Axion quality problem: keep calm and baryon

Journal article

Axion models generically suffer from a severe quality problem when coupled to gravity. In this article we provide a very simple model with a high quality axion. The axion is a pseudo-Nambu-Goldstone boson of the baryon number symmetry, U(1)B, of a new composite sector that breaks U(1)B spontaneously when it confines. A controlled example is a supersymmetric QCD (SQCD) with Nc = Nf. The axion shift symmetry is automatically protected due to the high dimension of the gauge-invariant baryon operator, with the Peccei-Quinn breaking operators arising at dimension Nc + 2. The standard model gauge group is embedded as a subgroup of the flavor symmetry group of SQCD that has an anomaly with U(1)B, generating the standard coupling with gluons.

Authors: Agrawal, P; Hook, A; Loladze, V; Reig, M

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer
• Journal: Journal of High Energy Physics
• Volume: 2026
• Issue: 3
• Article number: 41
• Publication date: 2026-03-04
• Acceptance date: 2026-01-11
• DOI: 10.1007/jhep03(2026)041
• EISSN: 1029-8479
• ISSN: 1126-6708
• Language: English
• Keywords: Compositeness; Axions and ALPs