Abstract
Experiments searching for the electric dipole moment (EDM) of the electron utilize atomic/molecular states with one or more uncompensated electron spins, and these paramagnetic systems have recently achieved remarkable sensitivity to . If the source of violation resides entirely in the hadronic sector, the two-photon exchange processes between electrons and the nucleus induce -odd semileptonic interactions, parametrized by the Wilson coefficient , and provide the dominant source of EDMs in paramagnetic systems instead of . We evaluate the coefficients induced by the leading hadronic sources of violation, namely, nucleon EDMs and -odd pion-nucleon couplings, by calculating the nucleon-number-enhanced -odd nuclear scalar polarizability, employing chiral perturbation theory at the nucleon level and the Fermi-gas model for the nucleus. This allows us to translate the ACME EDM limits from paramagnetic ThO into novel-independent constraints on the QCD theta term , proton EDM , isoscalar -odd pion-nucleon coupling , and color EDMs of quarks . We note that further experimental progress with EDM experiments in paramagnetic systems may allow them to rival the sensitivity of EDM experiments with neutrons and diamagnetic atoms to these quantities.
- Received 30 January 2020
- Accepted 7 July 2020
DOI:https://doi.org/10.1103/PhysRevD.102.035001
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.
Published by the American Physical Society