Hyperfine splitting in the bottomonium system on the lattice and in the continuum

Abstract

The latest experimental measurements of the hyperfine splitting $E_{\rm{hfs}}=M_{\Upsilon(1 S)}-M_{\eta_b(1 S)}$ done by the Belle collaboration and the perturbative and lattice QCD predictions show a tension with the current extraction within lattice non-relativistic QCD. In this talk we revise the analysis of radiative corrections to the bottomonium hyperfine splitting within lattice non-relativistic QCD at the next-to-leading order. The result of the analysis is in good agreement with the perturbative and lattice QCD result as well as the direct measurement.