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

TL;DR

This paper introduces hard pion Chiral Perturbation Theory, reviews its applications in meson decays, and discusses its relevance for $ ext{eta}^ ext{' }$ decay processes, highlighting its theoretical consistency.

Contribution

It provides an overview of hard pion Chiral Perturbation Theory applications and examines its relevance to $ ext{eta}^ ext{' }$ decays, connecting theory with specific decay processes.

Findings

Semileptonic decay results obey LEET relations between form factors.

Applications include $K o ext{pi} ext{pi}$, $B,D o D, ext{pi},K, ext{eta}$ decays.

Relevance of hard pion Chiral Perturbation Theory for $ ext{eta}^ ext{' }$ decays discussed.

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 $f_-$.