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G4XPDGElastic.cc
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27 // $Id: G4XPDGElastic.cc,v 1.4 2010-03-12 15:45:18 gunter Exp $ //
28 // -------------------------------------------------------------------
29 //
30 // PDG Elastic cross section
31 // PDG fits, Phys.Rev. D50 (1994), 1335
32 //
33 //
34 // -------------------------------------------------------------------
35 
36 #include "globals.hh"
37 #include "G4ios.hh"
38 #include "G4SystemOfUnits.hh"
39 #include "G4XPDGElastic.hh"
40 #include "G4KineticTrack.hh"
41 #include "G4ParticleDefinition.hh"
42 #include "G4DataVector.hh"
43 
44 #include "G4AntiProton.hh"
45 #include "G4AntiNeutron.hh"
46 #include "G4Proton.hh"
47 #include "G4Neutron.hh"
48 #include "G4PionPlus.hh"
49 #include "G4PionMinus.hh"
50 #include "G4KaonMinus.hh"
51 #include "G4KaonPlus.hh"
52 
53 const G4double G4XPDGElastic::_lowLimit = 5. * GeV;
54 const G4double G4XPDGElastic::_highLimit = DBL_MAX;
55 
56 // Parameters of the PDG Elastic cross-section fit (Rev. Particle Properties, 1998)
57 // Columns are: lower and higher fit range, X, Y1, Y2
58 const G4int G4XPDGElastic::nPar = 7;
59 // p pi+
60 const G4double G4XPDGElastic::pPiPlusPDGFit[7] = { 2., 200., 0., 11.4, -0.4, 0.079, 0. };
61 // p pi-
62 const G4double G4XPDGElastic::pPiMinusPDGFit[7] = { 2., 360., 1.76, 11.2, -0.64, 0.043, 0. };
63 // p K+
64 const G4double G4XPDGElastic::pKPlusPDGFit[7] = { 2., 175., 5.0, 8.1, -1.8, 0.16, -1.3 };
65 // p K-
66 const G4double G4XPDGElastic::pKMinusPDGFit[7] = { 2., 175., 7.3, 0., 0., 0.29, -2.40 };
67 // p p
68 const G4double G4XPDGElastic::ppPDGFit[7] = { 2., 2100., 11.9, 26.9, -1.21, 0.169, -1.85 };
69 // p pbar
70 const G4double G4XPDGElastic::ppbarPDGFit[7] = { 5., 1730000., 10.2, 52.7, -1.16, 0.125, -1.28 };
71 // n pbar
72 const G4double G4XPDGElastic::npbarPDGFit[7] = { 1.1, 5.55, 36.5, 0., 0., 0., -11.9 };
73 
74 
75 G4XPDGElastic::G4XPDGElastic()
76 {
77  G4ParticleDefinition * proton = G4Proton::ProtonDefinition();
78  G4ParticleDefinition * neutron = G4Neutron::NeutronDefinition();
79  G4ParticleDefinition * piPlus = G4PionPlus::PionPlusDefinition();
80  G4ParticleDefinition * piMinus = G4PionMinus::PionMinusDefinition();
81  G4ParticleDefinition * KPlus = G4KaonPlus::KaonPlusDefinition();
82  G4ParticleDefinition * KMinus = G4KaonMinus::KaonMinusDefinition();
83  G4ParticleDefinition * antiproton = G4AntiProton::AntiProtonDefinition();
84 
85  std::pair<G4ParticleDefinition *,G4ParticleDefinition *> pp(proton,proton);
86  std::pair<G4ParticleDefinition *,G4ParticleDefinition *> pn(proton,neutron);
87  std::pair<G4ParticleDefinition *,G4ParticleDefinition *> piPlusp(piPlus,proton);
88  std::pair<G4ParticleDefinition *,G4ParticleDefinition *> piMinusp(piMinus,proton);
89  std::pair<G4ParticleDefinition *,G4ParticleDefinition *> KPlusp(KPlus,proton);
90  std::pair<G4ParticleDefinition *,G4ParticleDefinition *> KMinusp(KMinus,proton);
91  std::pair<G4ParticleDefinition *,G4ParticleDefinition *> nn(neutron,neutron);
92  std::pair<G4ParticleDefinition *,G4ParticleDefinition *> ppbar(proton,antiproton);
93  std::pair<G4ParticleDefinition *,G4ParticleDefinition *> npbar(antiproton,neutron);
94 
95  std::vector<G4double> ppData;
96  std::vector<G4double> pPiPlusData;
97  std::vector<G4double> pPiMinusData;
98  std::vector<G4double> pKPlusData;
99  std::vector<G4double> pKMinusData;
100  std::vector<G4double> ppbarData;
101  std::vector<G4double> npbarData;
102 
103  G4int i;
104  for (i=0; i<2; i++)
105  {
106  ppData.push_back(ppPDGFit[i] * GeV);
107  pPiPlusData.push_back(pPiPlusPDGFit[i] * GeV);
108  pPiMinusData.push_back(pPiMinusPDGFit[i] * GeV);
109  pKPlusData.push_back(pKPlusPDGFit[i] * GeV);
110  pKMinusData.push_back(pKMinusPDGFit[i] * GeV);
111  ppbarData.push_back(ppbarPDGFit[i] * GeV);
112  npbarData.push_back(npbarPDGFit[i] * GeV);
113  }
114 
115  for (i=2; i<nPar; i++)
116  {
117  ppData.push_back(ppPDGFit[i]);
118  pPiPlusData.push_back(pPiPlusPDGFit[i]);
119  pPiMinusData.push_back(pPiMinusPDGFit[i]);
120  pKPlusData.push_back(pKPlusPDGFit[i]);
121  pKMinusData.push_back(pKMinusPDGFit[i]);
122  ppbarData.push_back(ppbarPDGFit[i]);
123  npbarData.push_back(npbarPDGFit[i]);
124  }
125 
126  xMap[nn] = ppData;
127  xMap[pp] = ppData;
128  xMap[pn] = ppData;
129  xMap[piPlusp] = pPiPlusData;
130  xMap[piMinusp] = pPiMinusData;
131  xMap[KPlusp] = pKPlusData;
132  xMap[KMinusp] = pKMinusData;
133  xMap[ppbar] = ppbarData;
134  xMap[npbar] = npbarData;
135 }
136 
137 
138 G4XPDGElastic::~G4XPDGElastic()
139 { }
140 
141 
142 G4bool G4XPDGElastic::operator==(const G4XPDGElastic &right) const
143 {
144  return (this == (G4XPDGElastic *) &right);
145 }
146 
147 
148 G4bool G4XPDGElastic::operator!=(const G4XPDGElastic &right) const
149 {
150  return (this != (G4XPDGElastic *) &right);
151 }
152 
153 
154 G4double G4XPDGElastic::CrossSection(const G4KineticTrack& trk1, const G4KineticTrack& trk2) const
155 {
156  // Elastic Cross-section fit, 1994 Review of Particle Properties, (1994), 1
157 
158  G4double sigma = 0.;
159 
160  G4ParticleDefinition* def1 = trk1.GetDefinition();
161  G4ParticleDefinition* def2 = trk2.GetDefinition();
162 
163  G4double sqrtS = (trk1.Get4Momentum() + trk2.Get4Momentum()).mag();
164  G4double m_1 = def1->GetPDGMass();
165  G4double m_2 = def2->GetPDGMass();
166  G4double m_max = std::max(m_1,m_2);
167  // if (m1 > m) m = m1;
168 
169  G4double pLab = 0.;
170 
171  if (m_max > 0. && sqrtS > (m_1 + m_2))
172  {
173  pLab = std::sqrt( (sqrtS*sqrtS - (m_1+m_2)*(m_1+m_2) ) * (sqrtS*sqrtS - (m_1-m_2)*(m_1-m_2)) ) / (2*m_max);
174 
175  // The PDG fit formula requires p in GeV/c
176 
177  // Order the pair: first is the lower mass particle, second is the higher mass one
178  std::pair<G4ParticleDefinition *,G4ParticleDefinition *> trkPair(def1,def2);
179  if (def1->GetPDGMass() > def2->GetPDGMass())
180  trkPair = std::pair<G4ParticleDefinition *,G4ParticleDefinition *>(def2,def1);
181 
182  std::vector<G4double> data;
183  G4double pMinFit = 0.;
184  G4double pMaxFit = 0.;
185  G4double aFit = 0.;
186  G4double bFit = 0.;
187  G4double cFit = 0.;
188  G4double dFit = 0.;
189  G4double nFit = 0.;
190 
191  // Debug
192 // G4cout << "Map has " << xMap.size() << " elements" << G4endl;
193  // Debug end
194 
195  if (xMap.find(trkPair) != xMap.end())
196  {
197  PairDoubleMap::const_iterator iter;
198  for (iter = xMap.begin(); iter != xMap.end(); ++iter)
199  {
200  std::pair<G4ParticleDefinition *,G4ParticleDefinition *> thePair = (*iter).first;
201  if (thePair == trkPair)
202  {
203  data = (*iter).second;
204  pMinFit = data[0];
205  pMaxFit = data[1];
206  aFit = data[2];
207  bFit = data[3];
208  cFit = data[5];
209  dFit = data[6];
210  nFit = data[4];
211 
212  if (pLab < pMinFit) return 0.0;
213  if (pLab > pMaxFit )
214  G4cout << "WARNING! G4XPDGElastic::PDGElastic "
215  << trk1.GetDefinition()->GetParticleName() << "-"
216  << trk2.GetDefinition()->GetParticleName()
217  << " elastic cross section: momentum "
218  << pLab / GeV << " GeV outside valid fit range "
219  << pMinFit /GeV << "-" << pMaxFit / GeV
220  << G4endl;
221 
222  pLab /= GeV;
223  if (pLab > 0.)
224  {
225  G4double logP = std::log(pLab);
226  sigma = aFit + bFit * std::pow(pLab, nFit) + cFit * logP*logP + dFit * logP;
227  sigma = sigma * millibarn;
228  }
229  }
230  }
231  }
232  else
233  {
234  G4cout << "G4XPDGElastic::CrossSection - Data not found in Map" << G4endl;
235  }
236  }
237 
238  if (sigma < 0.)
239  {
240  G4cout << "WARNING! G4XPDGElastic::PDGElastic "
241  << def1->GetParticleName() << "-" << def2->GetParticleName()
242  << " elastic cross section: momentum "
243  << pLab << " GeV, negative cross section "
244  << sigma / millibarn << " mb set to 0" << G4endl;
245  sigma = 0.;
246  }
247 
248  return sigma;
249 }
250 
251 
252 G4String G4XPDGElastic::Name() const
253 {
254  G4String name = "PDGElastic ";
255  return name;
256 }
257 
258 
259 G4bool G4XPDGElastic::IsValid(G4double e) const
260 {
261  G4bool answer = InLimits(e,_lowLimit,_highLimit);
262 
263  return answer;
264 }
265 
266 
267 
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