Study of χbJ(2P)→ωΥ(1S) at Belle

We report a study of the hadronic transitions χbJ(2P)→ωΥ(1S), with ω→π⁺π⁻π⁰, using 28.2×10⁶~Υ(3S) mesons recorded by the Belle detector. We present the first evidence for the near--threshold transition χb0(2P)→ωΥ(1S), the analog of the charm sector decay χc1(3872)→ω J/ψ, with a branching fraction of B(χb0(2P)→ωΥ(1S)) = (0.55±0.19±0.07)%. We also obtain branching fractions of B(χb1(2P)→ωΥ(1S)) = (2.39+0.20-0.19±0.24)% and B(χb2(2P)→ωΥ(1S)) = (0.47+0.13-0.12±0.06)%, confirming the measurement of the ω transitions of the $J=1,2~P$--wave states. The ratio for the $J=2$ to $J=1$ transitions is also measured and found to differ by 3.3 standard deviations from the expected value in the QCD multipole expansion.