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A<sc>bstract</sc> We investigate the dynamics responsible for generating the potential of theη′, the (would-be) Goldstone boson associated with the anomalous axial U(1) symmetry of QCD. The standard lore posits that pure QCD dynamics generates a confining potential with a branched structure as a function of theθangle, and that this same potential largely determines the properties of theη′once fermions are included. Here we test this picture by examining a supersymmetric extension of QCD with a small amount of supersymmetry breaking generated via anomaly mediation. For pure SU(N) QCD without flavors, we verify that there areNbranches generated by gaugino condensation. Once quarks are introduced, the flavor effects qualitatively change the strong dynamics of the pure theory. ForFflavors we find |N − F| branches, whose dynamical origin is gaugino condensation in the unbroken subgroup forF < N –1, and in the dual gauge group forF > N+ 1. For the special cases ofF=N –1,N,N+ 1 we find no branches and the entire potential is consistent with being a one-instanton effect. The number of branches is a simple consequence of the selection rules of an anomalous U(1)Rsymmetry. We find that theη′mass does not vanish in the largeNlimit for fixedF/N, since the anomaly is non-vanishing. The same dynamics that is responsible for theη′potential is also responsible for the axion potential. We present a simple derivation of the axion mass formula for an arbitrary number of flavors.
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This content will become publicly available on April 1, 2026
Broken conformal window
A<sc>bstract</sc> We show that near the edges of the conformal window of supersymmetric SU(Nc) QCD, perturbed by Anomaly Mediated Supersymmetry Breaking (AMSB), chiral symmetry can be broken depending on the initial conditions of the RG flow. We do so by perturbatively expanding around Banks-Zaks fixed points and taking advantage of Seiberg duality. Interpolating between the edges of the conformal window, we predict that non-supersymmetric QCD breaks chiral symmetry up toNf≤ 3Nc− 1, while we cannot say anything definitive forNf≥ 3Ncat this moment.
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- Award ID(s):
- 2210390
- PAR ID:
- 10635158
- Publisher / Repository:
- Springer
- Date Published:
- Journal Name:
- Journal of High Energy Physics
- Volume:
- 2025
- Issue:
- 4
- ISSN:
- 1029-8479
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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