Electric dipole moments of nucleons, nuclei, and atoms: The Standard Model and beyond

Abstract

Searches for the permanent electric dipole moments (EDMs) of molecules, atoms, nucleons and nuclei provide powerful probes of CP violation both within and beyond the Standard Model (BSM). The interpretation of experimental EDM limits requires careful delineation of physics at a wide range of distance scales, from the long-range atomic and molecular scales to the short-distance dynamics of physics at or beyond the Fermi scale. In this review, we provide a framework for disentangling contributions from physics at these disparate scales, building out from the set of dimension four and six effective operators that embody CP violation at the Fermi scale. We survey existing computations of hadronic and nuclear matrix elements associated with Fermi-scale CP violation in systems of experimental interest, and quantify the present level of theoretical uncertainty in these calculations. Using representative BSM scenarios of current interest, we illustrate how the interplay of physics at various scales generates EDMs at a potentially observable level.

Nuclear electric dipole moments in chiral effective field theory

“…This observation increases the uncertainty of nuclear EDM calculations, but the extent depends on the underlying CP-violating source(s). In addition, this implies that calculations of CP-violating moments of heavier nuclei should not, in general, be performed on the basis of one-pion-exchange potentials only -as is currently state of the art [72] -in order to obtain reliable error estimates. This especially affects analyses of CP-violating models inducing a large gluon chromo-EDM which generates relatively large CP-violating nucleon-nucleon contact terms [15].…”

Direct and indirect constraints on CP-violating Higgs-quark and Higgs-gluon interactions

“…[79][80][81]), the dependence of S A onḡ 0,1 is far more uncertain due to the complicated nuclear many-body problem [82,83] (for a detailed discussion, see ref. [84]). We give the best value and range for A and a 0,1 in table 5.…”

Comparison of ultracold neutron sources for fundamental physics measurements

“…In addition to the fundamental particle aspect, τ n is also an important quantity in understanding the primordial nucleo-synthesis and contributes presently one of the larger uncertainties to its description [14]. The search for an nEDM, which would violate CP, the combined symmetries of charge conjugation (C) and parity (P), is considered to be one of the most promising experiments in particle physics [15,16] to contribute to the understanding of the matter-antimatter asymmetry of the Universe.…”