Finite-size scaling for two-flavor QCD and comparison with O(N) models

TL;DR

This paper investigates the finite-size scaling behavior of the chiral transition in two-flavor QCD, comparing lattice data with 3d O(4) models, and finds improved agreement at larger quark masses.

Contribution

It applies finite-size scaling analysis to existing staggered-fermion lattice data to test universality class predictions for two-flavor QCD.

Findings

Better agreement with O(4) models at larger quark masses

Finite-size effects are significant in lattice QCD data

Supports universality class predictions with finite-size scaling

Abstract

The chiral transition for two-flavor QCD is predicted to be in the same universality class as the 3d O(4) model. This prediction is verified in the Wilson case, but not for the staggered-fermion case. The comparison is usually done assuming infinite-volume behavior. Here we make an analysis of existing staggered-fermion data using finite-size scaling and normalizing the QCD data. We find better agreement for larger quark masses.