Axial U(1) dynamics in η and η′ photoproduction Original Research Article

We discuss the sensitivity of η and η′ photoproduction near threshold to the gluonic OZI breaking parameters in the UA(1)-extended effective chiral Lagrangian for low-energy QCD. Our coupled-channels analysis hints at a strong correlation between the gluon-induced contributions to the η′ mass and the low-energy pp→ppη′ reaction and the near-threshold behaviour of the γp→ηp cross section.