New physics beyond the standard model in η and η' decays

Rare and symmetry-constrained decays of η, η′ mesons offer a flavor-conserving window into physics Beyond the Standard Model (BSM) that is complementary to other searches. Potential signatures include violations of fundamental symmetries and new light particles such as hidden photons or photon-like bosons, light Higgs bosons, or axion-like particles. In this talk, I will present an overview of theoretical motivations and models for BSM searches at current and future η, η′ factories, as well as promising targets for experimental searches.