Correlations of C and CP violation in η → π 0 ℓ + ℓ − and η ′ → ηℓ + ℓ

Abstract Based on recent progress in the systematic analysis of C and CP violation in the light-meson sector, we calculate the C-odd transition amplitudes η → π 0 ℓ + ℓ − and η ′ → ηℓ + ℓ − . Focusing on long-distance contributions driven by the lowest-lying hadronic intermediate states, we work out the correlations between these beyond-the-Standard-Model signals and the Dalitz-plot asymmetries in η → π 0 π + π − and η ′ → ηπ + π − , using dispersion theory.