K0pipipi0.cxx

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//
//  K0pipipi0.cxx is the single D0 tag code to reconstruct D0 or anti-D0 meson through the
//  final states of K0pipipi0 from D0 decays. K0pipipi0.cxx was transfered from the Fortran
//  routine "K0pipipi0.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 "K0pipipi0.f" used at the BES-II experiment was coded by G.
//  Rong in 2002.
//
//  K0pipipi0.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/K0pipipi0.h"
#include "SD0TagAlg/SingleBase.h"
 
K0pipipi0::K0pipipi0() {}
 
K0pipipi0::~K0pipipi0() {}
 
void K0pipipi0::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, m_chargepi3, m_chargepi4;
  int    ik1_temp, ipi1_temp, ipi2_temp, ipi3_temp, ipi4_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;
 
  k0pipipi0md    = false;
  double tagmode = 0;
 
  if ( ( evtRecEvent->totalCharged() < 4 || 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 pip1( xmass[2], mdcKalTrk1->getZHelix(), mdcKalTrk1->getZError() );
 
    //
    // select pi2
    //
 
    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_chargepi2 + m_chargepi1 ) != 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 pim1( xmass[2], mdcKalTrk2->getZHelix(), mdcKalTrk2->getZError() );
 
      HepVector pip1_val = HepVector( 7, 0 );
      HepVector pim1_val = HepVector( 7, 0 );
      pip1_val           = pip1.w();
      pim1_val           = pim1.w();
      HepLorentzVector ptrktagk0( pip1_val[0] + pim1_val[0], pip1_val[1] + pim1_val[1],
                                  pip1_val[2] + pim1_val[2], pip1_val[3] + pim1_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, pip1 );
      vtxfit0->AddTrack( 1, pim1 );
      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 );
 
      //
      // select pi3
      //
      for ( int k = 0; k < evtRecEvent->totalCharged(); k++ )
      {
        EvtRecTrackIterator itTrk = evtRecTrkCol->begin() + k;
 
        int ipi3 = ( *itTrk )->trackId();
        if ( ipi2 == ipi3 || ipi1 == ipi3 ) continue;
 
        if ( !( *itTrk )->isMdcKalTrackValid() ) continue;
        RecMdcKalTrack* mdcKalTrk3 = ( *itTrk )->mdcKalTrack();
        RecMdcKalTrack::setPidType( RecMdcKalTrack::pion );
 
        m_chargepi3 = mdcKalTrk3->charge();
        if ( abs( m_chargepi3 ) != 1 ) continue;
 
        /////////////////////////////////////////
        HepVector    a3  = mdcKalTrk3->getZHelix();
        HepSymMatrix Ea3 = mdcKalTrk3->getZError();
        VFHelix      helixip3_3( point0, a3, Ea3 );
        helixip3_3.pivot( IP );
        HepVector vecipa3 = helixip3_3.a();
 
        double dr3       = fabs( vecipa3[0] );
        double dz3       = fabs( vecipa3[3] );
        double costheta3 = cos( mdcKalTrk3->theta() );
        if ( dr3 >= 1.0 ) continue;
        if ( dz3 >= 10.0 ) continue;
        if ( fabs( costheta3 ) >= 0.93 ) continue;
        /////////////////////////////////////////
        if ( PID_flag == 5 )
        {
          simple_pid->preparePID( *itTrk );
          if ( simple_pid->probPion() < 0.0 ||
               simple_pid->probPion() < simple_pid->probKaon() )
            continue;
        }
        /////////////////////////////////////////
        WTrackParameter pip2( xmass[2], mdcKalTrk3->getZHelix(), mdcKalTrk3->getZError() );
 
        //
        // select pi4
        //
        for ( int l = 0; l < evtRecEvent->totalCharged(); l++ )
        {
          EvtRecTrackIterator itTrk = evtRecTrkCol->begin() + l;
 
          int ipi4 = ( *itTrk )->trackId();
          if ( ipi4 == ipi3 || ipi4 == ipi2 || ipi4 == ipi1 ) continue;
 
          if ( !( *itTrk )->isMdcKalTrackValid() ) continue;
          RecMdcKalTrack* mdcKalTrk4 = ( *itTrk )->mdcKalTrack();
          RecMdcKalTrack::setPidType( RecMdcKalTrack::pion );
 
          m_chargepi4 = mdcKalTrk4->charge();
          if ( ( m_chargepi4 + m_chargepi3 ) != 0 ) continue;
 
          /////////////////////////////////////////
          HepVector    a4  = mdcKalTrk4->getZHelix();
          HepSymMatrix Ea4 = mdcKalTrk4->getZError();
          VFHelix      helixip3_4( point0, a4, Ea4 );
          helixip3_4.pivot( IP );
          HepVector vecipa4 = helixip3_4.a();
 
          double dr4       = fabs( vecipa4[0] );
          double dz4       = fabs( vecipa4[3] );
          double costheta4 = cos( mdcKalTrk4->theta() );
          if ( dr4 >= 1.0 ) continue;
          if ( dz4 >= 10.0 ) continue;
          if ( fabs( costheta4 ) >= 0.93 ) continue;
          /////////////////////////////////////////
          if ( PID_flag == 5 )
          {
            simple_pid->preparePID( *itTrk );
            if ( simple_pid->probPion() < 0.0 ||
                 simple_pid->probPion() < simple_pid->probKaon() )
              continue;
          }
          /////////////////////////////////////////
          WTrackParameter pim2( xmass[2], mdcKalTrk4->getZHelix(), mdcKalTrk4->getZError() );
 
          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 );
              /////////////////////////////////////////////////////////////
 
              VertexFit* vtxfit_2 = VertexFit::instance();
              vtxfit_2->init();
              vtxfit_2->AddTrack( 0, pip2 );
              vtxfit_2->AddTrack( 1, pim2 );
              vtxfit_2->AddVertex( 0, vxpar, 0, 1 );
              if ( !vtxfit_2->Fit( 0 ) ) continue;
              vtxfit_2->Swim( 0 );
 
              WTrackParameter wpip2 = vtxfit_2->wtrk( 0 );
              WTrackParameter wpim2 = vtxfit_2->wtrk( 1 );
 
              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();
              WTrackParameter  para_ks = vtxfit0->wVirtualTrack( 0 );
 
              HepVector pip2_val = HepVector( 7, 0 );
              HepVector pim2_val = HepVector( 7, 0 );
              HepVector ksp_val  = HepVector( 7, 0 );
              HepVector ksm_val  = HepVector( 7, 0 );
 
              pip2_val = wpip2.w();
              pim2_val = wpim2.w();
              ksp_val  = wksp.w();
              ksm_val  = wksm.w();
 
              HepLorentzVector P_PIP2( pip2_val[0], pip2_val[1], pip2_val[2], pip2_val[3] );
              HepLorentzVector P_PIM2( pim2_val[0], pim2_val[1], pim2_val[2], pim2_val[3] );
              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] );
 
              p4kstag.boost( -0.011, 0, 0 );
              P_PIP2.boost( -0.011, 0, 0 );
              P_PIM2.boost( -0.011, 0, 0 );
              P_KSP.boost( -0.011, 0, 0 );
              P_KSM.boost( -0.011, 0, 0 );
 
              // pddd = P_PIP2 + P_PIM2 + P_KSP + P_KSM + p2gfit;
              pddd = P_PIP2 + P_PIM2 + p4kstag + p2gfit;
 
              double pk0pipipi0 = pddd.rho();
 
              double temp1 = ( ecms / 2 ) * ( ecms / 2 ) - pk0pipipi0 * pk0pipipi0;
              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;
                ipi3_temp  = ipi3;
                ipi4_temp  = ipi4;
                iGam1_temp = iGam[m];
                iGam2_temp = iGam[n];
 
                ncount1 = 1;
              }
            }
          }
        }
      }
    }
  }
 
  if ( ncount1 == 1 )
  {
    tagmode = 17;
    if ( m_chargetag < 0 ) tagmode = -17;
    tagmd    = tagmode;
    mass_bc  = mass_bcgg;
    delE_tag = delE_tag_temp;
    cqtm     = 0;
 
    iGoodtag.push_back( ipi1_temp );
    iGoodtag.push_back( ipi2_temp );
    iGoodtag.push_back( ipi3_temp );
    iGoodtag.push_back( ipi4_temp );
 
    iGamtag.push_back( iGam1_temp );
    iGamtag.push_back( iGam2_temp );
    iGamtag.push_back( 9999 );
    iGamtag.push_back( 9999 );
 
    ptag = pddd_temp;
 
    k0pipipi0md = true;
  }
}