Study of the radiative decay phi to a0(980) gamma with the KLOE detector

TL;DR

This study analyzes the radiative decay of phi mesons to eta pi0 gamma using a large dataset from the KLOE detector, providing precise measurements of branching ratios and properties of the a0(980) resonance.

Contribution

First detailed measurement of phi to eta pi0 gamma decay branching ratios and a0(980) parameters using extensive data from the KLOE experiment.

Findings

Branching ratios for phi to eta pi0 gamma measured as approximately 6.92 and 7.19 x 10^(-5).

Invariant mass distributions fitted to extract a0(980) resonance parameters.

High-statistics data enabled precise determination of decay characteristics.

Abstract

A sample of 1.25x10^9 phi decays, collected with the KLOE detector at the Frascati phi-factory DAFNE at center of mass energy ~ Mphi, has been used to study the radiative decay phi to eta pi0 gamma. This decay is dominated by phi to a0(980) gamma. Two decay chains, corresponding to eta to gamma gamma and eta to pi+ pi- pi0, have been selected. We found respectively: Br(phi to eta pi0 gamma)=(6.92 +/- 0.10 (stat.) +/- 0.20 (syst.))x10^(-5) and (7.19 +/- 0.17 (stat.) +/- 0.24 (syst.))x 10 ^(-5). The eta pi0 invariant mass distributions have been fitted to obtain the relevant a0(980) parameters.