2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42574In combined 2- and 3-channel analyses of experimental data on the coupled processes $ππ\toππ,K\bar{K},ηη$ in the channel with $I^GJ^{PC}=0^+0^{++}$, various scenarios of these reactions(with different numbers of resonances) are considered. In a model-independent approach, confirmation of the $σ$-meson below 1 GeV and definite indications of the QCD nature of other $f_0$ resonances are obtained. The conclusion on the linear realization of chiral symmetry is drawn.8 pages, LaTex; Talk at the XVI Int'l Baldin Seminar on High Energy Physics Problems "Relativistic Nuclear Physics and Quantum Chromodynamics" (Dubna, 10-15 June, 2002) and at Int. Conf. "Hadron Structure' 02" (Herl'any, Slovak Republic, 22-29 September 2002)High Energy Physics - Phenomenologytext