Study of the Decay phi --> eta pi0 gamma with the KLOE detector

TL;DR

This paper reports on the measurement of the decay phi --> eta pi0 gamma using the KLOE detector, providing branching ratios and insights into the decay process dominated by phi --> a0 gamma.

Contribution

It presents the first detailed analysis of the phi --> eta pi0 gamma decay with two eta decay modes, measuring the branching ratio and analyzing the mass spectrum.

Findings

Branching ratio BR(phi --> a0(980) gamma) = (7.4 +- 0.7) x 10^-5

Dominance of the phi --> a0 gamma process in the decay

Observation of 605 and 197 events for different eta decay modes

Abstract

In a sample of 5.3x10^7 phi-decays observed with the KLOE detector at the Frascati phi-factory Dafne we find 605 eta pi0 gamma events with eta --> gamma\gamma and 197 eta pi0 gamma events with eta --> pi+ pi- pi0. The decay phi --> eta pi0 gamma is dominated by the process phi --> a0 gamma. From a fit to the eta pi0 mass spectrum we find BR(phi --> ao(980) gamma)= (7.4 +- 0.7)x10^-5.