Bottomonium States in Radiative Y(2S) Decays

Abstract

A study of various bottomonium states, in Y(2S)-> gamma (b b-bar) decays, reconstructed exclusively in 26 hadronic final states is presented. The study is performed using a data sample recorded at the Y(2S) resonance with the Belle detector at KEKB, that contains 157.8 X 10^6 Y(2S) events. The chi_{bJ}(1P) states are found with their masses being consistent with the world average values. We find no evidence for the state claimed to have been observed around 9975 MeV/c^{2} in an analysis based on a data sample of 9.3 X 10^6 Y(2S) events collected with the CLEO~III detector, and place an upper limit an order of magnitude lower than the latter result. In the same study, the eta_{b}(1S) state is also searched for.