Dalitz plot analysis of e+ e- --> pi0 pi0 gamma events at SQRT(s) ~ M(phi) with the KLOE detector

TL;DR

This paper analyzes the Dalitz plot of e+ e- --> pi0 pi0 gamma events near the phi meson mass using the KLOE detector, revealing dominant processes and extracting properties of the f0(980).

Contribution

It provides the first detailed Dalitz plot analysis of these events at this energy, including modeling and extraction of f0(980) parameters.

Findings

Dominant process below 700 MeV is e+ e- --> omega pi0 with omega --> pi0 gamma.

Above 700 MeV, phi radiative decay to f0(980) dominates.

Extracted f0(980) mass and coupling constants.

Abstract

We have studied the Dalitz plot of the e+ e- --> pi0 pi0 gamma events collected at SQRT(s) ~ M(phi) with the KLOE detector. In the dipion invariant mass (Mpp) region below 700 MeV, the process under study is dominated by the non-resonant process e+ e- --> omega pi0 with omega --> pi0 gamma whereas, for higher Mpp values, the radiative phi decay to the f0(980) is the dominant mechanism. Different theoretical models are used to fit the Dalitz plot, taking also into account a possible contribution of the sigma(600). For each model, we extract the f0(980) mass and its coupling to pipi, KKbar and to the phi.