  Using data corresponding to an integrated luminosity of 1.3 fb^-1, we observe
a narrow mass state decaying into Upsilon(1S)+gamma, where the Upsilon(1S)
meson is detected by its decay into a pair of oppositely charged muons, and the
photon is identified through its conversion into an electron-positron pair. The
significance of this observation is 5.6 standard deviations. The mass of the
state is centered at 10.551 \pm 0.014 (stat.) \pm 0.017 (syst.) GeV/c^2, which
is consistent with that of the state recently observed by the ATLAS
Collaboration.

High Energy Physics - Experiment