Result of T-violating muon polarization measurement in the $K^+ \to π^0 μ^+ ν$ decay

Abstract

A search for T-violating muon polarization in the $K^+ \to π^0 μ^+ν$ decay has been performed at KEK using stopped kaons. A new improved limit was obtained, $P_T= -0.0017 \pm 0.0023 (stat) \pm 0.0011 (syst)$, corresponding to a 90 % confidence limit of $| P_T| < 0.0050$. The T-violating parameter was also determined to be Im$ξ= -0.0053 \pm 0.0071 (stat) \pm 0.0036 (syst)$, and $|{rm Im}ξ| < 0.016$ (90 % CL).

10 pages, 4 figures, XXXIXth Rencontres de Moriond, Electroweak Interactions and Unified Theories, La Thuile, Italy, March 21-28, 2004