Electric dipole moments of W boson and neutron from supersymmetry

Abstract

The supersymmetric standard model (SSM) has a CP-violating phase in its gauge-Higgs sector. This new source of CP violation induces the electric dipole moments (EDMs) of the neutron and electron at the one-loop level. The same CP-violating phase generates the EDM of the $W$ boson through one-loop diagrams mediated by the charginos and neutralinos, which leads to the EDMs of the neutron and electron at the two-loop level. We discuss these EDMs, assuming that the CP-violating phase has the magnitude of order 0.1--1 which may be suggested from the baryon asymmetry of the universe. Even at the two-loop level the neutron and the electron could have EDMs which are smaller than their experimental upper bounds by only one order of magnitude. Since these two-loop contributions do not depend on the values of SSM parameters for the squark or slepton sector, they provide predictions for the EDMs less ambiguous than the one-loop contributions.