ISSN - 00319007, EISSN - 10797114, Physical Review Letters, 2012, vol. 109, p. -
Evidence for the ηb(2S) and observation of h b(1P)→ηb(1S)γ and hb(2P) →ηb(1S)γ
We report the first evidence for the ηb(2S) using the h b(2P)→ηb(2S)γ transition and the first observation of the hb(1P)→ηb(1S)γ and hb(2P)→ηb(1S)γ transitions. The mass and width of the ηb(1S) and ηb(2S) are measured to be mηb (1S)=(9402.4±1.5±1.8) MeV/c2, m ηb (2S)=(9999.0±3.5-1.9+2.8) MeV/c2, and Γηb (1S)=(10.8-3.7-2.0+4.0+4.5) MeV. We also update the hb(1P) and hb(2P) mass measurements. We use a 133.4 fb-1 data sample collected at energies near the γ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e+e - collider. © 2012 American Physical Society.