## Seminar on Theoretical Nuclear Physics

## 25.06.13 16:15

# Radiative Beta Decay for Studies of CP Violation

## Susan Gardner (Kentucky)

A triple-product momentum correlation in the radiative beta decay rate of neutrons or of nuclei is naively T-violating and connects, through an assumption of CPT invariance, to constraints on sources of CP violation beyond the Standard Model (SM). Unlike searches for permanent electric dipole moments, or for the D term in beta decay, it probes spin-independent sources of CP violation. The correlation probes the imaginary part of its coupling constant associated with the pseudo-Chern-Simons term found by Harvey, Hill, and Hill as a consequence of the baryon vector current anomaly and SM electroweak gauge invariance at low energies. We compute the size of the associated asymmetry in chiral effective theory, compare it with the computed background from SM final-state interactions, and consider the new physics scenarios which would be limited by its experimental study.

(Seminarraum II)