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

Abstract

We study inclusive dipion decays using a sample of 108×10^6Υ(3S) events recorded with the BABAR detector. We search for the decay mode Υ(3S)→π^+π^-h_b(1P) and find no evidence for the bottomonium spin-singlet state h_b(1P) in the invariant mass distribution recoiling against the π^+π^- system. Assuming the h_b(1P) mass to be 9.900  GeV/c^2, we measure the upper limit on the branching fraction B[Υ(3S)→π^+π^-h_b(1P)]<1.2×10^(-4), at 90% confidence level. We also investigate the χ_(bJ)(2P)→π^+π^-χ_(bJ)(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.

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