Lepton number violation in theories with a large number of Standard Model copies

Understand

We examine lepton number violation (LNV) in theories with a saturated black hole bound on a large number of species.

• Such theories have been advocated recently as a possible solution to the hierarchy problem and an explanation of the smallness of neutrino masses.
• The violation of lepton number can be a potential phenomenological problem of this N-copy extension of the Standard Model as due to the low quantum gravity scale black holes may induce TeV scale LNV operators generating unacceptably large rates of LNV processes.
• We show, however, that this does not happen in this scenario due to a specific compensation mechanism between contributions of different Majorana neutrino states to these processes.