A natural and simple UV completion of the QCD axion model

Understand

The novel PQ mechanism replaces the strong CP problem with some challenges in a model building.

• In particular, the challenges arise regarding i) the origin of an anomalous global symmetry called a PQ symmetry, ii) the scale of the PQ symmetry breaking, and iii) the quality of the PQ symmetry.
• In this letter, we provide a natural and simple UV completed model that addresses these challenges.
• Extra quarks and anti-quarks are separated by two branes in the Randall-Sundrum ${\bf R}^4 \times S^1 / {\bf Z}_2$ spacetime while a hidden SU($N_H$) gauge field condensates in the bulk.