Gabriele Cosmo
133 lines
4.5 KiB
C++
133 lines
4.5 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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// G4MuonRadiativeDecayChannelWithSpin
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//
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// Class description:
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//
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// This class describes radiative muon decay kinematics, but
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// gives incorrect energy spectrum for neutrinos.
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// Samples Radiative Muon Decay.
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// References:
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// - TRIUMF/TWIST Technote TN-55:
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// "Radiative muon decay" by P. Depommier and A. Vacheret
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// - Yoshitaka Kuno and Yasuhiro Okada
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// "Muon Decays and Physics Beyond the Standard Model"
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// Rev. Mod. Phys. 73, 151 (2001)
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// Author: P.Gumplinger - Triumf, 25 July 2007
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// Revision: D. Mingming - Center for HEP, Tsinghua Univ., 10 August 2011
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// --------------------------------------------------------------------
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#ifndef G4MuonRadiativeDecayChannelWithSpin_hh
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#define G4MuonRadiativeDecayChannelWithSpin_hh 1
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#include "G4ThreeVector.hh"
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#include "G4VDecayChannel.hh"
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#include "Randomize.hh"
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#include "globals.hh"
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#include <CLHEP/Units/PhysicalConstants.h>
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class G4MuonRadiativeDecayChannelWithSpin : public G4VDecayChannel
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{
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public:
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G4MuonRadiativeDecayChannelWithSpin(const G4String& theParentName, G4double theBR);
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~G4MuonRadiativeDecayChannelWithSpin() 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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G4MuonRadiativeDecayChannelWithSpin(const G4MuonRadiativeDecayChannelWithSpin&) = default;
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G4MuonRadiativeDecayChannelWithSpin& operator=(const G4MuonRadiativeDecayChannelWithSpin&);
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private:
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G4MuonRadiativeDecayChannelWithSpin() = default;
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G4double fron(G4double Pmu, G4double x, G4double y, G4double cthetaE, G4double cthetaG,
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G4double cthetaEG);
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// Generates random vectors, uniformly distributed over the surface
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// of a sphere of given radius
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void rn3dim(G4double& x, G4double& y, G4double& z, G4double xlong);
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G4double atan4(G4double x, G4double y);
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};
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// ------------------------
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// Inline methods
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// ------------------------
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inline void G4MuonRadiativeDecayChannelWithSpin::rn3dim(G4double& x, G4double& y, G4double& z,
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G4double xlong)
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{
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G4double a = 0.;
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G4double b = 0.;
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G4double c = 0.;
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G4double r = 0.;
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do {
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a = G4UniformRand() - 0.5;
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b = G4UniformRand() - 0.5;
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c = G4UniformRand() - 0.5;
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r = a * a + b * b + c * c;
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} while (r > 0.25); // Loop checking, 09.08.2015, K.Kurashige
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G4double rinv = xlong / (std::sqrt(r));
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x = a * rinv;
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y = b * rinv;
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z = c * rinv;
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return;
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}
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inline G4double G4MuonRadiativeDecayChannelWithSpin::atan4(G4double x, G4double y)
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{
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G4double phi = 0.;
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if (x == 0. && y > 0.) {
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phi = 0.5 * CLHEP::pi;
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}
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else if (x == 0. && y < 0.) {
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phi = 1.5 * CLHEP::pi;
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}
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else if (y == 0. && x > 0.) {
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phi = 0.;
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}
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else if (y == 0. && x < 0.) {
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phi = CLHEP::pi;
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}
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else if (x > 0.) {
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phi = std::atan(y / x);
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}
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else if (x < 0.) {
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phi = std::atan(y / x) + CLHEP::pi;
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}
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return phi;
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}
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#endif
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