CP-violation through scalar tau oscillation

We point out that oscillation between the two scalar tau (τ̃) mass eigenstates can give rise to CP-violation if some parameters appearing in the stau or chargino/neutralino mass matrices are complex. If τ̃⁺ and τ̃^- decay into different charginos or neutralinos, rate asymmetries as large as 20% are possible. If both staus decay directly into τ + LSP, CP-violation can in principle still be observed through an energy asymmetry of the τ 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%.