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0ca57c2f | 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: EvtTVP.cc | |
12 | // | |
13 | // Description: Routine to implement radiative decay chi_c2 -> psi gamma | |
14 | // matrix element from [S.P Baranov et al, PRD 85, 014034 (2012)] | |
15 | // | |
16 | // Modification history: | |
17 | // AVL 6 July, 2012 Module created | |
18 | // | |
19 | //------------------------------------------------------------------------ | |
20 | // | |
21 | #include "EvtGenBase/EvtPatches.hh" | |
22 | #include <stdlib.h> | |
23 | #include "EvtGenBase/EvtParticle.hh" | |
24 | #include "EvtGenBase/EvtTensorParticle.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 | ||
31 | ||
32 | #include "EvtGenModels/EvtTVP.hh" | |
33 | ||
34 | ||
35 | #include <string> | |
36 | #include <iostream> | |
37 | ||
38 | using namespace std; | |
39 | ||
40 | ||
41 | ||
42 | EvtTVP::~EvtTVP() { | |
43 | // cout<<"(* AVL EvtTVP::destructor getProbMax(-1) = "<<getProbMax(-1)<<" *)"<<endl; | |
44 | // cout<<"(* AVL EvtTVP::destructor "<<ncall<<" calls *)"<<endl; | |
45 | } | |
46 | ||
47 | std::string EvtTVP::getName(){ | |
48 | return "TVP"; | |
49 | } | |
50 | ||
51 | ||
52 | EvtDecayBase* EvtTVP::clone(){ | |
53 | // cout<<" (* AVL: === EvtTVP::clone() ============ *)"<<endl; | |
54 | return new EvtTVP; | |
55 | ||
56 | } | |
57 | ||
58 | void EvtTVP::decay( EvtParticle *root ){ | |
59 | ncall++; | |
60 | // cout<<" (* AVL EvtTVP::decay() ============ *)"<<endl; | |
61 | double amp2=0; | |
62 | root ->initializePhaseSpace(getNDaug(),getDaugs()); | |
63 | ||
64 | EvtVector4R p = root->getDaug(1)->getP4(), // J/psi momentum | |
65 | k = root->getDaug(0)->getP4(); // Photon momentum | |
66 | /* | |
67 | cout<<"(* AVL *) p="<<p<<endl; | |
68 | cout<<"(* AVL *) k="<<k<<endl;*/ | |
69 | ||
70 | for(int iPsi = 0; iPsi < 4; iPsi++) { | |
71 | for(int iGamma = 0; iGamma < 1; iGamma++) { | |
72 | for(int iChi = 0; iChi<4; iChi++) { | |
73 | EvtTensor4C epsChi = root->epsTensor(iChi); | |
74 | EvtVector4C epsPsi = root->getDaug(1)->epsParent(iPsi).conj(); | |
75 | EvtVector4C epsGamma = root->getDaug(0)->epsParentPhoton(iGamma).conj(); | |
76 | ||
77 | // [Baranov, (11) | |
78 | // matr = p^mu epsPsi^a epsChi_{a b} ( k_mu epsGamma_b - k_b epsGamma_mu | |
79 | ||
80 | ||
81 | EvtVector4C eee = epsChi.cont1(epsPsi); | |
82 | EvtVector4C vvv = (p*k)*eee - (k*eee)*p; | |
83 | // cout <<" (* AVL: ginv "<<(vvv*k)<<" *) "<<endl; | |
84 | EvtComplex amp = vvv*epsGamma; | |
85 | ||
86 | // cout << "(* AVL *) amp="<<amp<<endl; | |
87 | vertex(iChi, iGamma, iPsi, amp); | |
88 | amp2 = amp2 + abs2(amp); | |
89 | }; | |
90 | }; | |
91 | }; | |
92 | // cout <<"(* AVL: amp2 = "<<amp2<<"*)"<<endl; | |
93 | ||
94 | } | |
95 | ||
96 | ||
97 | void EvtTVP::init(){ | |
98 | // cout<<" (* AVL: ==== EvtTVP::init() ============ *)"<<endl; | |
99 | ||
100 | ncall = 0; | |
101 | ||
102 | checkNArg(0); | |
103 | checkNDaug(2); | |
104 | ||
105 | ||
106 | checkSpinParent(EvtSpinType::TENSOR); | |
107 | ||
108 | checkSpinDaughter(0,EvtSpinType::PHOTON); | |
109 | checkSpinDaughter(1,EvtSpinType::VECTOR); | |
110 | ||
111 | } | |
112 | ||
113 | void EvtTVP::initProbMax() { | |
114 | setProbMax(1.); | |
115 | }; | |
116 |