  To reduce errors in light-quark mass determinations, it is now necessary to
consider electromagnetic contributions to light-meson masses. Calculations
using staggered quarks and quenched photons are currently underway.
Suitably-extended chiral perturbation theory is necessary to extrapolate the
lattice data to the physical limit. Here we give (preliminary) results for
light-meson masses using staggered chiral perturbation theory including
electromagnetism, and discuss the extent to which quenched-photon simulations
can improve quark-mass calculations.

High Energy Physics - Lattice