Lepton flavor violation in a supersymmetric grand unified theory model with nonuniversal sfermion masses

We analyze lepton flavor violating τ→μγ and μ→eγ processes in a supersymmetric grand unified theory model in which sfermions have a special mass spectrum. It is assumed that only third generation sfermions which are contained in 10(Q,Uc,Ec) of SU(5) can have a different mass from the others. This mass spectrum is derived from the E6 grand unified theory model with horizontal symmetries. It is shown that branching ratios of τ→μγ and μ→eγ depend strongly on a right-handed stau mass. The weak scale stability requires a light stau, so large decay rates can be expected in this scenario. When the stau mass is around 150 GeV and tanβ∼10, the branching ratios can be larger than Br(τ→μγ)≅10-8 and Br(μ→eγ)≅5x10-12, which are within reach of future experiments. In addition, this model has an interesting feature that the final state charged lepton tends to have right-handed chirality