A $\pmb{\nu}$ Solution to the Strong CP Problem

Understand

We present a new solution to the strong CP problem in which the imaginary component of the up quark mass, $\mathcal{I}[m_u]$, acquires a tiny, but non-vanishing value.

• This is achieved via a Dirac seesaw mechanism, which is also responsible for the generation of the small neutrino masses.
• Consistency with the observed value of the up quark mass is achieved via instanton contributions arising from QCD-like interactions.
• In this framework, the value of the neutron electric dipole moment is directly related to $\mathcal{I}[m_u]$, which, due to its common origin with the neutrino masses, implies that the neutron electric dipole moment is likely to be measured in the next round of experiments.