2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/95087We analyze longitudinal pion spectra from E_lab= 2AGeV to \sqrt s_NN=200GeV within Landau's hydrodynamical model. From the measured data on the widths of the pion rapidity spectra, we extract the sound velocity c_s in the early stage of the reactions. It is found that the sound velocity has a local minimum (indicating a softest point in the equation of state, EoS) at E_beam=30AGeV. This softening of the EoS is compatible with the assumption of the formation of a mixed phase at the onset of deconfinement.3 pages, 2 figuresHigh Energy Physics - Phenomenologytext