Abstract
Recent measurements of femtoscopic correlations at NA61/SHINE unravel that the shape of the particle emitting source is not Gaussian. The measurements are based on Lévy-stable symmetric sources, and we discuss the average pair transverse mass dependence of the source parameters. One of the parameters, the Lévy exponent α, is of particular importance. It describes the shape of the source, which, in the vicinity of the critical point of the QCD phase diagram, may be related to the critical exponent η. Its measurement hence may contribute to the search for and characterization of the critical point of the phase diagram.