Two or Four: A Hint from Scalar Mesons in Radiative phi Decays ?

Abstract

In this write-up, we summarize our recent analysis of radiative decays involving light scalar mesons. Our analysis using the vector meson dominance model at tree level indicates that it may be difficult to distinguish qqqq picture and qq picture for the light scalar nonet. Our result on the process of φ π0 η γ shows that the derivative-type f0 KK interaction reproduces experimental data below 950 GeV well, but gives a poor fit above 950 GeV, i.e., in the energy region around the mass of a0(980), but that the discrepancy can be compensated by the effect of the K loop.