EvtmH2.cc

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//--------------------------------------------------------------------------
//
// Environment:
//      This software is part of models developed at BES collaboration
//      based on the EvtGen framework.  If you use all or part
//      of it, please give an appropriate acknowledgement.
//
// Copyright Information: See EvtGen/BesCopyright
//      Copyright (A) 2006      Ping Rong-Gang @IHEP
//
// Module: EvtMassH1.cc
//
// Description: Routine to decay a particle  using a scatter
//    plot forn n-body decays (n>3).
//
// Modification history:
//
//    Ping R.-G.       Oct. 2011       Module created
//
//------------------------------------------------------------------------
//
#include "EvtmH2.hh"
#include "../EvtGenBase/EvtDiracParticle.hh"
#include "../EvtGenBase/EvtGenKine.hh"
#include "../EvtGenBase/EvtHelSys.hh"
#include "../EvtGenBase/EvtHighSpinParticle.hh"
#include "../EvtGenBase/EvtNeutrinoParticle.hh"
#include "../EvtGenBase/EvtPDL.hh"
#include "../EvtGenBase/EvtParticle.hh"
#include "../EvtGenBase/EvtPatches.hh"
#include "../EvtGenBase/EvtPhotonParticle.hh"
#include "../EvtGenBase/EvtRandom.hh"
#include "../EvtGenBase/EvtRaritaSchwingerParticle.hh"
#include "../EvtGenBase/EvtReport.hh"
#include "../EvtGenBase/EvtScalarParticle.hh"
#include "../EvtGenBase/EvtStringParticle.hh"
#include "../EvtGenBase/EvtTensor4C.hh"
#include "../EvtGenBase/EvtTensorParticle.hh"
#include "../EvtGenBase/EvtVector4C.hh"
#include "../EvtGenBase/EvtVector4R.hh"
#include "../EvtGenBase/EvtVectorParticle.hh"
#include <stdlib.h>
#include <string>
 
#include "TApplication.h"
#include "TAxis.h"
#include "TFile.h"
#include "TH1.h"
#include "TH2.h"
#include "TROOT.h"
// #include "CLHEP/config/CLHEP.h"
// #include "CLHEP/config/TemplateFunctions.h"
 
using std::endl;
 
EvtmH2::~EvtmH2() {}
 
void EvtmH2::getName( std::string& model_name ) { model_name = "mH2"; }
 
EvtDecayBase* EvtmH2::clone() { return new EvtmH2; }
 
void EvtmH2::init() {
 
  // check that there are 4 arguments: Invariant mass part. Index: i,j, histor. file name, Hid
  checkNArg( 2 );
  EvtSpinType::spintype parenttype = EvtPDL::getSpinType( getParentId() );
  nbx                              = getArg( 0 );
  nby                              = getArg( 1 );
}
void EvtmH2::initProbMax() { noProbMax(); }
 
void EvtmH2::decay( EvtParticle* p ) {
 
  const char* fl = setFileName();
  const char* hp = setHpoint();
 
  TFile  f( fl );
  TH2F*  hid   = (TH2F*)f.Get( "mH2" );
  TAxis* xaxis = hid->GetXaxis();
  TAxis* yaxis = hid->GetYaxis();
 
  int    BINSx = xaxis->GetLast();
  int    BINSy = yaxis->GetLast();
  int    BINS  = BINSx * BINSy;
  double yvalue, ymax = 0.0;
  int    i, j, binxy;
 
  for ( i = 1; i < BINSx + 1; i++ )
  {
    for ( j = 1; j < BINSy + 1; j++ )
    {
      binxy  = hid->GetBin( i, j );
      yvalue = hid->GetBinContent( binxy );
      //      cout<<"binxy,yvalue = "<<binxy<<"; "<<yvalue<<endl;
      if ( yvalue > ymax ) ymax = yvalue;
    }
  }
 
loop:
  p->initializePhaseSpace( getNDaug(), getDaugs() );
 
  if ( p->getNDaug() != nbx + nby )
  {
    std::cout
        << "The number of specified particles is not equal the number of decay daughters "
        << endl;
    ::abort();
  }
 
  EvtVector4R pt, pt2;
  double      xmass, ymass;
 
  pt = p->getDaug( 0 )->getP4Lab();
  for ( int ii = 1; ii < nbx; ii++ ) { pt = pt + p->getDaug( ii )->getP4Lab(); }
  xmass = pt.mass();
 
  pt2 = p->getDaug( nbx )->getP4Lab();
  for ( int jj = nbx + 1; jj < nbx + nby; jj++ ) pt2 = pt2 + p->getDaug( jj )->getP4Lab();
  ymass = pt2.mass();
 
  int    xbin   = hid->GetXaxis()->FindBin( xmass );
  int    ybin   = hid->GetYaxis()->FindBin( ymass );
  int    xybin  = hid->GetBin( xbin, ybin );
  double zvalue = hid->GetBinContent( xybin );
  double xratio = zvalue / ymax;
  //  cout<<"***************zvalue,ymax,xratio= "<<zvalue<<"; "<<ymax<<"; "<<xratio<<endl;
  double rd1 = EvtRandom::Flat( 0.0, 1.0 );
  if ( rd1 > xratio ) goto loop;
  return;
}