arXiv subjects

F. P. Di Meglio

Publications and source records attributed to F. P. Di Meglio.

2 recordsLinked to original sources

arXiv2026

Lepton mixing and charged lepton flavour violation from inverse seesaw with non-degenerate heavy states

We analyse an inverse seesaw scenario with 3+3 gauge singlets. The flavour structure is determined by a flavour symmetry, Delta (3 n^2) or Delta (6 n^2), n integer, and CP and their residual groups among charged leptons and the neutral states. For the latter, the Dirac mass matrix of the gauge singlets carries all non-trivial flavour structure. Consequently, the heavy sterile states form three pseudo-Dirac pairs which have in general distinct masses. We discuss the signal strength of different charged lepton flavour violating processes. Ensuring that the lepton mixing angles can be accommodated at the 3 sigma level or better, we find that the current bounds on the branching ratios of mu -> e gamma, mu -> 3 e, tau -> l gamma and tau -> 3 l, l=e, mu, as well as the rate of mu-e conversion in nuclei do not strongly constrain the considered parameter space, while the limits expected from the upcoming experiments Mu3E, COMET and Mu2e will have a relevant impact.

hep-ph↗

arXiv2025

Charged lepton flavour violation from inverse seesaw with flavour and CP symmetries

We study charged lepton flavour violation in a scenario in which light neutrino masses are generated via the inverse seesaw mechanism with 3+3 gauge singlet fermions, Ni and Sj, i,j=1,2,3. Lepton mixing is predicted with the help of the flavour symmetries Delta (3 n^2) and Delta (6 n^2) combined with CP. In the neutral lepton sector, the non-trivial flavour structure is only encoded in the Dirac neutrino Yukawa matrix (the coupling relating left-handed lepton doublets and gauge singlets Ni). Current experimental bounds on the processes mu -> e gamma, mu -> 3 e, mu-e conversion in nuclei and the tau lepton decays tau -> l gamma and tau -> 3 l, l=e, mu, do not constrain the considered parameter space of this scenario. Prospective limits on the decay mu -> 3 e and mu-e conversion in aluminium instead can markedly reduce the available parameter space. We also comment on the effects of the heavy sterile states on light neutrino masses and lepton mixing.

hep-ph↗