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

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

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 t...

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Dades bibliogràfiques
Autors principals: Bonvicini, G, Cinabro, D, Lincoln, A, Smith, M, Zhou, P, Zhu, J, Naik, P, Rademacker, J, Asner, D, Edwards, K, Reed, J, Robichaud, A, Tatishvili, G, White, E, Briere, R, Vogel, H, Onyisi, P, Rosner, J, Alexander, J, Cassel, D, Ehrlich, R, Fields, L, Galik, R, Gibbons, L, Gray, S
Format: Journal article
Idioma:English
Publicat: 2010
Descripció
Sumari: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. © 2010 The American Physical Society.

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