K3pi.cxx

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//
//  K3pi.cxx is the single D0 tag code to reconstruct D0 or anti-D0 meon through the final
//  states of K3pi from D0 decays. K3pi.cxx was transfered from the Fortran routine "K3pi.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 "K3pi.f" used at the BES-II experiment was coded by G. Rong in
//  2002.
//
//  K3pi.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/K3pi.h"
#include "SD0TagAlg/SingleBase.h"
 
K3pi::K3pi() {}
 
K3pi::~K3pi() {}
 
void K3pi::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_chargek, m_chargepi1, m_chargepi2, m_chargepi3;
  int              ika_temp, ipi1_temp, ipi2_temp, ipi3_temp, ipi4_temp;
  HepLorentzVector kmfit1, kmfit2, kmfit3, kmfit4, pddd;
 
  int               cqtm_temp;
  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;
 
  k3pimd         = false;
  double tagmode = 0;
 
  if ( ( evtRecEvent->totalCharged() < 4 ) ) { 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 );
  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] );
  }
 
  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 ptrk1_temp, ptrk2_temp, ptrk3_temp, ptrk4_temp;
  //////////////////////////////////////////////////////////////////
  for ( int i = 0; i < evtRecEvent->totalCharged(); i++ )
  {
    EvtRecTrackIterator itTrk1 = evtRecTrkCol->begin() + i;
 
    int ika = ( *itTrk1 )->trackId();
 
    if ( !( *itTrk1 )->isMdcKalTrackValid() ) continue;
    RecMdcKalTrack* mdcKalTrk1 = ( *itTrk1 )->mdcKalTrack();
    RecMdcKalTrack::setPidType( RecMdcKalTrack::kaon );
    /////////////////////////////////////////
    m_chargek = mdcKalTrk1->charge();
    if ( Charge_candidate_D != 0 )
    {
      if ( m_chargek != -Charge_candidate_D ) continue;
    }
    if ( Charge_candidate_D == 0 )
    {
      if ( abs( m_chargek ) != 1 ) continue;
    }
    /////////////////////////////////////////
    HepVector    a1  = mdcKalTrk1->getZHelixK();
    HepSymMatrix Ea1 = mdcKalTrk1->getZErrorK();
 
    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 >= 1.0 ) continue;
    if ( dz1 >= 10.0 ) continue;
    if ( fabs( costheta1 ) >= 0.93 ) continue;
    /////////////////////////////////////////
    if ( PID_flag == 5 )
    {
      simple_pid->preparePID( *itTrk1 );
      if ( simple_pid->probKaon() < 0.0 || simple_pid->probKaon() < simple_pid->probPion() )
        continue;
    }
    /////////////////////////////////////////
    WTrackParameter kam( xmass[3], mdcKalTrk1->getZHelixK(), mdcKalTrk1->getZErrorK() );
 
    //
    // select pi1
    //
    for ( int j = 0; j < evtRecEvent->totalCharged(); j++ )
    {
      EvtRecTrackIterator itTrk2 = evtRecTrkCol->begin() + j;
 
      int ipi1 = ( *itTrk2 )->trackId();
      if ( ipi1 == ika ) continue;
 
      if ( !( *itTrk2 )->isMdcKalTrackValid() ) continue;
      RecMdcKalTrack* mdcKalTrk2 = ( *itTrk2 )->mdcKalTrack();
      RecMdcKalTrack::setPidType( RecMdcKalTrack::pion );
      /////////////////////////////////////////
      m_chargepi1 = mdcKalTrk2->charge();
      if ( ( m_chargek + 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 >= 1.0 ) continue;
      if ( dz2 >= 10.0 ) continue;
      if ( fabs( costheta2 ) >= 0.93 ) continue;
      /////////////////////////////////////////
      if ( PID_flag == 5 )
      {
        simple_pid->preparePID( *itTrk2 );
        if ( simple_pid->probPion() < 0.0 || simple_pid->probPion() < simple_pid->probKaon() )
          continue;
      }
      /////////////////////////////////////////
      WTrackParameter pip1( xmass[2], mdcKalTrk2->getZHelix(), mdcKalTrk2->getZError() );
 
      //
      // select pi2
      //
      for ( int k = 0; k < evtRecEvent->totalCharged(); k++ )
      {
        EvtRecTrackIterator itTrk3 = evtRecTrkCol->begin() + k;
 
        int ipi2 = ( *itTrk3 )->trackId();
        if ( ipi2 == ika || ipi2 == ipi1 ) continue;
 
        if ( !( *itTrk3 )->isMdcKalTrackValid() ) continue;
        RecMdcKalTrack* mdcKalTrk3 = ( *itTrk3 )->mdcKalTrack();
        RecMdcKalTrack::setPidType( RecMdcKalTrack::pion );
        /////////////////////////////////////////
        m_chargepi2 = mdcKalTrk3->charge();
        if ( ( m_chargek + m_chargepi2 ) != 0 ) 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( *itTrk3 );
          if ( simple_pid->probPion() < 0.0 ||
               simple_pid->probPion() < simple_pid->probKaon() )
            continue;
        }
        /////////////////////////////////////////
        WTrackParameter pip2( xmass[2], mdcKalTrk3->getZHelix(), mdcKalTrk3->getZError() );
 
        //
        // select pi3
        //
        for ( int l = 0; l < evtRecEvent->totalCharged(); l++ )
        {
          EvtRecTrackIterator itTrk4 = evtRecTrkCol->begin() + l;
 
          int ipi3 = ( *itTrk4 )->trackId();
          if ( ipi3 == ika || ipi3 == ipi1 || ipi3 == ipi2 ) continue;
 
          if ( !( *itTrk4 )->isMdcKalTrackValid() ) continue;
          RecMdcKalTrack* mdcKalTrk4 = ( *itTrk4 )->mdcKalTrack();
          RecMdcKalTrack::setPidType( RecMdcKalTrack::pion );
          /////////////////////////////////////////
          m_chargepi3 = mdcKalTrk4->charge();
          if ( ( m_chargepi2 + 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( *itTrk4 );
            if ( simple_pid->probPion() < 0.0 ||
                 simple_pid->probPion() < simple_pid->probKaon() )
              continue;
          }
          /////////////////////////////////////////
          WTrackParameter pip3( xmass[2], mdcKalTrk4->getZHelix(), mdcKalTrk4->getZError() );
 
          //////////////////////////////////////////////////////////////
          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* vtxfit = VertexFit::instance();
          vtxfit->init();
          vtxfit->AddTrack( 0, kam );
          vtxfit->AddTrack( 1, pip1 );
          vtxfit->AddTrack( 2, pip2 );
          vtxfit->AddTrack( 3, pip3 );
          vtxfit->AddVertex( 0, vxpar, 0, 1, 2, 3 );
          if ( !vtxfit->Fit( 0 ) ) continue;
          vtxfit->Swim( 0 );
 
          WTrackParameter wkam  = vtxfit->wtrk( 0 );
          WTrackParameter wpip1 = vtxfit->wtrk( 1 );
          WTrackParameter wpip2 = vtxfit->wtrk( 2 );
          WTrackParameter wpip3 = vtxfit->wtrk( 3 );
 
          HepVector kam_val  = HepVector( 7, 0 );
          HepVector pip1_val = HepVector( 7, 0 );
          HepVector pip2_val = HepVector( 7, 0 );
          HepVector pip3_val = HepVector( 7, 0 );
          kam_val            = wkam.w();
          pip1_val           = wpip1.w();
          pip2_val           = wpip2.w();
          pip3_val           = wpip3.w();
 
          HepLorentzVector P_KAM( kam_val[0], kam_val[1], kam_val[2], kam_val[3] );
          HepLorentzVector P_PIP1( pip1_val[0], pip1_val[1], pip1_val[2], pip1_val[3] );
          HepLorentzVector P_PIP2( pip2_val[0], pip2_val[1], pip2_val[2], pip2_val[3] );
          HepLorentzVector P_PIP3( pip3_val[0], pip3_val[1], pip3_val[2], pip3_val[3] );
 
          P_KAM.boost( -0.011, 0, 0 );
          P_PIP1.boost( -0.011, 0, 0 );
          P_PIP2.boost( -0.011, 0, 0 );
          P_PIP3.boost( -0.011, 0, 0 );
          pddd = P_KAM + P_PIP1 + P_PIP2 + P_PIP3;
 
          double pk3pi = pddd.rho();
 
          double temp1 = ( ecms / 2 ) * ( ecms / 2 ) - pk3pi * pk3pi;
          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;
            cqtm_temp = m_chargek;
 
            ika_temp  = ika;
            ipi1_temp = ipi1;
            ipi2_temp = ipi2;
            ipi3_temp = ipi3;
            ncount1   = 1;
          }
        }
      }
    }
  }
 
  if ( ncount1 == 1 )
  {
    tagmode = 13;
    if ( cqtm_temp < 0 ) tagmode = -13;
    tagmd    = tagmode;
    mass_bc  = mass_bcgg;
    delE_tag = delE_tag_temp;
    cqtm     = -1.0 * cqtm_temp;
 
    iGoodtag.push_back( ika_temp );
    iGoodtag.push_back( ipi1_temp );
    iGoodtag.push_back( ipi2_temp );
    iGoodtag.push_back( ipi3_temp );
 
    iGamtag.push_back( 9999 );
    iGamtag.push_back( 9999 );
    iGamtag.push_back( 9999 );
    iGamtag.push_back( 9999 );
 
    ptag = pddd_temp;
 
    k3pimd = true;
  }
}