Search for the K-S -> e(+)e(-) decay with the KLOE detector

Abstract

We present the result of a direct search for the decay K-S -> e(+)e(-),obtained with a sample of e(+)e(-) -> phi -> KSKL events produced at DAphi NE, the Frascati phi-factory, for an integrated luminosity of 1.9fb(-1). The search has been performed using a pure K-S beam tagged bythe simultaneous detection of a K-L interaction in the calorimeter.Background rejection has been optimized by using both kinematic andparticle identification cuts. We find BR(KS -> e(+)e(-)) < 9 x 10(-9)at 90% CL, which improves by an order of magnitude on the previous bestlimit, (C) 2009 Elsevier B.V, All rights reserved.