Topological observables in many-flavour QCD

TL;DR

This paper investigates the infrared dynamics of SU(3) gauge theories with different numbers of flavors using topological susceptibility, revealing signs of near-conformal behavior as the number of flavors increases.

Contribution

It introduces the use of topological susceptibility as a probe to distinguish IR behaviors in many-flavor QCD theories, highlighting dynamical quenching effects.

Findings

Dynamical quenching effect observed at higher flavor numbers.

Topological susceptibility indicates near-conformal behavior.

Comparison with pure gauge theory supports IR behavior distinctions.

Abstract

SU(3) gauge theory with eight massless flavours is believed to be walking, while the corresponding twelve- and four-flavour appear IR-conformal and confining respectively. Looking at the simulations performed by the LatKMI collaboration of these theories, we use the topological susceptibility as an additional probe of the IR dynamics. By drawing a comparison with SU(3) pure gauge theory, we see a dynamical quenching effect emerge at larger number of flavours, which is suggestive of emerging near-conformal and conformal behaviour.