Quark Mass dependence at Two Loops for Meson Properties

Understand

This talks contains a short introduction to Chiral Perturbation Theory and the existing calculations to two-loop order in the mesonic sector.

• I include a discussion on which quantities the expansion can be organized in.
• The present best values of the Low-Energy-Constants as determined from continuum physics are given as well as the assumptions underlying the fits to experimental data.
• I present plots of masses, decay constants and $f_+(0)$ in $K_{\ell3}$ as a function of quark or meson masses.