G4HyperAlpha.cc

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// Author:       2021 Alberto Ribon
//
//----------------------------------------------------------------------------
 
#include "G4HyperAlpha.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "G4ParticleTable.hh"
 
#include "G4PhaseSpaceDecayChannel.hh"
#include "G4DecayTable.hh"
 
// ######################################################################
// ###                      HYPERALPHA                                ###
// ######################################################################
 
G4HyperAlpha* G4HyperAlpha::theInstance = nullptr;
 
 
G4HyperAlpha* G4HyperAlpha::Definition() {
  if ( theInstance != nullptr ) return theInstance;
  const G4String name = "hyperalpha";
  // search in particle table
  G4ParticleTable* pTable = G4ParticleTable::GetParticleTable();
  G4Ions* anInstance =  static_cast< G4Ions* >( pTable->FindParticle( name ) );
  if ( anInstance == nullptr ) {
    // create particle
    //
    //    Arguments for constructor are as follows
    //                            name             mass           width         charge
    //                          2*spin           parity   C-conjugation
    //                       2*Isospin       2*Isospin3        G-parity
    //                            type    lepton number   baryon number   PDG encoding
    //                          stable         lifetime     decay table
    //                      shortlived          subType   anti_encoding
    //                      excitation 
    anInstance = new G4Ions(      name,     3921.87*MeV, 2.501e-12*MeV,   +2.0*eplus,
                                     0,              +1,             0,
                                     0,               0,             0,
                             "nucleus",               0,            +4,   1010020040,
                                 false,       0.2631*ns,       nullptr,
                         false,        "static",   -1010020040, 
                           0.0,                0                             );
    // Magnetic Moment
    G4double mN = eplus*hbar_Planck/2.0/(proton_mass_c2 /c_squared);
    anInstance->SetPDGMagneticMoment( 2.97896248 * mN );
 
    // create Decay Table 
    G4DecayTable* table = new G4DecayTable;
    // create decay channels
    /*
    // The decay "mode[1]" produces the secondary "Li4" whose corresponding anti-particle
    // is not existing in Geant4: we therefore skip it for the time being, to keep the
    // symmetry with the decays of anti_hyperalpha.
    const G4double half_br_lambda_to_p_pim = 0.5*0.639;
    const G4double half_br_lambda_to_n_piz = 0.5*0.358;
    G4VDecayChannel** mode = new G4VDecayChannel*[4];
    // lambda -> proton + pi- , with 50% probability of capturing the proton
    mode[0] = new G4PhaseSpaceDecayChannel( "hyperalpha", half_br_lambda_to_p_pim, 3,
                        "He3", "proton", "pi-" );
    mode[1] = new G4PhaseSpaceDecayChannel( "hyperalpha", half_br_lambda_to_p_pim, 2,
                        "Li4", "pi-" );
    // lambda -> neutron + pi0 , with 50% probability of capturing the neutron
    mode[2] = new G4PhaseSpaceDecayChannel( "hyperalpha", half_br_lambda_to_n_piz, 3,
                        "He3", "neutron", "pi0" );
    mode[3] = new G4PhaseSpaceDecayChannel( "hyperalpha", half_br_lambda_to_n_piz, 2,
                        "alpha", "pi0" );
    for ( G4int index = 0; index < 4; ++index ) table->Insert( mode[index] );
    */
    // Replacement decay for the time being
    const G4double br_lambda_to_p_pim = 0.639;
    const G4double half_br_lambda_to_n_piz = 0.5*0.358;
    G4VDecayChannel** mode = new G4VDecayChannel*[3];
    // lambda -> proton + pi- , with 0% probability of capturing the proton
    mode[0] = new G4PhaseSpaceDecayChannel( "hyperalpha", br_lambda_to_p_pim, 3,
                        "He3", "proton", "pi-" );
    // lambda -> neutron + pi0 , with 50% probability of capturing the neutron
    mode[1] = new G4PhaseSpaceDecayChannel( "hyperalpha", half_br_lambda_to_n_piz, 3,
                        "He3", "neutron", "pi0" );
    mode[2] = new G4PhaseSpaceDecayChannel( "hyperalpha", half_br_lambda_to_n_piz, 2,
                        "alpha", "pi0" );
    for ( G4int index = 0; index < 3; ++index ) table->Insert( mode[index] );
    //---
    delete [] mode;
    anInstance->SetDecayTable( table );    
  }
  theInstance = static_cast< G4HyperAlpha* >( anInstance );
  return theInstance;
}
 
 
G4HyperAlpha* G4HyperAlpha::HyperAlphaDefinition() {
  return Definition();
}
 
 
G4HyperAlpha* G4HyperAlpha::HyperAlpha() {
  return Definition();
}