source: trunk/source/processes/hadronic/models/parton_string/hadronization/src/G4HadronBuilder.cc@ 1330

Last change on this file since 1330 was 1228, checked in by garnier, 16 years ago

update geant4.9.3 tag
File size: 9.4 KB
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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// $Id: G4HadronBuilder.cc,v 1.10 2009/05/22 16:34:31 gunter Exp $
28// GEANT4 tag $Name: geant4-09-03 $
29//
30// -----------------------------------------------------------------------------
31// GEANT 4 class implementation file
32//
33// History:
34// Gunter Folger, August/September 2001
35// Create class; algorithm previously in G4VLongitudinalStringDecay.
36// -----------------------------------------------------------------------------
37
38#include "G4HadronBuilder.hh"
39#include "G4HadronicException.hh"
40#include "Randomize.hh"
41#include "G4ParticleTable.hh"
42
43G4HadronBuilder::G4HadronBuilder(G4double mesonMix, G4double barionMix,
44 std::vector<double> scalarMesonMix,
45 std::vector<double> vectorMesonMix)
46{
47 mesonSpinMix=mesonMix;
48 barionSpinMix=barionMix;
49 scalarMesonMixings=scalarMesonMix;
50 vectorMesonMixings=vectorMesonMix;
51}
52
53G4ParticleDefinition * G4HadronBuilder::Build(G4ParticleDefinition * black, G4ParticleDefinition * white)
54{
55
56 if (black->GetParticleSubType()== "di_quark" || white->GetParticleSubType()== "di_quark" ) {
57
58// Barion
59 Spin spin = (G4UniformRand() < barionSpinMix) ? SpinHalf : SpinThreeHalf;
60 return Barion(black,white,spin);
61
62 } else {
63
64// Meson
65 Spin spin = (G4UniformRand() < mesonSpinMix) ? SpinZero : SpinOne;
66 return Meson(black,white,spin);
67
68 }
69}
70
71//-------------------------------------------------------------------------
72
73G4ParticleDefinition * G4HadronBuilder::BuildLowSpin(G4ParticleDefinition * black, G4ParticleDefinition * white)
74{
75 if ( black->GetParticleSubType()== "quark" && white->GetParticleSubType()== "quark" ) {
76 return Meson(black,white, SpinZero);
77 } else {
78// will return a SpinThreeHalf Barion if all quarks the same
79 return Barion(black,white, SpinHalf);
80 }
81}
82
83//-------------------------------------------------------------------------
84
85G4ParticleDefinition * G4HadronBuilder::BuildHighSpin(G4ParticleDefinition * black, G4ParticleDefinition * white)
86{
87 if ( black->GetParticleSubType()== "quark" && white->GetParticleSubType()== "quark" ) {
88 return Meson(black,white, SpinOne);
89 } else {
90 return Barion(black,white,SpinThreeHalf);
91 }
92}
93
94//-------------------------------------------------------------------------
95
96G4ParticleDefinition * G4HadronBuilder::Meson(G4ParticleDefinition * black,
97 G4ParticleDefinition * white, Spin theSpin)
98{
99#ifdef G4VERBOSE
100// Verify Input Charge
101
102 G4double charge = black->GetPDGCharge()
103 + white->GetPDGCharge();
104 if (std::abs(charge) > 2 || std::abs(3.*charge - 3*G4int(charge*1.001)) > perCent ) // 1.001 to avoid int(.9999) -> 0
105 {
106 G4cerr << " G4HadronBuilder::Build()" << G4endl;
107 G4cerr << " Invalid total charge found for on input: "
108 << charge<< G4endl;
109 G4cerr << " PGDcode input quark1/quark2 : " <<
110 black->GetPDGEncoding() << " / "<<
111 white->GetPDGEncoding() << G4endl;
112 G4cerr << G4endl;
113 }
114#endif
115
116 G4int id1= black->GetPDGEncoding();
117 G4int id2= white->GetPDGEncoding();
118// G4int ifl1= std::max(std::abs(id1), std::abs(id2));
119 if ( std::abs(id1) < std::abs(id2) )
120 {
121 G4int xchg = id1;
122 id1 = id2;
123 id2 = xchg;
124 }
125
126 if (std::abs(id1) > 3 )
127 throw G4HadronicException(__FILE__, __LINE__, "G4HadronBuilder::Meson : Illegal Quark content as input");
128
129 G4int PDGEncoding=0;
130
131 if (id1 + id2 == 0) {
132 G4double rmix = G4UniformRand();
133 G4int imix = 2*std::abs(id1) - 1;
134 if(theSpin == SpinZero) {
135 PDGEncoding = 110*(1 + (G4int)(rmix + scalarMesonMixings[imix - 1])
136 + (G4int)(rmix + scalarMesonMixings[imix])
137 ) + theSpin;
138 } else {
139 PDGEncoding = 110*(1 + (G4int)(rmix + vectorMesonMixings[imix - 1])
140 + (G4int)(rmix + vectorMesonMixings[imix])
141 ) + theSpin;
142 }
143 } else {
144 PDGEncoding = 100 * std::abs(id1) + 10 * std::abs(id2) + theSpin;
145 G4bool IsUp = (std::abs(id1)&1) == 0; // quark 1 up type quark (u or c)
146 G4bool IsAnti = id1 < 0; // quark 1 is antiquark?
147 if( (IsUp && IsAnti ) || (!IsUp && !IsAnti ) )
148 PDGEncoding = - PDGEncoding;
149 }
150
151
152 G4ParticleDefinition * MesonDef=
153 G4ParticleTable::GetParticleTable()->FindParticle(PDGEncoding);
154#ifdef G4VERBOSE
155 if (MesonDef == 0 ) {
156 G4cerr << " G4HadronBuilder - Warning: No particle for PDGcode= "
157 << PDGEncoding << G4endl;
158 }
159 if ( ( black->GetPDGCharge()
160 + white->GetPDGCharge()
161 - MesonDef->GetPDGCharge() ) > perCent ) {
162 G4cerr << " G4HadronBuilder - Warning: Incorrect Charge : "
163 << " Quark1/2 = "
164 << black->GetParticleName() << " / "
165 << white->GetParticleName()
166 << " resulting Hadron " << MesonDef->GetParticleName()
167 << G4endl;
168 }
169#endif
170
171 return MesonDef;
172}
173
174
175G4ParticleDefinition * G4HadronBuilder::Barion(G4ParticleDefinition * black,
176 G4ParticleDefinition * white,Spin theSpin)
177{
178
179#ifdef G4VERBOSE
180// Verify Input Charge
181 G4double charge = black->GetPDGCharge()
182 + white->GetPDGCharge();
183 if (std::abs(charge) > 2 || std::abs(3.*charge - 3*G4int(charge*1.001)) > perCent )
184 {
185 G4cerr << " G4HadronBuilder::Build()" << G4endl;
186 G4cerr << " Invalid total charge found for on input: "
187 << charge<< G4endl;
188 G4cerr << " PGDcode input quark1/quark2 : " <<
189 black->GetPDGEncoding() << " / "<<
190 white->GetPDGEncoding() << G4endl;
191 G4cerr << G4endl;
192 }
193#endif
194 G4int id1= black->GetPDGEncoding();
195 G4int id2= white->GetPDGEncoding();
196 if ( std::abs(id1) < std::abs(id2) )
197 {
198 G4int xchg = id1;
199 id1 = id2;
200 id2 = xchg;
201 }
202
203 if (std::abs(id1) < 1000 || std::abs(id2) > 3 )
204 throw G4HadronicException(__FILE__, __LINE__, "G4HadronBuilder::Barion: Illegal quark content as input");
205
206 G4int ifl1= std::abs(id1)/1000;
207 G4int ifl2 = (std::abs(id1) - ifl1 * 1000)/100;
208 G4int diquarkSpin = std::abs(id1)%10;
209 G4int ifl3 = id2;
210 if (id1 < 0)
211 {
212 ifl1 = - ifl1;
213 ifl2 = - ifl2;
214 }
215 //... Construct barion, distinguish Lambda and Sigma barions.
216 G4int kfla = std::abs(ifl1);
217 G4int kflb = std::abs(ifl2);
218 G4int kflc = std::abs(ifl3);
219
220 G4int kfld = std::max(kfla,kflb);
221 kfld = std::max(kfld,kflc);
222 G4int kflf = std::min(kfla,kflb);
223 kflf = std::min(kflf,kflc);
224
225 G4int kfle = kfla + kflb + kflc - kfld - kflf;
226
227 //... barion with content uuu or ddd or sss has always spin = 3/2
228 theSpin = (kfla == kflb && kflb == kflc)? SpinThreeHalf : theSpin;
229
230 G4int kfll = 0;
231 if(theSpin == SpinHalf && kfld > kfle && kfle > kflf) {
232// Spin J=1/2 and all three quarks different
233// Two states exist: (uds -> lambda or sigma0)
234// - lambda: s(ud)0 s : 3122; ie. reverse the two lighter quarks
235// - sigma0: s(ud)1 s : 3212
236 if(diquarkSpin == 1 ) {
237 if ( kfla == kfld) { // heaviest quark in diquark
238 kfll = 1;
239 } else {
240 kfll = (G4int)(0.25 + G4UniformRand());
241 }
242 }
243 if(diquarkSpin == 3 && kfla != kfld)
244 kfll = (G4int)(0.75 + G4UniformRand());
245 }
246
247 G4int PDGEncoding;
248 if (kfll == 1)
249 PDGEncoding = 1000 * kfld + 100 * kflf + 10 * kfle + theSpin;
250 else
251 PDGEncoding = 1000 * kfld + 100 * kfle + 10 * kflf + theSpin;
252
253 if (id1 < 0)
254 PDGEncoding = -PDGEncoding;
255
256
257 G4ParticleDefinition * BarionDef=
258 G4ParticleTable::GetParticleTable()->FindParticle(PDGEncoding);
259#ifdef G4VERBOSE
260 if (BarionDef == 0 ) {
261 G4cerr << " G4HadronBuilder - Warning: No particle for PDGcode= "
262 << PDGEncoding << G4endl;
263 }
264 if ( ( black->GetPDGCharge()
265 + white->GetPDGCharge()
266 - BarionDef->GetPDGCharge() ) > perCent ) {
267 G4cerr << " G4HadronBuilder - Warning: Incorrect Charge : "
268 << " DiQuark/Quark = "
269 << black->GetParticleName() << " / "
270 << white->GetParticleName()
271 << " resulting Hadron " << BarionDef->GetParticleName()
272 << G4endl;
273 }
274#endif
275
276 return BarionDef;
277}
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