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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: EvtHighSpinParticle.cc | |
12 | // | |
13 | // Description: Class to describe particles with spin>2. | |
14 | // | |
15 | // Modification history: | |
16 | // | |
17 | // RYD August 8, 2000 Module created | |
18 | // | |
19 | //------------------------------------------------------------------------ | |
20 | // | |
21 | #include "EvtGenBase/EvtPatches.hh" | |
22 | #include "EvtGenBase/EvtPatches.hh" | |
23 | #include <iostream> | |
24 | #include <math.h> | |
25 | #include <assert.h> | |
26 | #include "EvtGenBase/EvtHighSpinParticle.hh" | |
27 | #include "EvtGenBase/EvtVector4R.hh" | |
28 | #include "EvtGenBase/EvtPDL.hh" | |
29 | #include "EvtGenBase/EvtSpinDensity.hh" | |
30 | #include "EvtGenBase/EvtdFunction.hh" | |
31 | ||
32 | ||
33 | EvtHighSpinParticle::~EvtHighSpinParticle() {} | |
34 | ||
35 | ||
36 | void EvtHighSpinParticle::init(EvtId id,const EvtVector4R& p4){ | |
37 | ||
38 | _validP4=true; | |
39 | setp(p4); | |
40 | setpart_num(id); | |
41 | ||
42 | setLifetime(); | |
43 | ||
44 | } | |
45 | ||
46 | EvtSpinDensity EvtHighSpinParticle::rotateToHelicityBasis() const{ | |
47 | ||
48 | int n=EvtSpinType::getSpinStates(EvtPDL::getSpinType(getId())); | |
49 | ||
50 | EvtSpinDensity R; | |
51 | R.setDiag(n); | |
52 | ||
53 | return R; | |
54 | ||
55 | } | |
56 | ||
57 | ||
58 | ||
59 | EvtSpinDensity EvtHighSpinParticle::rotateToHelicityBasis(double alpha, | |
60 | double beta, | |
61 | double gamma) const{ | |
62 | ||
63 | int i,j; | |
64 | ||
65 | int n=EvtSpinType::getSpinStates(EvtPDL::getSpinType(getId())); | |
66 | ||
67 | EvtSpinDensity R; | |
68 | ||
69 | R.setDim(n); | |
70 | ||
71 | int J2=EvtSpinType::getSpin2(EvtPDL::getSpinType(getId())); | |
72 | ||
73 | assert(n==J2+1); | |
74 | ||
75 | int *lambda2; | |
76 | ||
77 | lambda2=new int[J2+1]; | |
78 | ||
79 | for(i=0;i<J2+1;i++){ | |
80 | lambda2[i]=J2-i*2; | |
81 | } | |
82 | ||
83 | ||
84 | for(i=0;i<n;i++){ | |
85 | for(j=0;j<n;j++){ | |
86 | R.set(i,j,EvtdFunction::d(J2,lambda2[j],lambda2[i],beta)* | |
87 | exp(EvtComplex(0.0,0.5*(alpha*lambda2[i]-gamma*lambda2[j])))); | |
88 | } | |
89 | } | |
90 | ||
91 | delete [] lambda2; | |
92 | ||
93 | return R; | |
94 | ||
95 | ||
96 | } | |
97 | ||
98 |