Low-lying baryon resonances from lattice QCD

Recent results studying the masses and widths of low-lying baryon resonances in lattice QCD are presented. The $S$-wave $N\pi$ scattering lengths for both total isospins $I=1\mathrm{/}2$ and $I=3\mathrm{/}2$ are inferred from the finite-volume spectrum below the inelastic threshold together with the $I=3\mathrm{/}2$ $P$-wave containing the $\mathrm{\Delta }(1232)$ resonance. A lattice QCD computation employing a combined basis of three-quark and meson-baryon interpolating operators with definite momentum to determine the coupled channel $\mathrm{\Sigma }\pi$-$N\bar{K}$ scattering amplitude in the $\mathrm{\Lambda }(1405)$ region is also presented. Our results support the picture of a two-pole structure suggested by theoretical approaches based on $SU(3)$ chiral symmetry and unitarity.