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

LHCb Collaboration, R. Aaij, B. Adeva, M. Adinolfi, A. Affolder, Z. Ajaltouni, S. Akar, J. Albrecht, F. Alessio, M. Alexander, S. Ali, G. Alkhazov, P. Alvarez Cartelle, A. A. Alves, S. Amato, S. Amerio, Y. Amhis, L. An, L. Anderlini, J. AndersonR. Andreassen, M. Andreotti, J. E. Andrews, R. B. Appleby, O. Aquines Gutierrez, F. Archilli, A. Artamonov, M. Artuso, E. Aslanides, G. Auriemma, M. Baalouch, S. Bachmann, J. J. Back, A. Badalov, C. Baesso, W. Baldini, R. J. Barlow, C. Barschel, S. Barsuk, S. Bifani, N. Farley, P. Griffith, P. Ilten, I. R. Kenyon, C. Lazzeroni, A. Mazurov, J. McCarthy, C. J. Parkinson, L. Pescatore, D. Popov, N. K. Watson

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We report on measurements of the mass and 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 → Ξ0cπ-, Ξ0c → pK-K-π+, channel and the mass and lifetime are measured using the Λ0b → Λ+Cπ- mode as a reference. We measure M(Ξ-b) - M(Λ0b) = 178.36±0.46±0.16 MeV/c2, (τΞ-b/τΛ0b) = 1.089±0.026±0.011, where the uncertainties are statistical and systematic, respectively. These results lead to a factor of 2 better precision on the Ξ-b mass and lifetime compared to previous best measurements, and are consistent with theoretical expectations.

Original languageEnglish
Article number242002
Number of pages9
JournalPhysical Review Letters
Issue number24
Publication statusPublished - 9 Dec 2014

ASJC Scopus subject areas

  • General Physics and Astronomy


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