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da0e9ce3 | 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: EvtVSSMix.cc | |
12 | // | |
13 | // Description: Routine to decay vector-> scalar scalar | |
14 | // | |
15 | // Modification history: | |
16 | // | |
17 | // RYD November 24, 1996 Module created | |
18 | // | |
19 | //------------------------------------------------------------------------ | |
20 | // | |
21 | #include "EvtGenBase/EvtPatches.hh" | |
22 | #include <stdlib.h> | |
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" | |
30 | #include <string> | |
31 | #include "EvtGenBase/EvtConst.hh" | |
32 | ||
33 | EvtVSSMix::~EvtVSSMix() {} | |
34 | ||
35 | std::string EvtVSSMix::getName(){ | |
36 | ||
37 | return "VSS_MIX"; | |
38 | ||
39 | } | |
40 | ||
41 | ||
42 | EvtDecayBase* EvtVSSMix::clone(){ | |
43 | ||
44 | return new EvtVSSMix; | |
45 | ||
46 | } | |
47 | ||
48 | void EvtVSSMix::init(){ | |
49 | ||
50 | // check that there are 1 arguments | |
51 | checkNArg(1); | |
52 | checkNDaug(2); | |
53 | ||
54 | checkSpinParent(EvtSpinType::VECTOR); | |
55 | ||
56 | checkSpinDaughter(0,EvtSpinType::SCALAR); | |
57 | checkSpinDaughter(1,EvtSpinType::SCALAR); | |
58 | ||
59 | } | |
60 | ||
61 | void EvtVSSMix::initProbMax(){ | |
62 | ||
63 | setProbMax(0.5); | |
64 | ||
65 | } | |
66 | ||
67 | void EvtVSSMix::decay( EvtParticle *p ){ | |
68 | ||
69 | //added by Lange Jan4,2000 | |
70 | static EvtId B0=EvtPDL::getId("B0"); | |
71 | static EvtId B0B=EvtPDL::getId("anti-B0"); | |
72 | ||
73 | p->initializePhaseSpace(getNDaug(),getDaugs()); | |
74 | EvtParticle *s1,*s2; | |
75 | s1 = p->getDaug(0); | |
76 | s2 = p->getDaug(1); | |
77 | EvtVector4R s1mom = s1->getP4(); | |
78 | ||
79 | double t1,t2,dm; | |
80 | ||
81 | s1->setLifetime(); | |
82 | s2->setLifetime(); | |
83 | ||
84 | t1=s1->getLifetime(); | |
85 | t2=s2->getLifetime(); | |
86 | ||
87 | //dm should probably be a parameter to this model. | |
88 | ||
89 | dm=getArg(0)/EvtConst::c; | |
90 | ||
91 | EvtId d1,d2; | |
92 | ||
93 | d1=s1->getId(); | |
94 | d2=s2->getId(); | |
95 | ||
96 | double mix_amp=0.; | |
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)); | |
101 | ||
102 | double norm=1.0/s1mom.d3mag(); | |
103 | ||
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))); | |
107 | ||
108 | return ; | |
109 | } | |
110 |