Hard Pion Chiral Perturbation Theory: What is it and is it relevant for ${\eta }^{\prime }$ decays?

Abstract

In this talk I give a short introduction to hard pion Chiral Perturbation Theory and an overview of the available applications $K\to \pi \pi$, $B,D\to D,\pi ,K,\eta$ semileptonic decays and ${\chi }_{c0,2}\to \pi \pi ,KK$. It is pointed out that the reults for the semileptonic decays obey the LEET relation between $f_{+}$ and $f_{-}$.

Comments: 4 pages, Talk presented at the PrimeNet meeting, Meson Physics in Low-Energy QCD, September 26 - 28, 2011, Forschungszentrum Juelich, Germany