2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/179274The linear sigma model with broken U3xU3 is compared with data on the lightest scalar and pseudoscalar mesons. When 5 of the 6 parameters are fixed by the pseudoscalar masses and decay constants one finds that, already at the tree level, a reasonable description for the 4 scalar masses, mixing and up to 8 tri-linear couplings of lightest scalars, taken as a0(980), f0(980), sigma(500) and K*0(1430). This clearly indicates that these scalars are the chiral partners of the pi, eta, eta', K and strongly suggests that they like the latter are (unitarized) quark-antiquark states.12 pages revtex, 1 figure, 2 tables, minor corrections, To appear in Eur. Phys. Journal CHigh Energy Physics - Phenomenologytext