Femtoscopy of identified particles in Pb–Pb collisions with ALICE at the LHC

Femtoscopy provides information on system size and its dynamics due to the effects of quantum statistics and final-state interactions. The results of femtoscopic correlations of different identified particles measured by ALICE in Pb–Pb collisions at sNN=2.76 TeV are presented. Hydrodynamic models predict a decrease of the radii with increasing pair transverse mass ( m T ) due to radial flow. Correlation measurements of heavy particles extend the range over which the transverse mass dependence of the source radii can be studied and thus can serve as a tool to learn about the dynamics of the deconfined medium. In particular, the measured three-dimensional radii of kaons are compared with a model where the hydrodynamic phase is succeeded by a hadronic rescattering phase and a purely hydrodynamical calculation. The latter predicts an approximate m T scaling of source radii obtained from pion and kaon correlations. This m T scaling appears to be broken in the data. The breaking of scaling is well reproduced by the full hydro-kinetic model calculations, thereby indicating the importance of the rescattering phase at LHC energies. The emission duration and the decoupling time of the system are also estimated for kaons and pions.