EPJ

2023 Impact factor 4.2
EPJ C - Particles and Fields
Particles and Fields
Eur. Phys. J. C 14, 319-334
DOI 10.1007/s100520000357

Charged-Lepton-Flavour Violation
in the light of the Super-Kamiokande data

J. Ellis1 - M.E. Gómez2 - G.K. Leontaris1,3 - S. Lola1 - D.V. Nanopoulos4,5,6

1 Theory Division, CERN, 1211 Geneva 23, Switzerland
2 Centro de Física das Interacções Fundamentais (CFIF), Departamento de Física, Instituto Superior Técnico,
Av. Rovisco Pais, 1049-001 Lisboa, Portugal
3 Theoretical Physics Division, Ioannina University, 45110 Ioannina, Greece
4 Center for Theoretical Physics, Department of Physics, Texas A&M University, College Station, TX 77843 4242, USA
5 Astroparticle Physics Group, Houston Advanced Research Center (HARC), The Mitchell Campus, Woodlands, TX 77381, USA
6 Academy of Athens, Chair of Theoretical Physics, Division of Natural Sciences, 28 Panepistimiou Ave., Athens 10679, Greece

Received: 18 December 1999 / Published online: 6 March 2000 - © Springer-Verlag 2000

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 $\mu \rightarrow e \gamma$ and $\tau \rightarrow \mu \gamma$, but also commenting on $\mu \rightarrow3e$ and $\tau \to 3 \mu/e$ decays, as well as $\mu \to e$ 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 $\mu \rightarrow e \gamma$ and $\tau \rightarrow \mu \gamma$, 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 $\mu \rightarrow e$ conversion on Titanium, which may also be accessible to future experiments.

Copyright Società Italiana di Fisica, Springer-Verlag 2000

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