Description of femtoscopic correlations with realistic pion-kaon interactions: the $\kappa \mathrm{/}{K}_0^{\ast }(700)$ case

In this work, we show how ${\pi }^{+}{K}_S$ femtoscopic correlations, recently reported by ALICE collaboration in $pp$ collisions, can be well described taking into account relativistic corrections and using realistic $\pi K$ interactions. These are obtained from a dispersive analysis of scattering data, which provides an accurate and model-independent description of the $\kappa \mathrm{/}{K}_0^{\ast }(700)$ resonance pole. The chiral symmetry suppression of the $\pi K$ interactions at low energies and the non-ordinary features of the $\kappa \mathrm{/}{K}_0^{\ast }(700)$ seem to suggest that the ${\pi }^{+}{K}_S$ source radius might be surprisingly smaller than for other hadronic processes when using the standard and simple Lednicky-Lyuboshits factorization approximation.