CMS-BPH-12-001 ; CERN-PH-EP-2012-118 | ||
Observation of a New Ξb Baryon | ||
CMS Collaboration | ||
27 April 2012 | ||
Phys. Rev. Lett. 108 (2012) 252002 | ||
Abstract: The observation of a new b baryon via its strong decay into Ξ−bπ+ (plus charge conjugates) is reported. The measurement uses a data sample of pp collisions at √s = 7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 5.3 inverse femtobarns. The known Ξ−b baryon is reconstructed via the decay chain Ξ−b→J/ψΞ−→μ+μ−Λ0π−, with Λ0→pπ−. A peak is observed in the distribution of the difference between the mass of the Ξ−bπ+ system and the sum of the masses of the Ξ−b and π+, with a significance exceeding five standard deviations. The mass difference of the peak is 14.84 +/- 0.74 (stat.) +/- 0.28 (syst.) MeV. The new state most likely corresponds to the JP=3/2+ companion of the Ξb. | ||
Links: e-print arXiv:1204.5955 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; Public twiki page ; CADI line (restricted) ; |
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Compact Muon Solenoid LHC, CERN |
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