Relating CP-violating decays to the neutron EDM

TL;DR

This paper estimates upper limits on CP-violating meson-neutron couplings and derives constraints on rare meson decays using neutron EDM bounds, informing ongoing and future experimental searches.

Contribution

It provides a novel link between neutron EDM limits and CP-violating meson decay couplings, offering new constraints for experimental investigations.

Findings

Upper bounds on CP-violating meson-neutron couplings

Constraints on CP-violating two-pion meson decays

Relevance for GlueX and LHCb measurements

Abstract

We use the present upper bound on the neutron electric dipole moment to give an estimate for the upper limit of the CP-violating couplings of the $\eta(\eta')$ meson to the neutron. Using this result, we derive constraints on the CP-violating two-pion decays of the $\eta(\eta')$. Our results are relevant for the running and planned GlueX and LHCb measurements of rare meson decays.