EvtSherpaPhotons.hh

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#ifdef EVTGEN_SHERPA
#ifndef EVTSHERPAPHOTONS_HH
#define EVTSHERPAPHOTONS_HH
 
#include "EvtGenBase/EvtAbsRadCorr.hh"
#include "EvtGenBase/EvtHepMCEvent.hh"
#include "EvtGenBase/EvtId.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtParticle.hh"
 
#include "SHERPA/Main/Sherpa.H"
 
#include <string>
 
class EvtParticle;
class EvtAbsExternalGen;
 
/* Description: EvtGen's interface to PHOTOS for generation of
 *              QED final state radiation.
 */
class EvtSherpaPhotons : public EvtAbsRadCorr {
  public:
    EvtSherpaPhotons( const bool useEvtGenRandom = true,
                      const double infraredCutOff = 1.0e-7, const int mode = 2,
                      const int useME = 0 );
 
    void initialise() override;
 
    void doRadCorr( EvtParticle* p ) override;
 
  private:
    // Provides vector of pointers to the configuration strings for Sherpa
    std::vector<char*> addParameters();
 
    // Updates the particle properties table of Sherpa
    void updateParticleLists();
 
    // Vector containing the configuration strings for Sherpa
    // INIT_ONLY=6 intialises the Sherpa objects without launching simulation.
    std::vector<std::string> m_configs{ "Sherpa", "INIT_ONLY=6" };
 
    // Use EvtGen's random number generator
    bool m_useEvtGenRandom = true;
 
    // Default settings for PHOTONS++
    // Minimum photon Energy (infrared cut-off).
    double m_infraredCutOff = 1.0e-7;
    // Switches on (default) the hard emission corrections (mode 2),
    // otherwise follow the soft-photon only approach (mode 1).
    int m_mode = 2;
    // Switches off (default) or on the exact matrix-element corrections (works only for mode 2)
    int m_useME = 0;
 
    // Default photon properties
    const std::string m_photonType = "gamma";
    EvtId m_gammaId = EvtId( -1, -1 );
    long int m_gammaPDG = 22;
 
    // The Sherpa instance.
    static std::unique_ptr<SHERPA::Sherpa> m_sherpaGen;
    static bool m_initialised;
    static std::mutex m_sherpa_mutex;
};
 
#endif
 
#endif