2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/216081Using the formalism of the Khalatnikov potential, we derive exact general formulae for the entropy flow dS/dy, where y is the rapidity, as a function of temperature for the (1+1) relativistic hydrodynamics of a perfect fluid. We study in particular flows dominated by a sufficiently long hydrodynamic evolution, and provide an explicit analytical solution for dS/dy. We discuss the theoretical implications of our general formulae and some phenomenological applications for heavy-ion collisions.17 pages, 2 figures, to appear in Phys.Rev.CNuclear TheoryHigh Energy Physics - PhenomenologyHigh Energy Physics - Theorytext