2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/176863We show that the phenomenology of isospin effects on heavy ion reactions at intermediate energies (few AGeV range) is extremely rich and can allow a ``direct'' study of the covariant structure of the isovector interaction in the hadron medium. We work within a relativistic transport frame, beyond a cascade picture, consistently derived from effective Lagrangians, where isospin effects are accounted for in the mean field and collision terms. Rather sensitive observables are proposed from collective flows (``differential'' flows) and from pion/kaon production ($π^-/π^+$, $K^0/K^+$ yields). For the latter point relevant non-equilibrium effects are stressed. The possibility of the transition to a mixed hadron-quark phase, at high baryon and isospin density, is finally suggested. Some signatures could come from an expected ``neutron trapping'' effect.8 pages, 4 figures, espcrc1 (latex) style. Conf. "Perspectives in Hadronic Physics", ICTP Trieste May 2006, Nucl.Phys. A, to appearNuclear Theorytext