Measuremént of the b baryon lifetime and branching fractions in Z decays

R. Barate*, D. Buskulic, D. Decamp, P. Ghez, C. Goy, J. P. Lees, A. Lucotte, M. N. Minard, J. Y. Nief, B. Pietrzyk, M. P. Casado, M. Chmeissani, P. Comas, J. M. Crespo, M. Delfino, E. Fernandez, M. Fernandez-Bosman, Ll Garrido, A. Juste, M. MartinezG. Merino, R. Miquel, Ll M. Mir, C. Padilla, I. C. Park, A. Pascual, J. A. Perlas, I. Riu, F. Sanchez, A. Colaleo, D. Creanza, M. De Palma, G. Gelao, G. Iaselli, G. Maggi, M. Maggi, N. Marinelli, S. Nuzzo, A. Ranieri, G. Raso, F. Ruggieri, G. Selvaggi, L. Silvestris, P. Tempesta, A. Tricomi, G. Zito, X. Huang, J. Lin, Q. Ouyang, T. Wang, Y. Xie, R. Xu, S. Xue, J. Zhang, L. Zhang, W. Zhao, D. Abbaneo, R. Alemany, U. Becker, A. O. Bazarko, P. Bright-Thomas, M. Cattaneo, F. Cerutti, G. Dissertori, H. Drevermann, R. W. Forty, M. Frank, R. Hagelberg, J. B. Hansen, J. Harvey, P. Janot, B. Jost, E. Kneringer, J. Knobloch, I. Lehraus, P. Mato, A. Minten, L. Moneta, A. Pacheco, J. F. Pusztaszeri, F. Ranjard, G. Rizzo, L. Rolandi, D. Rousseau, D. Schlatter, M. Schmitt, O. Schneider, W. Tejessy, F. Teubert, I. R. Tomalin, H. Wachsmuth, A. Wagner, T. Fearnley, J. D. Hansen, J. R. Hansen, P. H. Hansen, B. S. Nilsson, B. Rensch, A. Wäänänen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Using approximately 4 million hadronic Ζ decays recorded with the ALEPH detector from 1991 through 1995, the lifetime of the b baryon is measured with three independent methods. From the impact parameter distribution of candidate leptons in 1063 events with Λℓ- combinations, the average b baryon lifetime is measured to be 1.20 ± 0.08 ± 0.06 ps. From a sample of 193 fully reconstructed Λ+c candidates correlated with a lepton and a sample of 46 Λℓ+- combinations, the Λb lifetime is measured to be 1.21 ± 0.11 ps. The product branching fractions to these final states are Br(b → Λbb) · Br(Λb → Λℓ-v̄X) = 0.326 ± 0.016 ± 0.039% for the first sample and Br(b → Λb) · Br(Λb → Λ+c-v̄X) = 0.86 ± 0.07 ± 0.14% for the second and third samples combined.

Original languageEnglish (US)
Pages (from-to)197-211
Number of pages15
JournalEuropean Physical Journal C
Volume2
Issue number2
DOIs
StatePublished - 1998

ASJC Scopus subject areas

  • Engineering (miscellaneous)
  • Physics and Astronomy (miscellaneous)

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