Speaker
Description
We present a lattice QCD investigation of baryon resonances with strangeness, focusing on their possible exotic nature, associated with their dynamical origin in meson–baryon interactions. In particular, the $\Lambda(1405)$ and its long-standing two-pole structure are studied, as well as the poorly understood $\Xi(1620)$ and $\Xi(1690)$. We discuss published coupled-channel results for the $\Lambda(1405)$ obtained at $m_{\pi}\approx 200$ MeV, together with preliminary finite-volume spectra from an additional ensemble at heavier pion mass. The analysis employs temporal correlation functions constructed from both single- and multi-hadron interpolating operators, enabling access to the meson-baryon components of these states. Using the Lüscher formalism, we have extracted scattering amplitudes for one ensemble in the $\Lambda(1405)$ sector, which suggest a virtual bound state below the $\pi\Sigma$ threshold and a resonance pole near the $\bar{K}N$ threshold, in qualitative agreement with phenomenological approaches.