On the Quark and Gluon Substructure of the Sigma and other Scalar Mesons
Abstract
Description
Within the increasing experimental evidence of the existence of the I=0 scalar low mass and wide σmeson, we review the {\it first} analysis of its quark and gluon substructure from QCD spectral sum rules and some low-energy theorems. The present data favour equal components of \bar uu+ \bar dd and of gg in its wave function, which make the wide sigma and the narrow f_0(980) as η'-like particles. A coherent picture of the other I=0 scalar mesons spectra within this mixing scheme is shortly discussed. We also expect the a_0(980) to be the lowest isovector \bar ud state, and the K^*_0(1430) its \bar ds partner.
Latex2e sources 8 pages including 1 Table + espcrc1.sty file. Plenary talk given at the Workshop on `` Possible existence of the Light $σ$-resonance and its applications to hadron physics" (Yukawa Institute for Theoretical Physics, Kyoto, Japan, 11-14th June 2000) and Review talk given at the QCD 00 International Euroconference (15th anniversary) Montpellier, France 6-13th July 2000
Latex2e sources 8 pages including 1 Table + espcrc1.sty file. Plenary talk given at the Workshop on `` Possible existence of the Light $σ$-resonance and its applications to hadron physics" (Yukawa Institute for Theoretical Physics, Kyoto, Japan, 11-14th June 2000) and Review talk given at the QCD 00 International Euroconference (15th anniversary) Montpellier, France 6-13th July 2000