Probing a Core of the Interaction Potential of Two Λ-Hyperons with Femtoscopic Correlations at LEP

The analysis of ALEPH data on femtoscopic correlations of two Λ-hyperons in Z-boson decays yields a very small source radius of $$0.11 \pm 0.03$$ fm if taking into account only the repulsion due to the Fermi–Dirac quantum statistics. Such a small source radius is counter-intuitive in the string picture of particle production due to a moderate string tension of ~1 GeV/fm. It is shown that the ALEPH data can be described with an acceptable source radius of >~0.3 fm if taking into account the repulsive final state interaction between hyperons at distances smaller than a femtometer. Information on the potential core of two-hyperon interaction is difficult to obtain otherwise.