Conformal or Walking? Monte Carlo renormalization group studies of SU(3) gauge models with fundamental fermions

TL;DR

This study uses Monte Carlo renormalization group methods to analyze SU(3) gauge models with 8 and 12 fundamental fermions, exploring their fixed point structures and phase behaviors, including conformal and walking regimes.

Contribution

It applies an improved 2-lattice matching Monte Carlo RG technique to connect perturbative and confining regimes, providing new insights into the fixed point structure of these models.

Findings

N_f=8 system exhibits QCD-like behavior.

N_f=12 system shows evidence of an infrared fixed point.

Measured anomalous mass dimensions are close to free field values.

Abstract

Strongly coupled gauge systems with many fermions are important in many phenomenological models. I use the 2-lattice matching Monte Carlo renormalization group method to study the fixed point structure and critical indexes of SU(3) gauge models with 8 and 12 flavors of fundamental fermions. With an improved renormalization group block transformation I am able to connect the perturbative and confining regimes of the N_f=8 flavor system, thus verifying its QCD-like nature. With N_f=12 flavors the data favor the existence of an infrared fixed point and conformal phase, though the results are also consistent with very slow walking. I measure the anomalous mass dimension in both systems at several gauge couplings and find that they are barely different from the free field value.