The Chromoelectric and Purely Gluonic Operator Contributions to the Neutron Electric Dipole Moment in N=1 Supergravity

TL;DR

The work addresses the neutron EDM problem in $N=1$ supergravity with two physical CP-violating phases in the soft sector and emphasizes three EDM sources: the electric term, the chromoelectric term, and the purely gluonic operator. It performs a complete one-loop calculation of the chromoelectric contributions from gluino, chargino, and neutralino exchanges and re-evaluates Weinberg's purely gluonic dimension-6 operator under these phases. The RG analysis shows that the chromoelectric and gluonic contributions can be as large as, or larger than, the standard electric term in sizable regions of parameter space, requiring all three components for reliable predictions. These results have implications for SUSY CP-violation phenomenology, dark matter constraints, and baryogenesis, illustrating possible cancellations that reconcile EDM bounds with relatively light superpartner spectra.

Abstract

A complete one loop analysis of the chromoelectric dipole contribution to the electric dipole moment (edm) of the quarks and of the neutron in N=1 supergravity including the gluino, chargino and neutralino exchange contributions and exhibiting the dependence on the two CP violating phases allowed in the soft SUSY breaking sector of minimal supergravity models is given. It is found that in significant parts of the supergravity parameter space the chromoelectric dipole contribution to the neutron edm is comparable to the contribution from the electric dipole term and can exceed the contribution of the electric dipole term in certain regions of the parameter space. An analysis of the contribution of Weinberg's purely gluonic CP violating dimension six operator within supergravity unification is also given. It is found that this contribution can also be comparable to the contribution from the electric dipole term in certain regions of the supergravity parameter space.