New limit on T-violating parameters in kaon decays

Abstract

A search for a T-violating transverse muon polarization (P T ) in K + → π 0 µ + ν decay was carried out in the experiment E246 at the KEK-PS. The Standard model (SM) predicts vanishing value of the polarization (< 10 −7 ), so an observation of non-zero P T at the current experimental sensitivity level would be a definite signature of new physics beyond SM. The preliminary result of the analysis of the 1996-1998 data is presented here: P T = (−3.3±3.7(stat)±0.9(syst))×10 −3 , which corresponds to the T-violation parameter Im(ξ) = (−0.9 ± 1.2(stat) ± 0.3(syst)) × 10 −2 . There is no evidence for T-violation in K µ3 at the current level of sensitivity. * Speaker.