Charged-lepton decays from soft flavour violation

Author(s)
E. H. Aeikens, W. Grimus, Luis Lavoura
Abstract

We consider a two-Higgs-doublet extension of the Standard Model, with three right-handed neutrino singlets and the seesaw mechanism, wherein all the Yukawa-coupling matrices are lepton flavour-diagonal and lepton flavour violation is soft, originating solely in the non-flavour-diagonal Majorana mass matrix of the right-handed neutrinos. We consider the limit m(R) -> infinity of this model, where m(R) is the seesaw scale. We demonstrate that there is a region in parameter space where the branching ratios of all five charged-lepton decays l(1)-> l(2) l(3)(+) l(3) are close to their experimental upper bounds, while the radiative decays l(1)(-)-> l(2)(-)gamma are invisible because their branching ratios are suppressed by m(R)(-4). We also consider the anomalous magnetic moment of the muon and show that in our model the contributions from the extra scalars, both charged and neutral, can remove the discrepancy between its experimental and theoretical values. (C) 2017 The Author(s). Published by Elsevier B.V.

Organisation(s)
Particle Physics
External organisation(s)
Universidade de Lisboa
Journal
Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume
768
Pages
365-372
No. of pages
8
ISSN
0370-2693
DOI
https://doi.org/10.1016/j.physletb.2017.03.012
Publication date
05-2017
Peer reviewed
Yes
Austrian Fields of Science 2012
103034 Particle physics
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/chargedlepton-decays-from-soft-flavour-violation(1ae3e179-5341-432f-b153-cc6191ad56cf).html