include/EvtGenBase/EvtPhotonParticle.hh

0001
0002 /***********************************************************************
0003 * Copyright 1998-2020 CERN for the benefit of the EvtGen authors       *
0004 *                                                                      *
0005 * This file is part of EvtGen.                                         *
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0010 * (at your option) any later version.                                  *
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0019 ***********************************************************************/
0020
0021 #ifndef EVTPHOTONPARTICLE_HH
0022 #define EVTPHOTONPARTICLE_HH
0023
0024 #include "EvtGenBase/EvtParticle.hh"
0025 #include "EvtGenBase/EvtVector4C.hh"
0026 class EvtId;
0027
0028 //Class to handle massless spin 1 particles.
0029
0030 class EvtPhotonParticle : public EvtParticle {
0031   public:
0032     EvtPhotonParticle() = default;
0033
0034     void init( EvtId part_n, double e, double px, double py, double pz );
0035     void init( EvtId part_n, const EvtVector4R& p4 ) override;
0036
0037     //Return polarization vectors
0038     EvtVector4C epsParentPhoton( int i ) override;
0039     EvtVector4C epsPhoton( int i ) override;
0040
0041     EvtSpinDensity rotateToHelicityBasis() const override;
0042     EvtSpinDensity rotateToHelicityBasis( double alpha, double beta,
0043                                           double gamma ) const override;
0044
0045   private:
0046     EvtVector4C eps1, eps2;
0047     int _evalBasis;
0048
0049     EvtPhotonParticle( const EvtPhotonParticle& photon );
0050     EvtPhotonParticle& operator=( const EvtPhotonParticle& photon );
0051 };
0052
0053 #endif