Strong CP Problem

An introduction about strong CP problem and its solutions. Readers are assumed to have basic knowledge of quantum field theory, but not more.

A type of models that can solve the strong CP problem, with large potential to explain the origin of matter-antimatter asymmetry and provide dark matter candidate.

Space-time parity has been proposed as a solution to the strong CP problem for decades. However, electroweak (-like) baryogenesis from the $SU(2)_R \times U(1)_X \to U(1)_Y$ phase transition has been regarded as difficult. This paper investigates the possibility to realize the electroweak (-like) phase transition in such a phase transition, and discuss the resulting cosmological results.