Mesons of the $f_0$-family in the processes $\pi \pi \to \pi \pi ,K\bar{K},\eta \eta$ up to 1.9 GeV

Abstract

In combined 2- and 3-channel analyses of experimental data on the coupled processes $\pi \pi \to \pi \pi ,K\bar{K},\eta \eta$ in the channel with $I^G{J}^{PC}=0^{+}{0}^{++}$, various scenarios of these reactions(with different numbers of resonances) are considered. In a model-independent approach, confirmation of the $\sigma$-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.

Comments: 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)