Searches for Axion-Like Particles, Hidden Sectors, and CP Violation with η and η ′ Mesons
Light pseudoscalar mesons η and η′ provide a unique laboratory for searches of physics beyond the Standard Model (BSM), including axion-like particles (ALPs), hidden sector mediators, and sources of CP violation. Their suppressed decay widths, isoscalar quantum numbers, and rich radiative and leptonic decay channels ma...