIDrespPi[1] = resp1[2];
  fPIDrespKa[0] = resp0[3];
  fPIDrespKa[1] = resp1[3];
  fPIDrespPr[0] = resp0[4];
  fPIDrespPr[1] = resp1[4];

  return;
} 
//----------------------------------------------------------------------------
Double_t AliD0toKpi::LinearInterpolation(Double_t p,Int_t nBins,Double_t Bin,
					 const Double_t *values) const {
  // a linear interpolation method

  Double_t value=0; 
  Double_t slope;

  if(p<0.5*Bin) {
    value = values[0];
  } else if(p>=(nBins-0.5)*Bin) {
    slope = (2*values[nBins-1]-values[nBins-2]-values[nBins-3])/Bin/2;
    value = values[nBins-2]+slope*(p-Bin*(nBins-1.5));
  } else {
    for(Int_t i=0; i<nBins; i++) {
      if(p<(i+0.5)*Bin) {
	slope = (values[i]-values[i-1])/Bin;
	value = values[i-1]+slope*(p-Bin*(i-0.5));
	break;
      }
    }
  }

  if(value<0.) value=0.;
  if(value>1.) value=1.;

  return value;
}
//----------------------------------------------------------------------------
Commit	Line	Data
3a9a3487	1	/**************************************************************************
	2	* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
	3	* *
	4	* Author: The ALICE Off-line Project. *
	5	* Contributors are mentioned in the code where appropriate. *
	6	* *
	7	* Permission to use, copy, modify and distribute this software and its *
	8	* documentation strictly for non-commercial purposes is hereby granted *
	9	* without fee, provided that the above copyright notice appears in all *
	10	* copies and that both the copyright notice and this permission notice *
	11	* appear in the supporting documentation. The authors make no claims *
	12	* about the suitability of this software for any purpose. It is *
	13	* provided "as is" without express or implied warranty. *
	14	**************************************************************************/
	15
	16	//----------------------------------------------------------------------------
	17	// Implementation of the D0toKpi class
ef0182f7	18	// for pp and PbPb interactions
3a9a3487	19	// Note: the two decay tracks are labelled: 0 (positive track)
3a9a3487	20	// 1 (negative track)
ef0182f7	21	// Origin: A. Dainese andrea.dainese@lnl.infn.it
3a9a3487	22	//----------------------------------------------------------------------------
741f4d30	23
3a9a3487	24	#include <TH1.h>
	25	#include <TH2.h>
	26	#include <TCanvas.h>
	27	#include <TPaveLabel.h>
dab957fb	28	#include <TVector3.h>
3a9a3487	29
	30	#include "AliD0toKpi.h"
	31
	32	ClassImp(AliD0toKpi)
	33
	34	//----------------------------------------------------------------------------
	35	AliD0toKpi::AliD0toKpi() {
	36	// Default constructor
	37
	38	fSignal = kFALSE;
	39
	40	fEvent = 0;
	41
	42	fTrkNum[0] = 0;
	43	fTrkNum[1] = 0;
	44
	45	fV1x = 0.;
	46	fV1y = 0.;
	47	fV1z = 0.;
	48	fV2x = 0.;
	49	fV2y = 0.;
	50	fV2z = 0.;
	51	fDCA = 0.;
	52
	53	fPx[0] = 0.;
	54	fPy[0] = 0.;
	55	fPz[0] = 0.;
	56	fPx[1] = 0.;
	57	fPy[1] = 0.;
	58	fPz[1] = 0.;
	59
	60	fd0[0] = 0.;
	61	fd0[1] = 0.;
	62
	63	fPdg[0] = 0;
	64	fPdg[1] = 0;
	65	fMum[0] = 0;
	66	fMum[1] = 0;
	67
	68	fTagPi[0] = 0.;
	69	fTagPi[1] = 0.;
	70	fTagKa[0] = 0.;
	71	fTagKa[1] = 0.;
	72	fTagNid[0] = 0.;
	73	fTagNid[1] = 0.;
	74
	75	fWgtAD0=fWgtAD0bar=fWgtBD0=fWgtBD0bar=fWgtCD0=fWgtCD0bar=fWgtDD0=fWgtDD0bar=0;
	76
	77	}
	78	//----------------------------------------------------------------------------
	79	AliD0toKpi::AliD0toKpi(Int_t ev,Int_t trkNum[2],
	80	Double_t v1[3],Double_t v2[3],
	81	Double_t dca,
	82	Double_t mom[6],Double_t d0[2]) {
	83	// Constructor
	84
	85	fSignal = kFALSE;
	86
	87	fEvent = ev;
	88	fTrkNum[0] = trkNum[0];
	89	fTrkNum[1] = trkNum[1];
	90
	91	fV1x = v1[0];
	92	fV1y = v1[1];
93	fV1z = v1[2];
94	fV2x = v2[0];
95	fV2y = v2[1];
96	fV2z = v2[2];
97	fDCA = dca;
98
99	fPx[0] = mom[0];
100	fPy[0] = mom[1];
101	fPz[0] = mom[2];
102	fPx[1] = mom[3];
103	fPy[1] = mom[4];
104	fPz[1] = mom[5];
105
106	fd0[0] = d0[0];
107	fd0[1] = d0[1];
108
109	fPdg[0] = 0;
110	fPdg[1] = 0;
111	fMum[0] = 0;
112	fMum[1] = 0;
113
114	fTagPi[0] = 0.;
115	fTagPi[1] = 0.;
116	fTagKa[0] = 0.;
117	fTagKa[1] = 0.;
118	fTagNid[0] = 0.;
119	fTagNid[1] = 0.;
120
121	fWgtAD0=fWgtAD0bar=fWgtBD0=fWgtBD0bar=fWgtCD0=fWgtCD0bar=fWgtDD0=fWgtDD0bar=0;
122	}
123	//----------------------------------------------------------------------------
124	AliD0toKpi::~AliD0toKpi() {}
125	//____________________________________________________________________________
126	AliD0toKpi::AliD0toKpi( const AliD0toKpi& d0toKpi):TObject(d0toKpi) {
127	// dummy copy constructor
128	}
129	//----------------------------------------------------------------------------
ef0182f7	130	void AliD0toKpi::ApplyPID(TString pidScheme) {
741f4d30	131	// Applies particle identification
3a9a3487	132
ef0182f7	133	if((!pidScheme.CompareTo("TOFparamPbPb") \|\| !pidScheme.CompareTo("TOFparamPP")) && fPdg[0]==0) {
3a9a3487	134	printf("AliD0toKpi::ApplyPID :\n Warning: TOF parameterized PID can be used only for simulation!\n");
	135	return;
	136	}
	137
ef0182f7	138	if(!pidScheme.CompareTo("TOFparamPbPb")) {
3a9a3487	139	// tagging of the positive track
	140	if(TMath::Abs(fPdg[0])==211 \|\| TMath::Abs(fPdg[0])==13
	141	\|\| TMath::Abs(fPdg[0])==11) { // pion,muon,electron
741f4d30	142	fTagPi[0] = LinearInterpolation(PChild(0),kPiBinsPbPb,kPiBinWidthPbPb,kPiTagPiPbPb);
3a9a3487	143	fTagNid[0] = 1.-fTagPi[0];
	144	fTagKa[0] = 0.;
	145	fTagPr[0] = 0.;
	146	}
	147	if(TMath::Abs(fPdg[0])==321) { // kaon
741f4d30	148	fTagKa[0] = LinearInterpolation(PChild(0),kKBinsPbPb,kKBinWidthPbPb,kKTagKPbPb);
741f4d30	149	fTagNid[0] = LinearInterpolation(PChild(0),kKBinsPbPb,kKBinWidthPbPb,kKTagNidPbPb);
3a9a3487	150	if((fTagNid[0]+fTagKa[0])>1.) fTagNid[0] = 1.-fTagKa[0];
	151	fTagPi[0] = 1.-fTagNid[0]-fTagKa[0];
	152	fTagPr[0] = 0.;
	153	}
	154	if(TMath::Abs(fPdg[0])==2212) { // proton
741f4d30	155	fTagPr[0] = LinearInterpolation(PChild(0),kPBinsPbPb,kPBinWidthPbPb,kPTagPPbPb);
741f4d30	156	fTagNid[0] = LinearInterpolation(PChild(0),kPBinsPbPb,kPBinWidthPbPb,kPTagNidPbPb);
3a9a3487	157	if((fTagNid[0]+fTagPr[0])>1.) fTagNid[0] = 1.-fTagPr[0];
	158	fTagPi[0] = 1.-fTagNid[0]-fTagPr[0];
	159	fTagKa[0] = 0.;
	160	}
	161	// tagging of the negative track
	162	if(TMath::Abs(fPdg[1])==211 \|\| TMath::Abs(fPdg[1])==13
	163	\|\| TMath::Abs(fPdg[1])==11) { // pion,muon,electron
741f4d30	164	fTagPi[1] = LinearInterpolation(PChild(1),kPiBinsPbPb,kPiBinWidthPbPb,kPiTagPiPbPb);
3a9a3487	165	fTagNid[1] = 1.-fTagPi[1];
	166	fTagKa[1] = 0.;
	167	fTagPr[1] = 0.;
	168	}
	169	if(TMath::Abs(fPdg[1])==321) { // kaon
741f4d30	170	fTagKa[1] = LinearInterpolation(PChild(1),kKBinsPbPb,kKBinWidthPbPb,kKTagKPbPb);
741f4d30	171	fTagNid[1] = LinearInterpolation(PChild(1),kKBinsPbPb,kKBinWidthPbPb,kKTagNidPbPb);
3a9a3487	172	if((fTagNid[1]+fTagKa[1])>1.) fTagNid[1] = 1.-fTagKa[1];
	173	fTagPi[1] = 1.-fTagNid[1]-fTagKa[1];
	174	fTagPr[1] = 0.;
	175	}
	176	if(TMath::Abs(fPdg[1])==2212) { // proton
741f4d30	177	fTagPr[1] = LinearInterpolation(PChild(1),kPBinsPbPb,kPBinWidthPbPb,kPTagPPbPb);
741f4d30	178	fTagNid[1] = LinearInterpolation(PChild(1),kPBinsPbPb,kPBinWidthPbPb,kPTagNidPbPb);
3a9a3487	179	if((fTagNid[1]+fTagPr[1])>1.) fTagNid[1] = 1.-fTagPr[1];
	180	fTagPi[1] = 1.-fTagNid[1]-fTagPr[1];
	181	fTagKa[1] = 0.;
	182	}
	183	}
	184
	185
ef0182f7	186	if(!pidScheme.CompareTo("TOFparamPP")) {
3a9a3487	187	// tagging of the positive track
	188	if(TMath::Abs(fPdg[0])==211 \|\| TMath::Abs(fPdg[0])==13
	189	\|\| TMath::Abs(fPdg[0])==11) { // pion,muon,electron
741f4d30	190	fTagPi[0] = LinearInterpolation(PChild(0),kPiBinsPP,kPiBinWidthPP,kPiTagPiPP);
3a9a3487	191	fTagNid[0] = 1.-fTagPi[0];
	192	fTagKa[0] = 0.;
	193	fTagPr[0] = 0.;
	194	}
	195	if(TMath::Abs(fPdg[0])==321) { // kaon
741f4d30	196	fTagKa[0] = LinearInterpolation(PChild(0),kKBinsPP,kKBinWidthPP,kKTagKPP);
741f4d30	197	fTagNid[0] = LinearInterpolation(PChild(0),kKBinsPP,kKBinWidthPP,kKTagNidPP);
3a9a3487	198	if((fTagNid[0]+fTagKa[0])>1.) fTagNid[0] = 1.-fTagKa[0];
	199	fTagPi[0] = 1.-fTagNid[0]-fTagKa[0];
	200	fTagPr[0] = 0.;
	201	}
	202	if(TMath::Abs(fPdg[0])==2212) { // proton
741f4d30	203	fTagPr[0] = LinearInterpolation(PChild(0),kPBinsPP,kPBinWidthPP,kPTagPPP);
741f4d30	204	fTagNid[0] = LinearInterpolation(PChild(0),kPBinsPP,kPBinWidthPP,kPTagNidPP);
3a9a3487	205	if((fTagNid[0]+fTagPr[0])>1.) fTagNid[0] = 1.-fTagPr[0];
	206	fTagPi[0] = 1.-fTagNid[0]-fTagPr[0];
	207	fTagKa[0] = 0.;
	208	}
	209	// tagging of the negative track
	210	if(TMath::Abs(fPdg[1])==211 \|\| TMath::Abs(fPdg[1])==13
	211	\|\| TMath::Abs(fPdg[1])==11) { // pion,muon,electron
741f4d30	212	fTagPi[1] = LinearInterpolation(PChild(1),kPiBinsPP,kPiBinWidthPP,kPiTagPiPP);
3a9a3487	213	fTagNid[1] = 1.-fTagPi[1];
	214	fTagKa[1] = 0.;
	215	fTagPr[1] = 0.;
	216	}
	217	if(TMath::Abs(fPdg[1])==321) { // kaon
741f4d30	218	fTagKa[1] = LinearInterpolation(PChild(1),kKBinsPP,kKBinWidthPP,kKTagKPP);
741f4d30	219	fTagNid[1] = LinearInterpolation(PChild(1),kKBinsPP,kKBinWidthPP,kKTagNidPP);
3a9a3487	220	if((fTagNid[1]+fTagKa[1])>1.) fTagNid[1] = 1.-fTagKa[1];
	221	fTagPi[1] = 1.-fTagNid[1]-fTagKa[1];
	222	fTagPr[1] = 0.;
	223	}
	224	if(TMath::Abs(fPdg[1])==2212) { // proton
741f4d30	225	fTagPr[1] = LinearInterpolation(PChild(1),kPBinsPP,kPBinWidthPP,kPTagPPP);
741f4d30	226	fTagNid[1] = LinearInterpolation(PChild(1),kPBinsPP,kPBinWidthPP,kPTagNidPP);
3a9a3487	227	if((fTagNid[1]+fTagPr[1])>1.) fTagNid[1] = 1.-fTagPr[1];
	228	fTagPi[1] = 1.-fTagNid[1]-fTagPr[1];
	229	fTagKa[1] = 0.;
	230	}
	231	}
	232
	233	return;
	234	}
	235	//----------------------------------------------------------------------------
	236	Double_t AliD0toKpi::ChildrenRelAngle() const {
	237	// relative angle between K and pi
	238
	239	TVector3 mom0(fPx[0],fPy[0],fPz[0]);
	240	TVector3 mom1(fPx[1],fPy[1],fPz[1]);
	241
	242	Double_t angle = mom0.Angle(mom1);
	243
	244	return angle;
	245	}
	246	//----------------------------------------------------------------------------
	247	void AliD0toKpi::ComputeWgts() {
	248	// calculate the weights for PID
	249
	250
	251	// assignement of the weights from PID
	252	fWgtAD0 = fTagKa[1]*(fTagPi[0]+fTagNid[0]);
	253	fWgtAD0bar = fTagKa[0]*(fTagPi[1]+fTagNid[1]);
	254	fWgtBD0 = fTagPi[0]*fTagNid[1];
	255	fWgtBD0bar = fTagPi[1]*fTagNid[0];
	256	fWgtCD0 = fTagNid[0]*fTagNid[1];
	257	fWgtCD0bar = fTagNid[0]*fTagNid[1];
	258	fWgtDD0 = 1.-fWgtAD0-fWgtBD0-fWgtCD0;
	259	fWgtDD0bar = 1.-fWgtAD0bar-fWgtBD0bar-fWgtCD0bar;
	260
ef0182f7	261	/*
3a9a3487	262	cerr<<fWgtAD0<<" "<<fWgtAD0bar<<endl;
	263	cerr<<fWgtBD0<<" "<<fWgtBD0bar<<endl;
	264	cerr<<fWgtCD0<<" "<<fWgtCD0bar<<endl;
ef0182f7	265	cerr<<fWgtDD0<<" "<<fWgtDD0bar<<endl;
	266	*/
	267	/*
3a9a3487	268	if(fWgtAD0<0.) cerr<<"AliD0toKpi::ComputeWgts() Negative weight!!!\n";
	269	if(fWgtAD0bar<0.) cerr<<"AliD0toKpi::ComputeWgts() Negative weight!!!\n";
	270	if(fWgtBD0<0.) cerr<<"AliD0toKpi::ComputeWgts() Negative weight!!!\n";
	271	if(fWgtBD0bar<0.) cerr<<"AliD0toKpi::ComputeWgts() Negative weight!!!\n";
	272	if(fWgtCD0<0.) cerr<<"AliD0toKpi::ComputeWgts() Negative weight!!!\n";
	273	if(fWgtCD0bar<0.) cerr<<"AliD0toKpi::ComputeWgts() Negative weight!!!\n";
	274	*/
	275
	276	return;
	277	}
	278	//----------------------------------------------------------------------------
	279	void AliD0toKpi::CorrectWgt4BR(Double_t factor) {
	280	// correct weights of background from charm
	281
	282	fWgtAD0 *= factor;
	283	fWgtAD0bar *= factor;
	284	fWgtBD0 *= factor;
	285	fWgtBD0bar *= factor;
	286	fWgtCD0 *= factor;
	287	fWgtCD0bar *= factor;
	288	fWgtDD0 *= factor;
	289	fWgtDD0bar *= factor;
	290
	291	return;
	292	}
	293	//----------------------------------------------------------------------------
	294	Double_t AliD0toKpi::CosPointing() const {
	295	// cosine of pointing angle in space
	296
	297	TVector3 mom(Px(),Py(),Pz());
	298	TVector3 flight(fV2x-fV1x,fV2y-fV1y,fV2z-fV1z);
	299
	300	Double_t pta = mom.Angle(flight);
	301
	302	return TMath::Cos(pta);
	303	}
	304	//----------------------------------------------------------------------------
	305	Double_t AliD0toKpi::CosPointingXY() const {
	306	// cosine of pointing angle in transverse plane
	307
	308	TVector3 momXY(Px(),Py(),0.);
	309	TVector3 flightXY(fV2x-fV1x,fV2y-fV1y,0.);
	310
	311	Double_t ptaXY = momXY.Angle(flightXY);
	312
	313	return TMath::Cos(ptaXY);
	314	}
	315	//----------------------------------------------------------------------------
	316	void AliD0toKpi::CosThetaStar(Double_t &ctsD0,Double_t &ctsD0bar) const {
	317	// cosine of decay angle in the D0 rest frame
	318
	319	Double_t pStar = TMath::Sqrt(TMath::Power(kMD0kMD0-kMKkMK-kMPikMPi,2.)-4.kMKkMKkMPikMPi)/(2.kMD0);
	320
	321	Double_t beta = P()/Energy();
	322	Double_t gamma = Energy()/kMD0;
	323
	324	ctsD0 = (Ql(1)/gamma-betaTMath::Sqrt(pStarpStar+kMK*kMK))/pStar;
	325	// if(ctsD0 > 1.) { cerr<<"AliD0toKpi::CosThetaStar: > 1 "<<ctsD0<<"!\n"; }
	326	// if(ctsD0 < -1.) { cerr<<"AliD0toKpi::CosThetaStar: < -1 "<<ctsD0<<"!\n"; }
	327
	328	ctsD0bar = (Ql(0)/gamma-betaTMath::Sqrt(pStarpStar+kMK*kMK))/pStar;
	329	// if(ctsD0bar > 1.) { cerr<<"AliD0toKpi::CosThetaStar: > 1 "<<ctsD0bar<<"!\n"; }
	330	// if(ctsD0bar < -1.) { cerr<<"AliD0toKpi::CosThetaStar: < -1 "<<ctsD0bar<<"!\n";}
	331
332	return;
333	}
334	//----------------------------------------------------------------------------
335	Double_t AliD0toKpi::Eta() const {
336	// pseudorapidity of the D0
337
338	Double_t theta = TMath::Pi()/2.-TMath::ATan2(Pz(),Pt());
339	Double_t eta = -TMath::Log(TMath::Tan(theta/2.));
340	return eta;
341	}
342	//----------------------------------------------------------------------------
343	Double_t AliD0toKpi::EtaChild(Int_t child) const {
344	// pseudorapidity of the decay tracks
345
346	Double_t theta = TMath::Pi()/2.-TMath::ATan2(fPz[child],PtChild(child));
347	Double_t eta = -TMath::Log(TMath::Tan(theta/2.));
348	return eta;
349	}
350	//----------------------------------------------------------------------------
351	void AliD0toKpi::GetWgts(Double_t &WgtD0,Double_t &WgtD0bar,TString sample)
352	const {
353	// returns the weights for pid
354
ef0182f7	355	if(!sample.CompareTo("A")) { WgtD0 = fWgtAD0; WgtD0bar = fWgtAD0bar; }
	356	if(!sample.CompareTo("B")) { WgtD0 = fWgtBD0; WgtD0bar = fWgtBD0bar; }
	357	if(!sample.CompareTo("C")) { WgtD0 = fWgtCD0; WgtD0bar = fWgtCD0bar; }
	358	if(!sample.CompareTo("D")) { WgtD0 = fWgtDD0; WgtD0bar = fWgtDD0bar; }
	359	if(!sample.CompareTo("ABCD")) {
3a9a3487	360	WgtD0 = fWgtAD0+fWgtBD0+fWgtCD0+fWgtDD0;
	361	WgtD0bar = fWgtAD0bar+fWgtBD0bar+fWgtCD0bar+fWgtDD0bar;
	362	}
ef0182f7	363	if(!sample.CompareTo("ABC")) {
3a9a3487	364	WgtD0 = fWgtAD0+fWgtBD0+fWgtCD0;
	365	WgtD0bar = fWgtAD0bar+fWgtBD0bar+fWgtCD0bar;
	366	}
ef0182f7	367	if(!sample.CompareTo("BC")) {
3a9a3487	368	WgtD0 = fWgtBD0+fWgtCD0;
	369	WgtD0bar = fWgtBD0bar+fWgtCD0bar;
	370	}
	371
3a9a3487	372	return;
	373	}
	374	//----------------------------------------------------------------------------
ef0182f7	375	Double_t AliD0toKpi::ImpPar() const {
	376	// D0 impact parameter in the bending plane
	377
	378	Double_t k = -(fV2x-fV1x)Px()-(fV2y-fV1y)Py();
	379	k /= Pt()*Pt();
	380	Double_t dx = fV2x-fV1x+k*Px();
	381	Double_t dy = fV2y-fV1y+k*Py();
	382	Double_t absDD = TMath::Sqrt(dxdx+dydy);
	383	TVector3 mom(Px(),Py(),Pz());
	384	TVector3 flight(fV2x-fV1x,fV2y-fV1y,fV2z-fV1z);
	385	TVector3 cross = mom.Cross(flight);
	386	return (cross.Z()>0. ? absDD : -absDD);
	387	}
	388	//----------------------------------------------------------------------------
3a9a3487	389	void AliD0toKpi::InvMass(Double_t &mD0,Double_t &mD0bar) const {
	390	// invariant mass as D0 and as D0bar
	391
	392	Double_t energy[2];
	393
	394	// D0 -> K- Pi+
	395	energy[1] = TMath::Sqrt(kMKkMK+PChild(1)PChild(1));
	396	energy[0] = TMath::Sqrt(kMPikMPi+PChild(0)PChild(0));
	397
	398	mD0 = TMath::Sqrt((energy[0]+energy[1])(energy[0]+energy[1])-P()P());
	399
	400
	401	// D0bar -> K+ Pi-
	402	energy[0] = TMath::Sqrt(kMKkMK+PChild(0)PChild(0));
	403	energy[1] = TMath::Sqrt(kMPikMPi+PChild(1)PChild(1));
	404
	405	mD0bar = TMath::Sqrt((energy[0]+energy[1])(energy[0]+energy[1])-P()P());
	406
	407	return;
	408
	409	}
	410	//----------------------------------------------------------------------------
	411	Double_t AliD0toKpi::Ql(Int_t child) const {
	412	// longitudinal momentum of decay tracks w.r.t. to D0 momentum
	413
	414	Double_t qL;
	415	TVector3 mom(fPx[child],fPy[child],fPz[child]);
	416	TVector3 momD(Px(),Py(),Pz());
	417
	418	qL = mom.Dot(momD)/momD.Mag();
	419
	420	return qL ;
	421	}
	422	//----------------------------------------------------------------------------
	423	Double_t AliD0toKpi::Qt() const {
	424	// transverse momentum of decay tracks w.r.t. to D0 momentum
	425
	426	TVector3 mom0(fPx[0],fPy[0],fPz[0]);
	427	TVector3 momD(Px(),Py(),Pz());
	428
	429	return mom0.Perp(momD);
	430	}
	431	//----------------------------------------------------------------------------
	432	Bool_t AliD0toKpi::Select(const Double_t* cuts,Int_t& okD0,Int_t& okD0bar)
	433	const {
	434	//
	435	// This function compares the D0 with a set of cuts:
	436	//
	437	// cuts[0] = inv. mass half width [GeV]
	438	// cuts[1] = dca [micron]
	439	// cuts[2] = cosThetaStar
	440	// cuts[3] = pTK [GeV/c]
	441	// cuts[4] = pTPi [GeV/c]
	442	// cuts[5] = d0K [micron] upper limit!
	443	// cuts[6] = d0Pi [micron] upper limit!
	444	// cuts[7] = d0d0 [micron^2]
	445	// cuts[8] = cosThetaPoint
	446	//
	447	// If the D0/D0bar doesn't pass the cuts it sets the weights to 0
	448	// If neither D0 nor D0bar pass the cuts return kFALSE
	449	//
	450	Double_t mD0,mD0bar,ctsD0,ctsD0bar;
	451	okD0=1; okD0bar=1;
	452
453	if(PtChild(1) < cuts[3] \|\| PtChild(0) < cuts[4]) okD0 = 0;
454	if(PtChild(0) < cuts[3] \|\| PtChild(1) < cuts[4]) okD0bar = 0;
455	if(!okD0 && !okD0bar) return kFALSE;
456
457	if(TMath::Abs(Getd0Child(1)) > cuts[5] \|\|
458	TMath::Abs(Getd0Child(0)) > cuts[6]) okD0 = 0;
459	if(TMath::Abs(Getd0Child(0)) > cuts[6] \|\|
460	TMath::Abs(Getd0Child(1)) > cuts[5]) okD0bar = 0;
461	if(!okD0 && !okD0bar) return kFALSE;
462
463	if(GetDCA() > cuts[1]) { okD0 = okD0bar = 0; return kFALSE; }
464
465	InvMass(mD0,mD0bar);
466	if(TMath::Abs(mD0-kMD0) > cuts[0]) okD0 = 0;
467	if(TMath::Abs(mD0bar-kMD0) > cuts[0]) okD0bar = 0;
468	if(!okD0 && !okD0bar) return kFALSE;
469
470	CosThetaStar(ctsD0,ctsD0bar);
471	if(TMath::Abs(ctsD0) > cuts[2]) okD0 = 0;
472	if(TMath::Abs(ctsD0bar) > cuts[2]) okD0bar = 0;
473	if(!okD0 && !okD0bar) return kFALSE;
474
475	if(ProdImpParams() > cuts[7]) { okD0 = okD0bar = 0; return kFALSE; }
476
477	if(CosPointing() < cuts[8]) { okD0 = okD0bar = 0; return kFALSE; }
478
479	return kTRUE;
480	}
481	//-----------------------------------------------------------------------------
482	void AliD0toKpi::SetPIDresponse(Double_t resp0[5],Double_t resp1[5]) {
483	// Set combined PID detector response probabilities
484
485	fPIDrespEl[0] = resp0[0];
486	fPIDrespEl[1] = resp1[0];
487	fPIDrespMu[0] = resp0[1];
488	fPIDrespMu[1] = resp1[1];
489	fPIDrespPi[0] = resp0[2];
490	fPIDrespPi[1] = resp1[2];
491	fPIDrespKa[0] = resp0[3];
492	fPIDrespKa[1] = resp1[3];
493	fPIDrespPr[0] = resp0[4];
494	fPIDrespPr[1] = resp1[4];
495
496	return;
497	}
3a9a3487	498	//----------------------------------------------------------------------------
	499	Double_t AliD0toKpi::LinearInterpolation(Double_t p,Int_t nBins,Double_t Bin,
	500	const Double_t *values) const {
	501	// a linear interpolation method
	502
	503	Double_t value=0;
	504	Double_t slope;
	505
	506	if(p<0.5*Bin) {
	507	value = values[0];
	508	} else if(p>=(nBins-0.5)*Bin) {
	509	slope = (2*values[nBins-1]-values[nBins-2]-values[nBins-3])/Bin/2;
	510	value = values[nBins-2]+slope(p-Bin(nBins-1.5));
	511	} else {
	512	for(Int_t i=0; i<nBins; i++) {
	513	if(p<(i+0.5)*Bin) {
	514	slope = (values[i]-values[i-1])/Bin;
	515	value = values[i-1]+slope(p-Bin(i-0.5));
	516	break;
	517	}
	518	}
	519	}
	520
	521	if(value<0.) value=0.;
	522	if(value>1.) value=1.;
	523
	524	return value;
	525	}
	526	//----------------------------------------------------------------------------
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