Convergence of chiral effective field theory

TL;DR

This paper investigates the nucleon mass expansion in chiral perturbation theory using various regularisation schemes, demonstrating that finite-range regulators yield consistent results aligned with lattice QCD data.

Contribution

It compares different ultra-violet regularisation schemes in chiral perturbation theory for nucleon mass expansion, highlighting the effectiveness of finite-range regulators.

Findings

Finite-range regulators produce consistent, model-independent results.

The approach effectively matches lattice QCD data across a wide quark mass range.

Chiral extrapolation problem in lattice QCD is addressed successfully.

Abstract

We formulate the expansion for the mass of the nucleon as a function of pion mass within chiral perturbation theory using a number of different ultra-violet regularisation schemes; including dimensional regularisation and various finite-ranged regulators. Leading and next-to-leading order non-analytic contributions are included through the standard one-loop Feynman graphs. In addition to the physical nucleon mass, the expansion is constrained by recent, extremely accurate, lattice QCD data obtained with two flavors of dynamical quarks. The extent to which different regulators can describe the chiral expansion is examined, while varying the range of quark mass over which the expansions are matched. Renormalised chiral expansion parameters are recovered from each regularisation prescription and compared. We find that the finite-range regulators produce consistent, model-independent results over a wide range of quark mass sufficient to solve the chiral extrapolation problem in lattice QCD.