Test of lepton flavor violation with Ke2 decay at KLOE

Abstract

We present a precise measurement of the ratio R_K = \Gamma(Ke2(\gamma))/\Gamma(K\mu2(\gamma)) performed with the KLOE detector. The results are based on data collected at the Frascati e^+e^- collider DAFNE for an integrated luminosity of 2.2 fb^{-1}. We find R_K = (2.493\pm0.025_{stat}\pm0.019_{syst})\times 10^{-5}, in agreement with the Standard Model expectation. This result is used to improve constraints on parameters of the Minimal Supersymmetric Standard Model with lepton flavor violation.