A T-odd asymmetry in neutralino production and decay

We study CP-violating effects in neutralino production and subsequent decay within the Minimal Supersymmetric Standard Model with complex parameters M 1 and μ. The observable we propose is a T-odd asymmetry based on a triple product in neutralino production e+e- → χ̃i0χ̃i0, i = 1,...,4, with subsequent leptonic three-body decay χ̃i0 → χ̃i0l+l -, l = e, μ, at an e+e- linear collider with √s = 500 GeV and polarised beams. We provide compact analytical formulae for the cross section and the T-odd asymmetry taking into account the complete spin correlations between production and decay. We give numerical predictions for the cross section and the T-odd asymmetry. The asymmetry can go up to 10%. © SISSA/ISAS 2004.