Femtoscopic study of the Λα interaction

We examine the $\Lambda$-${}^4\mathrm{He}$ ($\alpha$) momentum correlation in high-energy collisions to elucidate the interaction between Lambdas ($\Lambda$) and nucleons ($N$). We compare phenomenological $\Lambda\alpha$ potentials with different strengths at short range. In addition to the conventional Gaussian-type potentials, we construct the $\Lambda\alpha$ potentials by substituting the nucleon density distribution in $\alpha$ into the Skyrme-type $\Lambda$ potentials. We find that the dependence on the employed potential models is visible in the correlation functions from a small-size source. This indicates that the $\Lambda\alpha$ momentum correlation could constrain the property of the $\Lambda N$ interaction at high densities, which is expected to play an essential role in dense nuclear matter. Also, we verify that the Lednicky-Lyuboshits formula can yield erroneous results for a small-size source with a potential which has a large interaction range, like the $\Lambda\alpha$ system.