Theta Vacua, QCD Sum Rules, and the Neutron Electric Dipole Moment
نویسندگان
چکیده
We present a detailed study of the electric dipole moment of the neutron induced by a vacuum theta angle within the framework of QCD sum rules. At next-to-next-to leading order in the operator product expansion, we find the result dn(θ) = 1.2 × 10 −16θ̄e · cm, to approximately 40% precision. With the current experimental bound this translates into a limit on the theta parameter of |θ̄| < 6 × 10−10. We compare this result with the long-standing estimates obtained within chiral perturbation theory, and observe a numerical similarity, but also significant differences in the source of the dominant contribution. [email protected] [email protected]
منابع مشابه
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