The Implementation of $\mu^- \mu^+$ Production by Muons in Geant4

When a high-energy muon interacts with a nucleus, a muon—anti-muon pair may be produced. This is known as muon pair production. It has a relatively low cross-section but becomes important in the regime of higher energies and is prominent when collecting high statistics. We implement it as a new electromagnetic process in Geant4. It is found that the muon pair production occurs times less frequently than electron pair production at an energy of 100 TeV. This process will be useful for the LHC and FCC as the related experiments run at high energies and collect large statistics. The new process will be included in the next public release of Geant4.