The pole structure of the Lambda(1405) in a recent QCD simulation

TL;DR

This paper compares lattice QCD eigenvalues of the Lambda(1405) with Unitary Chiral Perturbation Theory predictions, revealing good agreement and insights into its two-pole structure, but emphasizes the need for more precise data.

Contribution

It demonstrates that UCHPT can accurately predict the quark mass dependence of Lambda(1405) eigenvalues from lattice QCD, supporting its two-pole nature.

Findings

UCHPT predictions match lattice QCD eigenvalues across quark masses.

The overlap pattern with meson-baryon components varies with quark mass.

More precise lattice data are needed for definitive conclusions.

Abstract

The $\Lambda(1405)$ baryon is difficult to detect in experiment, absent in many quark model calculations, and supposedly manifested through a two-pole structure. Its uncommon properties made it subject to numerous experimental and theoretical studies in recent years. Lattice-QCD eigenvalues for different quark masses were recently reported by the Adelaide group. We compare these eigenvalues to predictions of a model based on Unitary Chiral Perturbation Theory. The UCHPT calculation predicts the quark mass dependence remarkably well. It also explains the overlap pattern with different meson-baryon components, mainly $\pi\Sigma$ and $\bar KN$, at different quark masses. More accurate lattice QCD data are required to draw definite conclusions on the nature of the $\Lambda(1405)$.