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25 // 25 //
26 // G4MuonDecayChannelWithSpin << 26 // ------------------------------------------------------------
>> 27 // GEANT 4 class header file
27 // 28 //
28 // Class decription: << 29 // History:
>> 30 // 17 August 2004 P.Gumplinger and T.MacPhail
>> 31 // samples Michel spectrum including 1st order
>> 32 // radiative corrections
>> 33 // Reference: Florian Scheck "Muon Physics", in Physics Reports
>> 34 // (Review Section of Physics Letters) 44, No. 4 (1978)
>> 35 // 187-248. North-Holland Publishing Company, Amsterdam
>> 36 // at page 210 cc.
29 // 37 //
30 // This class describes muon decay kinematics. << 38 // W.E. Fisher and F. Scheck, Nucl. Phys. B83 (1974) 25.
31 // It assumes V-A coupling with 1st order radi << 39 //
32 // standard model parameter values, but gives << 40 // ------------------------------------------------------------
33 // for neutrinos. <<
34 // References: <<
35 // - Florian Scheck "Muon Physics", in Physics <<
36 // (Review Section of Physics Letters) 44, N <<
37 // 187-248. North-Holland Publishing Company <<
38 // - W.E. Fisher and F. Scheck, Nucl. Phys. B8 <<
39 <<
40 // Authors: P.Gumplinger and T.MacPhail, 17 Au <<
41 // ------------------------------------------- <<
42 #ifndef G4MuonDecayChannelWithSpin_hh 41 #ifndef G4MuonDecayChannelWithSpin_hh
43 #define G4MuonDecayChannelWithSpin_hh 1 42 #define G4MuonDecayChannelWithSpin_hh 1
44 43
45 #include "G4MuonDecayChannel.hh" <<
46 #include "G4ThreeVector.hh" <<
47 #include "globals.hh" 44 #include "globals.hh"
48 << 45 #include "G4ThreeVector.hh"
49 #include <CLHEP/Units/PhysicalConstants.h> << 46 #include "G4MuonDecayChannel.hh"
50 47
51 class G4MuonDecayChannelWithSpin : public G4Mu 48 class G4MuonDecayChannelWithSpin : public G4MuonDecayChannel
52 { 49 {
53 public: << 50 // Class Decription
54 G4MuonDecayChannelWithSpin(const G4String& << 51 // This class describes muon decay kinemtics.
55 ~G4MuonDecayChannelWithSpin() override = d << 52 // This version assumes V-A coupling with 1st order radiative correctons,
56 << 53 // the standard model Michel parameter values, but
57 G4DecayProducts* DecayIt(G4double) overrid << 54 // gives incorrect energy spectrum for neutrinos
58 << 55
59 protected: << 56 public: // With Description
60 // Copy constructor and assignment operato << 57
61 G4MuonDecayChannelWithSpin(const G4MuonDec << 58 //Constructors
62 G4MuonDecayChannelWithSpin& operator=(cons << 59 G4MuonDecayChannelWithSpin(const G4String& theParentName,
63 << 60 G4double theBR);
64 private: << 61 // Destructor
65 G4MuonDecayChannelWithSpin() = default; << 62 virtual ~G4MuonDecayChannelWithSpin();
66 << 63
67 // Radiative Correction Factors << 64 public: // With Description
68 inline G4double F_c(G4double x, G4double x << 65
69 inline G4double F_theta(G4double x, G4doub << 66 virtual G4DecayProducts *DecayIt(G4double);
70 G4double R_c(G4double x, G4double omega); << 67
>> 68 void SetPolarization(G4ThreeVector);
>> 69 const G4ThreeVector& GetPolarization() const;
>> 70
>> 71 private:
>> 72
>> 73 G4ThreeVector parent_polarization;
>> 74
>> 75 // Radiative Correction Factors
>> 76
>> 77 G4double F_c(G4double x, G4double x0);
>> 78 G4double F_theta(G4double x, G4double x0);
>> 79 G4double R_c(G4double x);
>> 80
>> 81 G4double EMMU;
>> 82 G4double EMASS;
>> 83
71 }; 84 };
72 85
73 // ------------------------ << 86 inline void G4MuonDecayChannelWithSpin::SetPolarization(G4ThreeVector polar)
74 // Inline methods << 87 {
75 // ------------------------ << 88 parent_polarization = polar;
>> 89 }
>> 90
>> 91 inline const G4ThreeVector& G4MuonDecayChannelWithSpin::GetPolarization() const
>> 92 {
>> 93 return parent_polarization;
>> 94 }
76 95
77 inline G4double G4MuonDecayChannelWithSpin::F_ << 96 inline G4double G4MuonDecayChannelWithSpin::F_c(G4double x, G4double x0)
78 { 97 {
>> 98 G4double omega = std::log(EMMU/EMASS);
>> 99
79 G4double f_c; 100 G4double f_c;
80 101
81 f_c = (5. + 17. * x - 34. * x * x) * (omega << 102 f_c = (5.+17.*x-34.*x*x)*(omega+std::log(x))-22.*x+34.*x*x;
82 f_c = (1. - x) / (3. * x * x) * f_c; << 103 f_c = (1.-x)/(3.*x*x)*f_c;
83 f_c = (6. - 4. * x) * R_c(x, omega) + (6. - << 104 f_c = (6.-4.*x)*R_c(x)+(6.-6.*x)*std::log(x) + f_c;
84 f_c = (CLHEP::fine_structure_const / CLHEP:: << 105 f_c = (fine_structure_const/twopi) * (x*x-x0*x0) * f_c;
85 106
86 return f_c; 107 return f_c;
87 } 108 }
88 109
89 inline G4double G4MuonDecayChannelWithSpin::F_ << 110 inline G4double G4MuonDecayChannelWithSpin::F_theta(G4double x, G4double x0)
90 { 111 {
>> 112 G4double omega = std::log(EMMU/EMASS);
>> 113
91 G4double f_theta; 114 G4double f_theta;
92 115
93 f_theta = (1. + x + 34 * x * x) * (omega + s << 116 f_theta = (1.+x+34*x*x)*(omega+std::log(x))+3.-7.*x-32.*x*x;
94 f_theta = f_theta + ((4. * (1. - x) * (1. - << 117 f_theta = f_theta + ((4.*(1.-x)*(1.-x))/x)*std::log(1.-x);
95 f_theta = (1. - x) / (3. * x * x) * f_theta; << 118 f_theta = (1.-x)/(3.*x*x) * f_theta;
96 f_theta = (2. - 4. * x) * R_c(x, omega) + (2 << 119 f_theta = (2.-4.*x)*R_c(x)+(2.-6.*x)*std::log(x)-f_theta;
97 f_theta = (CLHEP::fine_structure_const / CLH << 120 f_theta = (fine_structure_const/twopi) * (x*x-x0*x0) * f_theta;
98 121
99 return f_theta; 122 return f_theta;
100 } 123 }
101 124
102 #endif 125 #endif
103 126