Study of e+e− → π+π−Υ(1D) at Belle II

Le résumé fourni par la source

A bstract The bottomonium spectrum, consisting of bound states of a b quark and an anti- b quark, provides an excellent laboratory for probing quantum chromodynamics in the non-perturbative regime. While S and P-wave bottomonium states are well studied experimentally, information on D-wave states remains scarce. We search for the D-wave bottomonium states Υ 2 (1 D ) and Υ 3 (1 D ) via the decay of a vector bottomonium-like state Υ(10753) in the reaction e + e − → π + π − Υ(1 D ), using 19 . 6 fb − 1 of data collected with the Belle II detector at center-of-mass energies $$\sqrt{s}=10.653$$ , 10.701, 10.745, and 10.805 GeV, in the vicinity of the Υ(10753) resonance. No significant signals are observed. We set upper limits at the 90% credibility level on the products of the cross sections and branching fractions, σ [ e + e − → π + π − Υ 2 (1 D )] × ℬ(Υ 2 (1 D ) → γχ b 1 ) and σ [ e + e − → π + π − Υ 3 (1 D )] × ℬ(Υ 3 (1 D ) → γχ b 2 ), at each center-of-mass energy.

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