EvtDecayAmp.cc

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//--------------------------------------------------------------------------
//
// Environment:
//      This software is part of the EvtGen package developed jointly
//      for the BaBar and CLEO collaborations.  If you use all or part
//      of it, please give an appropriate acknowledgement.
//
// Copyright Information: See EvtGen/COPYRIGHT
//      Copyright (C) 1998      Caltech, UCSB
//
// Module: EvtGen/EvtDecayAmp.cc
//
// Description:
//
// Modification history:
//
//    DJL/RYD     August 11, 1998         Module created
//
//------------------------------------------------------------------------
#include "EvtGenBase/EvtPatches.hh"
 
#include "EvtGenBase/EvtDecayBase.hh"
#include "EvtGenBase/EvtDecayAmp.hh"
#include "EvtGenBase/EvtParticle.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtRandom.hh"
#include "EvtGenBase/EvtRadCorr.hh"
#include "EvtGenBase/EvtAmp.hh"
#include "EvtGenBase/EvtReport.hh"
#include "EvtGenBase/EvtSpinDensity.hh"
#include <vector>
using std::endl;
 
 
void EvtDecayAmp::makeDecay(EvtParticle* p){
 
  int ntimes=10000;
 
  int i,more;
 
  EvtSpinDensity rho;
  double prob,prob_max;
 
  _amp2.init(p->getId(),getNDaug(),getDaugs());
//  report(INFO,"EvtGen") << "Decaying " << EvtPDL::name(p->getId()) << endl;
  do{
 
    _daugsDecayedByParentModel=false;
    _weight = 1.0;
    decay(p);
 
    rho=_amp2.getSpinDensity();
    prob=p->getSpinDensityForward().NormalizedProb(rho);
    if (prob<0.0) {
 
      report(ERROR,"EvtGen")<<"Negative prob:"<<p->getId().getId()
                <<" "<<p->getChannel()<<endl;
 
      report(ERROR,"EvtGen") << "rho_forward:"<<endl;
      report(ERROR,"EvtGen") << p->getSpinDensityForward();
      report(ERROR,"EvtGen") << "rho decay:"<<endl;
      report(ERROR,"EvtGen") << rho <<endl;
    }
 
    if (prob!=prob) {
 
      report(DEBUG,"EvtGen") << "Forward density matrix:"<<endl;
      report(ERROR,"EvtGen") << p->getSpinDensityForward();
 
      report(DEBUG,"EvtGen") << "Decay density matrix:"<<endl;
      report(ERROR,"EvtGen") << rho;
 
      report(DEBUG,"EvtGen") << "prob:"<<prob<<endl;
      
      report(DEBUG,"EvtGen") << "Particle:"
                 <<EvtPDL::name(p->getId()).c_str()<<endl;
      report(DEBUG,"EvtGen") << "channel        :"<<p->getChannel()<<endl;
      report(DEBUG,"EvtGen") << "Momentum:" << p->getP4() << " " << p->mass() << endl;
      if( p->getParent()!=0){
    report(DEBUG,"EvtGen") << "parent:"
                   <<EvtPDL::name(
                p->getParent()->getId()).c_str()<<endl;
    report(DEBUG,"EvtGen") << "parent channel        :"
                   <<p->getParent()->getChannel()<<endl;
 
        int i;
    report(DEBUG,"EvtGen") << "parent daughters  :";
        for (i=0;i<p->getParent()->getNDaug();i++){
      report(DEBUG,"") << EvtPDL::name(
                p->getParent()->getDaug(i)->getId()).c_str()
                 << " ";
        }
    report(DEBUG,"") << endl;
 
    report(DEBUG,"EvtGen") << "daughters  :";
        for (i=0;i<p->getNDaug();i++){
      report(DEBUG,"") << EvtPDL::name(
                p->getDaug(i)->getId()).c_str()
                 << " ";
        }
    report(DEBUG,"") << endl;
 
    report(DEBUG,"EvtGen") << "daughter momenta  :" << endl;;
        for (i=0;i<p->getNDaug();i++){
      report(DEBUG,"") << p->getDaug(i)->getP4() << " " << p->getDaug(i)->mass();
      report(DEBUG,"") << endl;
        }
 
      }
    }
 
 
    prob/=_weight;
 
 
    prob_max = getProbMax(prob);
    p->setDecayProb(prob/prob_max);
 
    //report(INFO,"EvtGen") << "Prob,prob_max,weight:"<<prob<<" "<<prob_max<<" "<<_weight<<endl;
 
    more=prob<EvtRandom::Flat(prob_max);
 
    ntimes--;
 
  }while(ntimes&&more);
  //report(INFO,"EvtGen") << "Done\n";
 
  if (ntimes==0){
    report(DEBUG,"EvtGen") << "Tried accept/reject:10000"
               <<" times, and rejected all the times!"<<endl;
    report(DEBUG,"")<<p->getSpinDensityForward()<<endl;
    report(DEBUG,"EvtGen") << "Is therefore accepting the last event!"<<endl;
    report(DEBUG,"EvtGen") << "Decay of particle:"<<
      EvtPDL::name(p->getId()).c_str()<<"(channel:"<<
      p->getChannel()<<") with mass "<<p->mass()<<endl;
    
    int ii;
    for(ii=0;ii<p->getNDaug();ii++){
      report(DEBUG,"EvtGen") <<"Daughter "<<ii<<":"<<
    EvtPDL::name(p->getDaug(ii)->getId()).c_str()<<" with mass "<<
    p->getDaug(ii)->mass()<<endl;
    }                  
  }
 
 
  EvtSpinDensity rho_list[10];
 
  rho_list[0]=p->getSpinDensityForward();
   
 
  EvtAmp ampcont;
 
  if (_amp2._pstates!=1){
    ampcont=_amp2.contract(0,p->getSpinDensityForward());   // J2BB2 bugging here
 
  }
  else{
    ampcont=_amp2;
  }
 
          
 
  // it may be that the parent decay model has already
  // done the decay - this should be rare and the
  // model better know what it is doing..
  
  if ( !daugsDecayedByParentModel() ){
    
 
 //   report(INFO,"EvtGen") << "Found " << p->getNDaug() << " daughters\n";
    for(i=0;i<p->getNDaug();i++){
    
      rho.SetDim(_amp2.dstates[i]);
 
      if (_amp2.dstates[i]==1) {
    rho.Set(0,0,EvtComplex(1.0,0.0));
      }
      else{
    rho=ampcont.contract(_amp2._dnontrivial[i],_amp2);
      }
      
      if (!rho.Check()) {
    
    report(ERROR,"EvtGen") << "-------start error-------"<<endl;
    report(ERROR,"EvtGen")<<"forward rho failed Check:"<<
      EvtPDL::name(p->getId()).c_str()<<" "<<p->getChannel()<<" "<<i<<endl;
    
    report(ERROR,"EvtGen")<<"Parent:"<<EvtPDL::name(p->getParent()->getId()).c_str()<<endl;
    report(ERROR,"EvtGen")<<"GrandParent:"<<EvtPDL::name(p->getParent()->getParent()->getId()).c_str()<<endl;
    report(ERROR,"EvtGen")<<"GrandGrandParent:"<<EvtPDL::name(p->getParent()->getParent()->getParent()->getId()).c_str()<<endl;
    
    report(ERROR,"EvtGen") << rho;
    int ii; 
    _amp2.dump();
        
    for(ii=0;ii<i+1;ii++){
      report(ERROR,"EvtGen") << rho_list[ii];
    }
    report(ERROR,"EvtGen") << "-------Done with error-------"<<endl;  
      }
 
 
      
      p->getDaug(i)->setSpinDensityForward(rho);
 
 
     p->getDaug(i)->decay();
 
     rho_list[i+1]= p->getDaug(i)->getSpinDensityBackward();
 
      if (_amp2.dstates[i]!=1){
    ampcont=ampcont.contract(_amp2._dnontrivial[i],rho_list[i+1]);
      }
  
      
    }
 
    p->setSpinDensityBackward(_amp2.getBackwardSpinDensity(rho_list));
   
    
    if (!p->getSpinDensityBackward().Check()) {
      
      report(ERROR,"EvtGen")<<"rho_backward failed Check"<<
    p->getId().getId()<<" "<<p->getChannel()<<endl;
      
      report(ERROR,"EvtGen") << p->getSpinDensityBackward();
      
    }
  }
 
  if (getPHOTOS() || EvtRadCorr::alwaysRadCorr()) {
    EvtRadCorr::doRadCorr(p);
 
  }
 
}