The Theta Term in QCD Sum Rules and the Electric Dipole Moment of the Vector Meson

Abstract

We demonstrate that the QCD sum rule method can be successfully applied to the calculation of CP-odd electromagnetic observables induced by a vacuum theta--angle. We implement the approach in calculating the electric dipole moment of the rho meson to ~30% precision, and find that the result can also be explicitly related to the vacuum topological susceptibility.

Comments: 16 pages, RevTeX: a sign corrected and other minor changes, to appear in Nucl. Phys. B