Cosmologically Safe QCD Axion without Fine-Tuning

Masaki Yamada, Tsutomu T. Yanagida, Kazuya Yonekura

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Although QCD axion models are widely studied as solutions to the strong CP problem, they generically confront severe fine-tuning problems to guarantee the anomalous Peccei-Quinn (PQ) symmetry. In this Letter, we propose a simple QCD axion model without any fine-tunings. We introduce an extra dimension and a pair of extra quarks living on two branes separately, which is also charged under a bulk Abelian gauge symmetry. We assume a monopole condensation on our brane at an intermediate scale, which implies that the extra quarks develop chiral symmetry breaking and the PQ symmetry is broken. In contrast to Kim's original model, our model explains the origin of the PQ symmetry thanks to the extra dimension and avoids the cosmological domain wall problem because of chiral symmetry breaking in Abelian gauge theory.

Original languageEnglish
Article number051801
JournalPhysical review letters
Volume116
Issue number5
DOIs
Publication statusPublished - Feb 5 2016

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'Cosmologically Safe QCD Axion without Fine-Tuning'. Together they form a unique fingerprint.

Cite this