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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: EvtVectorParticle.cc | |
12 | // | |
13 | // Description: Class to describe spin 1 particles | |
14 | // | |
15 | // Modification history: | |
16 | // | |
17 | // DJL/RYD September 25, 1996 Module created | |
18 | // | |
19 | //------------------------------------------------------------------------ | |
20 | // | |
21 | #include "EvtGenBase/EvtPatches.hh" | |
22 | #include <stdlib.h> | |
23 | #include <iostream> | |
24 | #include <math.h> | |
25 | #include "EvtGenBase/EvtComplex.hh" | |
26 | #include "EvtGenBase/EvtVectorParticle.hh" | |
27 | #include "EvtGenBase/EvtVector4C.hh" | |
28 | #include "EvtGenBase/EvtPDL.hh" | |
29 | #include "EvtGenBase/EvtReport.hh" | |
30 | ||
31 | EvtVectorParticle::~EvtVectorParticle(){} | |
32 | ||
33 | ||
34 | void EvtVectorParticle::init(EvtId part_n,double e,double px,double py,double pz){ | |
35 | ||
36 | _validP4=true; | |
37 | setp(e,px,py,pz); | |
38 | setpart_num(part_n); | |
39 | ||
40 | _eps[0].set(0.0,1.0,0.0,0.0); | |
41 | _eps[1].set(0.0,0.0,1.0,0.0); | |
42 | _eps[2].set(0.0,0.0,0.0,1.0); | |
43 | ||
44 | setLifetime(); | |
45 | } | |
46 | ||
47 | void EvtVectorParticle::init(EvtId part_n,const EvtVector4R& p4){ | |
48 | ||
49 | _validP4=true; | |
50 | setp(p4); | |
51 | setpart_num(part_n); | |
52 | ||
53 | _eps[0].set(0.0,1.0,0.0,0.0); | |
54 | _eps[1].set(0.0,0.0,1.0,0.0); | |
55 | _eps[2].set(0.0,0.0,0.0,1.0); | |
56 | setLifetime(); | |
57 | } | |
58 | ||
59 | void EvtVectorParticle::init(EvtId part_n,const EvtVector4R& p4, | |
60 | const EvtVector4C & epsin1, | |
61 | const EvtVector4C & epsin2, | |
62 | const EvtVector4C & epsin3){ | |
63 | ||
64 | _validP4=true; | |
65 | setp(p4); | |
66 | setpart_num(part_n); | |
67 | ||
68 | _eps[0]=epsin1; | |
69 | _eps[1]=epsin2; | |
70 | _eps[2]=epsin3; | |
71 | ||
72 | setLifetime(); | |
73 | } | |
74 | ||
75 | ||
76 | ||
77 | EvtSpinDensity EvtVectorParticle::rotateToHelicityBasis() const{ | |
78 | ||
79 | static EvtVector4C eplus(0.0,-1.0/sqrt(2.0),EvtComplex(0.0,-1.0/sqrt(2.0)),0.0); | |
80 | static EvtVector4C ezero(0.0,0.0,0.0,1.0); | |
81 | static EvtVector4C eminus(0.0,1.0/sqrt(2.0),EvtComplex(0.0,-1.0/sqrt(2.0)),0.0); | |
82 | ||
83 | static EvtVector4C eplusC(eplus.conj()); | |
84 | static EvtVector4C ezeroC(ezero.conj()); | |
85 | static EvtVector4C eminusC(eminus.conj()); | |
86 | ||
87 | EvtSpinDensity R; | |
88 | R.setDim(3); | |
89 | ||
90 | for ( int i=0; i<3; i++ ) { | |
91 | R.set(0,i,(eplusC)*_eps[i]); | |
92 | R.set(1,i,(ezeroC)*_eps[i]); | |
93 | R.set(2,i,(eminusC)*_eps[i]); | |
94 | } | |
95 | ||
96 | return R; | |
97 | ||
98 | } | |
99 | ||
100 | ||
101 | EvtSpinDensity EvtVectorParticle::rotateToHelicityBasis(double alpha, | |
102 | double beta, | |
103 | double gamma) const{ | |
104 | ||
105 | EvtVector4C eplus(0.0,-1.0/sqrt(2.0),EvtComplex(0.0,-1.0/sqrt(2.0)),0.0); | |
106 | EvtVector4C ezero(0.0,0.0,0.0,1.0); | |
107 | EvtVector4C eminus(0.0,1.0/sqrt(2.0),EvtComplex(0.0,-1.0/sqrt(2.0)),0.0); | |
108 | ||
109 | eplus.applyRotateEuler(alpha,beta,gamma); | |
110 | ezero.applyRotateEuler(alpha,beta,gamma); | |
111 | eminus.applyRotateEuler(alpha,beta,gamma); | |
112 | ||
113 | EvtSpinDensity R; | |
114 | R.setDim(3); | |
115 | ||
116 | ||
117 | for ( int i=0; i<3; i++ ) { | |
118 | R.set(0,i,(eplus.conj())*_eps[i]); | |
119 | R.set(1,i,(ezero.conj())*_eps[i]); | |
120 | R.set(2,i,(eminus.conj())*_eps[i]); | |
121 | } | |
122 | ||
123 | return R; | |
124 | ||
125 | } | |
126 | ||
127 |