1 //--------------------------------------------------------------------------
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.
8 // Copyright Information: See EvtGen/COPYRIGHT
9 // Copyright (C) 1998 Caltech, UCSB
11 // Module: EvtTauVectornu.cc
13 // Description: The vector decay of the tau meson.
14 // E.g., tau- -> rho- + nut
16 // Modification history:
18 // RYD/SHY April 23, 1997 Module created
20 //------------------------------------------------------------------------
22 #include "EvtGenBase/EvtPatches.hh"
26 #include "EvtGenBase/EvtParticle.hh"
27 #include "EvtGenBase/EvtPDL.hh"
28 #include "EvtGenBase/EvtGenKine.hh"
29 #include "EvtGenModels/EvtTauVectornu.hh"
30 #include "EvtGenBase/EvtDiracSpinor.hh"
31 #include "EvtGenBase/EvtReport.hh"
32 #include "EvtGenBase/EvtVector4C.hh"
34 EvtTauVectornu::~EvtTauVectornu() {}
36 std::string EvtTauVectornu::getName(){
43 EvtDecayBase* EvtTauVectornu::clone(){
45 return new EvtTauVectornu;
49 void EvtTauVectornu::init(){
51 // check that there are 0 arguments
55 checkSpinParent(EvtSpinType::DIRAC);
57 checkSpinDaughter(0,EvtSpinType::VECTOR);
58 checkSpinDaughter(1,EvtSpinType::NEUTRINO);
61 void EvtTauVectornu::initProbMax(){
67 void EvtTauVectornu::decay(EvtParticle *p){
69 static EvtId TAUM=EvtPDL::getId("tau-");
70 p->initializePhaseSpace(getNDaug(),getDaugs());
75 double mvec = v->mass();
76 EvtVector4C tau1, tau2;
78 if (p->getId()==TAUM) {
79 tau1=EvtLeptonVACurrent(nut->spParentNeutrino(),p->sp(0));
80 tau2=EvtLeptonVACurrent(nut->spParentNeutrino(),p->sp(1));
83 tau1=EvtLeptonVACurrent(p->sp(0),nut->spParentNeutrino());
84 tau2=EvtLeptonVACurrent(p->sp(1),nut->spParentNeutrino());
87 double norm=mvec*sqrt(mvec);
89 vertex(0,0,norm*tau1*(v->epsParent(0).conj()));
90 vertex(0,1,norm*tau1*(v->epsParent(1).conj()));
91 vertex(0,2,norm*tau1*(v->epsParent(2).conj()));
92 vertex(1,0,norm*tau2*(v->epsParent(0).conj()));
93 vertex(1,1,norm*tau2*(v->epsParent(1).conj()));
94 vertex(1,2,norm*tau2*(v->epsParent(2).conj()));