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, Sean A Dobbs, Z. Metreveli, K. K. Seth, B. J.Y. Tan, Amiran 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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

82 Scopus citations


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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