The observation of a new b baryon via its strong decay into Ξb-π+ (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  fb-1. The known Ξb- baryon is reconstructed via the decay chain Ξb-→J/ψΞ-→μ+μ-Λ0π-, with Λ0→pπ-. A peak is observed in the distribution of the difference between the mass of the Ξb-π+ system and the sum of the masses of the Ξb- and π+, with a significance exceeding 5 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.

Observation of a New Ξ_{b} Baryon

TOSI, SILVANO;
2012

Abstract

The observation of a new b baryon via its strong decay into Ξb-π+ (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  fb-1. The known Ξb- baryon is reconstructed via the decay chain Ξb-→J/ψΞ-→μ+μ-Λ0π-, with Λ0→pπ-. A peak is observed in the distribution of the difference between the mass of the Ξb-π+ system and the sum of the masses of the Ξb- and π+, with a significance exceeding 5 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.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11567/457917
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