K0kk.cxx

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//
//  K0kk.cxx is the single D0 tag code to reconstruct D0 or anti-D0 meson through the final
//  states of K0kk from D0 or anti-D0 meson decays. K0kk.cxx was transfered from the Fortran
//  routine "K0kk.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 "Pipipi0.f" used at the BES-II experiment was coded by G. Rong
//  in 2002.
//
//  K0kk.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/K0kk.h"
#include "SD0TagAlg/SingleBase.h"
 
K0kk::K0kk() {}
 
K0kk::~K0kk() {}
 
void K0kk::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_chargek1, m_chargek2;
  int              ik1_temp, ik2_temp, ipi1_temp, ipi2_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;
 
  k0kkmd         = 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 );
  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] );
  //////////////////////////////////////////////////////////////////
 
  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 ( abs( 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 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 pim( xmass[2], mdcKalTrk2->getZHelix(), mdcKalTrk2->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 );
 
      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;
 
      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 );
 
      //
      // select k1
      //
      for ( int k = 0; k < evtRecEvent->totalCharged(); k++ )
      {
        EvtRecTrackIterator itTrk = evtRecTrkCol->begin() + k;
 
        int ik1 = ( *itTrk )->trackId();
        if ( ipi2 == ik1 || ipi1 == ik1 ) continue;
 
        if ( !( *itTrk )->isMdcKalTrackValid() ) continue;
        RecMdcKalTrack* mdcKalTrk3 = ( *itTrk )->mdcKalTrack();
        RecMdcKalTrack::setPidType( RecMdcKalTrack::kaon );
 
        m_chargek1 = mdcKalTrk3->charge();
        if ( abs( m_chargek1 ) != 1 ) continue;
 
        /////////////////////////////////////////
        HepVector    a3  = mdcKalTrk3->getZHelixK();
        HepSymMatrix Ea3 = mdcKalTrk3->getZErrorK();
        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->probKaon() < 0.0 ||
               simple_pid->probKaon() < simple_pid->probPion() )
            continue;
        }
        /////////////////////////////////////////
        WTrackParameter kap( xmass[3], mdcKalTrk3->getZHelixK(), mdcKalTrk3->getZErrorK() );
 
        //
        // select k2
        //
        for ( int l = 0; l < evtRecEvent->totalCharged(); l++ )
        {
          EvtRecTrackIterator itTrk = evtRecTrkCol->begin() + l;
 
          int ik2 = ( *itTrk )->trackId();
          if ( ik2 == ik1 || ik2 == ipi2 || ik2 == ipi1 ) continue;
 
          if ( !( *itTrk )->isMdcKalTrackValid() ) continue;
          RecMdcKalTrack* mdcKalTrk4 = ( *itTrk )->mdcKalTrack();
          RecMdcKalTrack::setPidType( RecMdcKalTrack::kaon );
 
          m_chargek2 = mdcKalTrk4->charge();
          if ( ( m_chargek1 + m_chargek2 ) != 0 ) continue;
 
          /////////////////////////////////////////
          HepVector    a4  = mdcKalTrk4->getZHelixK();
          HepSymMatrix Ea4 = mdcKalTrk4->getZErrorK();
          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->probKaon() < 0.0 ||
                 simple_pid->probKaon() < simple_pid->probPion() )
              continue;
          }
          /////////////////////////////////////////
 
          WTrackParameter kam( xmass[3], mdcKalTrk4->getZHelixK(), mdcKalTrk4->getZErrorK() );
 
          VertexFit* vtxfit_2 = VertexFit::instance();
          vtxfit_2->init();
          vtxfit_2->AddTrack( 0, kap );
          vtxfit_2->AddTrack( 1, kam );
          vtxfit_2->AddVertex( 0, vxpar, 0, 1 );
          if ( !vtxfit_2->Fit( 0 ) ) continue;
          vtxfit_2->Swim( 0 );
 
          WTrackParameter wkap = vtxfit_2->wtrk( 0 );
          WTrackParameter wkam = 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 kap_val = HepVector( 7, 0 );
          HepVector kam_val = HepVector( 7, 0 );
          HepVector ksp_val = HepVector( 7, 0 );
          HepVector ksm_val = HepVector( 7, 0 );
 
          kap_val = wkap.w();
          kam_val = wkam.w();
          ksp_val = wksp.w();
          ksm_val = wksm.w();
 
          HepLorentzVector P_KAP( kap_val[0], kap_val[1], kap_val[2], kap_val[3] );
          HepLorentzVector P_KAM( kam_val[0], kam_val[1], kam_val[2], kam_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] );
 
          P_KAM.boost( -0.011, 0, 0 );
          P_KAP.boost( -0.011, 0, 0 );
          P_KSP.boost( -0.011, 0, 0 );
          P_KSM.boost( -0.011, 0, 0 );
          p4kstag.boost( -0.011, 0, 0 );
          // pddd = P_KAM + P_KAP + P_KSP + P_KSM;
          pddd = P_KAM + P_KAP + p4kstag;
 
          double pk0kk = pddd.rho();
 
          double temp1 = ( ecms / 2 ) * ( ecms / 2 ) - pk0kk * pk0kk;
          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;
            ik1_temp  = ik1;
            ik2_temp  = ik2;
 
            ncount1 = 1;
          }
        }
      }
    }
  }
 
  if ( ncount1 == 1 )
  {
    tagmode = 22;
    if ( m_chargetag < 0 ) tagmode = -22;
    tagmd    = tagmode;
    mass_bc  = mass_bcgg;
    delE_tag = delE_tag_temp;
    cqtm     = 0.0;
 
    iGoodtag.push_back( ipi1_temp );
    iGoodtag.push_back( ipi2_temp );
    iGoodtag.push_back( ik1_temp );
    iGoodtag.push_back( ik2_temp );
 
    iGamtag.push_back( 9999 );
    iGamtag.push_back( 9999 );
    iGamtag.push_back( 9999 );
    iGamtag.push_back( 9999 );
 
    ptag = pddd_temp;
 
    k0kkmd = true;
  }
}