G3 to G4
Muon nuclear interaction

Total cross section and Mean free path

• Geant3
  Cross section from Gheisha.
  

• Geant4
  S(E,Z): starting from the recent theoretical differential cross section, the total cross section is computed by numerical integration.
  Energy range: from ~1 GeV to 1000 PeV
  

Final state

• Geant3
  from Gheisha.
  

• Geant4
  The energy and scattering angle of the muon are sampled according the theoretical differential cross section.
  The hadronic part of the final state is generated by the hadronic processes, taking into account the 4-momentum conservation.