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24 // ********************************************************************
25 //
26 // ----------------------------------------------------------------------
27 // GEANT 4 class implementation file
28 //
29 // History: first implementation, based on object model of
30 // 4th April 1996, G.Cosmo
31 // 7 July 1996 H.Kurashige
32 // **********************************************************************
33 // New impelemenataion as an utility class M.Asai, 26 July 2004
34 // ----------------------------------------------------------------------
35
36 #include "G4TauMinus.hh"
37
38 #include "G4DecayTable.hh"
39 #include "G4ParticleTable.hh"
40 #include "G4PhaseSpaceDecayChannel.hh"
41 #include "G4PhysicalConstants.hh"
42 #include "G4String.hh"
43 #include "G4SystemOfUnits.hh"
44 #include "G4TauLeptonicDecayChannel.hh"
45 #include "G4Types.hh"
46 #include "G4VDecayChannel.hh"
47
48 G4TauMinus* G4TauMinus::theInstance = nullptr;
49
50 G4TauMinus* G4TauMinus::Definition()
51 {
52 if (theInstance != nullptr) return theInstance;
53 const G4String name = "tau-";
54 // search in particle table]
55 G4ParticleTable* pTable = G4ParticleTable::GetParticleTable();
56 G4ParticleDefinition* anInstance = pTable->FindParticle(name);
57 if (anInstance == nullptr) {
58 // create particle
59 //
60 // Arguments for constructor are as follows
61 // name mass width charge
62 // 2*spin parity C-conjugation
63 // 2*Isospin 2*Isospin3 G-parity
64 // type lepton number baryon number PDG encoding
65 // stable lifetime decay table
66 // shortlived subType anti_encoding
67
68 // clang-format off
69 anInstance = new G4ParticleDefinition(
70 name, 1.77686*GeV, 2.267e-9*MeV, -1.*eplus,
71 1, 0, 0,
72 0, 0, 0,
73 "lepton", 1, 0, 15,
74 false, 290.3e-6*ns, nullptr,
75 false, "tau"
76 );
77 // clang-format on
78
79 // Bohr Magnetron
80 G4double muB = -0.5 * eplus * hbar_Planck / (anInstance->GetPDGMass() / c_squared);
81
82 anInstance->SetPDGMagneticMoment(muB * 1.00118);
83
84 // create Decay Table
85 auto table = new G4DecayTable();
86
87 // create decay channels
88 G4VDecayChannel* mode;
89 // tau- -> mu- + anti_nu_mu + nu_tau
90 mode = new G4TauLeptonicDecayChannel("tau-", 0.1736, "mu-");
91 table->Insert(mode);
92 // tau- -> e- + anti_nu_e + nu_tau
93 mode = new G4TauLeptonicDecayChannel("tau-", 0.1784, "e-");
94 table->Insert(mode);
95 // tau- -> pi- + nu_tau
96 mode = new G4PhaseSpaceDecayChannel("tau-", 0.1106, 2, "pi-", "nu_tau");
97 table->Insert(mode);
98 // tau- -> pi0 + pi- + nu_tau
99 mode = new G4PhaseSpaceDecayChannel("tau-", 0.2541, 3, "pi0", "pi-", "nu_tau");
100 table->Insert(mode);
101 // tau- -> pi0 + pi0 + pi- + nu_tau
102 mode = new G4PhaseSpaceDecayChannel();
103 mode->SetParent("tau-");
104 mode->SetBR(0.0917);
105 mode->SetNumberOfDaughters(4);
106 mode->SetDaughter(0, "pi0");
107 mode->SetDaughter(1, "pi0");
108 mode->SetDaughter(2, "pi-");
109 mode->SetDaughter(3, "nu_tau");
110 table->Insert(mode);
111 // tau- -> pi- + pi- + pi+ + nu_tau
112 mode = new G4PhaseSpaceDecayChannel();
113 mode->SetParent("tau-");
114 mode->SetBR(0.0946);
115 mode->SetNumberOfDaughters(4);
116 mode->SetDaughter(0, "pi-");
117 mode->SetDaughter(1, "pi-");
118 mode->SetDaughter(2, "pi+");
119 mode->SetDaughter(3, "nu_tau");
120 table->Insert(mode);
121
122 anInstance->SetDecayTable(table);
123 }
124 theInstance = static_cast<G4TauMinus*>(anInstance);
125 return theInstance;
126 }
127
128 G4TauMinus* G4TauMinus::TauMinusDefinition()
129 {
130 return Definition();
131 }
132
133 G4TauMinus* G4TauMinus::TauMinus()
134 {
135 return Definition();
136 }
137