Constraints on light quark masses from the heavy meson spectrum.

Abstract

We use the observed SU(3) breaking in the mass spectrum of mesons containing a single heavy quark to place restrictions on the light quark current masses. A crucial ingredient in this analysis is our recent first-principles calculation of the electromagnetic contribution to the isospin-violating mass splittings. We also pay special attention to the role of higher-order corrections in chiral perturbation theory. We find that large corrections are necessary for the heavy meson data to be consistent with ${\mathit{m}}_{\mathit{u}}$=0.