New measurement of the rare decay $ϕ\to η' γ$ with CMD-2

Abstract

A new measurement of the rare decay ϕ\to η' γperformed with the CMD-2 detector at Novosibirsk is described. Of the data sample corresponding to the integrated luminosity of 14.5 pb^{-1}, twenty one events have been selected in the mode η'\toπ^+π^-η, η\toγγ. The following branching ratio was obtained: B(ϕ\to η' γ) = (8.2^{+2.1}_{-1.9} \pm 1.1) 10^{-5}.