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
13 // Description: The decay of a scalar meson to two leptons,
14 // or generally, two spin 1/2 particles.
15 // E.g., B0 -> tau+ tau-
17 // Modification history:
19 // SHY April 23, 1997 Module created
21 //------------------------------------------------------------------------
23 #include "EvtGenBase/EvtPatches.hh"
27 #include "EvtGenBase/EvtParticle.hh"
28 #include "EvtGenBase/EvtPDL.hh"
29 #include "EvtGenBase/EvtGenKine.hh"
30 #include "EvtGenModels/EvtSll.hh"
31 #include "EvtGenBase/EvtDiracSpinor.hh"
32 #include "EvtGenBase/EvtReport.hh"
33 #include "EvtGenBase/EvtVector4C.hh"
37 std::string EvtSll::getName(){
44 EvtDecayBase* EvtSll::clone(){
52 // check that there are 0 arguments
56 checkSpinParent(EvtSpinType::SCALAR);
58 checkSpinDaughter(0,EvtSpinType::DIRAC);
59 checkSpinDaughter(1,EvtSpinType::DIRAC);
63 void EvtSll::decay(EvtParticle *p){
66 p->initializePhaseSpace(getNDaug(),getDaugs());
72 p4_p.set(p->mass(),0.0,0.0,0.0);
74 EvtVector4C l11, l12, l21, l22;
76 l11=EvtLeptonVACurrent(l1->spParent(0),l2->spParent(0));
77 l12=EvtLeptonVACurrent(l1->spParent(0),l2->spParent(1));
78 l21=EvtLeptonVACurrent(l1->spParent(1),l2->spParent(0));
79 l22=EvtLeptonVACurrent(l1->spParent(1),l2->spParent(1));