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We present here the CP asymmetries in the decay rate and angular distributions of Formula: see text decays in the Standard Model (SM) and beyond (BSM). The CP asymmetries in the SM are induced by the CP violation in Formula: see text mixing. To investigate the BSM CP-violating (CPV) effects, a model-independent analysis is performed by using the low-energy effective field theory (LEFT) framework at Formula: see text GeV. If one further assumes the BSM physics to stem from above the electroweak scale, the LEFT shall then be matched onto the SM effective field theory (SMEFT), the operators of which contributing to Formula: see text decays will also contribute to the neutron electric dipole moment (EDM) and Formula: see text mixing. The stringent bounds from the latter suggest that no remarkable CPV effects can be observed in either the decay rate or the angular distributions. The prospects for future measurements of these observables are also mentioned.
Chen et al. (Fri,) studied this question.