Eta decays at and beyond ${\mathbf{p}}^4$ in Chiral Perturbation Theory

Abstract

An overview is given of Chiral Perturbation Theory and various applications to eta decays. In particular, the main decay $\eta \to 3\pi$ is discussed at the one-loop level, and estimates of the higher order corrections are given. The importance of $p^6$ and higher order effects in double Dalitz and $\eta \to {\pi }^0\gamma \gamma$ decays is pointed out. In all these cases the need for new experimental results is stressed.

Comments: Talks presented at the Workshop on Eta Physics, Angstrom laboratory, Uppsala, October 25-27, 2001; published version (Physica Scripta Topical Issues T99 (2002) 34). Typos corrected, conclusions unchanged. 31 pages