Electric dipole moments within and beyond the Standard Model

Abstract

Searches for electric dipole moments (EDMs) in fundamental particles, nucleons, atoms, and molecules provide a powerful test of fundamental symmetries. The smallness of the $CP$-violation in the Standard Model (SM) gives a clean background for the EDM experiments, making any non-zero signals of EDMs directly sensitive to the beyond Standard Model (BSM) physics. The interpretation of EDM experiments requires a wide range of inputs from particle physics, hadron physics, nuclear physics, to atomic physics. In this thesis, a series of work on the theory of EDMs from the point of view of particle physics is presented. Starting from the Kobayashi-Maskawa (KM) phase in the SM, the size of the electron-spin-dependent CP-odd electron-nucleon interaction (usually denoted as the Cs operator), which contributes to the EDMs of paramagnetic systems, is calculated. The result is three orders of magnitude larger than previously believed. Using the QCD sum rule technique, arbitrary choices of the interpolating current are shown to lead to inconsistent results in the calculations involving the QCD theta term, and the proper procedure is identified to solve this issue. In the presence of EDMs of heavy SM fermions, the effective CP-odd operators generated below the heavy fermion mass threshold and the further induced neutron and atomic EDMs are derived, which in turn allows indirect constraints on the muon, charm quark, and bottom quark EDMs to be set based on existing experiments.