Precision Υ spectroscopy from nonrelativistic lattice QCD

The spectrum of the Υ system is investigated using the nonrelativistic lattice QCD approach to heavy quarks and ignoring light quark vacuum polarization. We find good agreement with experiment for the Υ,Υ’,Υ’ ’ and for the center of mass and fine structure of the ${\mathrm{\chi }}_{\mathit{b}}$ states. The lattice calculations predict bb¯ D states with a center of mass at (10.20±0.07±0.03) GeV. Fitting procedures aimed at extracting both ground and excited state energies are developed. We calculate a nonperturbative dispersion mass for the Υ(1S) and compare it with tadpole-improved lattice perturbation theory.