Investigating SU(3) with Nf=8 fundamental fermions at strong renormalized coupling

TL;DR

This study investigates the phase structure of SU(3) gauge theory with 8 fundamental fermions, providing evidence for a continuous phase transition between a strong coupling SMG phase and a weak coupling conformal phase, indicating proximity to the conformal window.

Contribution

The paper offers new lattice simulation results confirming the existence of the SMG phase and characterizes the nature of the phase transition in the SU(3) 8-flavor system.

Findings

Evidence for a continuous phase transition between SMG and conformal phases.

The phase transition is likely governed by a merged fixed point.

SU(3) with 8 flavors is near the conformal window.

Abstract

Lattice simulations have observed a novel strong coupling symmetric mass generation (SMG) phase for the SU(3) gauge system with $N_f=8$ fundamental fermions (represented by two sets of staggered fields) at very large renormalized coupling ($g^2_{GF} \gtrsim 25$). The results of Phys.Rev.D 106 (2022) 014513 suggest that the SMG phase is separated from the weak coupling, conformal phase by a continuous phase transition, implying that the SMG phase exists in the continuum limit. To scrutinize these findings, we are generating a set of large volume zero temperature ensembles using nHYP improved staggered fermions with additional Pauli-Villars fields to tame gauge field fluctuations. We consider the low-lying meson spectrum and verify the existence of the SMG phase. Based on a finite size scaling analysis we predict that the phase transition between the strong and weak coupling phases is likely governed by a merged fixed point that is ultraviolet in the strong coupling but infrared in the weak coupling side. This finding suggests that the SU(3) 8-flavor system sits at the opening of the conformal window