Search for the KS -> e+e- decay with the KLOE detector
Abstract
We present the result of a direct search for the decay KS -> e+e-, obtained with a sample of e+e- -> phi -> KS KL events produced at DAFNE, the Frascati phi-factory, for an integrated luminosity of 1.9 fb-1. The search has been performed using a pure KS beam tagged by the simultaneous detection of a KL interaction in the calorimeter. Background rejection has been optimized by using both kinematic and particle identification cuts. We find BR(KS -> e+e-) < 9x10-9 at 90% CL, which improves by an order of magnitude on the previous best limit.
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