Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

ATLAS Collaboration

(Submitted on 21 Dec 2011)

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(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 Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.539+/-0.004 (stat.)+/-0.008 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.

Comments:	4 pages plus author list (17 pages total), 2 figures, 1 table, submitted to Physical Review Letters
Subjects:	High Energy Physics - Experiment (hep-ex)
Report number:	CERN-PH-EP-2011-225
Cite as:	arXiv:1112.5154v1 [hep-ex]

Submission history

From: Atlas Publications [view email] 

[v1] Wed, 21 Dec 2011 20:56:45 GMT (172kb)