Tests of Three-Flavor Chiral Perturbation Theory

Abstract

We review experimental tests of three-flavor (u,d,s) chiral perturbation theory (ChPT). These include measurements of pion and kaon polarizabilities, the chiral anomaly amplitudes for processes such as $\gamma \to \pi \pi \pi$, $\gamma \to \pi \pi \eta$, and $\gamma \to KK\pi$; as well as the lifetimes of the neutral pion and eta. These observables are extracted primarily through ultra-peripheral Primakoff scattering of high-energy particles from virtual photons in the Coulomb field of nuclei. Comparing data to two-flavor and three-flavor predictions allows us to evaluate how well ChPT describes light meson dynamics and the role of the strange quark in spontaneous chiral symmetry breaking.

Comments: 8 pages, 2 tables, Tests of Three-Flavor Chiral Perturbation Theory, shorter text and more focused discussion, further proofreading corrections and clarifications