On the Derivation of Chiral Symmetry Breaking in QCD-like Theories and S-confining Theories

TL;DR

This paper investigates how chiral symmetry breaking patterns in QCD-like theories can be derived from supersymmetric models with anomaly-mediated SUSY breaking, revealing conditions under which expected patterns emerge or are disrupted.

Contribution

It demonstrates derivation of chiral symmetry breaking without potential minimization in certain cases and analyzes the effects of AMSB on vacuum structure in SUSY QCD.

Findings

Successfully derives chiral symmetry breaking for N_f < N_c without potential minimization.

Identifies runaway directions and baryon number breaking for N_f = N_c or N_f = N_c+1.

Shows consistency of AMSB potential with holomorphic mass contributions.

Abstract

Recent works argue that the pattern of chiral symmetry breaking in QCD-like theories can be derived from supersymmetric (SUSY) QCD with perturbation of anomaly-mediated SUSY breaking (AMSB). Nevertheless, despite the fact that AMSB needs to be a small (but still exact) perturbation, there are two other major problems remaining unsolved: first, in order to derive the chiral symmetry breaking pattern, one needs to minimize the potential along a certain specific direction, identifying this direction fully as an outcome is nontrivial given the moduli space of degenerate vacua in the SUSY limit; second, when SUSY is broken, non-holomorphic states might emerge and be relevant for determining the vacuum structure. In this work, we focus on SUSY QCD with $N_f\leq N_c+1$ and perturb the theories using AMSB. Without minimizing the potential along a certain specific direction in the moduli space, we successfully derive the expected chiral symmetry breaking pattern when $N_f<N_c$. However, when $N_f=N_c$ and $N_f=N_c+1$, we show that tree-level AMSB would induce runaway directions, along which baryon number is spontaneously broken, and the vacua with broken baryon number can be deeper while the field values are not far from the origin. This implies that phase transitions and/or non-holomorphic physics are necessary. Moreover, we perform explicit consistency checks on ultraviolet insensitivity for different $N_f$ by adding the holomorphic mass term for the last flavor, we find that the jump of AMSB potential indeed matches the contribution from the holomorphic mass term. We also show in general that, when tree-level AMSB is not vanishing, the origin of the moduli space in s-confining theories does not persist as a minimum.