Large Long-Distance Contributions to the Electric Dipole Moments of Charged Leptons in the Standard Model

An improved bound on the electron's electric dipole moment

The imbalance of matter and antimatter in our Universe provides compelling motivation to search for undiscovered particles that violate charge-parity symmetry. Interactions with vacuum fluctuations of the fields associated with these new particles will induce an electric dipole moment of the electron (eEDM). We present the most precise measurement yet of the eEDM using electrons confined inside molecular ions, subjected to a huge intramolecular electric field, and evolving coherently for up to 3 seconds. Our result is consistent with zero and improves on the previous best upper bound by a factor of ~2.4. Our results provide constraints on broad classes of new physics above [Formula: see text] electron volts, beyond the direct reach of the current particle colliders or those likely to be available in the coming decades.

Standard Model Prediction for Paramagnetic Electric Dipole Moments

Standard model CP violation associated with the phase of the Cabibbo-Kobayashi-Maskawa quark mixing matrix is known to give small answers for the electric dipole moment (EDM) observables. Moreover, predictions for the EDMs of neutrons and diamagnetic atoms suffer from considerable uncertainties. We point out that the CP-violating observables associated with the electron spin (paramagnetic EDMs) are dominated by the combination of the electroweak penguin diagrams and ΔI=1/2 weak transitions in the baryon sector, and are calculable within chiral perturbation theory. The predicted size of the semileptonic operator C_{S} is 7×10^{-16}, which corresponds to the equivalent electron EDM d_{e}^{eq}=1.0×10^{-35}  e cm. While still far from the current observational limits, this result is 3 orders of magnitude larger than previously believed.

Electric dipole moment of light nuclei in chiral effective field theory

CP-violating interactions at quark level generate CP-violating nuclear interactions and currents, which could be revealed by looking at the presence of a permanent nuclear electric dipole moment. Within the framework of chiral effective field theory, we discuss the derivation of the CP-violating nuclear potential up to next-to-next-to leading order (N2LO) and the preliminary results for the charge operator up to next-to leading order (NLO). Moreover, we introduce some renormalization argument which indicates that we need to promote the short-distance operator to the leading order (LO) in order to reabsorb the divergences generated by the one pion exchange. Finally, we present some selected numerical results for the electric dipole moments of 2H, 3He and 3H discussing the systematic errors introduced by the truncation of the chiral expansion.

Rovibrational structure of the ytterbium monohydroxide molecule and the P,T-violation searches

The spectrum of triatomic molecules with close rovibrational opposite parity levels is sensitive to the P,T-odd effects. This makes them a convenient platform for the experimental search of a new physics. Among the promising candidates, one may distinguish YbOH as a non-radioactive compound with a heavy atom. The energy gap between levels of opposite parity, l-doubling, is of great interest as it determines the electric field strength required for the full polarization of the molecule. Likewise, the influence of the bending and stretching modes on the sensitivities to the P,T-violation requires a thorough investigation since the measurement would be performed on the excited vibrational states. This motivates us to obtain the rovibrational nuclear wavefunctions, taking into account the anharmonicity of the potential. As a result, we get the values of E_eff and E_s for the lowest excited vibrational state and determine the l-doubling.