Determination of SU(2) ChPT LECs from 2+1 flavor staggered lattice simulations

TL;DR

This paper uses lattice QCD simulations to accurately determine SU(2) chiral perturbation theory low-energy constants by fitting pion properties across a range of masses and lattice scales, validating the use of ChPT for extrapolation.

Contribution

It provides a precise determination of LECs l_3 and l_4 from staggered lattice data using NLO and NNLO ChPT, demonstrating the stability and applicability of continuum ChPT.

Findings

Stable and precise LECs obtained from continuum ChPT at NLO.

Validation of ChPT for extrapolating from higher to physical pion masses.

Lattice data covers a broad pion mass range, supporting ChPT applicability.

Abstract

By fitting pion masses and decay constants from 2+1 flavor staggered lattice simulations to the predictions of NLO and NNLO SU(2) chiral perturbation theory we determine the low-energy constants l_3 and l_4. The lattice ensembles were generated by the Wuppertal-Budapest collaboration and cover pion masses in the range of 135 to 435 MeV and lattice scales between 0.7 and 2.0 GeV. By choosing a suitable scaling trajectory, we were able to demonstrate that precise and stable results for the LECs can be obtained from continuum ChPT to NLO. The pion masses available in this work also allow us to study the applicability of using ChPT to extrapolate from higher masses to the physical pion mass.