source: trunk/source/processes/hadronic/models/im_r_matrix/src/G4AngularDistribution.cc@ 962

Last change on this file since 962 was 819, checked in by garnier, 17 years ago

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25//
26// hpw: done, but low quality at present.
27
28#include "globals.hh"
29#include "G4AngularDistribution.hh"
30#include "Randomize.hh"
31
32G4AngularDistribution::G4AngularDistribution(G4bool symmetrize)
33 : sym(symmetrize)
34{
35 // The following are parameters of the model - not to be confused with the PDG values!
36
37 mSigma = 0.55;
38 cmSigma = 1.20;
39 gSigma = 9.4;
40
41 mOmega = 0.783;
42 cmOmega = 0.808;
43 gOmega = 10.95;
44
45 mPion = 0.138;
46 cmPion = 0.51;
47 gPion = 7.27;
48
49 mNucleon = 0.938;
50
51 // Definition of constants for pion-Term (no s-dependence)
52
53 m42 = 4. * mNucleon * mNucleon;
54 mPion2 = mPion * mPion;
55 cmPion2 = cmPion * cmPion;
56 dPion1 = cmPion2-mPion2;
57 dPion2 = dPion1 * dPion1;
58 cm6gp = 1.5 * (cmPion2*cmPion2*cmPion2) * (gPion*gPion*gPion*gPion) * m42 * m42 / dPion2;
59
60 cPion_3 = -(cm6gp/3.);
61 cPion_2 = -(cm6gp * mPion2/dPion1);
62 cPion_1 = -(cm6gp * mPion2 * (2. * cmPion2 + mPion2) / dPion2);
63 cPion_m = -(cm6gp * cmPion2 * mPion2 / dPion2);
64 cPion_L = -(cm6gp * 2. * cmPion2 * mPion2 * (cmPion2 + mPion2) / dPion2 / dPion1);
65 cPion_0 = -(cPion_3 + cPion_2 + cPion_1 + cPion_m);
66
67 // Definition of constants for sigma-Term (no s-dependence)
68
69 G4double gSigmaSq = gSigma * gSigma;
70
71 mSigma2 = mSigma * mSigma;
72 cmSigma2 = cmSigma * cmSigma;
73 cmSigma4 = cmSigma2 * cmSigma2;
74 cmSigma6 = cmSigma2 * cmSigma4;
75 dSigma1 = m42 - cmSigma2;
76 dSigma2 = m42 - mSigma2;
77 dSigma3 = cmSigma2 - mSigma2;
78
79 G4double dSigma1Sq = dSigma1 * dSigma1;
80 G4double dSigma2Sq = dSigma2 * dSigma2;
81 G4double dSigma3Sq = dSigma3 * dSigma3;
82
83 cm2gs = 0.5 * cmSigma2 * gSigmaSq*gSigmaSq / dSigma3Sq;
84
85
86 cSigma_3 = -(cm2gs * dSigma1Sq / 3.);
87 cSigma_2 = -(cm2gs * cmSigma2 * dSigma1 * dSigma2 / dSigma3);
88 cSigma_1 = -(cm2gs * cmSigma4 * (2. * dSigma1 + dSigma2) * dSigma2 / dSigma3Sq);
89 cSigma_m = -(cm2gs * cmSigma6 * dSigma2Sq / mSigma2 / dSigma3Sq);
90 cSigma_L = -(cm2gs * cmSigma6 * dSigma2 * (dSigma1 + dSigma2) * 2. / (dSigma3 * dSigma3Sq));
91 cSigma_0 = -(cSigma_3 + cSigma_2 + cSigma_1 + cSigma_m);
92
93 // Definition of constants for omega-Term
94
95 G4double gOmegaSq = gOmega * gOmega;
96
97 mOmega2 = mOmega * mOmega;
98 cmOmega2 = cmOmega * cmOmega;
99 cmOmega4 = cmOmega2 * cmOmega2;
100 cmOmega6 = cmOmega2 * cmOmega4;
101 dOmega1 = m42 - cmOmega2;
102 dOmega2 = m42 - mOmega2;
103 dOmega3 = cmOmega2 - mOmega2;
104 sOmega1 = cmOmega2 + mOmega2;
105
106 G4double dOmega3Sq = dOmega3 * dOmega3;
107
108 cm2go = 0.5 * cmOmega2 * gOmegaSq * gOmegaSq / dOmega3Sq;
109
110 cOmega_3 = cm2go / 3.;
111 cOmega_2 = -(cm2go * cmOmega2 / dOmega3);
112 cOmega_1 = cm2go * cmOmega4 / dOmega3Sq;
113 cOmega_m = cm2go * cmOmega6 / (dOmega3Sq * mOmega2);
114 cOmega_L = -(cm2go * cmOmega6 * 4. / (dOmega3 * dOmega3Sq));
115
116 // Definition of constants for mix-Term
117
118 G4double fac1Tmp = (gSigma * gOmega * cmSigma2 * cmOmega2);
119 fac1 = -(fac1Tmp * fac1Tmp * m42);
120 dMix1 = cmOmega2 - cmSigma2;
121 dMix2 = cmOmega2 - mSigma2;
122 dMix3 = cmSigma2 - mOmega2;
123
124 G4double dMix1Sq = dMix1 * dMix1;
125 G4double dMix2Sq = dMix2 * dMix2;
126 G4double dMix3Sq = dMix3 * dMix3;
127
128 cMix_o1 = fac1 / (cmOmega2 * dMix1Sq * dMix2 * dOmega3);
129 cMix_s1 = fac1 / (cmSigma2 * dMix1Sq * dMix3 * dSigma3);
130 cMix_Omega = fac1 / (dOmega3Sq * dMix3Sq * (mOmega2 - mSigma2));
131 cMix_sm = fac1 / (dSigma3Sq * dMix2Sq * (mSigma2 - mOmega2));
132 fac2 = (-fac1) / (dMix1*dMix1Sq * dOmega3Sq * dMix2Sq);
133 fac3 = (-fac1) / (dMix1*dMix1Sq * dSigma3Sq * dMix3Sq);
134
135 cMix_oLc = fac2 * (3. * cmOmega2*cmOmega4 - cmOmega4 * cmSigma2
136 - 2. * cmOmega4 * mOmega2 - 2. * cmOmega4 * mSigma2
137 + cmOmega2 * mOmega2 * mSigma2 + cmSigma2 * mOmega2 * mSigma2
138 - 4. * cmOmega4 * m42 + 2. * cmOmega2 * cmSigma2 * m42
139 + 3. * cmOmega2 * mOmega2 * m42 - cmSigma2 * mOmega2 * m42
140 + 3. * cmOmega2 * mSigma2 * m42 - cmSigma2 * mSigma2 * m42
141 - 2. * mOmega2 * mSigma2 * m42);
142
143 cMix_oLs = fac2 * (8. * cmOmega4 - 4. * cmOmega2 * cmSigma2
144 - 6. * cmOmega2 * mOmega2 + 2. * cmSigma2 * mOmega2
145 - 6. * cmOmega2 * mSigma2 + 2. * cmSigma2 * mSigma2
146 + 4. * mOmega2 * mSigma2);
147
148 cMix_sLc = fac3 * (cmOmega2 * cmSigma4 - 3. * cmSigma6
149 + 2. * cmSigma4 * mOmega2 + 2. * cmSigma4 * mSigma2
150 - cmOmega2 * mOmega2 * mSigma2 - cmSigma2 * mOmega2 * mSigma2
151 - 2. * cmOmega2 * cmSigma2 * m42 + 4. * cmSigma4 * m42
152 + cmOmega2 * mOmega2 * m42 - 3. * cmSigma2 * mOmega2 * m42
153 + cmOmega2 * mSigma2 * m42 - 3. * cmSigma2 * mSigma2 * m42
154 + 2. * mOmega2 * mSigma2 * m42);
155
156 cMix_sLs = fac3 * (4. * cmOmega2 * cmSigma2 - 8. * cmSigma4
157 - 2. * cmOmega2 * mOmega2 + 6. * cmSigma2 * mOmega2
158 - 2. * cmOmega2 * mSigma2 + 6. * cmSigma2 * mSigma2
159 - 4. * mOmega2 * mSigma2);
160}
161
162
163G4AngularDistribution::~
164G4AngularDistribution()
165{ }
166
167
168G4double G4AngularDistribution::CosTheta(G4double s, G4double m1, G4double m2) const
169{
170 G4double random = G4UniformRand();
171 G4double dCosTheta = 2.;
172 G4double cosTheta = -1.;
173
174 // For jmax=12 the accuracy is better than 0.1 degree
175 G4int jMax = 12;
176
177 for (G4int j = 1; j <= jMax; ++j)
178 {
179 // Accuracy is 2^-jmax
180 dCosTheta *= 0.5;
181 G4double cosTh = cosTheta + dCosTheta;
182 if(DifferentialCrossSection(s, m1, m2, cosTh) <= random) cosTheta = cosTh;
183 }
184
185 // Randomize in final interval in order to avoid discrete angles
186 cosTheta += G4UniformRand() * dCosTheta;
187
188
189 if (cosTheta > 1. || cosTheta < -1.)
190 throw G4HadronicException(__FILE__, __LINE__, "G4AngularDistribution::CosTheta - std::cos(theta) outside allowed range");
191
192 return cosTheta;
193}
194
195
196G4double G4AngularDistribution::DifferentialCrossSection(G4double sIn, G4double m1, G4double m2,
197 G4double cosTheta) const
198{
199// local calculus is in GeV, ie. normalize input
200 sIn = sIn/sqr(GeV)+m42/2.;
201 m1 = m1/GeV;
202 m2 = m2/GeV;
203// G4cout << "Here we go"<<sIn << " "<<m1 << " " << m2 <<" " m42<< G4endl;
204// scaling from masses other than p,p.
205 G4double s = sIn - (m1+m2) * (m1+m2) + m42;
206 G4double tMax = s - m42;
207 G4double tp = 0.5 * (cosTheta + 1.) * tMax;
208 G4double twoS = 2. * s;
209
210 // Define s-dependent stuff for omega-Term
211 G4double brak1 = (twoS-m42) * (twoS-m42);
212 G4double bOmega_3 = cOmega_3 * (-2. * cmOmega4 - 2. * cmOmega2 * twoS - brak1);
213 G4double bOmega_2 = cOmega_2 * ( 2. * cmOmega2 * mOmega2 + sOmega1 * twoS + brak1);
214 G4double bOmega_1 = cOmega_1 * (-4. * cmOmega2 * mOmega2
215 - 2. * mOmega2*mOmega2
216 - 2. * (cmOmega2 + 2 * mOmega2) * twoS
217 - 3. * brak1);
218 G4double bOmega_m = cOmega_m * (-2. * mOmega2*mOmega2 - 2. * mOmega2 * twoS - brak1);
219 G4double bOmega_L = cOmega_L * (sOmega1 * mOmega2 + (cmOmega2 + 3. * mOmega2) * s + brak1);
220 G4double bOmega_0 = -(bOmega_3 + bOmega_2 + bOmega_1 + bOmega_m);
221
222 // Define s-dependent stuff for mix-Term
223 G4double bMix_o1 = cMix_o1 * (dOmega1 - twoS);
224 G4double bMix_s1 = cMix_s1 * (dSigma1 - twoS);
225 G4double bMix_Omega = cMix_Omega * (dOmega2 - twoS);
226 G4double bMix_sm = cMix_sm * (dSigma2 - twoS);
227 G4double bMix_oL = cMix_oLc + cMix_oLs * s;
228 G4double bMix_sL = cMix_sLc + cMix_sLs * s;
229
230 G4double t1_Pion = 1. / (1. + tMax / cmPion2);
231 G4double t2_Pion = 1. + tMax / mPion2;
232 G4double t1_Sigma = 1. / (1. + tMax / cmSigma2);
233 G4double t2_Sigma = 1. + tMax / mSigma2;
234 G4double t1_Omega = 1. / (1. + tMax / cmOmega2);
235 G4double t2_Omega = 1. + tMax / mOmega2;
236
237 G4double norm = Cross(t1_Pion, t1_Sigma, t1_Omega,
238 t2_Pion, t2_Sigma, t2_Omega,
239 bMix_o1, bMix_s1, bMix_Omega,
240 bMix_sm, bMix_oL, bMix_sL,
241 bOmega_0, bOmega_1, bOmega_2,
242 bOmega_3, bOmega_m, bOmega_L);
243
244 t1_Pion = 1. / (1. + tp / cmPion2);
245 t2_Pion = 1. + tp / mPion2;
246 t1_Sigma = 1. / (1. + tp / cmSigma2);
247 t2_Sigma = 1. + tp / mSigma2;
248 t1_Omega = 1. / (1. + tp / cmOmega2);
249 t2_Omega = 1. + tp / mOmega2;
250
251 G4double dSigma;
252 if (sym)
253 {
254 G4double to;
255 norm = 2. * norm;
256 to = tMax - tp;
257 G4double t3_Pion = 1. / (1. + to / cmPion2);
258 G4double t4_Pion = 1. + to / mPion2;
259 G4double t3_Sigma = 1. / (1. + to / cmSigma2);
260 G4double t4_Sigma = 1. + to / mSigma2;
261 G4double t3_Omega = 1. / (1. + to / cmOmega2);
262 G4double t4_Omega = 1. + to / mOmega2;
263
264 dSigma = ( Cross(t1_Pion, t1_Sigma, t1_Omega,
265 t2_Pion,t2_Sigma, t2_Omega,
266 bMix_o1, bMix_s1, bMix_Omega,
267 bMix_sm, bMix_oL, bMix_sL,
268 bOmega_0, bOmega_1, bOmega_2,
269 bOmega_3, bOmega_m, bOmega_L) -
270 Cross(t3_Pion,t3_Sigma, t3_Omega,
271 t4_Pion, t4_Sigma, t4_Omega,
272 bMix_o1, bMix_s1, bMix_Omega,
273 bMix_sm, bMix_oL, bMix_sL,
274 bOmega_0, bOmega_1, bOmega_2,
275 bOmega_3, bOmega_m, bOmega_L) )
276 / norm + 0.5;
277 }
278 else
279 {
280 dSigma = Cross(t1_Pion, t1_Sigma, t1_Omega,
281 t2_Pion, t2_Sigma, t2_Omega,
282 bMix_o1, bMix_s1, bMix_Omega,
283 bMix_sm, bMix_oL, bMix_sL,
284 bOmega_0, bOmega_1, bOmega_2,
285 bOmega_3, bOmega_m, bOmega_L)
286 / norm;
287 }
288
289 return dSigma;
290}
291
292
293G4double G4AngularDistribution::Cross(G4double tpPion,
294 G4double tpSigma,
295 G4double tpOmega,
296 G4double tmPion,
297 G4double tmSigma,
298 G4double tmOmega,
299 G4double bMix_o1,
300 G4double bMix_s1,
301 G4double bMix_Omega,
302 G4double bMix_sm,
303 G4double bMix_oL,
304 G4double bMix_sL,
305 G4double bOmega_0,
306 G4double bOmega_1,
307 G4double bOmega_2,
308 G4double bOmega_3,
309 G4double bOmega_m,
310 G4double bOmega_L) const
311{
312 G4double cross = 0;
313 // Pion
314 cross += ((cPion_3 * tpPion + cPion_2) * tpPion + cPion_1) * tpPion + cPion_m/tmPion + cPion_0 + cPion_L * std::log(tpPion*tmPion);
315// G4cout << "cross1 "<< cross<<G4endl;
316 // Sigma
317 cross += ((cSigma_3 * tpSigma + cSigma_2) * tpSigma + cSigma_1) * tpSigma + cSigma_m/tmSigma + cSigma_0 + cSigma_L * std::log(tpSigma*tmSigma);
318// G4cout << "cross2 "<< cross<<G4endl;
319 // Omega
320 cross += ((bOmega_3 * tpOmega + bOmega_2) * tpOmega + bOmega_1) * tpOmega + bOmega_m/tmOmega + bOmega_0 + bOmega_L * std::log(tpOmega*tmOmega)
321 // Mix
322 + bMix_o1 * (tpOmega - 1.)
323 + bMix_s1 * (tpSigma - 1.)
324 + bMix_Omega * std::log(tmOmega)
325 + bMix_sm * std::log(tmSigma)
326 + bMix_oL * std::log(tpOmega)
327 + bMix_sL * std::log(tpSigma);
328/* G4cout << "cross3 "<< cross<<" "
329 <<bMix_o1<<" "
330 <<bMix_s1<<" "
331 <<bMix_Omega<<" "
332 <<bMix_sm<<" "
333 <<bMix_oL<<" "
334 <<bMix_sL<<" "
335 <<tpOmega<<" "
336 <<tpSigma<<" "
337 <<tmOmega<<" "
338 <<tmSigma<<" "
339 <<tpOmega<<" "
340 <<tpSigma
341 <<G4endl;
342*/
343 return cross;
344
345}
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