Isosinglet Scalar Mesons Below 2 GeV and the Scalar Glueball Mass

A collective treatment of the I=0 scalar mesons below 2 GeV [sigma (550), f0(980), f0(1370), f0(1500) and f0(1710)] in a non-linear chiral Lagrangian framework that is constrained by the mass and the partial decay widths of the I=1/2,1 scalars [kappa(900), K0*(1430), a0(980) and a0(1450)] is presented. The sub-structure of these states in terms of two and four quark components, as well as a glueball component is explored, and its correlation with the mass of f0(1370) is studied. Consistency with the available experimental data suggests that the sigma(550) is dominantly a non-strange four-quark state, whereas the sub-structure of other I=0 states are sensitive to the input mass of f0(1370). This investigation estimates the scalar glueball mass in the range 1.47--1.64 GeV.Comment: 12 pages, revtex, 2 figs; numerical work updated, typos corrected, refs adde

Lowest-Lying Scalar Mesons and a Possible Probe of Their Quark Substructure

In this talk, an overview of the status of the light scalar mesons in the context of the non linear chiral Lagrangian of references [1-3] is presented. The evidence for the existence of a scalar nonet below 1 GeV is reviewed, and it is shown that by introducing a scalar nonet an indirect way of probing the quark substructure of these scalars through the scalar mixing angle can be obtained. It is then reviewed that consistency of this non-linear chiral Lagrangian framework with the experimental data on pi pi and pi K scattering, as well as the decay eta' to eta pi pi, results in a range for the mixing angle which indicates that the quark substructure of these light scalars are closer to a four quark picture.Comment: Talk given at 21st Annual MRST Conference: High Energy Physics at the Millenium, Ottawa, Ontario, Canada, 10-12 May 1999, 8 page

Comment on scalar glueball mass

We study the interaction of scalar glueball with quark-antiquark and four-quark spinless meson fields within the framework of a generalized linear sigma model in which the trace anomaly of QCD is exactly realized. To determine the pure scalar glueball mass ($m_h$), we consider the decoupling limit in which the scalar glueball decouples from the meson fields. We find the exact relationship $m_h = 2\, h_0$ where $h_0$ is the vacuum expectation value of the scalar glueball field independent of the properties of the framework used.Comment: 4 pages, 1 figur