CP-Violation through Scalar Tau Oscillation

Abstract

We point out that oscillation between the two scalar tau (stau) mass eigenstates can give rise to CP-violation if some parameters appearing in the stau or chargino/neutralino mass matrices are complex. If stau^+ and stau^- decay into different charginos or neutralinos, rate asymmetries as large as 20% are possible. If both staus decay directly into tau + LSP, CP-violation can in principle still be observed through an energy asymmetry of the tau decay products, but this asymmetry never exceeds the percent level. Even the rate asymmetries become small if the mass splitting between the two stau mass eigenstates is larger than 1%.

11 pages, LaTeX with equation.sty, 3 ps figures (included). Added a reference and a footnote, and slightly expanded the discussion; version to appear in Phys. Lett. B