Precision charmonium spectroscopy from lattice QCD

We present results for charmonium spectroscopy using nonrelativistic QCD (NRQCD). For the NRQCD action the leading order spin-dependent and next to leading order spin-independent interactions have been included with tadpole-improved coefficients. We use multi-exponential fits to multiple correlation functions to extract ground and excited S states. Splittings between the lowest S, P, and D states are given and we have accurate values for the S state hyperfine splitting and the ${\mathrm{\chi }}_{\mathit{c}}$ fine structure. Agreement with experiment is good—the remaining systematic errors are discussed.