The Spectrum and Scale Setting on 2+1-flavor NME Lattices

TL;DR

This paper analyzes 2+1-flavor lattice ensembles to determine meson and baryon spectra, decay constants, flow scales, and topological properties, providing new physical scale determinations and chiral perturbation theory fits.

Contribution

It introduces a comprehensive analysis of 2+1-flavor Wilson-clover fermion ensembles, including new determinations of flow scales and baryon masses using advanced chiral perturbation theory fits.

Findings

Preferred NNLO fit for octet baryons

No evidence of topological charge freezing

Determined physical flow scales and decay constant ratios

Abstract

This paper describes the thirteen ensembles, named NME, generated with 2+1-flavor Wilson-clover fermions by the JLab/W\&M/LANL/MIT/Marseille collaborations, and presents an analysis of the meson and baryon spectrum, decay constants $f_\pi$ and $f_K$, flow scales $t_0$ and $w_0$, and time histories of the $\Theta$ and Weinberg operators under gradient flow. Using these quantities, the physical point values of the two flow scales, ${t_0^{\rm Phy}}$ and ${w_0^{\rm Phy}}$, and the ratio $\mathop{f_K / f_\pi}^{\rm Phy}$ are determined. The masses of the octet and decuplet baryons are analyzed using both the next-to-leading order (NLO) and the next-next-to-leading order (NNLO) ansatz from heavy baryon chiral perturbation theory (HB$\chi$PT). The NNLO fit to the octet baryons, $M_N$, $M_\Sigma$, $M_\Lambda$ and $M_\Xi$, is preferred while the corresponding fits to the decuplet Omega mass, $M_\Omega$, are not distinguished. We also present a study of the autocorrelations in the data and show that there is no evidence, even at large flow time, of the freezing of the topological charge or the Weinberg three-gluon operator.