Lattice Study of the Conformal Window in QCD-like Theories

TL;DR

The extent of the conformal window for an SU(3) gauge theory with N{f} Dirac fermions in the fundamental representation is studied to present lattice evidence that the infrared behavior is governed by a fixed point.

Abstract

Using lattice simulations, we study the extent of the conformal window for an $\text{SU}(3)$ gauge theory with $N_f$ Dirac fermions in the fundamental representation. We present evidence that the infrared behavior is conformal for $12 \leq N_f \leq 16$, governed by an infrared fixed point, while confinement and chiral symmetry breaking are present for $N_f \leq 8$.

Figures (2)

• Figure 1: Continuum running coupling from step scaling for $N_f = 12$. The statistical error on each point is smaller than the size of the symbol. Systematic error is shown in the shaded band.
• Figure 2: Continuum running coupling from step scaling for $N_f = 8$. Errors are shown as in Fig. \ref{['fig:nf12_ssf']}. Perturbation theory is shown up to only $\overline{g}^2(L) \sim 10$.