Effects of lepto-quarks on π→lν, μ→eγ, and dee in E6 models based on the superstring

We investigate the helicity unsuppressed amplitude of π→lν, the μ→eγ decay, and the electric dipole moment of the electron, dee in E6 superstring models with light lepto-quarks. Both of the generation diagonal and off-diagonal couplings must be less than 10-3 if the mass of the lepto-quark is about 100 GeV. The branching ratio of μ→eγ depends on the top-quark mass. The contribution to dee is restricted by μ→eγ, and dee<10-25 e cm. (orig.)