Atmospheric neutrino oscillation and large lepton-flavour violation in the SUSY SU(5) GUT

The atmospheric neutrino anomaly reported by the super-Kamiokande collaboration suggests existence of a large flavour violating Yukawa coupling. We discuss lepton-flavour violation at low energies in the supersymmetric (SUSY) SU(5)GUT model with right-handed neutrinos assuming the hidden-sector SUSY breaking scenario in the minimal supergravity. We find that for a wide range of parameter space suggested from the atmospheric neutrino anomaly, if the tau-neutrino Yukawa coupling is as large as that of top quark, lower bounds of the branching ratios of μ+→e+γ, τ±→μ±γ, and the μ−e conversion rate on 2248Ti become around 10−14, 10−9, and 10−16, respectively. These reaction rates may be in the region accessible by near future experiments.