| 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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