Chirally motivated $\pi\Sigma$-$\bar{K}N$ model in a finite volume

TL;DR

This paper extends a chiral coupled channels model of meson-baryon interactions to finite volume, enabling direct comparison with lattice QCD spectra and providing insights into the nature of the $ ext{Lambda}(1405)$ resonance.

Contribution

It introduces a finite volume formulation of the chiral $ ext{pi} ext{-} ext{Sigma}$-$ar{ ext{K}} ext{N}$ model and compares its predictions with lattice QCD results, clarifying the resonance structure.

Findings

The finite volume spectrum matches lattice QCD results well.

The model supports the two-pole structure of $ ext{Lambda}(1405)$.

Pole positions relate to the observed energy levels.

Abstract

We generalize the chirally motivated $\pi\Sigma - \bar{K}N$ coupled channels model to the cubic finite volume and use it to calculate the stationary energy spectrum that appears in a nice agreement with the spectrum obtained in the lattice QCD simulations by the BaSc collaboration. Several other comparisons with the BaSc results are made, in particular relating their pole positions of the meson-baryon scattering matrix to the two-pole picture of $\Lambda(1405)$ generated by our chiral model in the infinite volume.