Our current understanding of particle physics, encapsulated in the Standard Model, does not provide enough CP-violation to explain the current matter-antimatter asymmetry, and new CP-violating sources are expected.
In this talk I will discuss how polarization observables in eta decays containing muons (which can be accessed at a proposed eta factory-REDTOP) can serve as a probe of CP-violating new physics. Assuming that CP-violating effects arise from new heavy degrees of freedom, I show that such an observation is not in conflict with other observables, such as the neutron EDM.