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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: EvtSemiLeptonicScalarAmp.cc | |
12 | // | |
13 | // Description: Routine to implement semileptonic decays to pseudo-scalar | |
14 | // mesons. | |
15 | // | |
16 | // Modification history: | |
17 | // | |
18 | // DJL April 17,1998 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/EvtVector4C.hh" | |
29 | #include "EvtGenBase/EvtTensor4C.hh" | |
30 | #include "EvtGenBase/EvtDiracSpinor.hh" | |
31 | #include "EvtGenBase/EvtSemiLeptonicScalarAmp.hh" | |
32 | #include "EvtGenBase/EvtId.hh" | |
33 | #include "EvtGenBase/EvtAmp.hh" | |
34 | #include "EvtGenBase/EvtSemiLeptonicFF.hh" | |
35 | ||
36 | void EvtSemiLeptonicScalarAmp::CalcAmp( EvtParticle *parent, | |
37 | EvtAmp& amp, | |
38 | EvtSemiLeptonicFF *FormFactors ) { | |
39 | ||
40 | static EvtId EM=EvtPDL::getId("e-"); | |
41 | static EvtId MUM=EvtPDL::getId("mu-"); | |
42 | static EvtId TAUM=EvtPDL::getId("tau-"); | |
43 | static EvtId EP=EvtPDL::getId("e+"); | |
44 | static EvtId MUP=EvtPDL::getId("mu+"); | |
45 | static EvtId TAUP=EvtPDL::getId("tau+"); | |
46 | ||
47 | //Add the lepton and neutrino 4 momenta to find q2 | |
48 | ||
49 | EvtVector4R q = parent->getDaug(1)->getP4() | |
50 | + parent->getDaug(2)->getP4(); | |
51 | double q2 = (q.mass2()); | |
52 | ||
53 | double fpf,f0f; | |
54 | double mesonmass = parent->getDaug(0)->mass(); | |
55 | double parentmass = parent->mass(); | |
56 | ||
57 | FormFactors->getscalarff(parent->getId(), | |
58 | parent->getDaug(0)->getId(), | |
59 | q2, | |
60 | mesonmass, | |
61 | &fpf, | |
62 | &f0f); | |
63 | ||
64 | ||
65 | EvtVector4R p4b; | |
66 | p4b.set(parent->mass(),0.0,0.0,0.0); | |
67 | EvtVector4R p4meson = parent->getDaug(0)->getP4(); | |
68 | double mdiffoverq2; | |
69 | mdiffoverq2 = parentmass*parentmass - mesonmass*mesonmass; | |
70 | mdiffoverq2 = mdiffoverq2 / q2; | |
71 | ||
72 | EvtVector4C l1,l2; | |
73 | ||
74 | EvtId l_num = parent->getDaug(1)->getId(); | |
75 | EvtVector4C tds; | |
76 | ||
77 | if (l_num==EM||l_num==MUM||l_num==TAUM){ | |
78 | ||
79 | tds = EvtVector4C(fpf*(p4b+p4meson - (mdiffoverq2*(p4b-p4meson)))+ | |
80 | + f0f*mdiffoverq2*(p4b-p4meson)); | |
81 | ||
82 | l1=EvtLeptonVACurrent(parent->getDaug(1)->spParent(0), | |
83 | parent->getDaug(2)->spParentNeutrino()); | |
84 | l2=EvtLeptonVACurrent(parent->getDaug(1)->spParent(1), | |
85 | parent->getDaug(2)->spParentNeutrino()); | |
86 | } | |
87 | else{ | |
88 | if (l_num==EP||l_num==MUP||l_num==TAUP){ | |
89 | ||
90 | tds = EvtVector4C(fpf*(p4b+p4meson - (mdiffoverq2*(p4b-p4meson)))+ | |
91 | + f0f*mdiffoverq2*(p4b-p4meson)); | |
92 | ||
93 | l1=EvtLeptonVACurrent(parent->getDaug(2)->spParentNeutrino(), | |
94 | parent->getDaug(1)->spParent(0)); | |
95 | l2=EvtLeptonVACurrent(parent->getDaug(2)->spParentNeutrino(), | |
96 | parent->getDaug(1)->spParent(1)); | |
97 | } | |
98 | else{ | |
99 | report(ERROR,"EvtGen") << "dfnb89agngri wrong lepton number\n"; | |
100 | } | |
101 | } | |
102 | ||
103 | amp.vertex(0,l1*tds); | |
104 | amp.vertex(1,l2*tds); | |
105 | ||
106 | } | |
107 |