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Observation of the Ωb- baryon and measurement of the properties of the Ξb- and Ωb- baryons

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Title: Observation of the Ωb- baryon and measurement of the properties of the Ξb- and Ωb- baryons
Author: Aaltonen, Timo; Mehtala, P.; Orava, R.; Maki, T.; Saarikko, H.; Osterberg, K.; CDF collaboration
Citation: Aaltonen , T , Mehtala , P , Orava , R , Maki , T , Saarikko , H , Osterberg , K & CDF collaboration 2009 , ' Observation of the Ωb- baryon and measurement of the properties of the Ξb- and Ωb- baryons ' , Physical Review D : Particles, Fields, Gravitation and Cosmology , vol 80 , no. 7 , pp. 072003 .
Belongs to series: Physical Review D : Particles, Fields, Gravitation and Cosmology
ISSN: 1550-7998
Abstract: We report the observation of the bottom, doubly-strange baryon Ωb- through the decay chain Ωb-→J/ψΩ-, where J/ψ→μ+μ-, Ω-→ΛK-, and Λ→pπ-, using 4.2  fb-1 of data from pp̅ collisions at √s=1.96  TeV, and recorded with the Collider Detector at Fermilab. A signal is observed whose probability of arising from a background fluctuation is 4.0×10-8, or 5.5 Gaussian standard deviations. The Ωb- mass is measured to be 6054.4±6.8(stat)±0.9(syst)  MeV/c2. The lifetime of the Ωb- baryon is measured to be 1.13-0.40+0.53(stat)±0.02(syst)  ps. In addition, for the Ξb- baryon we measure a mass of 5790.9±2.6(stat)±0.8(syst)  MeV/c2 and a lifetime of 1.56-0.25+0.27(stat)±0.02(syst)  ps. Under the assumption that the Ξb- and Ωb- are produced with similar kinematic distributions to the Λb0 baryon, we find σ(Ξb-)B(Ξb-→J/ψΞ-)/σ(Λb0)B(Λb0→J/ψΛ)=0.167-0.025+0.037(stat)±0.012(syst) and σ(Ωb-)B(Ωb-→J/ψΩ-)/σ(Λb0)B(Λb0→J/ψΛ)=0.045-0.012+0.017(stat)± 0.004(syst) for baryons produced with transverse momentum in the range of 6–20  GeV/c.
Peer review status: Peer reviewed
URI: http://hdl.handle.net/10138/24454
Date: 2009

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