Lattice Simulations and Infrared Conformality

TL;DR

This paper analyzes lattice simulation data to determine if certain gauge theories exhibit infrared conformality, finding evidence supporting conformality in some cases and not in others.

Contribution

It provides a systematic assessment of lattice data for infrared conformality, including a successful fit for SU(3) with 12 fermions, and clarifies the applicability of the conformal hypothesis.

Findings

Data for SU(3) with 12 fermions fits conformal models

Conformal hypothesis fails for confining theories

Conformal hypothesis works well for an expected conformal theory

Abstract

We examine several recent lattice-simulation data sets, asking whether they are consistent with infrared conformality. We observe, in particular, that for an SU(3) gauge theory with 12 Dirac fermions in the fundamental representation, recent simulation data can be described assuming infrared conformality. Lattice simulations include a fermion mass m which is then extrapolated to zero, and we note that this data can be fit by a small-m expansion, allowing a controlled extrapolation. We also note that the conformal hypothesis does not work well for two theories that are known or expected to be confining and chirally broken, and that it does work well for another theory expected to be infrared conformal.