Study of dipion bottomonium transitions and search for the h b(1P) state

Abstract

We study inclusive dipion decays using a sample of 108×106Υ(3S) events recorded with the BABAR detector. We search for the decay mode Υ(3S)→π+π-hb(1P) and find no evidence for the bottomonium spin-singlet state hb(1P) in the invariant mass distribution recoiling against the π+π - system. Assuming the hb(1P) mass to be 9.900GeV/c2, we measure the upper limit on the branching fraction B[Υ(3S) →π+π-hb(1P)]<1.2×10 -4, at 90% confidence level. We also investigate the χbJ(2P)→π+π -χbJ(1P), Υ(3S)→π+π -Υ(2S), and Υ(2S)→π+π -Υ(1S) dipion transitions and present an improved measurement of the branching fraction of the Υ(3S)→π+π -Υ(2S) decay and of the Υ(3S)-Υ(2S) mass difference. © 2011 American Physical Society.