K0pi0.cxx

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//
//  K0pi0.cxx is the single D0 tag code to reconstruct D0 or anti-D0 meson through the final states of
//  K0pi0 from D0 or anti-D0 meson decays. K0pi0.cxx was transfered from the Fortran routine "K0pi0.f" 
//  which was orignally used for study of the D0D0-bar production and D0 decays at the BES-II
//  experiment during the time period from 2002 to 2008.
//
//  The orignal Fortran routine "K0pi0.f" used at the BES-II experiment was coded by G. Rong in 2002.
//
//  K0pi0.cxx was transfered by G. Rong and J. Liu in December, 2005.
//
//  Since 2008, G. Rong and L.L. Jiang have been working on developing this code to analyze of
//  the data taken at 3.773 GeV with the BES-III detector at the BEPC-II collider.
//
//  During developing this code, many People made significant contributions to this code. These are
//          G. Rong, L.L. Jiang, J. Liu, H.L. Ma, J.C. Chen, D.H. Zhang,
//          M.G. Zhao, B. Zheng, L. Li, Y. Fang, Z.Y. Yi, H.H. Liu, Z.Q. Liu et al.
//
//                                       By G. Rong and L.L. Jiang
//                                       March, 2009
//
//  ==========================================================================================
//
#include "SD0TagAlg/K0pi0.h"
#include "SD0TagAlg/SingleBase.h"
 
 
K0pi0::K0pi0()
{}
 
K0pi0::~K0pi0()
{}
 
 
void K0pi0::MTotal(double event,SmartDataPtr<EvtRecTrackCol> evtRecTrkCol, Vint iGood,Vint
    iGam, double Ebeam, int PID_flag, int Charge_candidate_D)
{
 
  int nGood=iGood.size();
  int nGam=iGam.size();
 
  iGoodtag.clear();
  iGamtag.clear();
  
  double mass_bcgg,delE_tag_temp;
  int m_chargetag,m_chargepi1,m_chargepi2;
  int ika_temp,ipi1_temp,ipi2_temp,ipi3_temp, iGam1_temp, iGam2_temp;
  HepLorentzVector pddd;
  HepLorentzVector pddd_temp;
 
  IDataProviderSvc* eventSvc = NULL;
  Gaudi::svcLocator()->service("EventDataSvc", eventSvc);
  SmartDataPtr<EvtRecEvent> evtRecEvent(eventSvc,EventModel::EvtRec::EvtRecEvent);
  SmartDataPtr<Event::EventHeader> eventHeader(eventSvc,"/Event/EventHeader");
 
  int runNo=eventHeader->runNumber();
  int rec=eventHeader->eventNumber();
 
  double xecm=2*Ebeam;
 
  k0pi0md=false;
  double  tagmode=0;
 
  if((evtRecEvent->totalCharged() < 2||nGam<2)){    return;  }
 
  double ecms = xecm;
 
  ISimplePIDSvc* simple_pid;
  Gaudi::svcLocator()->service("SimplePIDSvc", simple_pid);
 
  double deltaE_tem = 0.20;
  int ncount1 = 0; 
 
  Hep3Vector xorigin(0,0,0);
  HepSymMatrix xoriginEx(3,0);
  IVertexDbSvc*  vtxsvc;
  Gaudi::svcLocator()->service("VertexDbSvc", vtxsvc);
  if(vtxsvc->isVertexValid())
  {
    double* dbv = vtxsvc->PrimaryVertex();
    double*  vv = vtxsvc->SigmaPrimaryVertex();
    xorigin.setX(dbv[0]);
    xorigin.setY(dbv[1]);
    xorigin.setZ(dbv[2]);
 
    xoriginEx[0][0] = vv[0] * vv[0];
    xoriginEx[1][1] = vv[1] * vv[1];
    xoriginEx[2][2] = vv[2] * vv[2];
 
  }
  
  double xv=xorigin.x();
  double yv=xorigin.y();
  double zv=xorigin.z();
 
  HepPoint3D point0(0.,0.,0.);
  HepPoint3D IP(xorigin[0],xorigin[1],xorigin[2]);
  //////////////////////////////////////////////////////////////////
  HepLorentzVector p2gfit;
  HepLorentzVector p2gg;
 
  for(int i = 0; i < evtRecEvent->totalCharged(); i++) {
    EvtRecTrackIterator itTrk = evtRecTrkCol->begin() + i;
 
    int ipi1= (*itTrk)->trackId();
 
    if(!(*itTrk)->isMdcKalTrackValid()) continue;
    RecMdcKalTrack*  mdcKalTrk1 = (*itTrk)->mdcKalTrack();
    RecMdcKalTrack::setPidType(RecMdcKalTrack::pion);
 
    m_chargepi1=mdcKalTrk1->charge();
    if(m_chargepi1 != 1) continue;
 
    /////////////////////////////////////////
    HepVector a1 = mdcKalTrk1->getZHelix();
    HepSymMatrix Ea1 = mdcKalTrk1->getZError();
 
    VFHelix helixip3_1(point0,a1,Ea1);
    helixip3_1.pivot(IP);
    HepVector  vecipa1 = helixip3_1.a();
 
    double dr1 = fabs(vecipa1[0]);
    double dz1 = fabs(vecipa1[3]);
    double costheta1 = cos(mdcKalTrk1->theta());
 
    if (  dr1 >= 15.0) continue;
    if (  dz1 >= 25.0) continue; 
    if ( fabs(costheta1) >= 0.93) continue; 
    /////////////////////////////////////////
    WTrackParameter pip(xmass[2],mdcKalTrk1->getZHelix(),mdcKalTrk1->getZError() );
    
    //  
    // select pi
    //  
    for(int j = 0; j < evtRecEvent->totalCharged();j++) {
      EvtRecTrackIterator itTrk = evtRecTrkCol->begin() + j;
      
      int ipi2= (*itTrk)->trackId();
      if(ipi1==ipi2)  continue;
     
      if(!(*itTrk)->isMdcKalTrackValid()) continue;
      RecMdcKalTrack*  mdcKalTrk2 = (*itTrk)->mdcKalTrack();
      RecMdcKalTrack::setPidType(RecMdcKalTrack::pion);
 
      m_chargepi2=mdcKalTrk2->charge();
      if((m_chargepi1 + m_chargepi2) != 0) continue;
 
      /////////////////////////////////////////
      HepVector a2 = mdcKalTrk2->getZHelix();
      HepSymMatrix Ea2 = mdcKalTrk2->getZError();
      VFHelix helixip3_2(point0,a2,Ea2);
      helixip3_2.pivot(IP);
      HepVector  vecipa2 = helixip3_2.a();
 
      double dr2 = fabs(vecipa2[0]);
      double dz2 = fabs(vecipa2[3]);
      double costheta2 = cos(mdcKalTrk2->theta());
      if (  dr2 >= 15.0) continue;
      if (  dz2 >= 25.0) continue; 
      if ( fabs(costheta2) >= 0.93) continue; 
      /////////////////////////////////////////
      WTrackParameter pim(xmass[2],mdcKalTrk2->getZHelix(),mdcKalTrk2->getZError() );
 
      HepVector pip_val = HepVector(7,0);
      HepVector pim_val = HepVector(7,0);
      pip_val = pip.w(); 
      pim_val = pim.w();
      HepLorentzVector ptrktagk0(pip_val[0]+pim_val[0],pip_val[1]+pim_val[1],pip_val[2]+pim_val[2],pip_val[3]+pim_val[3]);
      double m_xmtagk0_tem = ptrktagk0.mag();
      if(fabs(ptrktagk0.m()-0.498)>0.1) continue;
 
      HepPoint3D vx(xorigin.x(), xorigin.y(), xorigin.z());
      HepSymMatrix Evx(3, 0);
      double bx = 1E+6; Evx[0][0] = bx*bx;
      double by = 1E+6; Evx[1][1] = by*by;
      double bz = 1E+6; Evx[2][2] = bz*bz;
      VertexParameter vxpar; vxpar.setVx(vx); vxpar.setEvx(Evx);
 
      VertexFit *vtxfit0 = VertexFit::instance();
      vtxfit0->init();
      vtxfit0->AddTrack(0, pip);
      vtxfit0->AddTrack(1, pim);
      vtxfit0->AddVertex(0, vxpar, 0, 1);
      if(!(vtxfit0->Fit(0))) continue;
      vtxfit0->Swim(0); 
      vtxfit0->BuildVirtualParticle(0);
      WTrackParameter wksp = vtxfit0->wtrk(0);
      WTrackParameter wksm = vtxfit0->wtrk(1);
      WTrackParameter wks_Trk = vtxfit0->wVirtualTrack(0);
      VertexParameter wks_var = vtxfit0->vpar(0);
      
      SecondVertexFit *vtxfit = SecondVertexFit::instance();
      vtxfit->init();
      vxpar.setEvx(xoriginEx);
      vtxfit->setPrimaryVertex(vxpar);
      vtxfit->AddTrack(0, wks_Trk);
      vtxfit->setVpar(wks_var);
      if(!vtxfit->Fit()) continue;
      
      if(vtxfit->chisq() > 999.) continue;
      if(vtxfit->decayLength()<0.0) continue;
 
      double m_massks1_tem = vtxfit->p4par().m();
      if(m_massks1_tem < 0.485 || m_massks1_tem > 0.515)  continue;
      HepLorentzVector  p4kstag =  vtxfit->p4par();
      p4kstag.boost(-0.011,0,0);
      WTrackParameter para_ks = vtxfit0->wVirtualTrack(0);
 
      for(int m = 0; m < nGam-1; m++) {
        if(iGam[m]==-1) continue;
        RecEmcShower *g1Trk = (*(evtRecTrkCol->begin()+iGam[m]))->emcShower();
        double eraw1 = g1Trk->energy();
        double phi1 = g1Trk->phi();
        double the1 = g1Trk->theta();
        HepLorentzVector ptrkg1,ptrkg10,ptrkg12;
        ptrkg1.setPx(eraw1*sin(the1)*cos(phi1));
        ptrkg1.setPy(eraw1*sin(the1)*sin(phi1));
        ptrkg1.setPz(eraw1*cos(the1));
        ptrkg1.setE(eraw1);
        ptrkg10 = ptrkg1;
        ptrkg12 = ptrkg1.boost(-0.011,0,0);
 
        for(int n = m+1; n < nGam; n++) {
          if(iGam[n]==-1) continue;
          RecEmcShower *g2Trk = (*(evtRecTrkCol->begin()+iGam[n]))->emcShower();
          double eraw2 = g2Trk->energy();
          double phi2 = g2Trk->phi();
          double the2 = g2Trk->theta();
          HepLorentzVector ptrkg2,ptrkg20,ptrkg22;
          ptrkg2.setPx(eraw2*sin(the2)*cos(phi2));
          ptrkg2.setPy(eraw2*sin(the2)*sin(phi2));
          ptrkg2.setPz(eraw2*cos(the2));
          ptrkg2.setE(eraw2);
          ptrkg20 = ptrkg2;
          ptrkg22 = ptrkg2.boost(-0.011,0,0);
 
          /////////////////////////////////////////////////////////////
          HepLorentzVector  ptrkpi0;
          ptrkpi0 = ptrkg12+ptrkg22;
          double m_xmpi0_tem = ptrkpi0.m();
          if(m_xmpi0_tem>0.150||m_xmpi0_tem<0.115)  continue;
          /////////////////////////////////////////////////////////////
          bool IsEndcap1 = false; bool IsEndcap2 = false;
          if(fabs(cos(the1)) > 0.86 && fabs(cos(the1)) < 0.92) IsEndcap1 = true; 
          if(fabs(cos(the2)) > 0.86 && fabs(cos(the2)) < 0.92) IsEndcap2 = true; 
          if(IsEndcap1 && IsEndcap2)  continue;
          /////////////////////////////////////////////////////////////
          KalmanKinematicFit * kmfit = KalmanKinematicFit::instance();
          kmfit->init();
          kmfit->setChisqCut(2500);
          kmfit->AddTrack(0, 0.0, g1Trk);
          kmfit->AddTrack(1, 0.0, g2Trk);
          kmfit->AddResonance(0, mpi0, 0, 1);
 
          kmfit->Fit(0);  // Perform fit
          kmfit->BuildVirtualParticle(0);
 
          double pi0_chisq = kmfit->chisq(0);
          if ( pi0_chisq >= 2500) continue;
          HepLorentzVector p2gfit = kmfit->pfit(0) + kmfit->pfit(1);
          p2gfit.boost(-0.011,0,0);
          /////////////////////////////////////////////////////////////
 
          HepVector ksp_val = HepVector(7,0);
          HepVector ksm_val = HepVector(7,0);
          ksp_val = wksp.w();
          ksm_val = wksm.w();
 
          HepLorentzVector P_KSP(ksp_val[0],ksp_val[1],ksp_val[2],ksp_val[3]);
          HepLorentzVector P_KSM(ksm_val[0],ksm_val[1],ksm_val[2],ksm_val[3]);
 
          P_KSP.boost(-0.011,0,0);
          P_KSM.boost(-0.011,0,0);
          pddd = p4kstag + p2gfit;
 
          double   pk0pi0=pddd.rho();
 
          double temp1 = (ecms/2)*(ecms/2)-pk0pi0*pk0pi0 ;
          if(temp1<0) temp1 =0;
          double mass_bc_tem  = sqrt(temp1);
          if(mass_bc_tem < 1.82 || mass_bc_tem > 1.89) continue;
          
          double  delE_tag_tag = ecms/2-pddd.e();
 
          if(fabs(delE_tag_tag)<deltaE_tem){
            deltaE_tem = fabs(delE_tag_tag);
            delE_tag_temp = delE_tag_tag;
            mass_bcgg = mass_bc_tem;
 
            pddd_temp = pddd;
 
            ipi1_temp=ipi1;
            ipi2_temp=ipi2;
 
            iGam1_temp = iGam[m];
            iGam2_temp = iGam[n];
            
            ncount1 = 1;
          }   
        }   
      }
    }
  }
 
  if(ncount1 == 1){
    tagmode=18;
    if(m_chargetag<0)  tagmode=-18;
    tagmd=tagmode;
    mass_bc = mass_bcgg;
    delE_tag = delE_tag_temp;
    cqtm    = 0.0;
 
    iGoodtag.push_back(ipi1_temp);
    iGoodtag.push_back(ipi2_temp);
    iGamtag.push_back(iGam1_temp);
    iGamtag.push_back(iGam2_temp);
    iGamtag.push_back(9999);
    iGamtag.push_back(9999);
 
    ptag = pddd_temp;
 
    k0pi0md = true;
 
  }
}