A natural and simple UV completion of the QCD axion model

Masaki Yamada, Tsutomu T. Yanagida

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


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 R4×S1/Z2 spacetime while a hidden SU(NH) gauge field condensates in the bulk. The brane separation is the origin of the PQ symmetry and its breaking scale is given by the dynamical scale of the SU(NH) gauge interaction. The (generalized) Casimir force of SU(NH) condensation stabilizes the 5th dimension, which guarantees the quality of the PQ symmetry.

Original languageEnglish
Article number136267
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Publication statusPublished - 2021 May 10


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