| Geant4 Cross Reference |
1 //
2 // ********************************************************************
3 // * License and Disclaimer *
4 // * *
5 // * The Geant4 software is copyright of the Copyright Holders of *
6 // * the Geant4 Collaboration. It is provided under the terms and *
7 // * conditions of the Geant4 Software License, included in the file *
8 // * LICENSE and available at http://cern.ch/geant4/license . These *
9 // * include a list of copyright holders. *
10 // * *
11 // * Neither the authors of this software system, nor their employing *
12 // * institutes,nor the agencies providing financial support for this *
13 // * work make any representation or warranty, express or implied, *
14 // * regarding this software system or assume any liability for its *
15 // * use. Please see the license in the file LICENSE and URL above *
16 // * for the full disclaimer and the limitation of liability. *
17 // * *
18 // * This code implementation is the result of the scientific and *
19 // * technical work of the GEANT4 collaboration. *
20 // * By using, copying, modifying or distributing the software (or *
21 // * any work based on the software) you agree to acknowledge its *
22 // * use in resulting scientific publications, and indicate your *
23 // * acceptance of all terms of the Geant4 Software license. *
24 // ********************************************************************
25 //
26 //
27 //
28
29 // ------------------------------------------------------------
30 // GEANT 4 class implementation file
31 //
32 // ---------------- G4DiffractiveSplitableHadron----------------
33 // by Gunter Folger, August 1998.
34 // class splitting an interacting particle. Used by FTF String Model.
35 // ------------------------------------------------------------
36
37 #include "G4DiffractiveSplitableHadron.hh"
38
39 #include "G4ParticleDefinition.hh"
40 #include "Randomize.hh"
41
42
43 //============================================================================
44
45 G4DiffractiveSplitableHadron::G4DiffractiveSplitableHadron()
46 {
47 PartonIndex = -1;
48 G4LorentzVector tmp=G4LorentzVector(0.,0.,0.,0.);
49 Parton[0] = new G4Parton( 1 );
50 Parton[1] = new G4Parton(-1 );
51
52 Parton[0]->Set4Momentum(tmp); Parton[1]->Set4Momentum(tmp);
53 }
54
55
56 //============================================================================
57
58 G4DiffractiveSplitableHadron::G4DiffractiveSplitableHadron( const G4ReactionProduct& aPrimary ) :
59 G4VSplitableHadron( aPrimary )
60 {
61 PartonIndex = -1;
62 Parton[0] = nullptr;
63 Parton[1] = nullptr;
64 }
65
66
67 //============================================================================
68
69 G4DiffractiveSplitableHadron::G4DiffractiveSplitableHadron( const G4Nucleon& aNucleon ) :
70 G4VSplitableHadron( aNucleon )
71 {
72 PartonIndex = -1;
73 Parton[0] = nullptr;
74 Parton[1] = nullptr;
75 }
76
77
78 //============================================================================
79
80 G4DiffractiveSplitableHadron::G4DiffractiveSplitableHadron( const G4VKineticNucleon* aNucleon ) :
81 G4VSplitableHadron( aNucleon )
82 {
83 PartonIndex = -1;
84 Parton[0] = nullptr;
85 Parton[1] = nullptr;
86 }
87
88
89 //============================================================================
90
91 G4DiffractiveSplitableHadron::~G4DiffractiveSplitableHadron() {}
92
93
94 //============================================================================
95
96 void G4DiffractiveSplitableHadron::SplitUp() {
97
98 if ( IsSplit() ) return;
99 Splitting();
100 // Split once only...
101 if ( Parton[0] != nullptr ) return;
102
103 // flavours of quark ends
104 G4int PDGcode = GetDefinition()->GetPDGEncoding();
105 G4int stringStart, stringEnd;
106 ChooseStringEnds( PDGcode, &stringStart, &stringEnd );
107
108 Parton[0] = new G4Parton( stringStart );
109 Parton[1] = new G4Parton( stringEnd );
110
111 G4LorentzVector tmp=G4LorentzVector(0.,0.,0.,0.);
112 Parton[0]->Set4Momentum(tmp); Parton[1]->Set4Momentum(tmp);
113
114 /* // Inversion of a string
115 if ( G4UniformRand() < 1.75 ) { //0.75
116 Parton[0] = new G4Parton( stringStart );
117 Parton[1] = new G4Parton( stringEnd );
118 } else {
119 Parton[0] = new G4Parton( stringEnd );
120 Parton[1] = new G4Parton( stringStart );
121 }
122 */
123
124 PartonIndex = -1;
125 }
126
127
128 //============================================================================
129
130 G4Parton* G4DiffractiveSplitableHadron::GetNextParton() {
131 ++PartonIndex;
132 if ( PartonIndex > 1 || PartonIndex < 0 ) return nullptr;
133 G4int PartonInd( PartonIndex );
134 if ( PartonIndex == 1 ) PartonIndex = -1;
135 return Parton[ PartonInd ];
136 }
137
138
139 //============================================================================
140
141 G4Parton* G4DiffractiveSplitableHadron::GetNextAntiParton() {
142 ++PartonIndex;
143 if ( PartonIndex > 1 || PartonIndex < 0 ) return nullptr;
144 G4int PartonInd( PartonIndex );
145 if ( PartonIndex == 1 ) PartonIndex = -1;
146 return Parton[ PartonInd ];
147 }
148
149
150 //============================================================================
151
152 void G4DiffractiveSplitableHadron::SetFirstParton( G4int PDGcode ) {
153 delete Parton[0];
154 Parton[0] = new G4Parton( PDGcode );
155 G4LorentzVector tmp=G4LorentzVector(0.,0.,0.,0.);
156 Parton[0]->Set4Momentum(tmp);
157 }
158
159
160 //============================================================================
161
162 void G4DiffractiveSplitableHadron::SetSecondParton( G4int PDGcode ) {
163 delete Parton[1];
164 Parton[1] = new G4Parton( PDGcode );
165 G4LorentzVector tmp=G4LorentzVector(0.,0.,0.,0.);
166 Parton[1]->Set4Momentum(tmp);
167 }
168
169
170 //============================================================================
171
172 void G4DiffractiveSplitableHadron::ChooseStringEnds( G4int PDGcode, G4int* aEnd,
173 G4int* bEnd ) const {
174 G4int absPDGcode = std::abs( PDGcode );
175
176 if ( absPDGcode < 1000 ) { //-------------------- Meson -------------
177 G4int heavy(0), light(0);
178 if (!((absPDGcode == 111)||(absPDGcode == 221)||(absPDGcode == 331)))
179 { // Ordinary mesons =======================
180 heavy = absPDGcode/100;
181 light = (absPDGcode % 100)/10;
182 //G4int anti = std::pow( -1 , std::max( heavy, light ) );
183 G4int anti = 1 - 2*( std::max( heavy, light ) % 2 );
184 if (PDGcode < 0 ) anti *= -1;
185 heavy *= anti;
186 light *= -1 * anti;
187 }
188 else
189 { // Pi0, Eta, Eta' =======================
190 if ( G4UniformRand() < 0.5 ) {heavy = 1; light = -1;}
191 else {heavy = 2; light = -2;}
192 }
193 if ( G4UniformRand() < 0.5 ) {
194 *aEnd = heavy;
195 *bEnd = light;
196 } else {
197 *aEnd = light;
198 *bEnd = heavy;
199 }
200 } else { //-------------------- Baryon --------------
201 G4int j1000 = PDGcode/1000;
202 G4int j100 = (PDGcode % 1000)/100;
203 G4int j10 = (PDGcode % 100)/10;
204
205 if ( absPDGcode > 4000 ) {
206 *aEnd = j10;
207 if ( G4UniformRand() > 0.25 ) {
208 *bEnd = Diquark( j1000, j100, 0 );
209 } else {
210 *bEnd = Diquark( j1000, j100, 1 );
211 }
212 return;
213 }
214
215 G4double SuppresUUDDSS=1.0/2.0;
216 if ((j1000 == j100) && (j1000 == j10)) SuppresUUDDSS=1.;
217
218 const G4int maxNumberOfLoops = 1000;
219 G4int loopCounter = 0;
220 do
221 {
222 G4double random = G4UniformRand();
223
224 if (random < 0.33333)
225 {
226 if (( j100 == j10 ) && ( G4UniformRand() > SuppresUUDDSS )) continue;
227 *aEnd = j1000;
228 if ( j100 == j10 ) {*bEnd = Diquark( j100, j10, 1 );}
229 else
230 if ( G4UniformRand() > 0.25) {*bEnd = Diquark( j100, j10, 0 );}
231 else {*bEnd = Diquark( j100, j10, 1 );}
232 break;
233 }
234 else if (random < 0.66667)
235 {
236 if (( j1000 == j10 ) && ( G4UniformRand() > SuppresUUDDSS )) continue;
237 *aEnd = j100;
238 if ( j1000 == j10 ) {*bEnd = Diquark( j1000, j10, 1 );}
239 else
240 if ( G4UniformRand() > 0.25) {*bEnd = Diquark( j1000, j10, 0 );}
241 else {*bEnd = Diquark( j1000, j10, 1 );}
242 break;
243 }
244 else
245 {
246 if (( j1000 == j100 ) && ( G4UniformRand() > SuppresUUDDSS )) continue;
247 *aEnd = j10;
248 if ( j1000 == j100 ) {*bEnd = Diquark( j1000, j100, 1 );}
249 else
250 if ( G4UniformRand() > 0.25) {*bEnd = Diquark( j1000, j100, 0 );}
251 else {*bEnd = Diquark( j1000, j100, 1 );}
252 break;
253 }
254 } while ( (true) &&
255 ++loopCounter < maxNumberOfLoops ); /* Loop checking, 10.08.2015, A.Ribon */
256 if ( loopCounter >= maxNumberOfLoops ) {
257 *aEnd = j10; *bEnd = Diquark( j1000, j100, 1 ); // Just something acceptable, without any physics consideration.
258 }
259
260 }
261 }
262
263
264 //============================================================================
265
266 G4int G4DiffractiveSplitableHadron::Diquark( G4int aquark, G4int bquark, G4int Spin) const {
267 G4int diquarkPDG = std::max( std::abs( aquark ), std::abs( bquark ) ) * 1000 +
268 std::min( std::abs( aquark ), std::abs( bquark ) ) * 100 +
269 2*Spin + 1;
270 return ( aquark > 0 && bquark > 0 ) ? diquarkPDG : -1*diquarkPDG;
271 }
272
273