Novel constraints on $\Lambda\bar{\Lambda}$ and $p\bar{\Lambda}$ interactions using correlation data

Abstract

The interaction between baryons and antibaryons remains a fundamental topic in hadronic physics, particularly due to its potential to reveal exotic bound states such as baryonia. While the proton-antiproton system has been extensively studied, mainly via scattering experiments, interactions involving antihyperons, such as proton-antilambda and lambda-antilambda, are still poorly constrained due to limited experimental data. High-precision measurements of these systems, especially at low relative momentum, have recently become available through femtoscopic analyses in proton-proton collisions at the LHC. In this work, we extract for the first time the scattering parameters for the lambda-antilambda and proton-antilambda systems using correlation data measured by the ALICE experiment. Our aim is to investigate potential differences between the elastic and annihilation components of the interaction potential. We employ a novel analysis framework, iCATS (imaginary CATS), which solves the Schr\"odinger equation with complex optical potentials to model the strong final-state interactions in systems dominated by inelastic processes. Our results indicate distinct annihilation characteristics between the two systems, challenging the assumption of universal baryon-antibaryon dynamics. The extracted scattering amplitudes are compared with available production cross sections and invariant mass spectra. The consistency between femtoscopic constraints and other observables supports the use of this approach for future explorations of the baryon-antibaryon sector.