PRECISION UPSILON-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 χb states. The lattice calculations predict bb̄ 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. © 1994 The American Physical Society.