Detection of phi-->f0(980) photon, phi-->a0(980) photon into five photons final state with KLOE at DAFNE

TL;DR

This paper reports on the measurement of rare phi meson decays into f0(980) and a0(980) mesons with photon final states using the KLOE detector, achieving unprecedented statistical accuracy.

Contribution

First precise measurement of phi meson decays into f0(980) and a0(980) with five photon final states at DAFNE.

Findings

Branching ratio for phi-->f0(980) photon is (23.7 +- 0.6) x 10^-5.

Branching ratio for phi-->a0(980) photon is (5.8 +- 0.5) x 10^-5.

Ratio of branching ratios is 4.1 +- 0.4.

Abstract

The KLOE detector at DAFNE, the Frascati phi-factory, has collected about 30 pb^-1 by the end of 2000, corresponding to about 90 millions of phi(1020) mesons produced. The five photon final state has been exploited to study the rare decays of phi into f0(980) photon and a0(980) photon, with statistical accuracy never reached before. The preliminary results for these branching ratios, from a data sample of 17 pb^-1, are the following: BR(phi-->f0(980) photon)=(23.7 +- 0.6 (stat.) times 10^-5, BR(phi--> a0(980) photon)=(5.8 +- 0.5 (stat.)) times 10^-5. The systematic error is expected to be less than 10%, a precise evaluation is going on. For the ratio of the branching ratios of phi--> f0 photon to phi--> a0 photon we find 4.1 +- 0.4 (stat.).