Light meson physics with Crystal Ball/MAMI and at BES-III

Rare decays of light mesons like η, η', and ω offer excellent possibilities to study fundamental symmetries and symmetry-breaking patterns. Furthermore, electromagentic transitions with vertices Pγ*γ as in decays of light pseudoscalar mesons (P) or meson production in e+e− collisions give insight into hadronic structure through transition form factors and produce additional constraints for the determination of the anomalous magnetic moment of the muon (g − 2)μ. In this article, recent results on η and ω decays from the Crystal Ball at MAMI experiment as well as feasibility studies on transition form factors for the Crystal Ball and the BES–III at BEPC–II facility are presented.