T-odd Correlations in the Decay of Scalar Fermions

Abstract

We define a CP sensitive asymmetry in the sfermion decays $\ti f \to f \tiχ^0_j \ell \bar \ell, f \tiχ^0_j q \bar q$, based on triple product correlations between the momenta of the outgoing fermions. We study this asymmetry in the MSSM with complex parameters. We show that the asymmetry is sensitive to the phases of the parameters $μ$ and $M_1$. The leading contribution stems from the decay chain $\ti f\to f \tiχ^0_j\to f \tiχ^0_1 Z\to f \tiχ^0_1 \ell \bar \ell (f \tiχ^0_1 q \bar q)$, for which we obtain analytic formulae for the amplitude squared. The asymmetry can go up to 3% for $\ti f\to f \tiχ^0_1 \ell \bar \ell$, and up to 20% for $\ti f\to f \tiχ^0_1 q \bar q$. We also estimate the rates necessary to measure the asymmetry.