Λp femtoscopy in collisions of Ar+KCl at 1.76A GeV with HADES

Results on Λp femtoscopy are reported at the lowest energy so far. At a beam energy of 1.76A GeV, the reaction Ar+KCl was studied with HADES at SIS18/GSI. A high-statistics and high-purity Λ sample was collected, allowing for the investigation of Λp correlations at small relative momenta. The experimental correlation function is compared to corresponding model calculations allowing the determination of the space-time extent of the Λp emission source. The Λp radius is found significantly smaller than that for Au+Au/Pb+Pb collisions in the AGS, SPS and RHIC energy domains, but larger than that for electroproduction from He. Taking into account all available data, we find the Λp source radius to increase almost linearly with the number of participants to the power of one-third.