Measurement of the branching fraction for the decay K-S ->pi e nu

We present a measurement of the branching ratio BR(K-S --> pi(+/-)e(-/+)v(v)) performed using the KLOE detector. K-S-mesons are produced in the reaction e(+)e(-) --> phi --> KSKL at the DAPhiNE collider. In a sample of similar to 5 x 106 K-S-tagged events we find 624+/-30 semileptonic K-S decays. Normalizing to the K-S --> pi(+)pi(-) count in the same data sample, we obtain BR(K-S --> piev) = (6.91+/-0.37) x 10(-4), in agreement with the Standard Model expectation. (C) 2002 Elsevier Science B.V. All rights reserved. RI Gauzzi, Paolo/D-2615-2009; valente, paolo/A-6640-2010; ANTONELLI, ANTONELLA/C-6238-2011; Di Domenico, Antonio/G-6301-2011; De Lucia, Erika/D-2250-2011; Passalacqua, Luca/F-5127-2011; branchini, paolo/A-4857-2011; Murtas, Fabrizio/B-5729-2012