Light scalar meson spectrum

Abstract

We discuss the classification of the light scalar mesons with mass below 2 GeV into q qbar nonets and glueballs. The information on production and decay of these states, in particular recent information on f_0(980), f_0(400-1200) (or sigma(600)) and f_0(1500) is considered. Although the data are not yet very precise the recent information is in favour of the previously developed scheme which includes f_0(980), a_0(980), K_0^*(1430), f_0(1500) into the lightest scalar nonet. The glueball in this approach appears as broad object around 1 GeV. Alternative schemes find the glueball at somewhat higher mass or suggest his mixing with q qbar states spread over a similar mass range. We do not see sufficient evidence yet for a light scalar nonet below 1 GeV around a sigma(600) resonance.

Comments: Plenary talk at IXth International Conference on Hadron Spectroscopy (HADRON 2001), Protvino, Russia, August 2001; to be publ. in AIP Conf. Proceedings, 11 pages, Latex, AIP macros