Study of the Process e+ e- ---> eta gamma in c.m. Energy Range 600-1380 MeV at CMD-2

TL;DR

This study measures the e+ e- ---> eta gamma process cross section across 600-1380 MeV, determining branching ratios for several mesons and providing first evidence for rho'(1450) decay to eta gamma.

Contribution

It presents new measurements of the cross section and branching ratios, including the first evidence for rho'(1450) ---> eta gamma decay.

Findings

Branching ratios for rho, omega, and phi mesons to eta gamma are provided.

First evidence for rho'(1450) ---> eta gamma decay.

Cross section measurements span 600-1380 MeV energy range.

Abstract

The cross section of the process e+ e- ---> eta gamma has been measured in the 600-1380 MeV c.m. energy range with the CMD-2 detector. The following branching ratios have been determined: B(rho ---> eta gamma) = (3.28 +- 0.37 +- 0.23) 10^{-4}, B(omega ---> eta gamma) = (5.10 +- 0.72 +- 0.34) 10^{-4}, B(phi --> eta gamma) = (1.287 +- 0.013 +- 0.063) 10^{-2}. Evidence for the rho'(1450) ---> eta gamma decay has been obtained for the first time.