The general one-loop structure for the LFV Higgs decays Hr→lalb in multi-Higgs models with neutrino masses.

In this paper, we present general formulae for the calculation of LFV Higgs decays H r → l a l b at one-loop, with H r being part of the Higgs spectrum of a generic multi-scalar extension of the Standard Model (SM) with neutrino masses. We develop a method based on a classification of the particles appearing in the loop diagrams (scalars, fermions and vectors), and by identifying the corresponding couplings, we are able to present compact expressions for the form factors involved in the amplitudes. Our results are applicable to models where Flavor Changing Neutral Currents (FCNC) are forbidden at the tree level, but change of flavor is induced by charged currents. Then, as applications of our formalism, we evaluate the branching ratio for the mode h → l a l b , for two specific models: the See-Saw Type I- ν SM and the Scotogenic model (here h = H 1 corresponds to the SM-like Higgs boson); we find that the largest branching ratio for SM-like Higgs h boson within the ν SM is of the order ℬ ℛ (h → μ τ) ≃ 1 0 − 1 6 , while for the Scotogenic model we find ℬ ℛ (h → l a l b) ≲ 1 0 − 9 , which satisfy the latest experimental LHC results. [ABSTRACT FROM AUTHOR]