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25 //
26 //
27 /// \file eventgenerator/pythia/pythia8decayer/src/Py8DecayerPhysics.cc
28 /// \brief Implementation of the Py8DecayerPhysics class
29 ///
30 /// \author J. Yarba; FNAL
31
32 #include "Py8DecayerPhysics.hh"
33
34 #include "Py8Decayer.hh"
35
36 #include "G4Decay.hh"
37 #include "G4DecayTable.hh"
38 #include "G4ParticleDefinition.hh"
39 #include "G4ProcessManager.hh"
40
41 // factory
42 //
43 #include "G4PhysicsConstructorFactory.hh"
44 //
45 // register it with contructor factory
46 //
47 G4_DECLARE_PHYSCONSTR_FACTORY(Py8DecayerPhysics);
48
49 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
50
51 Py8DecayerPhysics::Py8DecayerPhysics(G4int) : G4VPhysicsConstructor("Py8DecayerPhysics") {}
52
53 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
54
55 Py8DecayerPhysics::~Py8DecayerPhysics() {}
56
57 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
58
59 void Py8DecayerPhysics::ConstructParticle()
60 {
61 // Nothing needs to be done here
62 }
63
64 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
65
66 void Py8DecayerPhysics::ConstructProcess()
67 {
68 // Adding external decayer to G4Decay process (per each thread).
69 // G4Decay will use the external decayer if G4Decay process is
70 // assigned to an unstable particle and that particle does not
71 // have its decay table.
72
73 // Loop over all particles instantiated and remove already-assigned
74 // decay table for tau's and B+/- so that they will decay through
75 // the external decayer (Pythia8).
76
77 // NOTE: The extDecayer will be deleted in G4Decay destructor
78
79 Py8Decayer* extDecayer = new Py8Decayer();
80 G4bool setOnce = true;
81
82 auto particleIterator = GetParticleIterator();
83 particleIterator->reset();
84 while ((*particleIterator)()) {
85 G4ParticleDefinition* particle = particleIterator->value();
86
87 // remove native/existing decay table for
88 // a)tau's
89 // b) B+/-
90 // so that G4Decay will use the external decayer
91 if (std::abs(particle->GetPDGEncoding()) == 15 || std::abs(particle->GetPDGEncoding()) == 521) {
92 if (particle->GetDecayTable()) {
93 delete particle->GetDecayTable();
94 particle->SetDecayTable(nullptr);
95 /*
96 if ( verboseLevel > 1 ) {
97 G4cout << "Use ext decayer for: "
98 << particleIterator->value()->GetParticleName()
99 << G4endl;
100 }
101 */
102 }
103 }
104
105 if (setOnce)
106 // One G4Decay object is shared by all unstable particles (per thread).
107 // Thus, we set the external decayer only once.
108 {
109 G4ProcessManager* pmanager = particle->GetProcessManager();
110 G4ProcessVector* processVector = pmanager->GetProcessList();
111 for (size_t i = 0; i < processVector->length(); ++i) {
112 G4Decay* decay = dynamic_cast<G4Decay*>((*processVector)[i]);
113 if (decay) {
114 decay->SetExtDecayer(extDecayer);
115 setOnce = false;
116 }
117 }
118 }
119 }
120
121 return;
122 }
123
124 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
125