C and CP violation in effective field theories and applications to eta-meson decays

by Bastian Kubis (Uni. Bonn)

Monday 13 Apr 2026, 16:00 → 17:00 Europe/Berlin

D 308 (ENC)

The light, flavour-neutral eta and eta' mesons are ideal test grounds for discrete symmetry tests, and potential searches for new sources of CP violation.  While the opportunity to test simultaneous violation of P and CP in their decays is severely limited by constraints from electric dipole moments, there is also the perhaps unconventional possibility of CP violation by parity conservation, but C violation.  The quest for sources of the simultaneous violation of C and CP symmetry was popular in the 1960s and has since been mostly neglected. We revisit the operators that break C and CP for flavour-conserving transitions in both the Standard Model effective field theory and the low-energy effective field theory. Subsequently, we match these quark operators to light-meson physics using chiral perturbation theory.  Applications in particular to C-odd Dalitz-plot asymmetries in eta --> 3pi and long-distance contributions to the rare semileptonic decays eta --> pi0 l+ l- are also discussed.