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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: EvtRaritaSchwingerParticle.cc | |
12 | // | |
13 | // Description: Class to describe spin 1/2 particles. | |
14 | // | |
15 | // Modification history: | |
16 | // | |
17 | // RYD August 9, 2000 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/EvtRaritaSchwingerParticle.hh" | |
27 | #include "EvtGenBase/EvtDiracSpinor.hh" | |
28 | #include "EvtGenBase/EvtVector4R.hh" | |
29 | #include "EvtGenBase/EvtPDL.hh" | |
30 | #include "EvtGenBase/EvtReport.hh" | |
31 | using std::endl; | |
32 | ||
33 | EvtRaritaSchwingerParticle::~EvtRaritaSchwingerParticle(){} | |
34 | ||
35 | ||
36 | EvtRaritaSchwingerParticle::EvtRaritaSchwingerParticle(){ | |
37 | ||
38 | return; | |
39 | ||
40 | } | |
41 | ||
42 | void EvtRaritaSchwingerParticle::init(EvtId id,const EvtVector4R& p4){ | |
43 | ||
44 | _validP4=true; | |
45 | setp(p4); | |
46 | setpart_num(id); | |
47 | ||
48 | if (EvtPDL::getStdHep(id)==0){ | |
49 | report(ERROR,"EvtGen") << "Error in EvtRaritaSchwingerParticle::init, part_n=" | |
50 | << id.getId()<<endl; | |
51 | ::abort(); | |
52 | } | |
53 | ||
54 | ||
55 | ||
56 | double sqmt2=sqrt(2.0*(this->getP4().mass())); | |
57 | ||
58 | EvtDiracSpinor spplus; | |
59 | EvtDiracSpinor spminus; | |
60 | ||
61 | if (EvtPDL::getStdHep(getId())>0){ | |
62 | spplus.set(sqmt2,0.0,0.0,0.0); | |
63 | spminus.set(0.0,sqmt2,0.0,0.0); | |
64 | } else { | |
65 | spplus.set(0.0,0.0,sqmt2,0.0); | |
66 | spminus.set(0.0,0.0,0.0,sqmt2); | |
67 | } | |
68 | ||
69 | static EvtVector4C eplus(0.0,-1.0/sqrt(2.0),EvtComplex(0.0,-1.0/sqrt(2.0)),0.0); | |
70 | static EvtVector4C ezero(0.0,0.0,0.0,1.0); | |
71 | static EvtVector4C eminus(0.0,1.0/sqrt(2.0),EvtComplex(0.0,-1.0/sqrt(2.0)),0.0); | |
72 | ||
73 | _spinorRest[0]=dirProd(eplus,spplus); | |
74 | _spinorRest[1]=dirProd(sqrt(2.0/3.0)*ezero,spplus)+ | |
75 | dirProd(sqrt(1.0/3.0)*eplus,spminus); | |
76 | _spinorRest[2]=dirProd(sqrt(2.0/3.0)*ezero,spminus)+ | |
77 | dirProd(sqrt(1.0/3.0)*eminus,spplus); | |
78 | _spinorRest[3]=dirProd(eminus,spminus); | |
79 | ||
80 | _spinor[0]=boostTo(_spinorRest[0],p4); | |
81 | _spinor[1]=boostTo(_spinorRest[1],p4); | |
82 | _spinor[2]=boostTo(_spinorRest[2],p4); | |
83 | _spinor[3]=boostTo(_spinorRest[3],p4); | |
84 | ||
85 | ||
86 | setLifetime(); | |
87 | } | |
88 | ||
89 | ||
90 | void EvtRaritaSchwingerParticle::init(EvtId id,const EvtVector4R& p4, | |
91 | const EvtRaritaSchwinger & prod1, | |
92 | const EvtRaritaSchwinger & prod2, | |
93 | const EvtRaritaSchwinger & prod3, | |
94 | const EvtRaritaSchwinger & prod4, | |
95 | const EvtRaritaSchwinger & rest1, | |
96 | const EvtRaritaSchwinger & rest2, | |
97 | const EvtRaritaSchwinger & rest3, | |
98 | const EvtRaritaSchwinger & rest4){ | |
99 | ||
100 | _validP4=true; | |
101 | setp(p4); | |
102 | setpart_num(id); | |
103 | ||
104 | if (EvtPDL::getStdHep(id)==0){ | |
105 | report(ERROR,"EvtGen") << "Error in EvtRaritaSchwingerParticle::init, part_n=" | |
106 | << id.getId()<<std::endl; | |
107 | ::abort(); | |
108 | } | |
109 | _spinorRest[0]=rest1; | |
110 | _spinorRest[1]=rest2; | |
111 | _spinorRest[2]=rest3; | |
112 | _spinorRest[3]=rest4; | |
113 | ||
114 | _spinor[0]=prod1; | |
115 | _spinor[1]=prod2; | |
116 | _spinor[2]=prod3; | |
117 | _spinor[3]=prod4; | |
118 | ||
119 | setLifetime(); | |
120 | } | |
121 | ||
122 | ||
123 | ||
124 | EvtRaritaSchwinger EvtRaritaSchwingerParticle::spRSParent(int i) const { | |
125 | ||
126 | return _spinor[i]; | |
127 | ||
128 | } | |
129 | ||
130 | EvtRaritaSchwinger EvtRaritaSchwingerParticle::spRS(int i) const { | |
131 | ||
132 | return _spinorRest[i]; | |
133 | ||
134 | } | |
135 | ||
136 | ||
137 | ||
138 | EvtSpinDensity EvtRaritaSchwingerParticle::rotateToHelicityBasis() const{ | |
139 | ||
140 | double sqmt2=sqrt(2.0*(this->getP4().mass())); | |
141 | ||
142 | EvtDiracSpinor spplus; | |
143 | EvtDiracSpinor spminus; | |
144 | ||
145 | if (EvtPDL::getStdHep(getId())>0){ | |
146 | spplus.set(1.0,0.0,0.0,0.0); | |
147 | spminus.set(0.0,1.0,0.0,0.0); | |
148 | } else { | |
149 | spplus.set(0.0,0.0,1.0,0.0); | |
150 | spminus.set(0.0,0.0,0.0,1.0); | |
151 | } | |
152 | ||
153 | EvtVector4C eplus(0.0,-1.0/sqrt(2.0),EvtComplex(0.0,-1.0/sqrt(2.0)),0.0); | |
154 | EvtVector4C ezero(0.0,0.0,0.0,1.0); | |
155 | EvtVector4C eminus(0.0,1.0/sqrt(2.0),EvtComplex(0.0,-1.0/sqrt(2.0)),0.0); | |
156 | ||
157 | EvtRaritaSchwinger sppp=dirProd(eplus,spplus); | |
158 | EvtRaritaSchwinger spp=dirProd(sqrt(2.0/3.0)*ezero,spplus)+ | |
159 | dirProd(sqrt(1.0/3.0)*eplus,spminus); | |
160 | EvtRaritaSchwinger spm=dirProd(sqrt(2.0/3.0)*ezero,spminus)+ | |
161 | dirProd(sqrt(1.0/3.0)*eminus,spplus); | |
162 | EvtRaritaSchwinger spmm=dirProd(eminus,spminus); | |
163 | ||
164 | ||
165 | EvtSpinDensity R; | |
166 | R.setDim(4); | |
167 | ||
168 | ||
169 | for ( int i=0; i<4; i++) { | |
170 | R.set(0,i,(sppp*_spinorRest[i])/sqmt2); | |
171 | R.set(1,i,(spp*_spinorRest[i])/sqmt2); | |
172 | R.set(2,i,(spm*_spinorRest[i])/sqmt2); | |
173 | R.set(3,i,(spmm*_spinorRest[i])/sqmt2); | |
174 | } | |
175 | ||
176 | return R; | |
177 | ||
178 | } | |
179 | ||
180 | ||
181 | EvtSpinDensity EvtRaritaSchwingerParticle::rotateToHelicityBasis(double alpha, | |
182 | double beta, | |
183 | double gamma) const{ | |
184 | ||
185 | EvtDiracSpinor spplus; | |
186 | EvtDiracSpinor spminus; | |
187 | ||
188 | if (EvtPDL::getStdHep(getId())>0){ | |
189 | spplus.set(1.0,0.0,0.0,0.0); | |
190 | spminus.set(0.0,1.0,0.0,0.0); | |
191 | } else { | |
192 | spplus.set(0.0,0.0,1.0,0.0); | |
193 | spminus.set(0.0,0.0,0.0,1.0); | |
194 | } | |
195 | ||
196 | EvtVector4C eplus(0.0,-1.0/sqrt(2.0),EvtComplex(0.0,-1.0/sqrt(2.0)),0.0); | |
197 | EvtVector4C ezero(0.0,0.0,0.0,1.0); | |
198 | EvtVector4C eminus(0.0,1.0/sqrt(2.0),EvtComplex(0.0,-1.0/sqrt(2.0)),0.0); | |
199 | ||
200 | EvtRaritaSchwinger sppp=dirProd(eplus,spplus); | |
201 | EvtRaritaSchwinger spp=dirProd(sqrt(2.0/3.0)*ezero,spplus)+ | |
202 | dirProd(sqrt(1.0/3.0)*eplus,spminus); | |
203 | EvtRaritaSchwinger spm=dirProd(sqrt(2.0/3.0)*ezero,spminus)+ | |
204 | dirProd(sqrt(1.0/3.0)*eminus,spplus); | |
205 | EvtRaritaSchwinger spmm=dirProd(eminus,spminus); | |
206 | ||
207 | ||
208 | sppp.applyRotateEuler(alpha,beta,gamma); | |
209 | spp.applyRotateEuler(alpha,beta,gamma); | |
210 | spm.applyRotateEuler(alpha,beta,gamma); | |
211 | spmm.applyRotateEuler(alpha,beta,gamma); | |
212 | ||
213 | EvtSpinDensity R; | |
214 | R.setDim(4); | |
215 | ||
216 | double sqmt2=sqrt(2.0*(this->getP4().mass())); | |
217 | ||
218 | for ( int i=0; i<4; i++) { | |
219 | R.set(0,i,(sppp*_spinorRest[i])/sqmt2); | |
220 | R.set(1,i,(spp*_spinorRest[i])/sqmt2); | |
221 | R.set(2,i,(spm*_spinorRest[i])/sqmt2); | |
222 | R.set(3,i,(spmm*_spinorRest[i])/sqmt2); | |
223 | } | |
224 | ||
225 | return R; | |
226 | ||
227 | } | |
228 |