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

Collaboration, D0 and Bertram, Iain and Borissov, Guennadi and Fox, Harald and Ross, Anthony and Williams, Mark and Ratoff, Peter (2012) Observation of a narrow mass state decaying into Upsilon(1S) + gamma in ppbar collisions at sqrt(s) = 1.96 TeV. Physical Review D, 86 (3). ISSN 1550-7998

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PhysRevD.86.031103.pdf - Published Version

## 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.

Item Type:
Journal Article
Journal or Publication Title:
Physical Review D