Chiral Perturbation Theory and Mesons

Abstract

The talk contains a short introduction to mesonic Chiral Perturbation Theory (ChPT). In addition four disparate areas where some progress has been made in recent years are discussed. These are the last fit of the order $p^4$ low-energy-constants $L_i^r$ to data, hard pion ChPT, the recent two-loop work on EFT for QCD like theories and the high order leading logarithm calculations in the massive $O(N)$ nonlinear sigma model.