EvtChi1BB2.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: EvtChi1BB2.cc
//
// Description: Routine to decay Chi1 to B10 B10bar.
//
// Modification history:
//
// Pang C.Y. and Ping R.-G.       April, 2007       Module created
//
//------------------------------------------------------------------------
//
#include "EvtChi1BB2.hh"
#include "../EvtGenBase/EvtGenKine.hh"
#include "../EvtGenBase/EvtHelSys.hh"
#include "../EvtGenBase/EvtPDL.hh"
#include "../EvtGenBase/EvtParticle.hh"
#include "../EvtGenBase/EvtPatches.hh"
#include "../EvtGenBase/EvtReport.hh"
#include "../EvtGenBase/EvtTensor4C.hh"
#include "../EvtGenBase/EvtVector4C.hh"
#include "../EvtGenBase/EvtVector4R.hh"
#include "../EvtGenBase/EvtdFunction.hh"
#include <stdlib.h>
#include <string>
using std::cout;
using std::endl;
EvtChi1BB2::~EvtChi1BB2() {}
 
void EvtChi1BB2::getName( std::string& model_name ) { model_name = "Chi1BB2"; }
 
EvtDecayBase* EvtChi1BB2::clone() { return new EvtChi1BB2; }
 
void EvtChi1BB2::init() {
  // check that there are 1 arguments
  checkNArg( 4 );
  checkNDaug( 2 );
  checkSpinParent( EvtSpinType::VECTOR );
  checkSpinDaughter( 0, EvtSpinType::RARITASCHWINGER );
  checkSpinDaughter( 1, EvtSpinType::RARITASCHWINGER );
}
 
/*
void EvtChi1BB2::initProbMax() {
 
  //Hard coded... should not be hard to calculate...
 setProbMax(50.0);
 
}
*/
 
void EvtChi1BB2::decay( EvtParticle* p ) {
 
  p->initializePhaseSpace( getNDaug(), getDaugs() );
 
  EvtParticle *v, *s1;
  EvtVector4R  pv, ps, ppr;
 
  v   = p->getDaug( 0 );
  s1  = p->getDaug( 1 );
  pv  = v->getP4();
  ps  = s1->getP4();
  ppr = p->getP4();
 
  //  Put phase space results into the daughters.
  EvtHelSys angles( ppr, pv ); // using helicity sys. angles
  double    theta = angles.getHelAng( 1 );
  double    phi   = angles.getHelAng( 2 );
  double    gamma = 0;
 
  /* double alpha=getArg(0);
   double F01=sqrt((1+alpha)/2);
   double F00=sqrt((1-alpha)/4);
  */
  double F00 = getArg( 0 );
  double F01 = getArg( 1 );
  double F03 = getArg( 2 );
  double F11 = getArg( 3 );
  double F33 = -F00;
  double F32 = -F01;
  double F30 = -F03;
  double F10 = F01;
  double F23 = -F10;
  double F22 = -F11;
  // cout<<"********F00,F01,F03,F10,F11,F22,F23,F30,F32,F33="<<F00<<F01<<F03<<F10<<F11<<F22<<F23<<F30<<F32<<F33<<endl;
  /*cout<<"********Djmn(1, 1, 0,phi,theta,gamma)="<<Djmn(1, 1, 0,phi,theta,gamma);
  cout<<"********Djmn(1, 1,-1,phi,theta,gamma)="<<Djmn(1, 1,-1,phi,theta,gamma);
  cout<<"********Djmn(1, 1, 1,phi,theta,gamma)="<<Djmn(1, 1, 1,phi,theta,gamma);
  */
  int j1, j2, j3;
  for ( j1 = 0; j1 <= 2; )
  {
    for ( j2 = 0; j2 <= 3; )
    {
      for ( j3 = 0; j3 <= 3; )
      {
        vertex( j1, j2, j3, 0.0 );
        j3++;
      }
      j2++;
    }
    j1++;
  }
 
  vertex( 0, 0, 0, Djmn( 1, 1, 0, phi, theta, gamma ) * F00 ); // Chi1  helicity =1
                                                               // corresponding index=0
  vertex( 0, 0, 1, Djmn( 1, 1, -1, phi, theta, gamma ) * F01 );
  vertex( 0, 0, 3, Djmn( 1, 1, 1, phi, theta, gamma ) * F03 );
  vertex( 0, 1, 0, Djmn( 1, 1, 1, phi, theta, gamma ) * F10 );
  vertex( 0, 1, 1, Djmn( 1, 1, 0, phi, theta, gamma ) * F11 );
  vertex( 0, 2, 2, Djmn( 1, 1, 0, phi, theta, gamma ) * F22 );
  vertex( 0, 2, 3, Djmn( 1, 1, -1, phi, theta, gamma ) * F23 );
  vertex( 0, 3, 0, Djmn( 1, 1, -1, phi, theta, gamma ) * F30 );
  vertex( 0, 3, 2, Djmn( 1, 1, 1, phi, theta, gamma ) * F32 );
  vertex( 0, 3, 3, Djmn( 1, 1, 0, phi, theta, gamma ) * F33 );
 
  vertex( 1, 0, 0, Djmn( 1, -1, 0, phi, theta, gamma ) * F00 ); // Chi1  helicity =-1
                                                                // corresponding index=1
  vertex( 1, 0, 1, Djmn( 1, -1, -1, phi, theta, gamma ) * F01 );
  vertex( 1, 0, 3, Djmn( 1, -1, 1, phi, theta, gamma ) * F03 );
  vertex( 1, 1, 0, Djmn( 1, -1, 1, phi, theta, gamma ) * F10 );
  vertex( 1, 1, 1, Djmn( 1, -1, 0, phi, theta, gamma ) * F11 );
  vertex( 1, 2, 2, Djmn( 1, -1, 0, phi, theta, gamma ) * F22 );
  vertex( 1, 2, 3, Djmn( 1, -1, -1, phi, theta, gamma ) * F23 );
  vertex( 1, 3, 0, Djmn( 1, -1, -1, phi, theta, gamma ) * F30 );
  vertex( 1, 3, 2, Djmn( 1, -1, 1, phi, theta, gamma ) * F32 );
  vertex( 1, 3, 3, Djmn( 1, -1, 0, phi, theta, gamma ) * F33 );
 
  vertex( 2, 0, 0, Djmn( 1, 0, 0, phi, theta, gamma ) * F00 ); // Chi1  helicity =0
                                                               // corresponding index=2
  vertex( 2, 0, 1, Djmn( 1, 0, -1, phi, theta, gamma ) * F01 );
  vertex( 2, 0, 3, Djmn( 1, 0, 1, phi, theta, gamma ) * F03 );
  vertex( 2, 1, 0, Djmn( 1, 0, 1, phi, theta, gamma ) * F10 );
  vertex( 2, 1, 1, Djmn( 1, 0, 0, phi, theta, gamma ) * F11 );
  vertex( 2, 2, 2, Djmn( 1, 0, 0, phi, theta, gamma ) * F22 );
  vertex( 2, 2, 3, Djmn( 1, 0, -1, phi, theta, gamma ) * F23 );
  vertex( 2, 3, 0, Djmn( 1, 0, -1, phi, theta, gamma ) * F30 );
  vertex( 2, 3, 2, Djmn( 1, 0, 1, phi, theta, gamma ) * F32 );
  vertex( 2, 3, 3, Djmn( 1, 0, 0, phi, theta, gamma ) * F33 );
 
  return;
}