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27 // ------------------------------------------- 27 // ------------------------------------------------------------
28 // GEANT 4 class implemetation file 28 // GEANT 4 class implemetation file
29 // 29 //
30 // ---------------- G4QuarkExchange ----- 30 // ---------------- G4QuarkExchange --------------
31 // by V. Uzhinsky, October 2016. 31 // by V. Uzhinsky, October 2016.
32 // QuarkExchange is used by strings mode 32 // QuarkExchange is used by strings models.
33 // Take a projectile and a target. 33 // Take a projectile and a target.
34 //Simulate Q exchange with excitation of proje 34 //Simulate Q exchange with excitation of projectile or target.
35 // ------------------------------------------- 35 // ------------------------------------------------------------
36 36
37 #include "G4QuarkExchange.hh" 37 #include "G4QuarkExchange.hh"
38 #include "globals.hh" 38 #include "globals.hh"
39 #include "G4PhysicalConstants.hh" 39 #include "G4PhysicalConstants.hh"
40 #include "G4SystemOfUnits.hh" 40 #include "G4SystemOfUnits.hh"
41 #include "Randomize.hh" 41 #include "Randomize.hh"
42 #include "G4LorentzRotation.hh" 42 #include "G4LorentzRotation.hh"
43 #include "G4ThreeVector.hh" 43 #include "G4ThreeVector.hh"
44 #include "G4ParticleDefinition.hh" 44 #include "G4ParticleDefinition.hh"
45 #include "G4VSplitableHadron.hh" 45 #include "G4VSplitableHadron.hh"
46 #include "G4ExcitedString.hh" 46 #include "G4ExcitedString.hh"
47 47
48 #include "G4ParticleTable.hh" // Uzhi June 20 48 #include "G4ParticleTable.hh" // Uzhi June 2020
49 49
50 #include "G4Log.hh" 50 #include "G4Log.hh"
51 #include "G4Pow.hh" 51 #include "G4Pow.hh"
52 52
53 //#define debugQuarkExchange 53 //#define debugQuarkExchange
54 54
55 G4QuarkExchange::G4QuarkExchange() 55 G4QuarkExchange::G4QuarkExchange()
56 { 56 {
57 StrangeSuppress = (1.0-0.04)/2.0; // Uzhi J 57 StrangeSuppress = (1.0-0.04)/2.0; // Uzhi June 2020 : suppression of strange quark pair prodution,
58 // 58 // i.e. u:d:s=1:1:0.04 . Need to be tuned!
59 } 59 }
60 60
61 G4QuarkExchange::~G4QuarkExchange(){} 61 G4QuarkExchange::~G4QuarkExchange(){}
62 62
63 G4bool G4QuarkExchange:: 63 G4bool G4QuarkExchange::
64 ExciteParticipants(G4VSplitableHadron *project 64 ExciteParticipants(G4VSplitableHadron *projectile, G4VSplitableHadron *target) const
65 { 65 {
66 #ifdef debugQuarkExchange 66 #ifdef debugQuarkExchange
67 G4cout<<G4endl<<"G4QuarkExchange::ExcitePa 67 G4cout<<G4endl<<"G4QuarkExchange::ExciteParticipants"<<G4endl;
68 #endif 68 #endif
69 69
70 G4LorentzVector Pprojectile = projectile->Ge 70 G4LorentzVector Pprojectile = projectile->Get4Momentum();
71 G4double Mprojectile = projectile->Ge 71 G4double Mprojectile = projectile->GetDefinition()->GetPDGMass();
72 G4double Mprojectile2 = sqr(Mprojectil 72 G4double Mprojectile2 = sqr(Mprojectile);
73 73
74 G4LorentzVector Ptarget = target->Get4Moment 74 G4LorentzVector Ptarget = target->Get4Momentum();
75 G4double Mtarget = target->GetDefinit 75 G4double Mtarget = target->GetDefinition()->GetPDGMass();
76 G4double Mtarget2 = sqr(Mtarget); 76 G4double Mtarget2 = sqr(Mtarget);
77 77
78 #ifdef debugQuarkExchange 78 #ifdef debugQuarkExchange
79 G4cout<<"Proj Targ "<<projectile->GetDefin 79 G4cout<<"Proj Targ "<<projectile->GetDefinition()->GetPDGEncoding()<<" "<<target->GetDefinition()->GetPDGEncoding()<<G4endl;
80 G4cout<<"Proj. 4-Mom "<<Pprojectile<<" "<< 80 G4cout<<"Proj. 4-Mom "<<Pprojectile<<" "<<Pprojectile.mag()<<G4endl
81 <<"Targ. 4-Mom "<<Ptarget <<" "<< 81 <<"Targ. 4-Mom "<<Ptarget <<" "<<Ptarget.mag() <<G4endl;
82 #endif 82 #endif
83 83
84 G4LorentzVector Psum=Pprojectile+Ptarget; 84 G4LorentzVector Psum=Pprojectile+Ptarget;
85 G4double SqrtS=Psum.mag(); 85 G4double SqrtS=Psum.mag();
86 G4double S =Psum.mag2(); 86 G4double S =Psum.mag2();
87 87
88 #ifdef debugQuarkExchange 88 #ifdef debugQuarkExchange
89 G4cout<<"SS Mpr Mtr SqrtS-Mprojectile-Mtar 89 G4cout<<"SS Mpr Mtr SqrtS-Mprojectile-Mtarget "<<SqrtS<<" "<<Mprojectile<<" "<<Mtarget
90 <<" "<<SqrtS-Mprojectile-Mtarget<<G4 90 <<" "<<SqrtS-Mprojectile-Mtarget<<G4endl;
91 #endif 91 #endif
92 if (SqrtS-Mprojectile-Mtarget <= 250.0*MeV) 92 if (SqrtS-Mprojectile-Mtarget <= 250.0*MeV) {
93 #ifdef debugQuarkExchange 93 #ifdef debugQuarkExchange
94 G4cerr<<"Energy is too small for quark e 94 G4cerr<<"Energy is too small for quark exchange!"<<G4endl;
95 G4cerr<<"Projectile: "<<projectile->GetD 95 G4cerr<<"Projectile: "<<projectile->GetDefinition()->GetPDGEncoding()<<" "
96 <<Pprojectile<<" "<<Pprojectile.ma 96 <<Pprojectile<<" "<<Pprojectile.mag()<<G4endl;
97 G4cerr<<"Target: "<<target->GetDefin 97 G4cerr<<"Target: "<<target->GetDefinition()->GetPDGEncoding()<<" "
98 <<Ptarget<<" "<<Ptarget.mag()<<G4e 98 <<Ptarget<<" "<<Ptarget.mag()<<G4endl;
99 G4cerr<<"sqrt(S) = "<<SqrtS<<" Mp + Mt = 99 G4cerr<<"sqrt(S) = "<<SqrtS<<" Mp + Mt = "<<Pprojectile.mag()+Ptarget.mag()<<G4endl;
100 #endif 100 #endif
101 return true; 101 return true;
102 } 102 }
103 103
104 G4LorentzRotation toCms(-1*Psum.boostVector( 104 G4LorentzRotation toCms(-1*Psum.boostVector());
105 105
106 G4LorentzVector Ptmp=toCms*Pprojectile; 106 G4LorentzVector Ptmp=toCms*Pprojectile;
107 107
108 if ( Ptmp.pz() <= 0. ) 108 if ( Ptmp.pz() <= 0. )
109 { 109 {
110 // "String" moving backwards in CMS, abor 110 // "String" moving backwards in CMS, abort collision !!
111 // G4cout << " abort Collision!! " 111 // G4cout << " abort Collision!! " << G4endl;
112 return false; 112 return false;
113 } 113 }
114 114
115 toCms.rotateZ(-1*Ptmp.phi()); 115 toCms.rotateZ(-1*Ptmp.phi());
116 toCms.rotateY(-1*Ptmp.theta()); 116 toCms.rotateY(-1*Ptmp.theta());
117 117
118 G4LorentzRotation toLab(toCms.inverse()); 118 G4LorentzRotation toLab(toCms.inverse());
119 119
120 Pprojectile.transform(toCms); 120 Pprojectile.transform(toCms);
121 Ptarget.transform(toCms); 121 Ptarget.transform(toCms);
122 122
123 #ifdef debugQuarkExchange 123 #ifdef debugQuarkExchange
124 G4cout << "Pprojectile in CMS " << Pproje 124 G4cout << "Pprojectile in CMS " << Pprojectile << G4endl;
125 G4cout << "Ptarget in CMS " << Ptarge 125 G4cout << "Ptarget in CMS " << Ptarget << G4endl;
126 #endif 126 #endif
127 G4double maxPtSquare=sqr(Ptarget.pz()); 127 G4double maxPtSquare=sqr(Ptarget.pz());
128 128
129 G4double ProjectileMinDiffrMass = Pprojectil 129 G4double ProjectileMinDiffrMass = Pprojectile.mag()/GeV;
130 G4double TargetMinDiffrMass = Ptarget.ma 130 G4double TargetMinDiffrMass = Ptarget.mag()/GeV;
131 131
132 G4double AveragePt2(0.); 132 G4double AveragePt2(0.);
133 133
134 G4int PDGcode=projectile->GetDefinition() 134 G4int PDGcode=projectile->GetDefinition()->GetPDGEncoding();
135 G4int absPDGcode=std::abs(PDGcode); 135 G4int absPDGcode=std::abs(PDGcode);
136 136
137 G4bool ProjectileDiffraction = true; 137 G4bool ProjectileDiffraction = true;
138 138
139 // Also for heavy hadrons, assume 50% probab 139 // Also for heavy hadrons, assume 50% probability of projectile diffraction.
140 if ( absPDGcode > 1000 ) 140 if ( absPDGcode > 1000 ) { ProjectileDiffraction = G4UniformRand() <= 0.5; }
141 if ( (absPDGcode == 211) || (absPDGcode == 1 141 if ( (absPDGcode == 211) || (absPDGcode == 111) ) { ProjectileDiffraction = G4UniformRand() <= 0.66; }
142 if ( (absPDGcode == 321) || (absPDGcode == 3 142 if ( (absPDGcode == 321) || (absPDGcode == 311) ||
143 ( PDGcode == 130) || ( PDGcode == 3 143 ( PDGcode == 130) || ( PDGcode == 310) ) { ProjectileDiffraction = G4UniformRand() <= 0.5; }
144 if ( absPDGcode > 400 && absPDGcode < 600 144 if ( absPDGcode > 400 && absPDGcode < 600 ) { ProjectileDiffraction = G4UniformRand() <= 0.5; }
145 145
146 //G4cout<<"ProjectileDiffr "<<ProjectileDiff 146 //G4cout<<"ProjectileDiffr "<<ProjectileDiffraction<<G4endl;
147 147
148 if ( ProjectileDiffraction ) { 148 if ( ProjectileDiffraction ) {
149 if ( absPDGcode > 1000 ) 149 if ( absPDGcode > 1000 ) //------Projectile is baryon --------
150 { 150 {
151 if ( absPDGcode > 4000 && absPDGcode < 6 151 if ( absPDGcode > 4000 && absPDGcode < 6000 ) // Projectile is a charm or bottom baryon
152 { 152 {
153 ProjectileMinDiffrMass = projectile->G 153 ProjectileMinDiffrMass = projectile->GetDefinition()->GetPDGMass()/CLHEP::GeV + 0.25; // GeV
154 AveragePt2 = 0.3; 154 AveragePt2 = 0.3; // GeV^2
155 } 155 }
156 else 156 else
157 { 157 {
158 ProjectileMinDiffrMass = 1.16; 158 ProjectileMinDiffrMass = 1.16; // GeV
159 AveragePt2 = 0.3; 159 AveragePt2 = 0.3; // GeV^2
160 } 160 }
161 } 161 }
162 else if( absPDGcode == 211 || absPDGcode = 162 else if( absPDGcode == 211 || absPDGcode == 111) //------Projectile is Pion -----------
163 { 163 {
164 ProjectileMinDiffrMass = 1.0; 164 ProjectileMinDiffrMass = 1.0; // GeV
165 AveragePt2 = 0.3; 165 AveragePt2 = 0.3; // GeV^2
166 } 166 }
167 else if( absPDGcode == 321 || absPDGcode = 167 else if( absPDGcode == 321 || absPDGcode == 130 || absPDGcode == 310) //Projectile is Kaon
168 { 168 {
169 ProjectileMinDiffrMass = 1.1; 169 ProjectileMinDiffrMass = 1.1; // GeV
170 AveragePt2 = 0.3; 170 AveragePt2 = 0.3; // GeV^2
171 } 171 }
172 else if( absPDGcode == 22) 172 else if( absPDGcode == 22) //------Projectile is Gamma -----------
173 { 173 {
174 ProjectileMinDiffrMass = 0.25; 174 ProjectileMinDiffrMass = 0.25; // GeV
175 AveragePt2 = 0.36; 175 AveragePt2 = 0.36; // GeV^2
176 } 176 }
177 else if( absPDGcode > 400 && absPDGcode < 177 else if( absPDGcode > 400 && absPDGcode < 600) // Projectile is a charm or bottom meson
178 { 178 {
179 ProjectileMinDiffrMass = projectile->Get 179 ProjectileMinDiffrMass = projectile->GetDefinition()->GetPDGMass()/CLHEP::GeV + 0.25; // GeV
180 AveragePt2 = 0.3; 180 AveragePt2 = 0.3; // GeV^2
181 } 181 }
182 else 182 else //------Projectile is undefined, Nucleon assumed
183 { 183 {
184 ProjectileMinDiffrMass = 1.1; 184 ProjectileMinDiffrMass = 1.1; // GeV
185 AveragePt2 = 0.3; 185 AveragePt2 = 0.3; // GeV^2
186 }; 186 };
187 187
188 ProjectileMinDiffrMass = ProjectileMinDiff 188 ProjectileMinDiffrMass = ProjectileMinDiffrMass * GeV;
189 Mprojectile2=sqr(ProjectileMinDiffrMass); 189 Mprojectile2=sqr(ProjectileMinDiffrMass);
190 190
191 if (G4UniformRand() <= 0.5) TargetMinDiffr 191 if (G4UniformRand() <= 0.5) TargetMinDiffrMass += 0.22;
192 TargetMinDiffrMass *= GeV; 192 TargetMinDiffrMass *= GeV;
193 Mtarget2 = sqr( TargetMinDiffrMass) ; 193 Mtarget2 = sqr( TargetMinDiffrMass) ;
194 } 194 }
195 else 195 else
196 { 196 {
197 if (G4UniformRand() <= 0.5) ProjectileMinD 197 if (G4UniformRand() <= 0.5) ProjectileMinDiffrMass += 0.22;
198 ProjectileMinDiffrMass *=GeV; 198 ProjectileMinDiffrMass *=GeV;
199 Mprojectile2=sqr(ProjectileMinDiffrMass); 199 Mprojectile2=sqr(ProjectileMinDiffrMass);
200 200
201 TargetMinDiffrMass = 1.16*GeV; 201 TargetMinDiffrMass = 1.16*GeV; // For target nucleon
202 Mtarget2 = sqr( TargetMinDiffrMass) ; 202 Mtarget2 = sqr( TargetMinDiffrMass) ;
203 AveragePt2 = 0.3; 203 AveragePt2 = 0.3; // GeV^2
204 } // end of if ( ProjectileDiffraction ) 204 } // end of if ( ProjectileDiffraction )
205 205
206 AveragePt2 = AveragePt2 * GeV*GeV; 206 AveragePt2 = AveragePt2 * GeV*GeV;
207 207
208 if ( SqrtS - (ProjectileMinDiffrMass+TargetM 208 if ( SqrtS - (ProjectileMinDiffrMass+TargetMinDiffrMass) < 220.0*MeV ) return false;
209 209
210 //----------------------- 210 //-----------------------
211 G4double Pt2, PZcms, PZcms2; 211 G4double Pt2, PZcms, PZcms2;
212 G4double ProjMassT2, ProjMassT; 212 G4double ProjMassT2, ProjMassT;
213 G4double TargMassT2, TargMassT; 213 G4double TargMassT2, TargMassT;
214 G4double PMinusMin, PMinusMax, sqrtPMinusMi 214 G4double PMinusMin, PMinusMax, sqrtPMinusMin, sqrtPMinusMax;
215 G4double TPlusMin, TPlusMax, sqrtTPlusMin 215 G4double TPlusMin, TPlusMax, sqrtTPlusMin, sqrtTPlusMax;
216 G4double PMinusNew, PPlusNew, TPlusNew(0.), 216 G4double PMinusNew, PPlusNew, TPlusNew(0.), TMinusNew;
217 217
218 G4LorentzVector Qmomentum; 218 G4LorentzVector Qmomentum;
219 G4double Qminus, Qplus; 219 G4double Qminus, Qplus;
220 220
221 G4double x(0.), y(0.); 221 G4double x(0.), y(0.);
222 G4int whilecount=0; 222 G4int whilecount=0;
223 do { 223 do {
224 whilecount++; 224 whilecount++;
225 225
226 if (whilecount > 1000 ) 226 if (whilecount > 1000 )
227 { 227 {
228 Qmomentum=G4LorentzVector(0.,0.,0.,0.); 228 Qmomentum=G4LorentzVector(0.,0.,0.,0.);
229 return false; // Ignore this intera 229 return false; // Ignore this interaction
230 } 230 }
231 231
232 // Generate pt 232 // Generate pt
233 Qmomentum=G4LorentzVector(GaussianPt(Avera 233 Qmomentum=G4LorentzVector(GaussianPt(AveragePt2,maxPtSquare),0);
234 234
235 Pt2 = G4ThreeVector( Qmomentum.vect() ).ma 235 Pt2 = G4ThreeVector( Qmomentum.vect() ).mag2();
236 ProjMassT2 = Mprojectile2 + Pt2; 236 ProjMassT2 = Mprojectile2 + Pt2;
237 ProjMassT = std::sqrt( ProjMassT2 ); 237 ProjMassT = std::sqrt( ProjMassT2 );
238 TargMassT2 = Mtarget2 + Pt2; 238 TargMassT2 = Mtarget2 + Pt2;
239 TargMassT = std::sqrt( TargMassT2 ); 239 TargMassT = std::sqrt( TargMassT2 );
240 240
241 #ifdef debugQuarkExchange 241 #ifdef debugQuarkExchange
242 G4cout<<"whilecount Pt2 ProjMassT Tar 242 G4cout<<"whilecount Pt2 ProjMassT TargMassT SqrtS S ProjectileDiffraction"<<G4endl;
243 G4cout<<whilecount<<" "<<Pt2<<" "<<ProjM 243 G4cout<<whilecount<<" "<<Pt2<<" "<<ProjMassT<<" "<<TargMassT<<" "<<SqrtS<<" "<<S<<" "<<ProjectileDiffraction<<G4endl;
244 #endif 244 #endif
245 245
246 if ( SqrtS < ProjMassT + TargMassT + 220.0 246 if ( SqrtS < ProjMassT + TargMassT + 220.0*MeV ) continue;
247 247
248 PZcms2 = ( S*S + ProjMassT2*ProjMassT2 + T 248 PZcms2 = ( S*S + ProjMassT2*ProjMassT2 + TargMassT2*TargMassT2
249 - 2.0*S*ProjMassT2 - 2.0*S*Targ 249 - 2.0*S*ProjMassT2 - 2.0*S*TargMassT2 - 2.0*ProjMassT2*TargMassT2 ) / 4.0 / S;
250 250
251 if ( PZcms2 < 0 ) continue; 251 if ( PZcms2 < 0 ) continue;
252 252
253 PZcms = std::sqrt( PZcms2 ); 253 PZcms = std::sqrt( PZcms2 );
254 254
255 if ( ProjectileDiffraction ) 255 if ( ProjectileDiffraction )
256 { // The projectile will fragment, the tar 256 { // The projectile will fragment, the target will saved.
257 PMinusMin = std::sqrt( ProjMassT2 + PZcm 257 PMinusMin = std::sqrt( ProjMassT2 + PZcms2 ) - PZcms;
258 PMinusMax = SqrtS - TargMassT; 258 PMinusMax = SqrtS - TargMassT;
259 sqrtPMinusMin = std::sqrt(PMinusMin); sq 259 sqrtPMinusMin = std::sqrt(PMinusMin); sqrtPMinusMax = std::sqrt(PMinusMax);
260 260
261 if ( absPDGcode > 1000 ) 261 if ( absPDGcode > 1000 )
262 { 262 {
263 PMinusNew = PMinusMax * (1.0 - (1.0 - PMinus 263 PMinusNew = PMinusMax * (1.0 - (1.0 - PMinusMin/PMinusMax)
264 * G4Pow:: 264 * G4Pow::GetInstance()->powA(G4UniformRand(),0.3333) );
265 } 265 }
266 else if ( (absPDGcode == 211) || (absPDG 266 else if ( (absPDGcode == 211) || (absPDGcode == 111) )
267 { 267 {
268 while (true) 268 while (true)
269 { 269 {
270 x=sqrtPMinusMax-(sqrtPMinusMax-sqrtP 270 x=sqrtPMinusMax-(sqrtPMinusMax-sqrtPMinusMin)*G4UniformRand();
271 y=G4UniformRand(); 271 y=G4UniformRand();
272 if ( y < 1.0-0.7 * x/sqrtPMinusMax ) 272 if ( y < 1.0-0.7 * x/sqrtPMinusMax ) break;
273 } 273 }
274 PMinusNew = sqr(x); 274 PMinusNew = sqr(x);
275 } 275 }
276 else if ( (absPDGcode == 321) || (absPDG 276 else if ( (absPDGcode == 321) || (absPDGcode == 311) ||
277 ( PDGcode == 130) || ( PDGcode = 277 ( PDGcode == 130) || ( PDGcode == 310) )
278 { // For K-mesons it must be found !!! 278 { // For K-mesons it must be found !!! Uzhi
279 while (true) 279 while (true)
280 { 280 {
281 x=sqrtPMinusMax-(sqrtPMinusMax-sqrtPMinusM 281 x=sqrtPMinusMax-(sqrtPMinusMax-sqrtPMinusMin)*G4UniformRand();
282 y=G4UniformRand(); 282 y=G4UniformRand();
283 if ( y < 1.0-0.7 * x/sqrtPMinusMax ) 283 if ( y < 1.0-0.7 * x/sqrtPMinusMax ) break;
284 } 284 }
285 PMinusNew = sqr(x); 285 PMinusNew = sqr(x);
286 } 286 }
287 else 287 else
288 { 288 {
289 PMinusNew = PMinusMax * (1.0 - (1.0 - PMinus 289 PMinusNew = PMinusMax * (1.0 - (1.0 - PMinusMin/PMinusMax)
290 * G4Pow::GetI 290 * G4Pow::GetInstance()->powA(G4UniformRand(),0.3333) );
291 }; 291 };
292 292
293 TMinusNew = SqrtS - PMinusNew; 293 TMinusNew = SqrtS - PMinusNew;
294 294
295 Qminus = Ptarget.minus() - TMinusNew; 295 Qminus = Ptarget.minus() - TMinusNew;
296 TPlusNew = TargMassT2 / TMinusNew; 296 TPlusNew = TargMassT2 / TMinusNew;
297 Qplus = Ptarget.plus() - TPlusNew; 297 Qplus = Ptarget.plus() - TPlusNew;
298 298
299 } 299 }
300 else 300 else
301 { // The target will fragment, the project 301 { // The target will fragment, the projectile will saved.
302 TPlusMin = std::sqrt( TargMassT2 + PZcms 302 TPlusMin = std::sqrt( TargMassT2 + PZcms2 ) - PZcms;
303 TPlusMax = SqrtS - ProjMassT; 303 TPlusMax = SqrtS - ProjMassT;
304 sqrtTPlusMin = std::sqrt(TPlusMin); sqrt 304 sqrtTPlusMin = std::sqrt(TPlusMin); sqrtTPlusMax = std::sqrt(TPlusMax);
305 305
306 if ( absPDGcode > 1000 ) 306 if ( absPDGcode > 1000 )
307 { 307 {
308 TPlusNew = TPlusMax * (1.0 - (1.0 - TP 308 TPlusNew = TPlusMax * (1.0 - (1.0 - TPlusMin/TPlusMax)
309 * G4Pow::G 309 * G4Pow::GetInstance()->powA(G4UniformRand(),0.3333) );
310 } 310 }
311 else if ( (absPDGcode == 211) || (absPDG 311 else if ( (absPDGcode == 211) || (absPDGcode == 111) )
312 { 312 {
313 while (true) 313 while (true)
314 { 314 {
315 x=sqrtTPlusMax-(sqrtTPlusMax-sqrtTPl 315 x=sqrtTPlusMax-(sqrtTPlusMax-sqrtTPlusMin)*G4UniformRand();
316 y=G4UniformRand(); 316 y=G4UniformRand();
317 if ( y < 1.0-0.7 * x/sqrtTPlusMax ) 317 if ( y < 1.0-0.7 * x/sqrtTPlusMax ) break;
318 } 318 }
319 TPlusNew = sqr(x); 319 TPlusNew = sqr(x);
320 } 320 }
321 else if ( (absPDGcode == 321) || (absPDG 321 else if ( (absPDGcode == 321) || (absPDGcode == 311) ||
322 ( PDGcode == 130) || ( PDGcode = 322 ( PDGcode == 130) || ( PDGcode == 310) )
323 { // For K-mesons it must be found !!! U 323 { // For K-mesons it must be found !!! Uzhi
324 while (true) 324 while (true)
325 { 325 {
326 x=sqrtTPlusMax-(sqrtTPlusMax-sqrtTPl 326 x=sqrtTPlusMax-(sqrtTPlusMax-sqrtTPlusMin)*G4UniformRand();
327 y=G4UniformRand(); 327 y=G4UniformRand();
328 if ( y < 1.0-0.7 * x/sqrtTPlusMax ) break; 328 if ( y < 1.0-0.7 * x/sqrtTPlusMax ) break;
329 } 329 }
330 } 330 }
331 else 331 else
332 { 332 {
333 TPlusNew = TPlusMax * (1.0 - (1.0 - TP 333 TPlusNew = TPlusMax * (1.0 - (1.0 - TPlusMin/TPlusMax)
334 * G4Pow::G 334 * G4Pow::GetInstance()->powA(G4UniformRand(),0.3333) );
335 }; 335 };
336 336
337 PPlusNew = SqrtS - TPlusNew; 337 PPlusNew = SqrtS - TPlusNew;
338 338
339 Qplus = PPlusNew - Pprojectile.plus(); 339 Qplus = PPlusNew - Pprojectile.plus();
340 PMinusNew = ProjMassT2 / PPlusNew; 340 PMinusNew = ProjMassT2 / PPlusNew;
341 Qminus = PMinusNew - Pprojectile.minus() 341 Qminus = PMinusNew - Pprojectile.minus();
342 } 342 }
343 343
344 Qmomentum.setPz( (Qplus - Qminus)/2 ); 344 Qmomentum.setPz( (Qplus - Qminus)/2 );
345 Qmomentum.setE( (Qplus + Qminus)/2 ); 345 Qmomentum.setE( (Qplus + Qminus)/2 );
346 346
347 #ifdef debugQuarkExchange 347 #ifdef debugQuarkExchange
348 G4cout<<"ProjectileDiffraction (Pproject 348 G4cout<<"ProjectileDiffraction (Pprojectile + Qmomentum).mag2() Mprojectile2"<<G4endl;
349 G4cout<<ProjectileDiffraction<<" "<<( Pp 349 G4cout<<ProjectileDiffraction<<" "<<( Pprojectile + Qmomentum ).mag2()<<" "<< Mprojectile2<<G4endl;
350 G4cout<<"TargetDiffraction (Ptarget 350 G4cout<<"TargetDiffraction (Ptarget - Qmomentum).mag2() Mtarget2"<<G4endl;
351 G4cout<<!ProjectileDiffraction<<" "<<( P 351 G4cout<<!ProjectileDiffraction<<" "<<( Ptarget - Qmomentum ).mag2()<<" "<< Mtarget2<<G4endl;
352 #endif 352 #endif
353 353
354 } while ( ( ProjectileDiffraction&&( Pprojec 354 } while ( ( ProjectileDiffraction&&( Pprojectile + Qmomentum ).mag2() < Mprojectile2 ) ||
355 (!ProjectileDiffraction&&( Ptarget 355 (!ProjectileDiffraction&&( Ptarget - Qmomentum ).mag2() < Mtarget2 ) );
356 // Repeat the sampling because there was n 356 // Repeat the sampling because there was not any excitation
357 357
358 Pprojectile += Qmomentum; 358 Pprojectile += Qmomentum;
359 359
360 Ptarget -= Qmomentum; 360 Ptarget -= Qmomentum;
361 361
362 // Transform back and update SplitableHadron 362 // Transform back and update SplitableHadron Participant.
363 Pprojectile.transform(toLab); 363 Pprojectile.transform(toLab);
364 Ptarget.transform(toLab); 364 Ptarget.transform(toLab);
365 365
366 #ifdef debugQuarkExchange 366 #ifdef debugQuarkExchange
367 G4cout << "Pprojectile in Lab. " << Pproj 367 G4cout << "Pprojectile in Lab. " << Pprojectile << G4endl;
368 G4cout << "Ptarget in Lab. " << Ptarg 368 G4cout << "Ptarget in Lab. " << Ptarget << G4endl;
369 G4cout << "G4QuarkExchange: Projectile mas 369 G4cout << "G4QuarkExchange: Projectile mass " << Pprojectile.mag() << G4endl;
370 G4cout << "G4QuarkExchange: Target mass 370 G4cout << "G4QuarkExchange: Target mass " << Ptarget.mag() << G4endl;
371 #endif 371 #endif
372 372
373 target->Set4Momentum(Ptarget); 373 target->Set4Momentum(Ptarget);
374 projectile->Set4Momentum(Pprojectile); 374 projectile->Set4Momentum(Pprojectile);
375 375
376 //=================================== Quark 376 //=================================== Quark exchange ================================
377 projectile->SplitUp(); 377 projectile->SplitUp();
378 target->SplitUp(); 378 target->SplitUp();
379 379
380 G4Parton* PrQuark = nullptr; 380 G4Parton* PrQuark = nullptr;
381 G4Parton* TrQuark = nullptr; 381 G4Parton* TrQuark = nullptr;
382 382
383 if( projectile->GetDefinition()->GetBaryonNu 383 if( projectile->GetDefinition()->GetBaryonNumber() >= 0 ) { // Uzhi June 2020
384 // Quark exchange ---- 384 // Quark exchange ----
385 PrQuark = projectile->GetNextParton(); 385 PrQuark = projectile->GetNextParton();
386 TrQuark = target->GetNextParton(); 386 TrQuark = target->GetNextParton();
387 G4ParticleDefinition * Tmp = PrQuark->GetD 387 G4ParticleDefinition * Tmp = PrQuark->GetDefinition();
388 PrQuark->SetDefinition(TrQuark->GetDefinit 388 PrQuark->SetDefinition(TrQuark->GetDefinition());
389 TrQuark->SetDefinition(Tmp); 389 TrQuark->SetDefinition(Tmp);
390 return true; 390 return true;
391 } 391 }
392 392
393 // Quark exchage for projectile anti-baryon 393 // Quark exchage for projectile anti-baryon (annihilation and new Q pair creation ---
394 // This part added by Uzhi June 2020 394 // This part added by Uzhi June 2020
395 PrQuark = projectile->GetNextAntiParton(); 395 PrQuark = projectile->GetNextAntiParton();
396 TrQuark = target->GetNextParton(); 396 TrQuark = target->GetNextParton();
397 if( -PrQuark->GetDefinition()->GetPDGEncodin 397 if( -PrQuark->GetDefinition()->GetPDGEncoding() == TrQuark->GetDefinition()->GetPDGEncoding() ){
398 G4int QuarkCode = 1 + (int)(G4UniformRand( 398 G4int QuarkCode = 1 + (int)(G4UniformRand()/StrangeSuppress);
399 G4ParticleDefinition* AQpr = G4ParticleTab 399 G4ParticleDefinition* AQpr = G4ParticleTable::GetParticleTable()->FindParticle(-QuarkCode);
400 G4ParticleDefinition* Qtr = G4ParticleTab 400 G4ParticleDefinition* Qtr = G4ParticleTable::GetParticleTable()->FindParticle( QuarkCode);
401 if( (AQpr != nullptr) && (Qtr != nullptr) 401 if( (AQpr != nullptr) && (Qtr != nullptr) ) {
402 PrQuark->SetDefinition(AQpr); 402 PrQuark->SetDefinition(AQpr);
403 TrQuark->SetDefinition( Qtr); 403 TrQuark->SetDefinition( Qtr);
404 } 404 }
405 } 405 }
406 406
407 return true; 407 return true;
408 } 408 }
409 409
410 410
411 // --------- private methods ----------------- 411 // --------- private methods ----------------------
412 412
413 G4ThreeVector G4QuarkExchange::GaussianPt(G4do 413 G4ThreeVector G4QuarkExchange::GaussianPt(G4double widthSquare, G4double maxPtSquare) const
414 { // @@ this method is used in FTF 414 { // @@ this method is used in FTFModel as well. Should go somewhere common!
415 415
416 G4double pt2; 416 G4double pt2;
417 417
418 const G4int maxNumberOfLoops = 1000; 418 const G4int maxNumberOfLoops = 1000;
419 G4int loopCounter = 0; 419 G4int loopCounter = 0;
420 do { 420 do {
421 pt2=-widthSquare * G4Log( G4UniformRand() 421 pt2=-widthSquare * G4Log( G4UniformRand() );
422 } while ( ( pt2 > maxPtSquare) && ++loopCoun 422 } while ( ( pt2 > maxPtSquare) && ++loopCounter < maxNumberOfLoops ); /* Loop checking, 07.08.2015, A.Ribon */
423 if ( loopCounter >= maxNumberOfLoops ) { 423 if ( loopCounter >= maxNumberOfLoops ) {
424 pt2 = 0.99*maxPtSquare; // Just an accept 424 pt2 = 0.99*maxPtSquare; // Just an acceptable value, without any physics consideration.
425 } 425 }
426 426
427 pt2=std::sqrt(pt2); 427 pt2=std::sqrt(pt2);
428 428
429 G4double phi=G4UniformRand() * twopi; 429 G4double phi=G4UniformRand() * twopi;
430 430
431 return G4ThreeVector (pt2*std::cos(phi), pt2 431 return G4ThreeVector (pt2*std::cos(phi), pt2*std::sin(phi), 0.);
432 } 432 }
433 433
434 434