θ and the η ′ in large N supersymmetric QCD

• Main Authors: Michael Dine, Patrick Draper, Laurel Stephenson-Haskins, Di Xu
• Format: Article
• Language: English
• Published: SpringerOpen 2017-05-01
• Series: Journal of High Energy Physics
• Subjects: Phase Diagram of QCD; Supersymmetric Effective Theories
• Online Access: http://link.springer.com/article/10.1007/JHEP05(2017)122

Abstract We study the large N θ dependence and the η ′ potential in supersymmetric QCD with small soft SUSY-breaking terms. Known exact results in SUSY QCD are found to reflect a variety of expectations from large N perturbation theory, including the presence of branches and the behavior of theories with matter (both with N f ≪ N and N f ∼ N ). However, there are also striking departures from ordinary QCD and the conventional large N description: instanton effects, when under control, are not exponentially suppressed at large N , and branched structure in supersymmetric QCD is always associated with approximate discrete symmetries. We suggest that these differences motivate further study of large N QCD on the lattice.