Study of the interaction between $Ξ$ baryons and light mesons via femtoscopy at the LHC

Abstract

Meson-baryon systems with strangeness content provide a unique laboratory for investigating the strong interaction and testing theoretical models of hadron structure and dynamics. In this work, the measured correlation functions for oppositely charged $Ξ-{\rm K}$ and $Ξ-π$ pairs obtained in high-multiplicity pp collisions at $\sqrt{s} = 13$ TeV at the LHC are presented. For the first time, high-precision data on the $Ξ-{\rm K}$ interaction are delivered at small relative momenta. The scattering lengths, extracted via the Lednický-Lyuboshits expression of the pair wavefunction, indicate a repulsive and a shallow attractive strong interaction for the $Ξ-{\rm K}$ and $Ξ-π$ systems, respectively. The $Ξ(1620)$ and $Ξ(1690)$ states are observed in the $Ξ-π$ correlation function and their properties, mass and width, are determined. These measurements are in agreement with other available results. Such high-precision data can help refine the understanding of these resonant states, provide stronger constraints for chirally motivated potentials, and address the key challenge of describing the coupled-channel dynamics that may give rise to molecular configurations.