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26 //
27 //---------------------------------------------------------------------------
28 //
29 // ClassName: G4CRCoalescence ("CR" stands for "Cosmic Ray")
30 //
31 // Author: 2020 Alberto Ribon , based on code written by
32 // Diego Mauricio Gomez Coral for the GAPS Collaboration
33 //
34 // Description: This class can be optionally used in the method:
35 //
36 // G4TheoFSGenerator::ApplyYourself
37 //
38 // to coalesce pairs of proton-neutron and antiproton-antineutron
39 // into deuterons and antideuterons, respectively, from the list
40 // of secondaries produced by a string model.
41 // This class can be useful in particular for Cosmic Ray (CR)
42 // applications.
43 // By default, this class is not used.
44 // However, it can be enabled via the UI command:
45 //
46 // /process/had/enableCRCoalescence true
47 //
48 // It is assumed that the candidate proton-neutron and
49 // antiproton-antideuteron pairs originate from the same
50 // spatial position, so the condition for coalescence takes
51 // into account only their closeness in momentum space.
52 //
53 // This class is based entirely on code written by
54 // Diego Mauricio Gomez Coral for the GAPS Collaboration.
55 // The main application of this work is for cosmic ray physics.
56 //
57 // Notes:
58 // - In its current version, coalescence can occur only for
59 // proton projectile (because the coalescence parameters
60 // for deuteron and antideuteron are set to non-null values
61 // only for the case of proton projectile).
62 // - This class is not meant be used for secondaries produces
63 // by intranuclear cascade models - such as BERT, BIC and
64 // INCL - which should have already a coalescence phase.
65 //
66 // Modified:
67 //
68 //----------------------------------------------------------------------------
69 //
70 #ifndef G4CRCoalescence_h
71 #define G4CRCoalescence_h 1
72
73 #include "G4ReactionProductVector.hh"
74 #include "G4HadProjectile.hh"
75 #include "G4HadronicInteraction.hh"
76
77 class G4CRCoalescence : public G4HadronicInteraction {
78 public:
79
80 explicit G4CRCoalescence();
81 ~G4CRCoalescence() override;
82 G4CRCoalescence( const G4CRCoalescence &right ) = delete;
83 const G4CRCoalescence & operator=( const G4CRCoalescence &right ) = delete;
84 G4bool operator==( const G4CRCoalescence &right ) const = delete;
85 G4bool operator!=( const G4CRCoalescence &right ) const = delete;
86
87 // Set the parameter used in the coalescence condition
88 void SetP0Coalescence( const G4HadProjectile &thePrimary, G4String /* model */ );
89
90 // Main method: form deuterons and antideuterons by coalescence of, respectively,
91 // proton-neutron and antiproton-antineutron pairs with close momenta
92 void GenerateDeuterons( G4ReactionProductVector* result );
93
94 private:
95
96 // Utility methods
97 void PushDeuteron( const G4ThreeVector &p1, const G4ThreeVector &p2, G4int charge,
98 G4ReactionProductVector* result );
99 G4int FindPartner( const G4ThreeVector &p1, G4double m1,
100 std::vector< std::pair< G4int, G4ThreeVector > > &neutron,
101 G4double m2, G4int charge );
102 G4bool Coalescence( const G4ThreeVector &p1, G4double m1,
103 const G4ThreeVector &p2, G4double m2, G4int charge );
104 G4bool Coalescence( G4double p1x, G4double p1y, G4double p1z, G4double m1,
105 G4double p2x, G4double p2y, G4double p2z, G4double m2, G4int charge );
106 G4double GetPcm( const G4ThreeVector& p1, G4double m1,
107 const G4ThreeVector& p2, G4double m2 );
108 G4double GetPcm( G4double p1x, G4double p1y, G4double p1z, G4double m1,
109 G4double p2x, G4double p2y, G4double p2z, G4double m2 );
110 G4double GetS( G4double p1x, G4double p1y, G4double p1z, G4double m1,
111 G4double p2x, G4double p2y, G4double p2z, G4double m2 );
112
113 G4double fP0_d; // Coalescence parameter for deuterons
114 G4double fP0_dbar; // Coalescence parameter for antideuterons
115
116 G4int secID; // Creator model ID for the secondaries created by this model
117 };
118
119 #endif
120