ИСТИНА

We report the results of femtoscopic analysis of meson and baryon pairs measured by the ALICE Collaboration in Pb-Pb collisions at $\sqrt{s_{NN}}=2.76$~TeV, and in pp collisions at $\sqrt{s}=0.9$, $2.76$ and $7$~TeV. The femtoscopic correlations allow one to measure the space-time characteristics of particle production due to the effects of quantum statistics (for identical particles) and final state interactions. The main features of the femtoscopic measurements in heavy-ion collisions at SPS and RHIC were i) values of correlation radii which are almost independent on the beam energy, ii) the increase of the correlation radii with increasing multiplicity of events and iii) the decrease of radii with increasing pair transverse momentum. This may be understood as a manifestation of the strong collective flow. Such effects were also observed at the LHC; the interferometry volume found twice as large as that at RHIC. Previous femtoscopic studies revealed scaling in transverse mass: the source sizes versus $m_{\rm T}$ for different particle types ($\pi$, K, p, ...) fall on the same curve. This ``$m_{\rm T}$-scaling'' is expected to be an additional confirmation of the hydrodynamic type of expansion. Such approximate scaling was observed for pion, kaon and baryon pairs in Pb-Pb collisions by the ALICE collaboration at the LHC. A similar analysis was carried out for pp collisions. In the high multiplicity pp collisions the particle densities are comparable with the ones measured in peripheral Cu-Cu and Au-Au collisions at RHIC. So it is natural to investigate collective behaviour in pp. The similarities and differences between pp and heavy-ion data are discussed and the comparison with hydrodinamical models is presented.