A viable model with violation.

We extend the Standard Model gauge group by and introduce two scalars, a doublet and a singlet, that are charged under this new group and have lepton flavour violating couplings. Since in this model processes can only be mediated by interactions, bounds from transitions can be avoided while allowing for accessible new physics. We consider the case of a boson with a mass of GeV and a gauge coupling , which is in reach of Belle-II, and a long-lived boson with a mass of which can be probed by searching for . Neutrino masses and mixing angles can also be accounted for if sterile neutrinos are added to the spectrum.