G4TauPlus.cc

Go to the documentation of this file. Or view the newest version in sPHENIX GitHub for file G4TauPlus.cc

//
// ********************************************************************
// * License and Disclaimer                                           *
// *                                                                  *
// * The  Geant4 software  is  copyright of the Copyright Holders  of *
// * the Geant4 Collaboration.  It is provided  under  the terms  and *
// * conditions of the Geant4 Software License,  included in the file *
// * LICENSE and available at  http://cern.ch/geant4/license .  These *
// * include a list of copyright holders.                             *
// *                                                                  *
// * Neither the authors of this software system, nor their employing *
// * institutes,nor the agencies providing financial support for this *
// * work  make  any representation or  warranty, express or implied, *
// * regarding  this  software system or assume any liability for its *
// * use.  Please see the license in the file  LICENSE  and URL above *
// * for the full disclaimer and the limitation of liability.         *
// *                                                                  *
// * This  code  implementation is the result of  the  scientific and *
// * technical work of the GEANT4 collaboration.                      *
// * By using,  copying,  modifying or  distributing the software (or *
// * any work based  on the software)  you  agree  to acknowledge its *
// * use  in  resulting  scientific  publications,  and indicate your *
// * acceptance of all terms of the Geant4 Software license.          *
// ********************************************************************
//
//
//
// 
// ----------------------------------------------------------------------
//      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 "G4TauPlus.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "G4ParticleTable.hh"

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

// ######################################################################
// ###                          TAPLUS                                ###
// ######################################################################
G4TauPlus* G4TauPlus::theInstance = 0;

G4TauPlus* G4TauPlus::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,     1.77686*GeV,  2.267e-9*MeV,     1.*eplus, 
        1,               0,             0,          
        0,               0,             0,             
       "lepton",              -1,             0,         -15,
    false,     290.3e-6*ns,          NULL,
             false,           "tau"
              );
   // Bohr Magnetron
   G4double muB =  0.5*eplus*hbar_Planck/(anInstance->GetPDGMass()/c_squared) ;
   
   anInstance->SetPDGMagneticMoment( muB * 1.00118);

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

  // create decay channels
  G4VDecayChannel* mode;
  // tau+ -> mu+ + nu_mu + anti_nu_tau
  mode = new G4TauLeptonicDecayChannel("tau+",0.1736,"mu+");
  table->Insert(mode);
  // tau+ -> e+ + nu_e + anti_nu_tau
  mode = new G4TauLeptonicDecayChannel("tau+",0.1784,"e+");
  table->Insert(mode);
  // tau+ -> pi+ + anti_nu_tau
  mode = new G4PhaseSpaceDecayChannel("tau+",0.1106,2,"pi+","anti_nu_tau");
  table->Insert(mode);
  // tau+ -> pi0 + pi0 + pi+ + anti_nu_tau
  mode = new G4PhaseSpaceDecayChannel("tau+",0.2541,3,"pi0","pi+","anti_nu_tau");
  table->Insert(mode);
  // tau+ -> pi0 + pi0 + pi+ + anti_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,"anti_nu_tau");
  table->Insert(mode);
  // tau+ -> pi+ + pi+ + pi- + anti_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,"anti_nu_tau");
  table->Insert(mode);

   anInstance->SetDecayTable(table);
  }
  theInstance = reinterpret_cast<G4TauPlus*>(anInstance);
  return theInstance;
}

G4TauPlus*  G4TauPlus::TauPlusDefinition()
{
  return Definition();
}

G4TauPlus*  G4TauPlus::TauPlus()
{
  return Definition();
}