G4TauMinus.cc

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//
// $Id$
//
// 
// ----------------------------------------------------------------------
//      GEANT 4 class implementation file
//
//      History: first implementation, based on object model of
//      4th April 1996, G.Cosmo
//      7 July 1996                   H.Kurashige 
// **********************************************************************
//  New impelemenataion as an utility class  M.Asai, 26 July 2004
// ----------------------------------------------------------------------

#include "G4TauMinus.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "G4ParticleTable.hh"

#include "G4PhaseSpaceDecayChannel.hh"
#include "G4TauLeptonicDecayChannel.hh"
#include "G4DecayTable.hh"

// ######################################################################
// ###                          TAUMINUS                             ###
// ######################################################################
G4TauMinus* G4TauMinus::theInstance = 0;

G4TauMinus* G4TauMinus::Definition()
{
  if (theInstance !=0) return theInstance;
  const G4String name = "tau-";
  // search in particle table]
  G4ParticleTable* pTable = G4ParticleTable::GetParticleTable();
  G4ParticleDefinition* anInstance = pTable->FindParticle(name);
  if (anInstance ==0)
  {
  // 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
   anInstance = new G4ParticleDefinition(
                 name,     1.77682*GeV,  2.265e-9*MeV,    -1.*eplus, 
            1,               0,             0,          
            0,               0,             0,             
         "lepton",               1,             0,          15,
        false,     290.6e-6*ns,          NULL,
             false,           "tau"
              );

   // Bohr Magnetron
   G4double muB =  -0.5*eplus*hbar_Planck/(1.77699*GeV/c_squared) ;
   
   anInstance->SetPDGMagneticMoment( muB * 2. * 1.00116);

  //create Decay Table 
  G4DecayTable* table = new G4DecayTable();

  // create decay channels
  G4VDecayChannel* mode;
  // tau- -> mu- + anti_nu_mu + nu_tau
  mode = new G4TauLeptonicDecayChannel("tau-",0.1736,"mu-");
  table->Insert(mode);
  // tau- -> e- + anti_nu_e + nu_tau
  mode = new G4TauLeptonicDecayChannel("tau-",0.1784,"e-");
  table->Insert(mode);
  // tau- -> pi- + nu_tau
  mode = new G4PhaseSpaceDecayChannel("tau-",0.1106,2,"pi-","nu_tau");
  table->Insert(mode);
  // tau- -> pi0 + pi- + nu_tau
  mode = new G4PhaseSpaceDecayChannel("tau-",0.2541,3,"pi0","pi-","nu_tau");
  table->Insert(mode);
  // tau- -> pi0 + pi0 + pi- + nu_tau
  mode = new G4PhaseSpaceDecayChannel();
  mode->SetParent("tau-");
  mode->SetBR(0.0917);
  mode->SetNumberOfDaughters(4);
  mode->SetDaughter(0,"pi0");
  mode->SetDaughter(1,"pi0");
  mode->SetDaughter(2,"pi-");
  mode->SetDaughter(3,"nu_tau");
  table->Insert(mode);
  // tau- -> pi- + pi- + pi+ + nu_tau
  mode = new G4PhaseSpaceDecayChannel();
  mode->SetParent("tau-");
  mode->SetBR(0.0946);
  mode->SetNumberOfDaughters(4);
  mode->SetDaughter(0,"pi-");
  mode->SetDaughter(1,"pi-");
  mode->SetDaughter(2,"pi+");
  mode->SetDaughter(3,"nu_tau");
  table->Insert(mode);

  anInstance->SetDecayTable(table);
  }
  theInstance = reinterpret_cast<G4TauMinus*>(anInstance);
  return theInstance;
}

G4TauMinus*  G4TauMinus::TauMinusDefinition()
{
  return Definition();
}

G4TauMinus*  G4TauMinus::TauMinus()
{
  return Definition();
}