Lepton Flavour Violating tau Decays in the Left-Right Symmetric Model

Abstract

The Left-Right symmetric extension of the Standard Model with Higgs isospin triplets can provide neutrino masses via a TeV scale seesaw mechanism. The doubly charged Higgs bosons H^{\pm\pm}_L and H^{\pm\pm}_R induce lepton flavour violating decays τ^\pm \to lll at tree-level via a coupling which is related to the Maki-Nakagawa-Sakata matrix (V_{\rm MNS}). We study the magnitude and correlation of τ^\pm \to lll and μ\to eγwith specific assumptions for the origin of the large mixing in V_{\rm MNS} while respecting the stringent bound for μ\to eee. It is also shown that an angular asymmetry for τ^\pm \to lll is sensitive to the relative strength of the H^{\pm\pm}_L and H^{\pm\pm}_R mediated contributions and provides a means of distinguishing models with doubly charged Higgs bosons.