ar X iv : h ep - p h / 02 07 18 6 v 1 1 5 Ju l 2 00 2

We present a phenomenological study of τ-sleptons˜τ1,2 and τ-sneutrinos˜ντ in the Minimal Su-persymmetric Standard Model with complex parameters Aτ , µ and M1. We analyse production and decays of the˜τ1,2 and˜ντ at a future e + e − collider. We present numerical predictions for the important decay rates, paying particular attention to their dependence on the complex parameters. The branching ratios of the fermionic decays of˜τ1 and˜ντ show a significant phase dependence for tan β < ∼ 10. For tan β > ∼ 10 the branching ratios for the˜τ2 decays into Higgs bosons depend very sensitively on the phases. We show how information on the phase ϕA τ and the other fundamental˜τi parameters can be obtained from measurements of the˜τi masses, polarized cross sections and bosonic and fermionic decay branching ratios, for small and large tan β values. We estimate the expected errors for these parameters. The error of Aτ is about 10%, and that of tan β about 2% for large tan β and about 1% for small tan β. The remaining parameters can be determined with O(1%) accuracy. We also show that the induced electric dipole moment of the τ –lepton is well below the current experimental limit.