Chiral symmetry breaking and effective lagrangians for softly broken supersymmetric QCD

TL;DR

This paper investigates supersymmetric QCD with fewer flavors than colors, analyzing chiral symmetry breaking, deriving effective Lagrangians, and exploring the effects of supersymmetry breaking on pion properties and scaling behaviors.

Contribution

It provides a detailed calculation of the spectrum and effective Lagrangian for softly broken supersymmetric QCD, including novel insights into the behavior of pion decay constants and masses in various limits.

Findings

Chiral symmetry breaking pattern similar to standard QCD

Derived the chiral effective Lagrangian for pions

Identified different scaling behaviors of pion properties in supersymmetric contexts

Abstract

We study supersymmetric QCD with N_f<N_c in the limit of small supersymmetry-breaking masses and smaller quark masses using the weak-coupling Kahler potential. We calculate the full spectrum of this theory, which manifests a chiral symmetry breaking pattern similar to that caused by the strong interactions of the standard model. We derive the chiral effective lagrangian for the pion degrees of freedom, and discuss the behavior in the formal limit of large squark and gluino masses and for large N_c. We show that the resulting scalings of the pion decay constant and pion masses in these limits differ from those expected in ordinary nonsupersymmetric QCD. Although there is no weak coupling expansion with N_f=N_c, we extend our results to this case by constructing a superfield quantum modified constraint in the presence of supersymmetry breaking.