A review of heavy-heavy spectroscopy

Calculations of the heavy-heavy spectrum present a good opportunity for precision tests of QCD using lattice techniques. All methods make use of a non-relativistic expansion of the action and its systematic improvement to remove lattice artefacts. There was convincing demonstration this year that these methods work and that the associated perturbation theory is well-behaved. Comparison to experimental results yields an accurate value for the lattice spacing, a, a key result in the determination of αs, and (for the first time this year) the mass of the b quark (4.7(1) GeV).