Test of lepton flavor violation with Ke2 decay at KLOE

TL;DR

This paper reports a precise measurement of the ratio of decay rates of kaons to electrons versus muons, confirming Standard Model predictions and constraining new physics models involving lepton flavor violation.

Contribution

First precise measurement of R_K at KLOE, improving constraints on lepton flavor violation in the Minimal Supersymmetric Standard Model.

Findings

Measured R_K = (2.493±0.025_{stat}±0.019_{syst})×10^{-5}

Results agree with Standard Model predictions

Tightened bounds on lepton flavor violating parameters in SUSY models

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.