ISSN - 16741137, Chinese Physics C, 2010, vol. 34, p. 831-835
Measurement of J/ψ → ηcγ at KEDR
We present a study of the inclusive photon spectra from 5.9 million J/ψ decays collected with the KEDR detector at the VEPP-4M e+e - collider. We measure the branching fraction of radiative decay J/ψ ηcγ, ηc width and mass. Our preliminary results are: M(ηc) 2979.4±1.5±1.9 MeV/c2, Γ(ηc) = 27.8±5.1±3.3 MeV, Γ(J/ψ → ηcγ) = (2.34±0.15±0. 40)%. © 2010 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.