source: trunk/source/processes/hadronic/models/low_energy/src/G4LEAntiXiZeroInelastic.cc@ 1036

Last change on this file since 1036 was 1007, checked in by garnier, 17 years ago

update to geant4.9.2
File size: 14.2 KB
Line 
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: G4LEAntiXiZeroInelastic.cc,v 1.11 2006/06/29 20:44:55 gunter Exp $
28// GEANT4 tag $Name: geant4-09-02 $
29//
30 // Hadronic Process: AntiXiZero Inelastic Process
31 // J.L. Chuma, TRIUMF, 20-Feb-1997
32 // Last modified: 27-Mar-1997
33 // Modified by J.L.Chuma 30-Apr-97: added originalTarget for CalculateMomenta
34 //
35 // NOTE: The FORTRAN version of the cascade, CASAXO, simply called the
36 // routine for the XiZero particle. Hence, the ApplyYourself function
37 // below is just a copy of the ApplyYourself from the XiZero particle.
38
39#include "G4LEAntiXiZeroInelastic.hh"
40#include "Randomize.hh"
41
42 G4HadFinalState *
43 G4LEAntiXiZeroInelastic::ApplyYourself( const G4HadProjectile &aTrack,
44 G4Nucleus &targetNucleus )
45 {
46 const G4HadProjectile *originalIncident = &aTrack;
47 //
48 // create the target particle
49 //
50 G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle();
51
52 if( verboseLevel > 1 )
53 {
54 const G4Material *targetMaterial = aTrack.GetMaterial();
55 G4cout << "G4LEAntiXiZeroInelastic::ApplyYourself called" << G4endl;
56 G4cout << "kinetic energy = " << originalIncident->GetKineticEnergy()/MeV << "MeV, ";
57 G4cout << "target material = " << targetMaterial->GetName() << ", ";
58 G4cout << "target particle = " << originalTarget->GetDefinition()->GetParticleName()
59 << G4endl;
60 }
61 //
62 // Fermi motion and evaporation
63 // As of Geant3, the Fermi energy calculation had not been Done
64 //
65 G4double ek = originalIncident->GetKineticEnergy()/MeV;
66 G4double amas = originalIncident->GetDefinition()->GetPDGMass()/MeV;
67 G4ReactionProduct modifiedOriginal;
68 modifiedOriginal = *originalIncident;
69
70 G4double tkin = targetNucleus.Cinema( ek );
71 ek += tkin;
72 modifiedOriginal.SetKineticEnergy( ek*MeV );
73 G4double et = ek + amas;
74 G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) );
75 G4double pp = modifiedOriginal.GetMomentum().mag()/MeV;
76 if( pp > 0.0 )
77 {
78 G4ThreeVector momentum = modifiedOriginal.GetMomentum();
79 modifiedOriginal.SetMomentum( momentum * (p/pp) );
80 }
81 //
82 // calculate black track energies
83 //
84 tkin = targetNucleus.EvaporationEffects( ek );
85 ek -= tkin;
86 modifiedOriginal.SetKineticEnergy( ek*MeV );
87 et = ek + amas;
88 p = std::sqrt( std::abs((et-amas)*(et+amas)) );
89 pp = modifiedOriginal.GetMomentum().mag()/MeV;
90 if( pp > 0.0 )
91 {
92 G4ThreeVector momentum = modifiedOriginal.GetMomentum();
93 modifiedOriginal.SetMomentum( momentum * (p/pp) );
94 }
95 G4ReactionProduct currentParticle = modifiedOriginal;
96 G4ReactionProduct targetParticle;
97 targetParticle = *originalTarget;
98 currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere
99 targetParticle.SetSide( -1 ); // target always goes in backward hemisphere
100 G4bool incidentHasChanged = false;
101 G4bool targetHasChanged = false;
102 G4bool quasiElastic = false;
103 G4FastVector<G4ReactionProduct,GHADLISTSIZE> vec; // vec will contain the secondary particles
104 G4int vecLen = 0;
105 vec.Initialize( 0 );
106
107 const G4double cutOff = 0.1;
108 const G4double anni = std::min( 1.3*currentParticle.GetTotalMomentum()/GeV, 0.4 );
109 if( (currentParticle.GetKineticEnergy()/MeV > cutOff) || (G4UniformRand() > anni) )
110 Cascade( vec, vecLen,
111 originalIncident, currentParticle, targetParticle,
112 incidentHasChanged, targetHasChanged, quasiElastic );
113
114 CalculateMomenta( vec, vecLen,
115 originalIncident, originalTarget, modifiedOriginal,
116 targetNucleus, currentParticle, targetParticle,
117 incidentHasChanged, targetHasChanged, quasiElastic );
118
119 SetUpChange( vec, vecLen,
120 currentParticle, targetParticle,
121 incidentHasChanged );
122
123 delete originalTarget;
124 return &theParticleChange;
125 }
126
127 void
128 G4LEAntiXiZeroInelastic::Cascade(
129 G4FastVector<G4ReactionProduct,GHADLISTSIZE> &vec,
130 G4int& vecLen,
131 const G4HadProjectile *originalIncident,
132 G4ReactionProduct &currentParticle,
133 G4ReactionProduct &targetParticle,
134 G4bool &incidentHasChanged,
135 G4bool &targetHasChanged,
136 G4bool &quasiElastic )
137 {
138 // derived from original FORTRAN code CASAX0 by H. Fesefeldt (20-Jan-1989)
139 // which is just a copy of CASX0 (cascade for Xi0)
140 //
141 // AntiXiZero undergoes interaction with nucleon within a nucleus. Check if it is
142 // energetically possible to produce pions/kaons. In not, assume nuclear excitation
143 // occurs and input particle is degraded in energy. No other particles are produced.
144 // If reaction is possible, find the correct number of pions/protons/neutrons
145 // produced using an interpolation to multiplicity data. Replace some pions or
146 // protons/neutrons by kaons or strange baryons according to the average
147 // multiplicity per inelastic reaction.
148 //
149 const G4double mOriginal = originalIncident->GetDefinition()->GetPDGMass()/MeV;
150 const G4double etOriginal = originalIncident->GetTotalEnergy()/MeV;
151 const G4double targetMass = targetParticle.GetMass()/MeV;
152 G4double centerofmassEnergy = std::sqrt( mOriginal*mOriginal +
153 targetMass*targetMass +
154 2.0*targetMass*etOriginal );
155 G4double availableEnergy = centerofmassEnergy-(targetMass+mOriginal);
156 if( availableEnergy <= G4PionPlus::PionPlus()->GetPDGMass()/MeV )
157 {
158 quasiElastic = true;
159 return;
160 }
161 static G4bool first = true;
162 const G4int numMul = 1200;
163 const G4int numSec = 60;
164 static G4double protmul[numMul], protnorm[numSec]; // proton constants
165 static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
166 // np = number of pi+, nm = number of pi-, nz = number of pi0
167 G4int counter, nt=0, np=0, nm=0, nz=0;
168 G4double test;
169 const G4double c = 1.25;
170 const G4double b[] = { 0.7, 0.7 };
171 if( first ) // compute normalization constants, this will only be Done once
172 {
173 first = false;
174 G4int i;
175 for( i=0; i<numMul; ++i )protmul[i] = 0.0;
176 for( i=0; i<numSec; ++i )protnorm[i] = 0.0;
177 counter = -1;
178 for( np=0; np<(numSec/3); ++np )
179 {
180 for( nm=std::max(0,np-2); nm<=(np+1); ++nm )
181 {
182 for( nz=0; nz<numSec/3; ++nz )
183 {
184 if( ++counter < numMul )
185 {
186 nt = np+nm+nz;
187 if( nt>0 && nt<=numSec )
188 {
189 protmul[counter] = Pmltpc(np,nm,nz,nt,b[0],c);
190 protnorm[nt-1] += protmul[counter];
191 }
192 }
193 }
194 }
195 }
196 for( i=0; i<numMul; ++i )neutmul[i] = 0.0;
197 for( i=0; i<numSec; ++i )neutnorm[i] = 0.0;
198 counter = -1;
199 for( np=0; np<numSec/3; ++np )
200 {
201 for( nm=std::max(0,np-1); nm<=(np+2); ++nm )
202 {
203 for( nz=0; nz<numSec/3; ++nz )
204 {
205 if( ++counter < numMul )
206 {
207 nt = np+nm+nz;
208 if( nt>0 && nt<=numSec )
209 {
210 neutmul[counter] = Pmltpc(np,nm,nz,nt,b[1],c);
211 neutnorm[nt-1] += neutmul[counter];
212 }
213 }
214 }
215 }
216 }
217 for( i=0; i<numSec; ++i )
218 {
219 if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
220 if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
221 }
222 } // end of initialization
223
224 const G4double expxu = 82.; // upper bound for arg. of exp
225 const G4double expxl = -expxu; // lower bound for arg. of exp
226 G4ParticleDefinition *aNeutron = G4Neutron::Neutron();
227 G4ParticleDefinition *aProton = G4Proton::Proton();
228 G4ParticleDefinition *aKaonMinus = G4KaonMinus::KaonMinus();
229 G4ParticleDefinition *aSigmaPlus = G4SigmaPlus::SigmaPlus();
230 G4ParticleDefinition *aXiMinus = G4XiMinus::XiMinus();
231 //
232 // energetically possible to produce pion(s) --> inelastic scattering
233 //
234 G4double n, anpn;
235 GetNormalizationConstant( availableEnergy, n, anpn );
236 G4double ran = G4UniformRand();
237 G4double dum, excs = 0.0;
238 if( targetParticle.GetDefinition() == aProton )
239 {
240 counter = -1;
241 for( np=0; np<numSec/3 && ran>=excs; ++np )
242 {
243 for( nm=std::max(0,np-2); nm<=(np+1) && ran>=excs; ++nm )
244 {
245 for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
246 {
247 if( ++counter < numMul )
248 {
249 nt = np+nm+nz;
250 if( nt>0 && nt<=numSec )
251 {
252 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
253 dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
254 if( std::fabs(dum) < 1.0 )
255 {
256 if( test >= 1.0e-10 )excs += dum*test;
257 }
258 else
259 excs += dum*test;
260 }
261 }
262 }
263 }
264 }
265 if( ran >= excs ) // 3 previous loops continued to the end
266 {
267 quasiElastic = true;
268 return;
269 }
270 np--; nm--; nz--;
271 //
272 // number of secondary mesons determined by kno distribution
273 // check for total charge of final state mesons to determine
274 // the kind of baryons to be produced, taking into account
275 // charge and strangeness conservation
276 //
277 if( np < nm+1 )
278 {
279 if( np != nm ) // charge mismatch
280 {
281 currentParticle.SetDefinitionAndUpdateE( aSigmaPlus );
282 incidentHasChanged = true;
283 //
284 // correct the strangeness by replacing a pi- by a kaon-
285 //
286 vec.Initialize( 1 );
287 G4ReactionProduct *p = new G4ReactionProduct;
288 p->SetDefinition( aKaonMinus );
289 (G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
290 vec.SetElement( vecLen++, p );
291 --nm;
292 }
293 }
294 else if( np == nm+1 )
295 {
296 if( G4UniformRand() < 0.5 )
297 {
298 targetParticle.SetDefinitionAndUpdateE( aNeutron );
299 targetHasChanged = true;
300 }
301 else
302 {
303 currentParticle.SetDefinitionAndUpdateE( aXiMinus );
304 incidentHasChanged = true;
305 }
306 }
307 else
308 {
309 currentParticle.SetDefinitionAndUpdateE( aXiMinus );
310 incidentHasChanged = true;
311 targetParticle.SetDefinitionAndUpdateE( aNeutron );
312 targetHasChanged = true;
313 }
314 }
315 else // target must be a neutron
316 {
317 counter = -1;
318 for( np=0; np<numSec/3 && ran>=excs; ++np )
319 {
320 for( nm=std::max(0,np-1); nm<=(np+2) && ran>=excs; ++nm )
321 {
322 for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
323 {
324 if( ++counter < numMul )
325 {
326 nt = np+nm+nz;
327 if( nt>0 && nt<=numSec )
328 {
329 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
330 dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
331 if( std::fabs(dum) < 1.0 )
332 {
333 if( test >= 1.0e-10 )excs += dum*test;
334 }
335 else
336 excs += dum*test;
337 }
338 }
339 }
340 }
341 }
342 if( ran >= excs ) // 3 previous loops continued to the end
343 {
344 quasiElastic = true;
345 return;
346 }
347 np--; nm--; nz--;
348 if( np < nm )
349 {
350 if( np+1 == nm )
351 {
352 targetParticle.SetDefinitionAndUpdateE( aProton );
353 targetHasChanged = true;
354 }
355 else // charge mismatch
356 {
357 currentParticle.SetDefinitionAndUpdateE( aSigmaPlus );
358 incidentHasChanged = true;
359 targetParticle.SetDefinitionAndUpdateE( aProton );
360 targetHasChanged = true;
361 //
362 // correct the strangeness by replacing a pi- by a kaon-
363 //
364 vec.Initialize( 1 );
365 G4ReactionProduct *p = new G4ReactionProduct;
366 p->SetDefinition( aKaonMinus );
367 (G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
368 vec.SetElement( vecLen++, p );
369 --nm;
370 }
371 }
372 else if( np == nm )
373 {
374 if( G4UniformRand() >= 0.5 )
375 {
376 currentParticle.SetDefinitionAndUpdateE( aXiMinus );
377 incidentHasChanged = true;
378 targetParticle.SetDefinitionAndUpdateE( aProton );
379 targetHasChanged = true;
380 }
381 }
382 else
383 {
384 currentParticle.SetDefinitionAndUpdateE( aXiMinus );
385 incidentHasChanged = true;
386 }
387 }
388 SetUpPions( np, nm, nz, vec, vecLen );
389 return;
390 }
391
392 /* end of file */
393
Note: See TracBrowser for help on using the repository browser.