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We show that a bag can be automatically formed in a model where the Skyrme Lagrangian is modified to possess the correct QCD scaling behavior.The nonlinear chiral Lagrangian provides a succinct summary of the "current-algebra" results in low-energy pion physics which agree nicely with experiment. Since the algebra of currents is respected by QCD, this Lagrangian may be considered to be a basic building block for an effective low-energy QCD Lagrangian. The leading term' is where F,= 132 MeV is the pion-decay constant and C#I is the pseudoscalar field multiplet. A long-standing question of great importance has been to determine what additional terms are needed to fill in the three dots in (1). The whole question has been made more topical by the revival of Skyrme's for explaining the nucleon as a topological soliton of (1). To stabilize the soliton against collapse he added a term (where e, is a new dimensionless parameter), which might result from "integrating out" some of the heavier particles. It is remarkable that a model as economical as the sum of (1) and (2) can roughly explain the low-energy properties of

We investigate the properties of a possible low-lying scalar glueball as well as the ordinary scalarquark states using an effective chiral Lagrangian which satisfies the trace anomaly and U(1), anomaly of QCD. An interesting mass bound for the lightest particle in the scalar-singlet channel is discussed. Detailed arguments against the existence of a very light (less than 400 MeV) scalar glueball are presented. It is shown that the introduction of a derivative-coupling term in the usual type of linear a model cures the problem of excessively large widths for the ordinary (nonet) scalar mesons. In fact, chiral symmetry enables one to nicely correlate the widths of the entire scalar nonet. It is noted that the same derivative-coupling term allows a heavy (1-2 GeV) scalar glueball to have sufficiently narrow width to permit its observation as an ordinary resonance, in contrast with a recent claim. Our model can naturally explain the unusually large partial width for the 7717' mode of the glueball candidate G(1590). A symmetrical ansatz for the anomaly terms is suggested which enables one to successfully calculate the 7' mass as the ratio of gluon condensate to pion-decay constant. In addition, the theoretically interesting limit where the glueball becomes a true dilaton is formulated in a new and illustrative way.

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