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Observation of a New X-b State in Radiative Transitions to Y(1S) and Y(2S) at ATLAS

Research output: Contribution to journalJournal article


  • ATLAS Collaboration
Article number152001
<mark>Journal publication date</mark>9/04/2012
<mark>Journal</mark>Physical Review Letters
Issue number15
Number of pages17
<mark>Original language</mark>English


The χb(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider at √s=7  TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4  fb-1, these states are reconstructed through their radiative decays to Υ(1S,2S) with Υ→μ+μ-. In addition to the mass peaks corresponding to the decay modes χb(1P,2P)→Υ(1S)γ, a new structure centered at a mass of 10.530±0.005(stat)±0.009(syst)  GeV is also observed, in both the Υ(1S)γ and Υ(2S)γ decay modes. This structure is interpreted as the χb(3P) system.

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Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
© 2012 CERN, for the ATLAS Collaboration