TEvtGen/EvtGenBase/EvtSemiLeptonicBaryonAmp.cxx

   1 //--------------------------------------------------------------------------
   2 //
   3 // Environment:
   4 //      This software is part of the EvtGen package developed jointly
   5 //      for the BaBar and CLEO collaborations.  If you use all or part
   6 //      of it, please give an appropriate acknowledgement.
   7 //
   8 // Copyright Information: See EvtGen/COPYRIGHT
   9 //      Copyright (C) 1998      Caltech, UCSB
  10 //
  11 // Module: EvtSemiLeptonicBaryonAmp.cc
  12 //
  13 // Description: Routine to implement semileptonic decays to vector
  14 //              mesons.
  15 //
  16 // Modification history:
  17 //
  18 //    Lange    Oct 20, 2004   Module created.
  19 //
  20 //------------------------------------------------------------------------
  21 //
  22 #include "EvtGenBase/EvtPatches.hh"
  23 #include "EvtGenBase/EvtPatches.hh"
  24 #include "EvtGenBase/EvtParticle.hh"
  25 #include "EvtGenBase/EvtGenKine.hh"
  26 #include "EvtGenBase/EvtPDL.hh"
  27 #include "EvtGenBase/EvtReport.hh"
  28 #include "EvtGenBase/EvtTensor4C.hh"
  29 #include "EvtGenBase/EvtVector4C.hh"
  30 #include "EvtGenBase/EvtDiracSpinor.hh"
  31 #include "EvtGenBase/EvtSemiLeptonicBaryonAmp.hh"
  32 #include "EvtGenBase/EvtId.hh"
  33 #include "EvtGenBase/EvtAmp.hh"
  34 #include "EvtGenBase/EvtSemiLeptonicFF.hh"
  35 #include "EvtGenBase/EvtGammaMatrix.hh"
  36 using std::endl;
  37
  38 void EvtSemiLeptonicBaryonAmp::CalcAmp( EvtParticle *parent,
  39                                         EvtAmp& amp,
  40                                         EvtSemiLeptonicFF *FormFactors ) {
  41
  42   static EvtId EM=EvtPDL::getId("e-");
  43   static EvtId MUM=EvtPDL::getId("mu-");
  44   static EvtId TAUM=EvtPDL::getId("tau-");
  45   static EvtId EP=EvtPDL::getId("e+");
  46   static EvtId MUP=EvtPDL::getId("mu+");
  47   static EvtId TAUP=EvtPDL::getId("tau+");
  48
  49
  50   //Add the lepton and neutrino 4 momenta to find q2
  51
  52   EvtVector4R q = parent->getDaug(1)->getP4()
  53                     + parent->getDaug(2)->getP4();
  54   double q2 = (q.mass2());
  55
  56   double f1v,f1a,f2v,f2a;
  57   double m_meson = parent->getDaug(0)->mass();
  58
  59   FormFactors->getbaryonff(parent->getId(),
  60                            parent->getDaug(0)->getId(),
  61                            q2,
  62                            m_meson,
  63                            &f1v,
  64                            &f1a,
  65                            &f2v,
  66                            &f2a);
  67
  68   EvtVector4R p4b;
  69   p4b.set(parent->mass(),0.0,0.0,0.0);
  70
  71   EvtVector4C temp_00_term1;
  72   EvtVector4C temp_00_term2;
  73
  74   EvtVector4C temp_01_term1;
  75   EvtVector4C temp_01_term2;
  76
  77   EvtVector4C temp_10_term1;
  78   EvtVector4C temp_10_term2;
  79
  80   EvtVector4C temp_11_term1;
  81   EvtVector4C temp_11_term2;
  82
  83   EvtDiracSpinor p0=parent->sp(0);
  84   EvtDiracSpinor p1=parent->sp(1);
  85
  86   EvtDiracSpinor d0=parent->getDaug(0)->spParent(0);
  87   EvtDiracSpinor d1=parent->getDaug(0)->spParent(1);
  88
  89   temp_00_term1.set(0,f1v*(d0*(EvtGammaMatrix::g0()*p0)));
  90   temp_00_term2.set(0,f1a*(d0*((EvtGammaMatrix::g0()*EvtGammaMatrix::g5())*p0)));
  91   temp_01_term1.set(0,f1v*(d0*(EvtGammaMatrix::g0()*p1)));
  92   temp_01_term2.set(0,f1a*(d0*((EvtGammaMatrix::g0()*EvtGammaMatrix::g5())*p1)));
  93   temp_10_term1.set(0,f1v*(d1*(EvtGammaMatrix::g0()*p0)));
  94   temp_10_term2.set(0,f1a*(d1*((EvtGammaMatrix::g0()*EvtGammaMatrix::g5())*p0)));
  95   temp_11_term1.set(0,f1v*(d1*(EvtGammaMatrix::g0()*p1)));
  96   temp_11_term2.set(0,f1a*(d1*((EvtGammaMatrix::g0()*EvtGammaMatrix::g5())*p1)));
  97
  98   temp_00_term1.set(1,f1v*(d0*(EvtGammaMatrix::g1()*p0)));
  99   temp_00_term2.set(1,f1a*(d0*((EvtGammaMatrix::g1()*EvtGammaMatrix::g5())*p0)));
 100   temp_01_term1.set(1,f1v*(d0*(EvtGammaMatrix::g1()*p1)));
 101   temp_01_term2.set(1,f1a*(d0*((EvtGammaMatrix::g1()*EvtGammaMatrix::g5())*p1)));
 102   temp_10_term1.set(1,f1v*(d1*(EvtGammaMatrix::g1()*p0)));
 103   temp_10_term2.set(1,f1a*(d1*((EvtGammaMatrix::g1()*EvtGammaMatrix::g5())*p0)));
 104   temp_11_term1.set(1,f1v*(d1*(EvtGammaMatrix::g1()*p1)));
 105   temp_11_term2.set(1,f1a*(d1*((EvtGammaMatrix::g1()*EvtGammaMatrix::g5())*p1)));
 106
 107   temp_00_term1.set(2,f1v*(d0*(EvtGammaMatrix::g2()*p0)));
 108   temp_00_term2.set(2,f1a*(d0*((EvtGammaMatrix::g2()*EvtGammaMatrix::g5())*p0)));
 109   temp_01_term1.set(2,f1v*(d0*(EvtGammaMatrix::g2()*p1)));
 110   temp_01_term2.set(2,f1a*(d0*((EvtGammaMatrix::g2()*EvtGammaMatrix::g5())*p1)));
 111   temp_10_term1.set(2,f1v*(d1*(EvtGammaMatrix::g2()*p0)));
 112   temp_10_term2.set(2,f1a*(d1*((EvtGammaMatrix::g2()*EvtGammaMatrix::g5())*p0)));
 113   temp_11_term1.set(2,f1v*(d1*(EvtGammaMatrix::g2()*p1)));
 114   temp_11_term2.set(2,f1a*(d1*((EvtGammaMatrix::g2()*EvtGammaMatrix::g5())*p1)));
 115
 116   temp_00_term1.set(3,f1v*(d0*(EvtGammaMatrix::g3()*p0)));
 117   temp_00_term2.set(3,f1a*(d0*((EvtGammaMatrix::g3()*EvtGammaMatrix::g5())*p0)));
 118   temp_01_term1.set(3,f1v*(d0*(EvtGammaMatrix::g3()*p1)));
 119   temp_01_term2.set(3,f1a*(d0*((EvtGammaMatrix::g3()*EvtGammaMatrix::g5())*p1)));
 120   temp_10_term1.set(3,f1v*(d1*(EvtGammaMatrix::g3()*p0)));
 121   temp_10_term2.set(3,f1a*(d1*((EvtGammaMatrix::g3()*EvtGammaMatrix::g5())*p0)));
 122   temp_11_term1.set(3,f1v*(d1*(EvtGammaMatrix::g3()*p1)));
 123   temp_11_term2.set(3,f1a*(d1*((EvtGammaMatrix::g3()*EvtGammaMatrix::g5())*p1)));
 124
 125
 126
 127   EvtVector4C l1,l2;
 128
 129   EvtId l_num = parent->getDaug(1)->getId();
 130   if (l_num==EM||l_num==MUM||l_num==TAUM){
 131
 132     l1=EvtLeptonVACurrent(parent->getDaug(1)->spParent(0),
 133                           parent->getDaug(2)->spParentNeutrino());
 134     l2=EvtLeptonVACurrent(parent->getDaug(1)->spParent(1),
 135                           parent->getDaug(2)->spParentNeutrino());
 136   }
 137   else{
 138     if (l_num==EP||l_num==MUP||l_num==TAUP){
 139     l1=EvtLeptonVACurrent(parent->getDaug(2)->spParentNeutrino(),
 140                             parent->getDaug(1)->spParent(0));
 141     l2=EvtLeptonVACurrent(parent->getDaug(2)->spParentNeutrino(),
 142                             parent->getDaug(1)->spParent(1));
 143     }
 144     else{
 145       report(ERROR,"EvtGen") << "Wrong lepton number"<<endl;
 146     }
 147   }
 148
 149   amp.vertex(0,0,0,l1.cont(temp_00_term1+temp_00_term2));
 150   amp.vertex(0,0,1,l2.cont(temp_00_term1+temp_00_term2));
 151
 152   amp.vertex(0,1,0,l1.cont(temp_01_term1+temp_01_term2));
 153   amp.vertex(0,1,1,l2.cont(temp_01_term1+temp_01_term2));
 154
 155   amp.vertex(1,0,0,l1.cont(temp_10_term1+temp_10_term2));
 156   amp.vertex(1,0,1,l2.cont(temp_10_term1+temp_10_term2));
 157
 158   amp.vertex(1,1,0,l1.cont(temp_11_term1+temp_11_term2));
 159   amp.vertex(1,1,1,l2.cont(temp_11_term1+temp_11_term2));
 160
 161   return;
 162 }
 163