Reconstruction of the Proton Source in Relativistic Heavy Ion Collisions

It has been recently shown that a simple description of the proton phase space distribution can provide a good qualitative understanding of deuteron spectra [1]. On the other hand, it appeared clear that a more solid method to extract the properties of the source had to be established. We have therefore reconstructed the phase space distribution of protons directly from the observed proton and deuteron spectra, exploiting the coalescence prescription together with the notion of collective flow. Here we will outline the procedure while all details can be found in [2]. We make use of a relativistic description of collective flow based on the boost-invariant picture for the longitudinal expansion, together with a longitudinally-independent transverse velocity, and therefore write the proton phase space distribution as