EvtSVSCPiso.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: EvtSVSCPiso.cc
//
// Description: Routine to decay scalar -> vectors scalar
//              with CP violation and isospin amplitudes.
//              More specifically, it is indended to handle
//              decays like B->rho pi and B->a1 pi.
//
// Modification history:
//
//    RYD/NK    Febuary 16, 1998          Module created
//
//------------------------------------------------------------------------
// 
#include "EvtGenBase/EvtPatches.hh"
#include <stdlib.h>
#include "EvtGenBase/EvtParticle.hh"
#include "EvtGenBase/EvtRandom.hh"
#include "EvtGenBase/EvtGenKine.hh"
#include "EvtGenBase/EvtCPUtil.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtReport.hh"
#include "EvtGenBase/EvtVector4C.hh"
#include "EvtGenModels/EvtSVSCPiso.hh"
#include "EvtGenBase/EvtId.hh"
#include <string>
#include "EvtGenBase/EvtConst.hh"
 
EvtSVSCPiso::~EvtSVSCPiso() {}
 
void EvtSVSCPiso::getName(std::string& model_name){
 
  model_name="SVS_CP_ISO";     
 
}
 
 
EvtDecayBase* EvtSVSCPiso::clone(){
 
  return new EvtSVSCPiso;
 
}
 
void EvtSVSCPiso::init(){
 
  // check that there are 26 arguments
  checkNArg(26);
  checkNDaug(2);
 
  checkSpinParent(EvtSpinType::SCALAR);
 
  checkSpinDaughter(0,EvtSpinType::VECTOR);
  checkSpinDaughter(1,EvtSpinType::SCALAR);
 
}
 
 
void EvtSVSCPiso::initProbMax(){
 
//this might need some revision..
 
if ((EvtPDL::chg3(getDaug(0)) > 0) && (EvtPDL::chg3(getDaug(1)) == 0)) {
  setProbMax(2.0*(getArg(3)*getArg(3) + 4.0*getArg(23)*getArg(23)));
}
 
if ((EvtPDL::chg3(getDaug(0)) < 0) && (EvtPDL::chg3(getDaug(1)) == 0)) {
  setProbMax(2.0*(getArg(5)*getArg(5) + 4.0*getArg(25)*getArg(25)));
}
 
if ((EvtPDL::chg3(getDaug(0)) == 0) && (EvtPDL::chg3(getDaug(1)) > 0)) {
  setProbMax(2.0*(getArg(7)*getArg(7) + 4.0*getArg(23)*getArg(23)));
}
 
if ((EvtPDL::chg3(getDaug(0)) == 0) && (EvtPDL::chg3(getDaug(1)) < 0)) {
  setProbMax(2.0*(getArg(9)*getArg(9) + 4.0*getArg(25)*getArg(25)));
}
 
if ((EvtPDL::chg3(getDaug(0)) > 0) && (EvtPDL::chg3(getDaug(1)) < 0)) {
  setProbMax(2.0*(getArg(11)*getArg(11) + getArg(23)*getArg(23) + 
                  getArg(19)*getArg(19) + getArg(13)*getArg(13) + 
                  getArg(25)*getArg(25) + getArg(21)*getArg(21)));
}
 
if ((EvtPDL::chg3(getDaug(0)) < 0) && (EvtPDL::chg3(getDaug(1)) > 0)) {
  setProbMax(2.0*(getArg(15)*getArg(15) + getArg(23)*getArg(23) + 
                  getArg(19)*getArg(19) + getArg(17)*getArg(17) + 
                  getArg(25)*getArg(25) + getArg(21)*getArg(21)));
}
 
if ((EvtPDL::chg3(getDaug(0)) == 0) && (EvtPDL::chg3(getDaug(1)) == 0)) {
   setProbMax(2.0*(getArg(7)*getArg(7) + getArg(3)*getArg(3) + getArg(11)*getArg(11) + 
                  getArg(15)*getArg(15) + 4.0*getArg(19)*getArg(19) + getArg(9)*getArg(9)+
                   getArg(5)*getArg(5) + getArg(13)*getArg(13) + getArg(17)*getArg(17) + 
                   4.0*getArg(21)*getArg(21)));
}
 
}
 
 
void EvtSVSCPiso::decay( EvtParticle *p){
 
  //added by Lange Jan4,2000
  static EvtId B0=EvtPDL::getId("B0");
  static EvtId B0B=EvtPDL::getId("anti-B0");
 
  double t;
  EvtId other_b;
  int charged(0);
 
  int first_time=0;
  int flip=0;
  EvtId ds[2];
 
 
//randomly generate the tag (B0 or B0B) 
 
   double tag = EvtRandom::Flat(0.0,1.0);
   if (tag < 0.5) {
 
    EvtCPUtil::OtherB(p,t,other_b,1.0);
    other_b = B0;
   }
   else {
    
    EvtCPUtil::OtherB(p,t,other_b,0.0);
    other_b = B0B;
   }
 
  if (p->getNDaug()==0) first_time=1;
 
  if (first_time){
    if (EvtRandom::Flat(0.0,1.0)<getArg(3)) flip=1;
  }
  else{
    if (getDaug(0)!=p->getDaug(0)->getId()) flip=1;
  }
 
  if (!flip) {
    ds[0]=getDaug(0);
    ds[1]=getDaug(1);
  }
  else{
    ds[0]=EvtPDL::chargeConj(getDaug(0));
    ds[1]=EvtPDL::chargeConj(getDaug(1));
  }
 
  p->initializePhaseSpace(getNDaug(),ds);
 
  EvtParticle *v,*s;
  v=p->getDaug(0);
  s=p->getDaug(1);
 
   EvtComplex amp;
 
   EvtComplex A_f,Abar_f;
   EvtComplex A_fbar,Abar_fbar;
   EvtComplex Apm, Apm_bar, Amp, Amp_bar;
 
   EvtComplex Tp0, Tp0_bar, T0p, T0p_bar,Tpm, Tpm_bar, Tmp, Tmp_bar;
   EvtComplex P1, P1_bar, P0, P0_bar;
 
   Tp0 = EvtComplex(getArg(3)*cos(getArg(4)),getArg(3)*sin(getArg(4)));
   Tp0_bar = EvtComplex(getArg(5)*cos(getArg(6)),getArg(5)*sin(getArg(6)));
   T0p = EvtComplex(getArg(7)*cos(getArg(8)),getArg(7)*sin(getArg(8)));
   T0p_bar = EvtComplex(getArg(9)*cos(getArg(10)),getArg(9)*sin(getArg(10)));
   Tpm = EvtComplex(getArg(11)*cos(getArg(12)),getArg(11)*sin(getArg(12)));
   Tpm_bar = EvtComplex(getArg(13)*cos(getArg(14)),getArg(13)*sin(getArg(14)));
   Tmp = EvtComplex(getArg(15)*cos(getArg(16)),getArg(15)*sin(getArg(16)));
   Tmp_bar = EvtComplex(getArg(17)*cos(getArg(18)),getArg(17)*sin(getArg(18)));
   P0 = EvtComplex(getArg(19)*cos(getArg(20)),getArg(19)*sin(getArg(20)));
   P0_bar = EvtComplex(getArg(21)*cos(getArg(22)),getArg(21)*sin(getArg(22)));
   P1 = EvtComplex(getArg(23)*cos(getArg(24)),getArg(23)*sin(getArg(24)));
   P1_bar = EvtComplex(getArg(25)*cos(getArg(26)),getArg(25)*sin(getArg(26)));
 
 
//***********************charged modes****************************
 
 if ((EvtPDL::chg3(getDaug(0)) > 0 ) && (EvtPDL::chg3(getDaug(1)) == 0)) {
 
//V+ S0, so T+0 + 2 P1
   
   charged = 1;
   A_f = Tp0 + 2.0*P1;
 }
 
 if ((EvtPDL::chg3(getDaug(0)) < 0 ) && (EvtPDL::chg3(getDaug(1)) == 0)) {
 
//V- S0, so T+0_bar + 2P1_bar
   
   charged = 1;
   A_f = Tp0_bar + 2.0*P1_bar; 
 }
 
 if ((EvtPDL::chg3(getDaug(0)) == 0 ) && (EvtPDL::chg3(getDaug(1)) > 0)) {
 
//V0 S+, so T0+ - 2 P1
 
   charged = 1;
   A_f = T0p - 2.0*P1;
 }
 
 if ((EvtPDL::chg3(getDaug(0)) == 0 ) && (EvtPDL::chg3(getDaug(1)) < 0)) {
 
//V0 S-, so T0+_bar - 2 P1_bar
 
   charged = 1;
   A_f = T0p_bar - 2.0*P1_bar;
 }
 
 
//***********************neutral modes***************************
 
 
//V+ S-, so Af = T+- + P1 + P0
Apm = Tpm + P1 + P0;
Apm_bar = Tpm_bar + P1_bar + P0_bar;
 
//V- S+, so Af = T-+ - P1 + P0
Amp = Tmp - P1 + P0;
Amp_bar = Tmp_bar - P1_bar + P0;
 
 
 if ((EvtPDL::chg3(getDaug(0)) > 0 ) && (EvtPDL::chg3(getDaug(1)) < 0)) {
 
//V+ S-
   charged = 0;
   A_f = Apm; 
   Abar_f = Apm_bar;
   A_fbar = Amp;
   Abar_fbar = Amp_bar;
 
 }
 
 if ((EvtPDL::chg3(getDaug(0)) < 0 ) && (EvtPDL::chg3(getDaug(1)) > 0)) {
 
//V- S+
   charged = 0;
   A_f = Amp; 
   Abar_f = Amp_bar;
   A_fbar = Apm;
   Abar_fbar = Apm_bar;
 
 }
 
 if ((EvtPDL::chg3(getDaug(0)) == 0 ) && (EvtPDL::chg3(getDaug(1)) == 0)) {
 
//V0 S0
   charged = 0;
   A_f = T0p + Tp0 - Tpm - Tmp - 2.0*P0 ; 
   Abar_f = T0p_bar + Tp0_bar - Tpm_bar - Tmp_bar - 2.0*P0_bar;
   A_fbar = A_f;
   Abar_fbar = Abar_f;
 
 }
 
if (charged==0) {
   
   if (!flip) {
     if (other_b==B0B){
 
       amp=A_f*cos(getArg(1)*t/(2*EvtConst::c))+
     EvtComplex(cos(-2.0*getArg(0)),sin(-2.0*getArg(0)))*
     EvtComplex(0.0,1.0)*Abar_f*sin(getArg(1)*t/(2*EvtConst::c));
     }
     if (other_b==B0){
            
       amp=A_f*EvtComplex(cos(2.0*getArg(0)),sin(2.0*getArg(0)))*
     EvtComplex(0.0,1.0)*sin(getArg(1)*t/(2*EvtConst::c))+       
     Abar_f*cos(getArg(1)*t/(2*EvtConst::c));
     }
   }
   else{
     if (other_b==B0B){
 
       amp=A_fbar*cos(getArg(1)*t/(2*EvtConst::c))+
     EvtComplex(cos(-2.0*getArg(0)),sin(-2.0*getArg(0)))*
     EvtComplex(0.0,1.0)*Abar_fbar*sin(getArg(1)*t/(2*EvtConst::c));
     }
     if (other_b==B0){
 
       amp=A_fbar*EvtComplex(cos(2.0*getArg(0)),sin(2.0*getArg(0)))*
     EvtComplex(0.0,1.0)*sin(getArg(1)*t/(2*EvtConst::c))+       
     Abar_fbar*cos(getArg(1)*t/(2*EvtConst::c));
     }
   }
 
}
else amp = A_f;
 
  EvtVector4R p4_parent;
 
  p4_parent=v->getP4()+s->getP4();
 
  double norm=1.0/v->getP4().d3mag();
 
   vertex(0,amp*norm*p4_parent*(v->epsParent(0)));
   vertex(1,amp*norm*p4_parent*(v->epsParent(1)));
   vertex(2,amp*norm*p4_parent*(v->epsParent(2)));
 
  return ;
}