We report on measurements of the mass ; lifetime of the Ξ- b baryon using about 1800 Ξ- b decays reconstructed in a proton-proton collision data set corresponding to an integrated luminosity of 3.0 fb-1, collected by the LHCb experiment. The decays are reconstructed in the Ξ- b → Ξ0 cπ-, Ξ0 c → pK-K-π+, channel ; the mass ; lifetime are measured using the Λ0 b → Λ+ Cπ-, mode as a reference. We measure M (Ξ- b) - M(Λ0 b)= 178.36 ± 0.46 ± 0.16 MeV=c2, (τξ- B/τΛ0 b) = 1.089 ± 0.026 ± 0.011, where the uncertainties are statistical ; systematic, respectively. These results lead to a factor of 2 better precision on the Ξ- b mass ; lifetime compared to previous best measurements, ; are consistent with theoretical expectations. © 2014 CERN, for the LHCb Collaboration.

Precision measurement of the mass ; lifetime of the Ξ- b baryon

PALANO, Antimo;PAPPAGALLO, MARCO IGNAZIO;
2014-01-01

Abstract

We report on measurements of the mass ; lifetime of the Ξ- b baryon using about 1800 Ξ- b decays reconstructed in a proton-proton collision data set corresponding to an integrated luminosity of 3.0 fb-1, collected by the LHCb experiment. The decays are reconstructed in the Ξ- b → Ξ0 cπ-, Ξ0 c → pK-K-π+, channel ; the mass ; lifetime are measured using the Λ0 b → Λ+ Cπ-, mode as a reference. We measure M (Ξ- b) - M(Λ0 b)= 178.36 ± 0.46 ± 0.16 MeV=c2, (τξ- B/τΛ0 b) = 1.089 ± 0.026 ± 0.011, where the uncertainties are statistical ; systematic, respectively. These results lead to a factor of 2 better precision on the Ξ- b mass ; lifetime compared to previous best measurements, ; are consistent with theoretical expectations. © 2014 CERN, for the LHCb Collaboration.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11586/179730
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