Light-Quark FLIC Fermion Simulations of the $1^{-+}$ Exotic Meson

TL;DR

This study uses FLIC fermion simulations on large lattices to estimate the mass of the $1^{-+}$ exotic meson, finding results consistent with the $ ext{pi}_1(1600)$ candidate and near the chiral limit.

Contribution

It introduces the use of FLIC fermion action for light quark masses approaching 25 MeV in exotic meson mass calculations.

Findings

The $1^{-+}$ exotic meson mass aligns with the $ ext{pi}_1(1600)$.

Significant curvature observed near the chiral limit.

Results exclude the $ ext{pi}_1(1400)$ as the candidate.

Abstract

We investigate the mass of the $1^{-+}$ exotic meson, created with hybrid interpolating fields. Access to light quark masses approaching 25 MeV is facilitated by the use of the Fat-Link Irrelevant Clover (FLIC) fermion action, and large ($20^3 \times 40$) lattices. Our results indicate that the $1^{-+}$ exotic exhibits significant curvature close to the chiral limit, and yield a $1^{-+}$ mass in agreement with the $\pi_1 (1600)$ candidate and exclusive of the $\pi_1 (1400)$.