We show that the procedure of maximizing $G^{\mathrm{-}1}$(α), the inverse of Newton’s constant within the wormhole calculus, subject to the constraint that the effective cosmological constant vanish, drives the QCD θ parameter to θ=0,π which are the CP conserving values. We argue that, in fact, θ=π is the preferred value and discuss the phenomenological consistency of this choice.

• Received 25 January 1989

DOI:https://doi.org/10.1103/PhysRevLett.62.2575