In addition to the hadronic code mentioned in the preceeding sections, an additional feature has been added to SNOMAN that allows for high energy leptons to be properly tracked. High energy muons interactions (above 2 GeV) can now be handled by LEPTO 6.3 . LEPTO is a standard CERN package that allows one to properly simulate leptonic electroweak interactions in deep inelastic scattering (DIS). LEPTO, like FLUKA, is a well-tested code used in high energy physics. It properly models showers created by high energy interactions between leptons and nuclei. Since the hadronic showers produced by the interaction produce a wide range of high energy hadrons, it was imperative that FLUKA be implemented prior to LEPTO. In theory, LEPTO can handle both muons and neutrinos. However, the current implementation only supports muons (wait for next version of SNOMAN for neutrino update).
Currently, muons which have energies above 2 GeV and undergo a nuclear interaction are passed to the msw_lundevent.for routine, which call lepto63.for. Since lepto cannot handle resonance-type of interactions (W < 2 GeV), muons which undergo nuclear interactions at energies less than 2 GeV are passed through the original muon_nucl.for routine, which simulates a high energy photon as part of the interaction ( this, of course, is incorrect and will be fixed in the future).
In the current implementation, the flags set for the LEPTO6.3 call are fixed. Since Lepto allows for a variety of settings, the future implementations of lepto will allow the user to adjust the settings of lepto using a titles file. A full explanation of all lepto flags and settings (as well as the structure of the code) can be found in detailed outside references [32]. Also in the home directory for snoman@surf.sno.laurentian.ca will be found the file
lepto63_doc.pswhich is a write-up of LEPTO 6.3.