Аннотация:

Based on four-quark interactions, an effective meson Lagrangian is constructed, which consistently takes into account the effect of explicit violation of chiral symmetry. Applications of this effective theory to describe the physics of pseudo-Goldstone bosons are considered. In particular, we obtain estimates for light quark mass ratios, calculate corrections arising from explicit chiral symmetry breaking to the contributions of the gluon anomaly and the Wess-Zumino-Witten triangular anomaly, and discuss results for two-photon decays of π, η and η′ mesons, as well as the contact contribution to the decay amplitude η′→π⁺π⁻γ, measured by the BESIII collaboration.