Meson Properties in Partially Quenched Effective Field Theory

Sammanfattning: Mass corrections and decay constants for light mesons have been calculated in Partially Quenched Chiral Perturbation Theory. The calculations of the charged meson masses have been performed to third order, first for degenerate quark masses, and then, in a second project, for the general case. Another calculation also shows that a resummation of unphysical double poles in the neutral propagators of the partially quenched theory allows for the determination of the low-energy constants needed to determine the physical eta mass. Finally, electromagnetic corrections are included into the theory as dynamical fields and their effects on the masses and decay constants of the charged mesons have been calculated to second order. Some consequences concerning the fitting of these results to Lattice QCD simulations are also considered.