Search for non-standard time-reversal violation

The E246 experiment, performed at the Japanese National Laboratory KEK, is a search for a transverse muon polarization in the K+ -> pi(0) mu(+) V-mu(K-mu 3) decay. Such a transverse polarization is free from final-state-interaction effects, and negligibly small (similar to 10(-6)) in the Standard Model (SM). On the other hand, several extensions of the SM make predictions which are within the reach of experiment. The E246 experiment has already improved the upper limit obtained previously.