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G4PomeronCrossSection.cc
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27 // $Id$
28 //
29 
30 #include "G4PomeronCrossSection.hh"
31 #include "G4PhysicalConstants.hh"
32 #include "G4SystemOfUnits.hh"
33 #include "G4Pow.hh" // factorial()
34 
35 G4PomeronCrossSection::G4PomeronCrossSection() :
36  pomeron_Alpha(0), pomeron_Alpha_Hard(0), pomeron_Alphaprime(0),
37  pomeron_C(0), pomeron_Gamma(0), pomeron_Gamma_Hard(0),
38  pomeron_Rsquare(0), pomeron_S(0)
39 {}
40 
41 
42 G4PomeronCrossSection::~G4PomeronCrossSection()
43 {;}
44 //**********************************************************************************************
45 
46 G4PomeronCrossSection::G4PomeronCrossSection(const G4ParticleDefinition * particle)
47  {
48  G4int Encoding = std::abs(particle->GetPDGEncoding());
49 
50  if (std::abs(particle->GetBaryonNumber())!=0)
51  InitForNucleon();
52  else if (Encoding/100== 3 || Encoding/10 == 3)
53  InitForKaon();
54  else
55  InitForPion();
56  }
57 
58 //**********************************************************************************************
59 
60 G4PomeronCrossSection::G4PomeronCrossSection(const G4Proton * )
61 {
62  InitForNucleon();
63 }
64 G4PomeronCrossSection::G4PomeronCrossSection(const G4Neutron * )
65 {
66  InitForNucleon();
67 }
68 
69 G4PomeronCrossSection::G4PomeronCrossSection(const G4PionPlus * )
70 {
71  InitForPion();
72 }
73 G4PomeronCrossSection::G4PomeronCrossSection(const G4PionMinus * )
74 {
75  InitForPion();
76 }
77 G4PomeronCrossSection::G4PomeronCrossSection(const G4PionZero * )
78 {
79  InitForPion();
80 }
81 
82 G4PomeronCrossSection::G4PomeronCrossSection(const G4KaonPlus * )
83 {
84  InitForKaon();
85 }
86 G4PomeronCrossSection::G4PomeronCrossSection(const G4KaonMinus * )
87 {
88  InitForKaon();
89 }
90 G4PomeronCrossSection::G4PomeronCrossSection(const G4KaonZero * )
91 {
92  InitForKaon();
93 }
94 G4PomeronCrossSection::G4PomeronCrossSection(const G4KaonZeroLong * )
95 {
96  InitForKaon();
97 }
98 G4PomeronCrossSection::G4PomeronCrossSection(const G4KaonZeroShort * )
99 {
100  InitForKaon();
101 }
102 G4PomeronCrossSection::G4PomeronCrossSection(const G4Gamma * )
103 {
104  InitForGamma();
105 }
106 
107 G4double G4PomeronCrossSection::GetTotalCrossSection(const G4double S)
108 {
109  G4double FZ2= Expand(Z(S)/2);
110  return SigP(S) * FZ2;
111 }
112 
113 
114 G4double G4PomeronCrossSection::GetElasticCrossSection(const G4double S)
115 {
116  return SigP(S)/pomeron_C *(Expand(Z(S)/2) - Expand(Z(S)));
117 }
118 
119 G4double G4PomeronCrossSection::GetDiffractiveCrossSection(const G4double S)
120 {
121  return ( pomeron_C -1) * GetElasticCrossSection(S);
122 }
123 
124 G4double G4PomeronCrossSection::GetInelasticCrossSection(const G4double S)
125 {
126  return GetTotalCrossSection(S) - GetElasticCrossSection(S);
127 }
128 
129 //-------------------------Probabilities ----------------------------
130 
131 G4double G4PomeronCrossSection::GetTotalProbability(const G4double S,
132  const G4double impactsquare)
133 {
134  return 2/pomeron_C*(1-std::exp(-1*Eikonal(S,impactsquare)));
135 }
136 
137 G4double G4PomeronCrossSection::GetDiffractiveProbability(const G4double S,
138  const G4double impactsquare)
139 {
140  return (pomeron_C-1)/pomeron_C *
141  (GetTotalProbability(S,impactsquare) -
142  GetNondiffractiveProbability(S,impactsquare));
143 }
144 
145 G4double G4PomeronCrossSection::GetNondiffractiveProbability(const G4double S,
146  const G4double impactsquare)
147 {
148  return (1-std::exp(-2*Eikonal(S,impactsquare)))/pomeron_C;
149 }
150 
151 G4double G4PomeronCrossSection::GetElasticProbability(const G4double S,
152  const G4double impactsquare)
153 {
154  return (GetTotalProbability(S,impactsquare) -
155  GetInelasticProbability(S,impactsquare));
156 }
157 
158 G4double G4PomeronCrossSection::GetInelasticProbability(const G4double S,
159  const G4double impactsquare)
160 {
161  return GetNondiffractiveProbability(S,impactsquare) +
162  GetDiffractiveProbability(S,impactsquare);
163 }
164 
165 G4double G4PomeronCrossSection::GetCutPomeronProbability(const G4double S,
166  const G4double impactsquare, const G4int nPomerons)
167 {
168  G4double factorial=G4Pow::GetInstance()->factorial(nPomerons);
169 
170  return std::exp(-2*Eikonal(S,impactsquare))/pomeron_C*
171  std::pow(2*Eikonal(S,impactsquare),nPomerons)/factorial;
172 }
173 
174 // ---------------Temporary --- GF
175 void G4PomeronCrossSection::Setgamma(const G4double agam)
176 {
177  pomeron_Gamma=agam/GeV/GeV;
178 }
179 
180 
181 //----------------- private/Implementation methods
182 
183 void G4PomeronCrossSection::InitForNucleon()
184 {
185 // pomeron_S= 3.0*GeV*GeV;
186  pomeron_S= 2.7*GeV*GeV;
187 // pomeron_Gamma= 2.16/GeV/GeV;
188 // pomeron_Gamma= 3.96/GeV/GeV;
189  pomeron_Gamma= (2.6+3.96)/GeV/GeV;
190  pomeron_C= 1.4;
191  pomeron_Rsquare= 3.56/GeV/GeV;
192 // pomeron_Alpha= 1.0808;
193  pomeron_Alpha= 0.9808;
194  pomeron_Alphaprime= 0.25/GeV/GeV;
195  pomeron_Gamma_Hard = 0.0002/GeV/GeV; // Note! if pomeron_Gamma_Hard != 0 to fit total pp-crosscection
196  // pomeron_Gamma_Soft shold be 2.35/GeV/GeV
197  pomeron_Alpha_Hard = 1.47;
198 }
199 
200 void G4PomeronCrossSection::InitForPion()
201 {
202  pomeron_S= 1.5*GeV*GeV;
203 // pomeron_Gamma= 1.46/GeV/GeV;
204  pomeron_Gamma= 2.17/GeV/GeV;
205  pomeron_C= 1.6;
206  pomeron_Rsquare= 2.36/GeV/GeV;
207  pomeron_Alpha= 1.0808;
208  pomeron_Alphaprime= 0.25/GeV/GeV;
209  pomeron_Gamma_Hard = 0.0002/GeV/GeV;
210  pomeron_Alpha_Hard = 1.47;
211 }
212 
213 void G4PomeronCrossSection::InitForKaon()
214 {
215  pomeron_S= 2.3*GeV*GeV;
216 // pomeron_Gamma= 1.31/GeV/GeV;
217  pomeron_Gamma= 1.92/GeV/GeV;
218  pomeron_C= 1.8;
219  pomeron_Rsquare= 1.96/GeV/GeV;
220  pomeron_Alpha= 1.0808;
221  pomeron_Alphaprime= 0.25/GeV/GeV;
222  pomeron_Gamma_Hard = 0.0002/GeV/GeV;
223  pomeron_Alpha_Hard = 1.47;
224 }
225 
226 void G4PomeronCrossSection::InitForGamma()
227 {
228  pomeron_S= 1.7*GeV*GeV;
229 // pomeron_Gamma= 1.42/GeV/GeV;
230  pomeron_Gamma= 2.07/GeV/GeV;
231  pomeron_C= 1.7;
232  pomeron_Rsquare= 2.16/GeV/GeV;
233  pomeron_Alpha= 1.0808;
234  pomeron_Alphaprime= 0.25/GeV/GeV;
235  pomeron_Gamma_Hard = 0.0002/GeV/GeV;
236  pomeron_Alpha_Hard = 1.47;
237 }
238 
239 G4double G4PomeronCrossSection::Expand(G4double z)
240 {
241 
242  G4double sum=1.;
243  G4double current=1.;
244  for (G4int j=2; j<21; j++ )
245  {
246  current *= -z *(j-1)/sqr(j);
247  sum+=current;
248  }
249  return sum;
250 }
251 
252 inline G4double G4PomeronCrossSection::Power(const G4double S)
253 {
254  return pomeron_Gamma *std::pow(S/pomeron_S, pomeron_Alpha -1);
255 }
256 
257 inline G4double G4PomeronCrossSection::Z(const G4double S)
258 {
259  return 2*pomeron_C * Power(S) / Lambda(S);
260 }
261 
262 inline G4double G4PomeronCrossSection::Lambda(const G4double S)
263 {
264  return pomeron_Rsquare+pomeron_Alphaprime*std::log(S/pomeron_S);
265 }
266 
267 inline G4double G4PomeronCrossSection::SigP(const G4double S)
268 {
269  return 8 * pi * hbarc_squared * Power(S);
270 }
271 
272 inline G4double G4PomeronCrossSection::Eikonal(const G4double S,
273  const G4double impactsquare)
274 {
275  return Z(S)/2 * std::exp(-impactsquare/(4*Lambda(S)*hbarc_squared));
276 }
277 //*************************************************************************************************
278 inline G4double G4PomeronCrossSection::PowerSoft(const G4double S)
279  {
280  return pomeron_Gamma *std::pow(S/pomeron_S, pomeron_Alpha -1);
281  }
282 
283 inline G4double G4PomeronCrossSection::PowerHard(const G4double S)
284  {
285  return pomeron_Gamma_Hard*std::pow(S/pomeron_S, pomeron_Alpha_Hard -1);
286  }
287 
288 inline G4double G4PomeronCrossSection::LambdaSoft(const G4double S)
289  {
290  return pomeron_Rsquare+pomeron_Alphaprime*std::log(S/pomeron_S);
291  }
292 
293 inline G4double G4PomeronCrossSection::LambdaHard(const G4double /*S*/)
294  {
295  return pomeron_Rsquare; //+pomeron_Alphaprime*std::log(s/pomeron_S);
296  }
297 
298 inline G4double G4PomeronCrossSection::Zsoft(const G4double S)
299  {
300  return 2*pomeron_C*PowerHard(S) / LambdaSoft(S);
301  }
302 
303 inline G4double G4PomeronCrossSection::Zhard(const G4double S)
304  {
305  return 2*pomeron_C*PowerHard(S)/LambdaHard(S);
306  }
307 
308 G4double G4PomeronCrossSection::SoftEikonal(G4double S, G4double impactsquare)
309  {
310  return Zsoft(S)/2*std::exp(-impactsquare/LambdaSoft(S)/hbarc_squared/4);
311  }
312 
313 G4double G4PomeronCrossSection::HardEikonal(G4double S, G4double impactsquare)
314  {
315  return Zhard(S)/2*std::exp(-impactsquare/LambdaHard(S)/hbarc_squared/4);
316  }
317 
318 //*************************************************************************************************
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