Femtoscopic Proton-Lambda Correlations in Pb-Pb Collisions at $\sqrt {s_{NN}} = $ 2.76 TeV with ALICE

Two-particle correlations at small relative momenta give insight into the size of the emitting source. Of particular interest is the test of hydrodynamic models which predict a universal, apparent decrease of the extent of the system with increasing transverse mass mT as a consequence of the strong radial flow in heavy-ion collisions at LHC energies. This contribution presents a study of correlations for protons and {\Lambda} particles in Pb-Pb collisions at sqrt(sNN) = 2.76 TeV measured with ALICE. The investigated particle species expand the experimental reach in mT due to their high rest mass. Residual impurities in the samples from misidentification and contributions from feed-down are corrected using data-driven techniques. Correlation functions are obtained in several centrality classes and mT intervals at large mT and show the expected decrease in volume of the strongly interacting fireball for more peripheral collisions. We observe the decrease of the source size with mT, predicted by hydrodynamical calculations, out to mean mT = 2.18 GeV/c2.