Study of the a0(980) meson via the radiative decay phi -> eta pi0 gamma with the KLOE detector

Abstract

We have studied the phi-> a0(980) gamma process with the KLOE detector at the Frascati phi-factory DAFNE by detecting the phi -> eta pi0 gamma decays in the final states with η -> gamma gamma and eta -> pi+ pi- pi0. We have measured the branching ratios for both final states: Br(phi -> eta pi0 gamma) = (7.01 ± 0.10 ± 0.20)×10−5 and (7.12 ± 0.13 ± 0.22)×10−5, respectively. We have also extracted the a0(980) mass and its couplings to eta-pi0, K+K−, and to the φ-meson from the fit of the eta-pi0 invariant mass distributions using different phenomenological models.