source: trunk/source/processes/hadronic/models/low_energy/src/G4LEAntiSigmaMinusInelastic.cc@ 1036

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

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27// $Id: G4LEAntiSigmaMinusInelastic.cc,v 1.11 2006/06/29 20:44:49 gunter Exp $
28// GEANT4 tag $Name: geant4-09-02 $
29//
30 // Hadronic Process: AntiSigmaMinus Inelastic Process
31 // J.L. Chuma, TRIUMF, 19-Feb-1997
32 // Last modified: 27-Mar-1997
33 // J.P. Wellisch: 25.Apr-97: counter errors removed lines 426, 447
34 // Modified by J.L.Chuma 30-Apr-97: added originalTarget for CalculateMomenta
35
36#include "G4LEAntiSigmaMinusInelastic.hh"
37#include "Randomize.hh"
38
39 G4HadFinalState *
40 G4LEAntiSigmaMinusInelastic::ApplyYourself( const G4HadProjectile &aTrack,
41 G4Nucleus &targetNucleus )
42 {
43 const G4HadProjectile *originalIncident = &aTrack;
44 if (originalIncident->GetKineticEnergy()<= 0.1*MeV)
45 {
46 theParticleChange.SetStatusChange(isAlive);
47 theParticleChange.SetEnergyChange(aTrack.GetKineticEnergy());
48 theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit());
49 return &theParticleChange;
50 }
51 //
52 // create the target particle
53 //
54 G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle();
55
56 if( verboseLevel > 1 )
57 {
58 const G4Material *targetMaterial = aTrack.GetMaterial();
59 G4cout << "G4LEAntiSigmaMinusInelastic::ApplyYourself called" << G4endl;
60 G4cout << "kinetic energy = " << originalIncident->GetKineticEnergy()/MeV << "MeV, ";
61 G4cout << "target material = " << targetMaterial->GetName() << ", ";
62 G4cout << "target particle = " << originalTarget->GetDefinition()->GetParticleName()
63 << G4endl;
64 }
65 //
66 // Fermi motion and evaporation
67 // As of Geant3, the Fermi energy calculation had not been Done
68 //
69 G4double ek = originalIncident->GetKineticEnergy()/MeV;
70 G4double amas = originalIncident->GetDefinition()->GetPDGMass()/MeV;
71 G4ReactionProduct modifiedOriginal;
72 modifiedOriginal = *originalIncident;
73
74 G4double tkin = targetNucleus.Cinema( ek );
75 ek += tkin;
76 modifiedOriginal.SetKineticEnergy( ek*MeV );
77 G4double et = ek + amas;
78 G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) );
79 G4double pp = modifiedOriginal.GetMomentum().mag()/MeV;
80 if( pp > 0.0 )
81 {
82 G4ThreeVector momentum = modifiedOriginal.GetMomentum();
83 modifiedOriginal.SetMomentum( momentum * (p/pp) );
84 }
85 //
86 // calculate black track energies
87 //
88 tkin = targetNucleus.EvaporationEffects( ek );
89 ek -= tkin;
90 modifiedOriginal.SetKineticEnergy( ek*MeV );
91 et = ek + amas;
92 p = std::sqrt( std::abs((et-amas)*(et+amas)) );
93 pp = modifiedOriginal.GetMomentum().mag()/MeV;
94 if( pp > 0.0 )
95 {
96 G4ThreeVector momentum = modifiedOriginal.GetMomentum();
97 modifiedOriginal.SetMomentum( momentum * (p/pp) );
98 }
99 G4ReactionProduct currentParticle = modifiedOriginal;
100 G4ReactionProduct targetParticle;
101 targetParticle = *originalTarget;
102 currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere
103 targetParticle.SetSide( -1 ); // target always goes in backward hemisphere
104 G4bool incidentHasChanged = false;
105 G4bool targetHasChanged = false;
106 G4bool quasiElastic = false;
107 G4FastVector<G4ReactionProduct,GHADLISTSIZE> vec; // vec will contain the secondary particles
108 G4int vecLen = 0;
109 vec.Initialize( 0 );
110
111 const G4double cutOff = 0.1;
112 const G4double anni = std::min( 1.3*currentParticle.GetTotalMomentum()/GeV, 0.4 );
113 if( (currentParticle.GetKineticEnergy()/MeV > cutOff) || (G4UniformRand() > anni) )
114 Cascade( vec, vecLen,
115 originalIncident, currentParticle, targetParticle,
116 incidentHasChanged, targetHasChanged, quasiElastic );
117
118 CalculateMomenta( vec, vecLen,
119 originalIncident, originalTarget, modifiedOriginal,
120 targetNucleus, currentParticle, targetParticle,
121 incidentHasChanged, targetHasChanged, quasiElastic );
122
123 SetUpChange( vec, vecLen,
124 currentParticle, targetParticle,
125 incidentHasChanged );
126
127 delete originalTarget;
128 return &theParticleChange;
129 }
130
131 void
132 G4LEAntiSigmaMinusInelastic::Cascade(
133 G4FastVector<G4ReactionProduct,GHADLISTSIZE> &vec,
134 G4int& vecLen,
135 const G4HadProjectile *originalIncident,
136 G4ReactionProduct &currentParticle,
137 G4ReactionProduct &targetParticle,
138 G4bool &incidentHasChanged,
139 G4bool &targetHasChanged,
140 G4bool &quasiElastic )
141 {
142 // derived from original FORTRAN code CASASM by H. Fesefeldt (13-Sep-1987)
143 //
144 // AntiSigmaMinus undergoes interaction with nucleon within a nucleus. Check if it is
145 // energetically possible to produce pions/kaons. In not, assume nuclear excitation
146 // occurs and input particle is degraded in energy. No other particles are produced.
147 // If reaction is possible, find the correct number of pions/protons/neutrons
148 // produced using an interpolation to multiplicity data. Replace some pions or
149 // protons/neutrons by kaons or strange baryons according to the average
150 // multiplicity per Inelastic reaction.
151 //
152 const G4double mOriginal = originalIncident->GetDefinition()->GetPDGMass()/MeV;
153 const G4double etOriginal = originalIncident->GetTotalEnergy()/MeV;
154 const G4double pOriginal = originalIncident->GetTotalMomentum()/MeV;
155 const G4double targetMass = targetParticle.GetMass()/MeV;
156 G4double centerofmassEnergy = std::sqrt( mOriginal*mOriginal +
157 targetMass*targetMass +
158 2.0*targetMass*etOriginal );
159 G4double availableEnergy = centerofmassEnergy-(targetMass+mOriginal);
160
161 static G4bool first = true;
162 const G4int numMul = 1200;
163 const G4int numMulA = 400;
164 const G4int numSec = 60;
165 static G4double protmul[numMul], protnorm[numSec]; // proton constants
166 static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
167 static G4double protmulA[numMulA], protnormA[numSec]; // proton constants
168 static G4double neutmulA[numMulA], neutnormA[numSec]; // neutron constants
169 // np = number of pi+, nm = number of pi-, nz = number of pi0
170 G4int counter, nt=0, np=0, nm=0, nz=0;
171 G4double test;
172 const G4double c = 1.25;
173 const G4double b[2] = { 0.7, 0.7 };
174 if( first ) // compute normalization constants, this will only be Done once
175 {
176 first = false;
177 G4int i;
178 for( i=0; i<numMul; ++i )protmul[i] = 0.0;
179 for( i=0; i<numSec; ++i )protnorm[i] = 0.0;
180 counter = -1;
181 for( np=0; np<(numSec/3); ++np )
182 {
183 for( nm=std::max(0,np-2); nm<=np; ++nm )
184 {
185 for( nz=0; nz<numSec/3; ++nz )
186 {
187 if( ++counter < numMul )
188 {
189 nt = np+nm+nz;
190 if( nt>0 && nt<=numSec )
191 {
192 protmul[counter] = Pmltpc(np,nm,nz,nt,b[0],c);
193 protnorm[nt-1] += protmul[counter];
194 }
195 }
196 }
197 }
198 }
199 for( i=0; i<numMul; ++i )neutmul[i] = 0.0;
200 for( i=0; i<numSec; ++i )neutnorm[i] = 0.0;
201 counter = -1;
202 for( np=0; np<numSec/3; ++np )
203 {
204 for( nm=std::max(0,np-1); nm<=(np+1); ++nm )
205 {
206 for( nz=0; nz<numSec/3; ++nz )
207 {
208 if( ++counter < numMul )
209 {
210 nt = np+nm+nz;
211 if( nt>0 && nt<=numSec )
212 {
213 neutmul[counter] = Pmltpc(np,nm,nz,nt,b[1],c);
214 neutnorm[nt-1] += neutmul[counter];
215 }
216 }
217 }
218 }
219 }
220 for( i=0; i<numSec; ++i )
221 {
222 if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
223 if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
224 }
225 //
226 // do the same for annihilation channels
227 //
228 for( i=0; i<numMulA; ++i )protmulA[i] = 0.0;
229 for( i=0; i<numSec; ++i )protnormA[i] = 0.0;
230 counter = -1;
231 for( np=2; np<(numSec/3); ++np )
232 {
233 nm = np-2;
234 for( nz=0; nz<numSec/3; ++nz )
235 {
236 if( ++counter < numMulA )
237 {
238 nt = np+nm+nz;
239 if( nt>1 && nt<=numSec )
240 {
241 protmulA[counter] = Pmltpc(np,nm,nz,nt,b[0],c);
242 protnormA[nt-1] += protmulA[counter];
243 }
244 }
245 }
246 }
247 for( i=0; i<numMulA; ++i )neutmulA[i] = 0.0;
248 for( i=0; i<numSec; ++i )neutnormA[i] = 0.0;
249 counter = -1;
250 for( np=1; np<numSec/3; ++np )
251 {
252 nm = np-1;
253 for( nz=0; nz<numSec/3; ++nz )
254 {
255 if( ++counter < numMulA )
256 {
257 nt = np+nm+nz;
258 if( nt>1 && nt<=numSec )
259 {
260 neutmulA[counter] = Pmltpc(np,nm,nz,nt,b[1],c);
261 neutnormA[nt-1] += neutmulA[counter];
262 }
263 }
264 }
265 }
266 for( i=0; i<numSec; ++i )
267 {
268 if( protnormA[i] > 0.0 )protnormA[i] = 1.0/protnormA[i];
269 if( neutnormA[i] > 0.0 )neutnormA[i] = 1.0/neutnormA[i];
270 }
271 } // end of initialization
272 const G4double expxu = 82.; // upper bound for arg. of exp
273 const G4double expxl = -expxu; // lower bound for arg. of exp
274 G4ParticleDefinition *aNeutron = G4Neutron::Neutron();
275 G4ParticleDefinition *aProton = G4Proton::Proton();
276 G4ParticleDefinition *aPiPlus = G4PionPlus::PionPlus();
277 G4ParticleDefinition *aKaonMinus = G4KaonMinus::KaonMinus();
278 G4ParticleDefinition *aKaonZL = G4KaonZeroLong::KaonZeroLong();
279 G4ParticleDefinition *aKaonPlus = G4KaonPlus::KaonPlus();
280 G4ParticleDefinition *anAntiLambda = G4AntiLambda::AntiLambda();
281 G4ParticleDefinition *anAntiSigmaZero = G4AntiSigmaZero::AntiSigmaZero();
282 const G4double anhl[] = {1.00,1.00,1.00,1.00,1.00,1.00,1.00,1.00,0.97,0.88,
283 0.85,0.81,0.75,0.64,0.64,0.55,0.55,0.45,0.47,0.40,
284 0.39,0.36,0.33,0.10,0.01};
285 G4int iplab = G4int( pOriginal/GeV*10.0 );
286 if( iplab > 9 )iplab = G4int( (pOriginal/GeV- 1.0)*5.0 ) + 10;
287 if( iplab > 14 )iplab = G4int( pOriginal/GeV- 2.0 ) + 15;
288 if( iplab > 23 )iplab = G4int( (pOriginal/GeV-10.0)/10.0 ) + 23;
289 if( iplab > 24 )iplab = 24;
290 if( G4UniformRand() > anhl[iplab] )
291 {
292 if( availableEnergy <= aPiPlus->GetPDGMass()/MeV )
293 {
294 quasiElastic = true;
295 return;
296 }
297 G4double n, anpn;
298 GetNormalizationConstant( availableEnergy, n, anpn );
299 G4double ran = G4UniformRand();
300 G4double dum, excs = 0.0;
301 if( targetParticle.GetDefinition() == aProton )
302 {
303 counter = -1;
304 for( np=0; np<numSec/3 && ran>=excs; ++np )
305 {
306 for( nm=std::max(0,np-2); nm<=np && ran>=excs; ++nm )
307 {
308 for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
309 {
310 if( ++counter < numMul )
311 {
312 nt = np+nm+nz;
313 if( nt>0 && nt<=numSec )
314 {
315 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
316 dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
317 if( std::fabs(dum) < 1.0 )
318 {
319 if( test >= 1.0e-10 )excs += dum*test;
320 }
321 else
322 excs += dum*test;
323 }
324 }
325 }
326 }
327 }
328 if( ran >= excs ) // 3 previous loops continued to the end
329 {
330 quasiElastic = true;
331 return;
332 }
333 np--; nm--; nz--;
334 G4int ncht = std::min( 3, std::max( 1, np-nm+1 ) );
335 switch( ncht )
336 {
337 case 1:
338 break;
339 case 2:
340 if( G4UniformRand() < 0.5 )
341 {
342 targetParticle.SetDefinitionAndUpdateE( aNeutron );
343 targetHasChanged = true;
344 }
345 else
346 {
347 if( G4UniformRand() < 0.5 )
348 currentParticle.SetDefinitionAndUpdateE( anAntiLambda );
349 else
350 currentParticle.SetDefinitionAndUpdateE( anAntiSigmaZero );
351 incidentHasChanged = true;
352 }
353 break;
354 case 3:
355 if( G4UniformRand() < 0.5 )
356 currentParticle.SetDefinitionAndUpdateE( anAntiLambda );
357 else
358 currentParticle.SetDefinitionAndUpdateE( anAntiSigmaZero );
359 incidentHasChanged = true;
360 targetParticle.SetDefinitionAndUpdateE( aNeutron );
361 targetHasChanged = true;
362 break;
363 }
364 }
365 else // target must be a neutron
366 {
367 counter = -1;
368 for( np=0; np<numSec/3 && ran>=excs; ++np )
369 {
370 for( nm=std::max(0,np-1); nm<=(np+1) && ran>=excs; ++nm )
371 {
372 for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
373 {
374 if( ++counter < numMul )
375 {
376 nt = np+nm+nz;
377 if( nt>0 && nt<=numSec )
378 {
379 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
380 dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
381 if( std::fabs(dum) < 1.0 )
382 {
383 if( test >= 1.0e-10 )excs += dum*test;
384 }
385 else
386 excs += dum*test;
387 }
388 }
389 }
390 }
391 }
392 if( ran >= excs ) // 3 previous loops continued to the end
393 {
394 quasiElastic = true;
395 return;
396 }
397 np--; nm--; nz--;
398 G4int ncht = std::min( 3, std::max( 1, np-nm+2 ) );
399 switch( ncht )
400 {
401 case 1:
402 {
403 targetParticle.SetDefinitionAndUpdateE( aProton );
404 targetHasChanged = true;
405 }
406 break;
407 case 2:
408 if( G4UniformRand() < 0.5 )
409 {
410 if( G4UniformRand() < 0.5 )
411 {
412 currentParticle.SetDefinitionAndUpdateE( anAntiLambda );
413 incidentHasChanged = true;
414 targetParticle.SetDefinitionAndUpdateE( aProton );
415 targetHasChanged = true;
416 }
417 }
418 else
419 {
420 if( G4UniformRand() < 0.5 )
421 {
422 currentParticle.SetDefinitionAndUpdateE( anAntiSigmaZero );
423 incidentHasChanged = true;
424 targetParticle.SetDefinitionAndUpdateE( aProton );
425 targetHasChanged = true;
426 }
427 }
428 break;
429 case 3:
430 if( G4UniformRand() < 0.5 )
431 currentParticle.SetDefinitionAndUpdateE( anAntiLambda );
432 else
433 currentParticle.SetDefinitionAndUpdateE( anAntiSigmaZero );
434 incidentHasChanged = true;
435 break;
436 }
437 }
438 }
439 else // random number <= anhl[iplab]
440 {
441 if( centerofmassEnergy <= aPiPlus->GetPDGMass()/MeV+aKaonPlus->GetPDGMass()/MeV )
442 {
443 quasiElastic = true;
444 return;
445 }
446 G4double n, anpn;
447 GetNormalizationConstant( -centerofmassEnergy, n, anpn );
448 G4double ran = G4UniformRand();
449 G4double dum, excs = 0.0;
450 if( targetParticle.GetDefinition() == aProton )
451 {
452 counter = -1;
453 for( np=2; np<numSec/3 && ran>=excs; ++np )
454 {
455 nm=np-2;
456 for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
457 {
458 if( ++counter < numMulA )
459 {
460 nt = np+nm+nz;
461 if( nt>1 && nt<=numSec )
462 {
463 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
464 dum = (pi/anpn)*nt*protmulA[counter]*protnormA[nt-1]/(2.0*n*n);
465 if( std::fabs(dum) < 1.0 )
466 {
467 if( test >= 1.0e-10 )excs += dum*test;
468 }
469 else
470 excs += dum*test;
471 }
472 }
473 }
474 }
475 if( ran >= excs ) // 3 previous loops continued to the end
476 {
477 quasiElastic = true;
478 return;
479 }
480 np--; nz--;
481 }
482 else // target must be a neutron
483 {
484 counter = -1;
485 for( np=1; np<numSec/3 && ran>=excs; ++np )
486 {
487 nm = np-1;
488 for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
489 {
490 if( ++counter < numMulA )
491 {
492 nt = np+nm+nz;
493 if( nt>1 && nt<=numSec )
494 {
495 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
496 dum = (pi/anpn)*nt*neutmulA[counter]*neutnormA[nt-1]/(2.0*n*n);
497 if( std::fabs(dum) < 1.0 )
498 {
499 if( test >= 1.0e-10 )excs += dum*test;
500 }
501 else
502 excs += dum*test;
503 }
504 }
505 }
506 }
507 if( ran >= excs ) // 3 previous loops continued to the end
508 {
509 quasiElastic = true;
510 return;
511 }
512 np--; nz--;
513 }
514 if( nz > 0 )
515 {
516 if( nm > 0 )
517 {
518 if( G4UniformRand() < 0.5 )
519 {
520 vec.Initialize( 1 );
521 G4ReactionProduct *p = new G4ReactionProduct;
522 p->SetDefinition( aKaonMinus );
523 (G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
524 vec.SetElement( vecLen++, p );
525 --nm;
526 }
527 else // random number >= 0.5
528 {
529 vec.Initialize( 1 );
530 G4ReactionProduct *p = new G4ReactionProduct;
531 p->SetDefinition( aKaonZL );
532 (G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
533 vec.SetElement( vecLen++, p );
534 --nz;
535 }
536 }
537 else // nm == 0
538 {
539 vec.Initialize( 1 );
540 G4ReactionProduct *p = new G4ReactionProduct;
541 p->SetDefinition( aKaonZL );
542 (G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
543 vec.SetElement( vecLen++, p );
544 --nz;
545 }
546 }
547 else // nz == 0
548 {
549 if( nm > 0 )
550 {
551 vec.Initialize( 1 );
552 G4ReactionProduct *p = new G4ReactionProduct;
553 p->SetDefinition( aKaonMinus );
554 (G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
555 vec.SetElement( vecLen++, p );
556 --nm;
557 }
558 }
559 currentParticle.SetMass( 0.0 );
560 targetParticle.SetMass( 0.0 );
561 }
562 SetUpPions( np, nm, nz, vec, vecLen );
563 return;
564 }
565
566 /* end of file */
567
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