eta-X mixing and chiral-symmetry breaking

Certain properties of the pseudoscalar mesons and the strange scalar mesons are discussed in the context of the chiral-symmetry-breaking model of Glashow, Weinberg, Gell-Mann, Oakes, and Renner. In particular, the approach of Glashow and Weinberg is followed, with particular attention being paid to η-X mixing. In order to obtain reasonable agreement with experiment, it is found that unequal wave-function renormalization constants must be assumed for the fields which belong to the representation breaking SU(3) × SU(3) symmetry. The η-X mixing angle is predicted to be zero and this result is compared with predictions of other authors. Mechanisms other than η-X mixing are conjectured for the enhancement of the decay rate η→2γ.