2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/82186We study the formation of resonances in terms of the chiral SU(3) Lagrangian. At leading order parameter-free predictions are obtained for the scattering of Goldstone bosons off any hadron once we insist on approximate crossing symmetry of the unitarized scattering amplitude. A wealth of empirically established resonances are recovered and so far unseen resonances are predicted. Here we review in some detail the properties of light axial-vector mesons.Invited talk given at Hirschegg 2004, 12 pages, 6 figuresNuclear Theorytext