Charged-Lepton-Flavour Violation in the Light of the Super-Kamiokande Data

TL;DR

This paper investigates charged-lepton-flavour violation processes in light of Super-Kamiokande neutrino data, using supersymmetry models and flavor symmetries to predict decay rates that could be observed in upcoming experiments.

Contribution

It introduces a method to calculate flavour-violating soft masses via renormalization group and classifies violation patterns based on neutrino textures aligned with Super-Kamiokande results.

Findings

Predicted mu -> e gamma and tau -> mu gamma rates near current experimental limits.

Identified flavor violation patterns distinguishable by decay rate measurements.

Discussed mu -> e conversion on Titanium as a promising experimental probe.

Abstract

Motivated by the data from Super-Kamiokande and elsewhere indicating oscillations of atmospheric and solar neutrinos, we study charged-lepton-flavour violation, in particular the radiative decays mu -> e gamma and tau -> mu gamma, but also commenting on mu -> 3e and tau -> 3 mu/e decays, as well as mu - e conversion on nuclei. We first show how the renormalization group may be used to calculate flavour-violating soft supersymmetry-breaking masses for charged sleptons and sneutrinos in models with universal input parameters. Subsequently, we classify possible patterns of lepton-flavour violation in the context of phenomenological neutrino mass textures that accommodate the Super-Kamiokande data, giving examples based on Abelian flavour symmetries. Then we calculate in these examples rates for mu -> e gamma and tau ->mu gamma, which may be close to the present experimental upper limits, and show how they may distinguish between the different generic mixing patterns. The rates are promisingly large when the soft supersymmetry-breaking mass parameters are chosen to be consistent with the cosmological relic-density constraints. In addition, we discuss mu -> e conversion on Titanium, which may also be accessible to future experiments.