EvtBody3.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: EvtBody3.cc
//
// Description: Routine to decay a particle into three bodies  using the Dalitz plots and two
// particle
//             angular distributions.
//
// Modification history:
//
//    Ping R.-G.       December, 2006       Module created
//
//------------------------------------------------------------------------
//
#include "EvtBody3.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 namespace CLHEP;
using std::endl;
 
EvtBody3::~EvtBody3() {}
 
void EvtBody3::getName( std::string& model_name ) { model_name = "Body3"; }
 
EvtDecayBase* EvtBody3::clone() { return new EvtBody3; }
 
void EvtBody3::init() {
 
  // check that there are 4 arguments: Invariant mass part. Index: i,j, histor. file name, Hid
  checkNArg( 0 );
  EvtSpinType::spintype parenttype = EvtPDL::getSpinType( getParentId() );
}
void EvtBody3::initProbMax() { noProbMax(); }
 
void EvtBody3::decay( EvtParticle* p ) {
 
  const char* fl = setFileName();
  const char* hp = setHpoint();
  int*        dp;
  int         nd1, nd2, ii, sn;
 
  sn = setDaugAngNo();
 
  if ( sn == 2 )
  {
    nd1 = 0;
    nd2 = 1;
  }
 
  if ( sn == 0 )
  {
    nd1 = 1;
    nd2 = 2;
  }
 
  if ( sn == 1 )
  {
    nd1 = 0;
    nd2 = 2;
  }
  const char* DA1 = setDaugAng( nd1 );
  const char* DA2 = setDaugAng( nd2 );
 
  dp     = setDaugPair();
  int d1 = dp[0]; // m(d1,d2) pair at X axis
  int d2 = dp[1];
  int d3 = dp[2]; // m(d3,d4) pair at Y axis
  int d4 = dp[3];
 
  TFile f( fl );
  TH1F* did1 = (TH1F*)f.Get( DA1 );
  TH1F* did2 = (TH1F*)f.Get( DA2 );
  TH2F* hid  = (TH2F*)f.Get( hp );
 
  TAxis* d1x   = did1->GetXaxis();
  TAxis* d2x   = did2->GetXaxis();
  TAxis* xaxis = hid->GetXaxis();
  TAxis* yaxis = hid->GetYaxis();
 
  int BINSd1 = did1->GetXaxis()->GetLast();
  int BINSd2 = did2->GetXaxis()->GetLast();
  int BINSx  = xaxis->GetLast();
  int BINSy  = yaxis->GetLast();
  int BINS   = BINSx * BINSy;
 
  double av1, av2, avm1, avm2;
  avm1 = 0.;
  avm2 = 0.;
  double yvalue, ymax = 0.0;
  int    i, j, binxy;
 
  // look for maxmum for the first hist.1
  for ( i = 1; i < BINSd1 + 1; i++ )
  {
    av1 = did1->GetBinContent( i );
    if ( av1 > avm1 ) avm1 = av1;
  }
 
  // look for maxmum for the second hist.1
  for ( i = 1; i < BINSd2 + 1; i++ )
  {
    av2 = did2->GetBinContent( i );
    if ( av2 > avm2 ) avm2 = av2;
  }
 
  // look for maxmum for the Dalitz plot
 
  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() );
 
  EvtParticle *id1, *id2, *id3, *id4, *s1;
  EvtVector4R  pd1, pd2, pd3, pd4, ps;
  EvtVector4R  dp1, dp2;
  double       xmass2, ymass2;
 
  id1 = p->getDaug( d1 );
  id2 = p->getDaug( d2 );
  id3 = p->getDaug( d3 );
  id4 = p->getDaug( d4 );
 
  pd1 = id1->getP4Lab();
  pd2 = id2->getP4Lab();
  pd3 = id3->getP4Lab();
  pd4 = id4->getP4Lab();
 
  dp1 = p->getDaug( nd1 )->getP4Lab();
  dp2 = p->getDaug( nd2 )->getP4Lab();
 
  xmass2 = ( pd1 + pd2 ).mass2();
  ymass2 = ( pd3 + pd4 ).mass2();
 
  int    xbin   = hid->GetXaxis()->FindBin( xmass2 );
  int    ybin   = hid->GetYaxis()->FindBin( ymass2 );
  int    xybin  = hid->GetBin( xbin, ybin );
  double zvalue = hid->GetBinContent( xybin );
  double xratio = zvalue / ymax;
  if ( xratio == 0 ) goto loop;
  double rd1 = EvtRandom::Flat( 0.0, 1.0 );
  if ( rd1 > xratio ) goto loop; // sigle out event by 2-D mass distribution histo.
 
  double da1 = dp1.get( 3 ) / dp1.d3mag();
  double da2 = dp2.get( 3 ) / dp2.d3mag();
 
  int dbin1 = did1->FindBin( da1 );
  int dbin2 = did2->FindBin( da2 );
 
  double dr1 = ( did1->GetBinContent( dbin1 ) ) / avm1;
  double dr2 = ( did2->GetBinContent( dbin2 ) ) / avm2;
  if ( dr1 == 0 || dr2 == 0 ) goto loop;
  rd1 = EvtRandom::Flat( 0.0, 1.0 );
  if ( rd1 > dr1 ) goto loop; // sigle out event by the first angular distribution histo.
 
  rd1 = EvtRandom::Flat( 0.0, 1.0 );
  if ( rd1 > dr2 ) goto loop; // sigle out event by the second angular distribution histo.
 
  return;
}