Observation of a narrow mass state decaying into Upsilon(1S) + gamma in ppbar collisions at sqrt(s) = 1.96 TeV

TL;DR

This paper reports the observation of a new narrow mass state decaying into Upsilon(1S)+gamma in proton-antiproton collisions at 1.96 TeV, confirming a state previously observed by ATLAS with high significance.

Contribution

The study provides the first observation of this state in ppbar collisions with detailed mass measurement and significance analysis, confirming prior findings.

Findings

Mass of the state: 10.551 GeV/c^2

Significance of observation: 5.6 sigma

Consistent with ATLAS observation

Abstract

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.