Levy-shaped femtoscopic sources from an exact solution of relativistic hydrodynamics

Abstract: An important goal of high-energy physics is to better understand the spacetime structure of particle emitting sources created in heavy-ion collisions. For a fraction of a second a special form of matter, the so-called quark-gluon plasma (QGP) is created, which can be examined with the toolkit of femtoscopy. With the measurement of correlation functions it was determined that Lévy distributions describe the shape of QGP sources the most accurately, however, based on hydrodynamics Gaussian distributions are typically expected. In this article we showcase an exact solution of the equations of relativistic hydrodynamics, which aims to resolve this puzzle by providing Lévy distributions directly from hydrodynamics. A detailed analysis reveals whether the predictions of this solution are in accordance with observations.