[824] | 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 7 | // * conditions of the Geant4 Software License, included in the file * |
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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| 9 | // * include a list of copyright holders. * |
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| 10 | // * * |
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| 11 | // * Neither the authors of this software system, nor their employing * |
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| 12 | // * institutes,nor the agencies providing financial support for this * |
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| 13 | // * work make any representation or warranty, express or implied, * |
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| 14 | // * regarding this software system or assume any liability for its * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 16 | // * for the full disclaimer and the limitation of liability. * |
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| 17 | // * * |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 19 | // * technical work of the GEANT4 collaboration. * |
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| 20 | // * By using, copying, modifying or distributing the software (or * |
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| 21 | // * any work based on the software) you agree to acknowledge its * |
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| 22 | // * use in resulting scientific publications, and indicate your * |
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| 23 | // * acceptance of all terms of the Geant4 Software license. * |
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| 24 | // ******************************************************************** |
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| 25 | // |
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| 26 | // ------------------------------------------------------------ |
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| 27 | // GEANT 4 class header file |
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| 28 | // |
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| 29 | // History: |
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| 30 | // 17 August 2004 P.Gumplinger and T.MacPhail |
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| 31 | // samples Michel spectrum including 1st order |
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| 32 | // radiative corrections |
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| 33 | // Reference: Florian Scheck "Muon Physics", in Physics Reports |
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| 34 | // (Review Section of Physics Letters) 44, No. 4 (1978) |
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| 35 | // 187-248. North-Holland Publishing Company, Amsterdam |
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| 36 | // at page 210 cc. |
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| 37 | // |
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| 38 | // W.E. Fisher and F. Scheck, Nucl. Phys. B83 (1974) 25. |
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| 39 | // |
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| 40 | // ------------------------------------------------------------ |
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| 41 | #ifndef G4MuonDecayChannelWithSpin_hh |
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| 42 | #define G4MuonDecayChannelWithSpin_hh 1 |
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| 43 | |
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| 44 | #include "globals.hh" |
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| 45 | #include "G4ThreeVector.hh" |
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| 46 | #include "G4MuonDecayChannel.hh" |
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| 47 | |
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| 48 | class G4MuonDecayChannelWithSpin : public G4MuonDecayChannel |
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| 49 | { |
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| 50 | // Class Decription |
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| 51 | // This class describes muon decay kinemtics. |
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| 52 | // This version assumes V-A coupling with 1st order radiative correctons, |
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| 53 | // the standard model Michel parameter values, but |
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| 54 | // gives incorrect energy spectrum for neutrinos |
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| 55 | |
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| 56 | public: // With Description |
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| 57 | |
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| 58 | //Constructors |
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| 59 | G4MuonDecayChannelWithSpin(const G4String& theParentName, |
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| 60 | G4double theBR); |
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| 61 | // Destructor |
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| 62 | virtual ~G4MuonDecayChannelWithSpin(); |
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| 63 | |
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| 64 | public: // With Description |
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| 65 | |
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| 66 | virtual G4DecayProducts *DecayIt(G4double); |
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| 67 | |
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| 68 | void SetPolarization(G4ThreeVector); |
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| 69 | const G4ThreeVector& GetPolarization() const; |
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| 70 | |
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| 71 | private: |
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| 72 | |
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| 73 | G4ThreeVector parent_polarization; |
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| 74 | |
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| 75 | // Radiative Correction Factors |
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| 76 | |
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| 77 | G4double F_c(G4double x, G4double x0); |
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| 78 | G4double F_theta(G4double x, G4double x0); |
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| 79 | G4double R_c(G4double x); |
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| 80 | |
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| 81 | G4double EMMU; |
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| 82 | G4double EMASS; |
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| 83 | |
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| 84 | }; |
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| 85 | |
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| 86 | inline void G4MuonDecayChannelWithSpin::SetPolarization(G4ThreeVector polar) |
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| 87 | { |
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| 88 | parent_polarization = polar; |
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| 89 | } |
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| 90 | |
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| 91 | inline const G4ThreeVector& G4MuonDecayChannelWithSpin::GetPolarization() const |
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| 92 | { |
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| 93 | return parent_polarization; |
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| 94 | } |
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| 95 | |
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| 96 | inline G4double G4MuonDecayChannelWithSpin::F_c(G4double x, G4double x0) |
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| 97 | { |
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| 98 | G4double omega = std::log(EMMU/EMASS); |
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| 99 | |
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| 100 | G4double f_c; |
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| 101 | |
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| 102 | f_c = (5.+17.*x-34.*x*x)*(omega+std::log(x))-22.*x+34.*x*x; |
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| 103 | f_c = (1.-x)/(3.*x*x)*f_c; |
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| 104 | f_c = (6.-4.*x)*R_c(x)+(6.-6.*x)*std::log(x) + f_c; |
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| 105 | f_c = (fine_structure_const/twopi) * (x*x-x0*x0) * f_c; |
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| 106 | |
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| 107 | return f_c; |
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| 108 | } |
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| 109 | |
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| 110 | inline G4double G4MuonDecayChannelWithSpin::F_theta(G4double x, G4double x0) |
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| 111 | { |
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| 112 | G4double omega = std::log(EMMU/EMASS); |
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| 113 | |
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| 114 | G4double f_theta; |
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| 115 | |
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| 116 | f_theta = (1.+x+34*x*x)*(omega+std::log(x))+3.-7.*x-32.*x*x; |
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| 117 | f_theta = f_theta + ((4.*(1.-x)*(1.-x))/x)*std::log(1.-x); |
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| 118 | f_theta = (1.-x)/(3.*x*x) * f_theta; |
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| 119 | f_theta = (2.-4.*x)*R_c(x)+(2.-6.*x)*std::log(x)-f_theta; |
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| 120 | f_theta = (fine_structure_const/twopi) * (x*x-x0*x0) * f_theta; |
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| 121 | |
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| 122 | return f_theta; |
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| 123 | } |
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| 124 | |
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| 125 | #endif |
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