Homogeneity volume (top) and decoupling time $\tau_f$ (bottom) measured at \sqrtSnn = 2.76 TeV compared to those obtained for central \AuAu\ and \PbPb\ collisions at lower energies at the AGS , SPS , and RHIC . The homogeneity region is determined as the product of the three pion femtoscopic radii at $\langle\kT\rangle = 0.3$ \GeVc for 0--5\% central events, whereas the decoupling time $\tau_f$ is extracted from \Rlong(\kT) according to \eq ???. |   |