Strong CP Problem with 10^{32} Standard Model Copies

Abstract

We show that a recently proposed solution to the Hierarchy Problem simultaneously solves the Strong CP Problem, without requiring an axion or any further new physics. Consistency of black hole physics implies a non-trivial relation between the number of particle species and particle masses, so that with ~10^{32} copies of the standard model, the TeV scale is naturally explained. At the same time, as shown here, this setup predicts a typical expected value of the strong-CP parameter in QCD of theta ~ 10^{-9}. This strongly motivates a more sensitive measurement of the neutron electric dipole moment.