Nature of excited $\Xi$ baryons with threshold effects

Abstract

Spectroscopy of excited baryons with strangeness $S=-2$ is stimulated by recent experimental developments. Here we focus on the $\Xi (1620)$ which locates close to the $\bar{K}\Lambda$ threshold. To take into account the threshold effects, we construct the coupled-channels meson-baryon scattering amplitude where the $\Xi (1620)$ appears as a resonance. We demonstrate that the $\bar{K}\Lambda$ threshold effects distort the peak of the $\Xi (1620)$ resonance from the simple Breit-Wigner distribution.

Comments: 4 pages, Proceedings of the 14th International Conference on Hypernuclear and Strange Particle Physics (HYP2022), 27 June to 1 July 2022. v2: modified the right panel of the figure2