Light meson decays at BESIII

Abstract

At present the world’s largest sample of 1.3 billion J/psi decay has been collected by the BESIII detector, which provides a unique opportunity to investigate light meson decays. The η and η ′ hadronic decays are sensitive tools for the investigations of π-π and η-π interactions, symmetry breaking, and for testing the Chiral Perturbation Theory. In this article, BESIII presents new results on amplitude analyses of the Dalitz decays η ′ → 3π , η ′ → ηππ , η ′ → γππ and η ′ → γγπ0, on the observation of new decay modes and on searches for rare or forbidden decays. The a0(980)f0(980) mixing is an important probe to the nature of these two light scalars. The first observation of a0(980)f0(980) mixing will be presented.