Gabriele Cosmo
103 lines
4.2 KiB
C++
103 lines
4.2 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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// G4MuonDecayChannelWithSpin
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//
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// Class decription:
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//
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// This class describes muon decay kinematics.
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// It assumes V-A coupling with 1st order radiative corrections, the
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// standard model parameter values, but gives incorrect energy spectrum
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// for neutrinos.
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// References:
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// - Florian Scheck "Muon Physics", in Physics Reports
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// (Review Section of Physics Letters) 44, No. 4 (1978)
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// 187-248. North-Holland Publishing Company, Amsterdam at page 210 cc.
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// - W.E. Fisher and F. Scheck, Nucl. Phys. B83 (1974) 25.
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// Authors: P.Gumplinger and T.MacPhail, 17 August 2004
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// --------------------------------------------------------------------
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#ifndef G4MuonDecayChannelWithSpin_hh
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#define G4MuonDecayChannelWithSpin_hh 1
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#include "G4MuonDecayChannel.hh"
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#include "G4ThreeVector.hh"
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#include "globals.hh"
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#include <CLHEP/Units/PhysicalConstants.h>
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class G4MuonDecayChannelWithSpin : public G4MuonDecayChannel
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{
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public:
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G4MuonDecayChannelWithSpin(const G4String& theParentName, G4double theBR);
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~G4MuonDecayChannelWithSpin() override = default;
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G4DecayProducts* DecayIt(G4double) override;
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protected:
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// Copy constructor and assignment operator
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G4MuonDecayChannelWithSpin(const G4MuonDecayChannelWithSpin&) = default;
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G4MuonDecayChannelWithSpin& operator=(const G4MuonDecayChannelWithSpin&);
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private:
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G4MuonDecayChannelWithSpin() = default;
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// Radiative Correction Factors
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inline G4double F_c(G4double x, G4double x0, G4double omega);
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inline G4double F_theta(G4double x, G4double x0, G4double omega);
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G4double R_c(G4double x, G4double omega);
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};
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// ------------------------
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// Inline methods
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// ------------------------
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inline G4double G4MuonDecayChannelWithSpin::F_c(G4double x, G4double x0, G4double omega)
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{
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G4double f_c;
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f_c = (5. + 17. * x - 34. * x * x) * (omega + std::log(x)) - 22. * x + 34. * x * x;
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f_c = (1. - x) / (3. * x * x) * f_c;
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f_c = (6. - 4. * x) * R_c(x, omega) + (6. - 6. * x) * std::log(x) + f_c;
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f_c = (CLHEP::fine_structure_const / CLHEP::twopi) * (x * x - x0 * x0) * f_c;
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return f_c;
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}
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inline G4double G4MuonDecayChannelWithSpin::F_theta(G4double x, G4double x0, G4double omega)
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{
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G4double f_theta;
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f_theta = (1. + x + 34 * x * x) * (omega + std::log(x)) + 3. - 7. * x - 32. * x * x;
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f_theta = f_theta + ((4. * (1. - x) * (1. - x)) / x) * std::log(1. - x);
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f_theta = (1. - x) / (3. * x * x) * f_theta;
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f_theta = (2. - 4. * x) * R_c(x, omega) + (2. - 6. * x) * std::log(x) - f_theta;
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f_theta = (CLHEP::fine_structure_const / CLHEP::twopi) * (x * x - x0 * x0) * f_theta;
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return f_theta;
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}
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#endif
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