Measurement of the ηb(1S) mass and the branching fraction for Υ(3S)→γηb(1S)

G. Bonvicini, D. Cinabro, A. Lincoln, M. J. Smith, P. Zhou, J. Zhu, P. Naik, J. Rademacker, D. M. Asner, K. W. Edwards, J. Reed, A. N. Robichaud, G. Tatishvili, E. J. White, R. A. Briere, H. Vogel, P. U.E. Onyisi, J. L. Rosner, J. P. Alexander, D. G. CasselR. Ehrlich, L. Fields, R. S. Galik, L. Gibbons, S. W. Gray, D. L. Hartill, B. K. Heltsley, J. M. Hunt, D. L. Kreinick, V. E. Kuznetsov, J. Ledoux, H. Mahlke-Krüger, J. R. Patterson, D. Peterson, D. Riley, A. Ryd, A. J. Sadoff, X. Shi, S. Stroiney, W. M. Sun, J. Yelton, P. Rubin, N. Lowrey, S. Mehrabyan, M. Selen, J. Wiss, M. Kornicer, R. E. Mitchell, M. R. Shepherd, C. M. Tarbert, D. Besson, T. K. Pedlar, J. Xavier, D. Cronin-Hennessy, K. Y. Gao, J. Hietala, R. Poling, P. Zweber, S. Dobbs, Z. Metreveli, K. K. Seth, B. J.Y. Tan, A. Tomaradze, S. Brisbane, J. Libby, L. Martin, A. Powell, P. Spradlin, C. Thomas, G. Wilkinson, H. Mendez, J. Y. Ge, D. H. Miller, I. P.J. Shipsey, B. Xin, G. S. Adams, D. Hu, B. Moziak, J. Napolitano, K. M. Ecklund, J. Insler, H. Muramatsu, C. S. Park, E. H. Thorndike, F. Yang, M. Artuso, S. Blusk, S. Khalil, R. Mountain, K. Randrianarivony, T. Skwarnicki, J. C. Wang, L. M. Zhang

Research output: Contribution to journalArticlepeer-review


We report evidence for the ground state of bottomonium, ηb(1S), in the radiative decay Υ(3S)→γηb in e+e- annihilation data taken with the CLEO III detector. Using 6×106 Υ(3S) decays, and assuming Γ(ηb)=10±5MeV/c2, we obtain B(Υ(3S)→γηb)=(7.1±1.8±1.3)×10 -4, where the first error is statistical and the second is systematic. The statistical significance is ∼4σ. The mass is determined to be M(ηb)=9391.8±6.6±2.0MeV/c2, which corresponds to the hyperfine splitting ΔMhf(1S)b=68.5±6.6±2.0MeV/c2. Using 9×106 Υ(2S) decays, we place an upper limit on the corresponding Υ(2S) decay, B(Υ(2S)→γηb)<8. 4×10-4 at 90% confidence level.

Original languageEnglish (US)
Article number031104
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number3
StatePublished - Feb 24 2010

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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