Work

Regulated chiral gauge theory and the strong C P problem

Year: 2026

Type: article

Abstract: Four-dimensional chiral gauge theory can be formulated as the boundary theory on a five-dimensional manifold in a manner that may be realized on a finite lattice. There are interesting features of these theories that defy a purely four-dimensional conception of universality. We find that QCD when embedded in a chiral gauge theory (the Standard Model) and regulated this way can simultaneously avoid both the U ( 1 ) A problem and the strong C P problem, with a central role played by fermion zero modes localized far away in the fifth dimension. In this way it differs from conventional lattice QCD formulated as a stand-alone theory, universality being violated by inaccessible light modes in the five-dimensional bulk. Our analysis builds on recent work by others that highlights the role of global U ( 1 ) symmetries in five-dimensional formulations of four-dimensional chiral gauge theories, and the generic appearance of fermion zero modes in the bulk.

Source: Physical review. D/Physical review. D.

DOI: 10.1103/wld4-f12c

Authors: David B. Kaplan, Srimoyee Sen

Institution: Iowa State University

Language: English

Topic: Quantum Chromodynamics and Particle Interactions

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid