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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" <<
48 <<
49 #include <CLHEP/Units/PhysicalConstants.h> 44 #include <CLHEP/Units/PhysicalConstants.h>
50 45
>> 46 #include "globals.hh"
>> 47 #include "G4ThreeVector.hh"
>> 48 #include "G4MuonDecayChannel.hh"
>> 49
51 class G4MuonDecayChannelWithSpin : public G4Mu 50 class G4MuonDecayChannelWithSpin : public G4MuonDecayChannel
52 { 51 {
53 public: << 52 // Class Decription
54 G4MuonDecayChannelWithSpin(const G4String& << 53 // This class describes muon decay kinemtics.
55 ~G4MuonDecayChannelWithSpin() override = d << 54 // This version assumes V-A coupling with 1st order radiative correctons,
56 << 55 // the standard model Michel parameter values, but
57 G4DecayProducts* DecayIt(G4double) overrid << 56 // gives incorrect energy spectrum for neutrinos
58 << 57
59 protected: << 58 public: // With Description
60 // Copy constructor and assignment operato << 59
61 G4MuonDecayChannelWithSpin(const G4MuonDec << 60 //Constructors
62 G4MuonDecayChannelWithSpin& operator=(cons << 61 G4MuonDecayChannelWithSpin(const G4String& theParentName,
63 << 62 G4double theBR);
64 private: << 63 // Destructor
65 G4MuonDecayChannelWithSpin() = default; << 64 virtual ~G4MuonDecayChannelWithSpin();
66 << 65
67 // Radiative Correction Factors << 66 protected:
68 inline G4double F_c(G4double x, G4double x << 67 // Copy constructor and assignment operator
69 inline G4double F_theta(G4double x, G4doub << 68 G4MuonDecayChannelWithSpin(const G4MuonDecayChannelWithSpin &);
70 G4double R_c(G4double x, G4double omega); << 69 G4MuonDecayChannelWithSpin & operator=(const G4MuonDecayChannelWithSpin &);
71 }; << 70
>> 71 private:
>> 72 G4MuonDecayChannelWithSpin();
>> 73
>> 74 public: // With Description
>> 75
>> 76 virtual G4DecayProducts *DecayIt(G4double);
>> 77
>> 78 private:
>> 79 // Radiative Correction Factors
>> 80
>> 81 G4double F_c(G4double x, G4double x0);
>> 82 G4double F_theta(G4double x, G4double x0);
>> 83 G4double R_c(G4double x);
72 84
73 // ------------------------ << 85 G4double EMMU;
74 // Inline methods << 86 G4double EMASS;
75 // ------------------------ <<
76 87
77 inline G4double G4MuonDecayChannelWithSpin::F_ << 88 };
>> 89
>> 90 inline G4double G4MuonDecayChannelWithSpin::F_c(G4double x, G4double x0)
78 { 91 {
>> 92 G4double omega = std::log(EMMU/EMASS);
>> 93
79 G4double f_c; 94 G4double f_c;
80 95
81 f_c = (5. + 17. * x - 34. * x * x) * (omega << 96 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; << 97 f_c = (1.-x)/(3.*x*x)*f_c;
83 f_c = (6. - 4. * x) * R_c(x, omega) + (6. - << 98 f_c = (6.-4.*x)*R_c(x)+(6.-6.*x)*std::log(x) + f_c;
84 f_c = (CLHEP::fine_structure_const / CLHEP:: << 99 f_c = (CLHEP::fine_structure_const/CLHEP::twopi) * (x*x-x0*x0) * f_c;
85 100
86 return f_c; 101 return f_c;
87 } 102 }
88 103
89 inline G4double G4MuonDecayChannelWithSpin::F_ << 104 inline G4double G4MuonDecayChannelWithSpin::F_theta(G4double x, G4double x0)
90 { 105 {
>> 106 G4double omega = std::log(EMMU/EMASS);
>> 107
91 G4double f_theta; 108 G4double f_theta;
92 109
93 f_theta = (1. + x + 34 * x * x) * (omega + s << 110 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. - << 111 f_theta = f_theta + ((4.*(1.-x)*(1.-x))/x)*std::log(1.-x);
95 f_theta = (1. - x) / (3. * x * x) * f_theta; << 112 f_theta = (1.-x)/(3.*x*x) * f_theta;
96 f_theta = (2. - 4. * x) * R_c(x, omega) + (2 << 113 f_theta = (2.-4.*x)*R_c(x)+(2.-6.*x)*std::log(x)-f_theta;
97 f_theta = (CLHEP::fine_structure_const / CLH << 114 f_theta = (CLHEP::fine_structure_const/CLHEP::twopi) * (x*x-x0*x0) * f_theta;
98 115
99 return f_theta; 116 return f_theta;
100 } 117 }
101 118
102 #endif 119 #endif
103 120