A CP asymmetry in e^+e^- \to χ^0_iχ^0_j \to χ^0_j τstau_k with tau polarization

Abstract

We propose a CP-odd asymmetry in the supersymmetric process e^+e^- \to χ^0_i χ^0_j \to χ^0_j τstau_k by means of the transverse τpolarization. We calculate the asymmetry and cross sections at a future linear collider in the 500 GeV c.m.s. energy range with longitudinal polarized beams and high luminosity. We work in the Minimal Supersymmetric Standard Model with complex parameters μ, M_1 and A_τ. The asymmetry can reach values up to 60 %. We also estimate the sensitivity for measuring the τpolarization necessary to probe the CP asymmetry.