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: EvtVSSMix.cc
13 // Description: Routine to decay vector-> scalar scalar
15 // Modification history:
17 // RYD November 24, 1996 Module created
19 //------------------------------------------------------------------------
21 #include "EvtGenBase/EvtPatches.hh"
23 #include "EvtGenBase/EvtParticle.hh"
24 #include "EvtGenBase/EvtGenKine.hh"
25 #include "EvtGenBase/EvtPDL.hh"
26 #include "EvtGenBase/EvtReport.hh"
27 #include "EvtGenBase/EvtVector4C.hh"
28 #include "EvtGenModels/EvtVSSMix.hh"
29 #include "EvtGenBase/EvtId.hh"
31 #include "EvtGenBase/EvtConst.hh"
33 EvtVSSMix::~EvtVSSMix() {}
35 std::string EvtVSSMix::getName(){
42 EvtDecayBase* EvtVSSMix::clone(){
48 void EvtVSSMix::init(){
50 // check that there are 1 arguments
54 checkSpinParent(EvtSpinType::VECTOR);
56 checkSpinDaughter(0,EvtSpinType::SCALAR);
57 checkSpinDaughter(1,EvtSpinType::SCALAR);
61 void EvtVSSMix::initProbMax(){
67 void EvtVSSMix::decay( EvtParticle *p ){
69 //added by Lange Jan4,2000
70 static EvtId B0=EvtPDL::getId("B0");
71 static EvtId B0B=EvtPDL::getId("anti-B0");
73 p->initializePhaseSpace(getNDaug(),getDaugs());
77 EvtVector4R s1mom = s1->getP4();
87 //dm should probably be a parameter to this model.
89 dm=getArg(0)/EvtConst::c;
97 if (d1==B0&&d2==B0B) mix_amp=cos(0.5*dm*(t1-t2));
98 if (d1==B0B&&d2==B0) mix_amp=cos(0.5*dm*(t1-t2));
99 if (d1==B0&&d2==B0) mix_amp=sin(0.5*dm*(t1-t2));
100 if (d1==B0B&&d2==B0B) mix_amp=sin(0.5*dm*(t1-t2));
102 double norm=1.0/s1mom.d3mag();
104 vertex(0,norm*mix_amp*s1mom*(p->eps(0)));
105 vertex(1,norm*mix_amp*s1mom*(p->eps(1)));
106 vertex(2,norm*mix_amp*s1mom*(p->eps(2)));