# Measurement of the KS->gg branching ratio using a pure KS beam with the KLOE detector - High Energy Physics - Experiment

Abstract: We have searched for the decay KS->gg in a sample of 2x10^9 phi->KS KL decayscollected at DAPHNE with an integrated luminosity of 1.9 fb^{-1}. KS are taggedby the KL interaction in the calorimeter. Two prompt photons must also bedetected. Kinematic constraints reduce the initial 6x10^5 events to 2740candidates, from which a signal of 711\pm 35 events is extracted. Bynormalizing to the KS->2pi^0 decays counted in the same sample, we measureBRKS->gg= 2.26\pm0.12 {stat}\pm0.06 {syst}x10^{-6}, in agreement withOp^4 Chiral Perturbation Theory predictions.

Author: The KLOE collaboration

Source: https://arxiv.org/