$\eta$ and ${\eta }^{\prime }$ decays and what can we learn from them?

Abstract

In this talk a short overview of $\eta$ and ${\eta }^{\prime }$ decays is given with an emphasis on what can be learned for the strong interaction from them. The talk consists of a short introduction to ChPT, a discussion of $\eta \to 3\pi$ beyond $p^4$ and some of the physics involved in ${\eta }^{\prime }\to \eta \pi \pi ,3\pi$ as well as an overview of anomalous processes.

Comments: 13 pages. Talk presented at the Eta'05 Workshop on production and decay of $\eta$ and ${\eta }^{\prime }$ mesons 15th--18th September 2005, Jagellonian University, Cracow, Poland. v2 :Changes in figures, misprints corrected, reference added