EvtCBTo3piMPP.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: EvtCBTo3piMPP.cc
//
// Description: Routine to decay B+/-->pi+ pi- pi+/-
//              and has CP violation.
//
// Modification history:
//
//    RYD/Versille     May 6, 1997         Module created
//
//------------------------------------------------------------------------
//
#include "EvtGenBase/EvtPatches.hh"
#include <stdlib.h>
#include "EvtGenBase/EvtParticle.hh"
#include "EvtGenBase/EvtGenKine.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtReport.hh"
#include "EvtGenBase/EvtId.hh"
#include "EvtGenModels/EvtCBTo3piMPP.hh"
#include <string>
 
//Below you will have do modify the declaration to be appropriate
//for your new routine for the calculation of the amplitude
 
extern "C" void evt3pionsmpp_(double *,int *,double *,
             double *,double *,double *,
             double *,double *,double *);
 
 
EvtCBTo3piMPP::~EvtCBTo3piMPP() {}
 
void EvtCBTo3piMPP::getName(std::string& model_name){
 
  model_name="CB3PI-MPP";     
 
}
 
 
EvtDecayBase* EvtCBTo3piMPP::clone(){
 
  return new EvtCBTo3piMPP;
 
}
 
void EvtCBTo3piMPP::init(){
 
  // check that there are 1 argument
  checkNArg(1);
  checkNDaug(3);
 
  checkSpinParent(EvtSpinType::SCALAR);
 
  checkSpinDaughter(0,EvtSpinType::SCALAR);
  checkSpinDaughter(1,EvtSpinType::SCALAR);
  checkSpinDaughter(2,EvtSpinType::SCALAR);
 
}
 
void EvtCBTo3piMPP::initProbMax(){
 
  setProbMax(1.5);
 
}
 
void EvtCBTo3piMPP::decay( EvtParticle *p ){
 
  //added by Lange Jan4,2000
  static EvtId BM=EvtPDL::getId("B-");
  static EvtId BP=EvtPDL::getId("B+");
 
  EvtParticle *pi1,*pi2,*pi3;
 
  p->makeDaughters(getNDaug(),getDaugs());
  pi1=p->getDaug(0);
  pi2=p->getDaug(1);
  pi3=p->getDaug(2);
 
  EvtVector4R p4[3];
  double alpha = getArg(0);
 
  int iset;
 
  static int first=1;
 
  if (first==1) {
    iset=10000;
    first=0;
  }
  else{
    iset=0;
  }
 
  double p4pi1[4],p4pi2[4],p4pi3[4]; 
 
  double realA,imgA,realbarA,imgbarA;
 
  evt3pionsmpp_(&alpha,&iset,p4pi1,p4pi2,p4pi3,
         &realA,&imgA,&realbarA,&imgbarA);
 
 
  p4[0].set(p4pi1[3],p4pi1[0],p4pi1[1],p4pi1[2]);
  p4[1].set(p4pi2[3],p4pi2[0],p4pi2[1],p4pi2[2]);
  p4[2].set(p4pi3[3],p4pi3[0],p4pi3[1],p4pi3[2]);
 
  pi1->init( getDaug(0), p4[0] );
  pi2->init( getDaug(1), p4[1] );
  pi3->init( getDaug(2), p4[2] );
 
  EvtComplex A(realA,imgA);
  EvtComplex Abar(realbarA, imgbarA);
 
   //amp is filled just to make sure the compiler will
   //do its job!! but one has to define amp differently
   // if one wants the B+ or the B- to decay to 3pi!
   // 
 
 
   EvtComplex  amp;
   if(p->getId()==BP)
     {
       amp = A;
     }
   if(p->getId()==BM)
     {
       amp = Abar;
     }  
 
   vertex(amp);
 
  return ;
}