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G4INCLKinematicsUtils.cc
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25 //
26 // INCL++ intra-nuclear cascade model
27 // Alain Boudard, CEA-Saclay, France
28 // Joseph Cugnon, University of Liege, Belgium
29 // Jean-Christophe David, CEA-Saclay, France
30 // Pekka Kaitaniemi, CEA-Saclay, France, and Helsinki Institute of Physics, Finland
31 // Sylvie Leray, CEA-Saclay, France
32 // Davide Mancusi, CEA-Saclay, France
33 //
34 #define INCLXX_IN_GEANT4_MODE 1
35 
36 #include "globals.hh"
37 
38 #include "G4INCLKinematicsUtils.hh"
39 #include "G4INCLParticleTable.hh"
40 
41 namespace G4INCL {
42 
43  namespace KinematicsUtils {
44 
45  void transformToLocalEnergyFrame(Nucleus const * const n, Particle * const p) {
46 // assert(!p->isMeson()); // No local energy for mesons
47  const G4double localEnergy = getLocalEnergy(n, p);
48  const G4double localTotalEnergy = p->getEnergy() - localEnergy;
49  p->setEnergy(localTotalEnergy);
51  }
52 
53  G4double getLocalEnergy(Nucleus const * const n, Particle * const p) {
54 // assert(!p->isMeson()); // No local energy for mesons
55 
56  G4double vloc = 0.0;
57  const G4double r = p->getPosition().mag();
58  const G4double mass = p->getMass();
59 
60  // Local energy is constant outside the surface
61  if(r > n->getUniverseRadius()) {
62  INCL_WARN("Tried to evaluate local energy for a particle outside the maximum radius."
63  << '\n' << p->print() << '\n'
64  << "Maximum radius = " << n->getDensity()->getMaximumRadius() << '\n'
65  << "Universe radius = " << n->getUniverseRadius() << '\n');
66  return 0.0;
67  }
68 
69  G4double pfl0 = 0.0;
70  const ParticleType t = p->getType();
71  const G4double kinE = p->getKineticEnergy();
72  if(kinE <= n->getPotential()->getFermiEnergy(t)) {
73  pfl0 = n->getPotential()->getFermiMomentum(p);
74  } else {
75  const G4double tf0 = p->getPotentialEnergy() - n->getPotential()->getSeparationEnergy(p);
76  if(tf0<0.0) return 0.0;
77  pfl0 = std::sqrt(tf0*(tf0 + 2.0*mass));
78  }
79  const G4double pReflection = p->getReflectionMomentum()/pfl0;
80  const G4double reflectionRadius = n->getDensity()->getMaxRFromP(p->getType(), pReflection);
81  const G4double pNominal = p->getMomentum().mag()/pfl0;
82  const G4double nominalReflectionRadius = n->getDensity()->getMaxRFromP(p->getType(), pNominal);
83  const G4double pl = pfl0*n->getDensity()->getMinPFromR(t, r*nominalReflectionRadius/reflectionRadius);
84  vloc = std::sqrt(pl*pl + mass*mass) - mass;
85 
86  return vloc;
87  }
88 
89  ThreeVector makeBoostVector(Particle const * const p1, Particle const * const p2){
90  const G4double totalEnergy = p1->getEnergy() + p2->getEnergy();
91  return ((p1->getMomentum() + p2->getMomentum())/totalEnergy);
92  }
93 
94  G4double totalEnergyInCM(Particle const * const p1, Particle const * const p2){
95  return std::sqrt(squareTotalEnergyInCM(p1,p2));
96  }
97 
98  G4double squareTotalEnergyInCM(Particle const * const p1, Particle const * const p2) {
99  G4double beta2 = makeBoostVector(p1, p2).mag2();
100  if(beta2 > 1.0) {
101  INCL_ERROR("squareTotalEnergyInCM: beta2 == " << beta2 << " > 1.0" << '\n');
102  beta2 = 0.0;
103  }
104  return (1.0 - beta2)*std::pow(p1->getEnergy() + p2->getEnergy(), 2);
105  }
106 
107  G4double momentumInCM(Particle const * const p1, Particle const * const p2) {
108  const G4double m1sq = std::pow(p1->getMass(),2);
109  const G4double m2sq = std::pow(p2->getMass(),2);
110  const G4double z = p1->getEnergy()*p2->getEnergy() - p1->getMomentum().dot(p2->getMomentum());
111  G4double pcm2 = (z*z-m1sq*m2sq)/(2*z+m1sq+m2sq);
112  if(pcm2 < 0.0) {
113  INCL_ERROR("momentumInCM: pcm2 == " << pcm2 << " < 0.0" << '\n');
114  pcm2 = 0.0;
115  }
116  return std::sqrt(pcm2);
117  }
118 
119  G4double momentumInCM(const G4double E, const G4double M1, const G4double M2) {
120  return 0.5*std::sqrt((E*E - std::pow(M1 + M2, 2))
121  *(E*E - std::pow(M1 - M2, 2)))/E;
122  }
123 
124  G4double momentumInLab(const G4double s, const G4double m1, const G4double m2) {
125  const G4double m1sq = m1*m1;
126  const G4double m2sq = m2*m2;
127  G4double plab2 = (s*s-2*s*(m1sq+m2sq)+(m1sq-m2sq)*(m1sq-m2sq))/(4*m2sq);
128  if(plab2 < 0.0) {
129  INCL_ERROR("momentumInLab: plab2 == " << plab2 << " < 0.0; m1sq == " << m1sq << "; m2sq == " << m2sq << "; s == " << s << '\n');
130  plab2 = 0.0;
131  }
132  return std::sqrt(plab2);
133  }
134 
135  G4double momentumInLab(Particle const * const p1, Particle const * const p2) {
136  const G4double m1 = p1->getMass();
137  const G4double m2 = p2->getMass();
138  const G4double s = squareTotalEnergyInCM(p1, p2);
139  return momentumInLab(s, m1, m2);
140  }
141 
143  G4double E = 0.0;
144  for(ParticleIter i=pl.begin(), e=pl.end(); i!=e; ++i) {
145  E += (*i)->getEnergy();
146  }
147  return E;
148  }
149 
151  ThreeVector p(0.0, 0.0, 0.0);
152  for(ParticleIter i=pl.begin(), e=pl.end(); i!=e; ++i) {
153  p += (*i)->getMomentum();
154  }
155  return p;
156  }
157 
159  return std::sqrt(p.mag2() + m*m);
160  }
161 
163  return std::sqrt(squareInvariantMass(E, p));
164  }
165 
167  return E*E - p.mag2();
168  }
169 
171  G4double mass;
172  if(p.theType==Composite)
173  mass = ParticleTable::getTableMass(p.theA, p.theZ, p.theS);
174  else
176  return (1.+EKin/mass);
177  }
178 
179  }
180 
181 }