Splittings of low-lying charmonium masses at the physical point

Understand

We present high-precision results from lattice QCD for the mass splittings of the low-lying charmonium states.

• For the valence charm quark, the calculation uses Wilson-clover quarks in the Fermilab interpretation.
• The gauge-field ensembles are generated in the presence of up, down, and strange sea quarks, based on the improved staggered (asqtad) action, and gluon fields, based on the one-loop, tadpole-improved gauge action.
• We use five lattice spacings and two values of the light sea quark mass to extrapolate the results to the physical point.