Test of Scalar Meson Structure in $\varphi$ Radiative Decays

Abstract

We show that $\varphi$ radiative decays into scalar mesons [$f_0$(975), $a_0$(980)$\equiv S$] can provide important clues on the internal structures of these mesons. Radiative decay widths vary widely: $B.R.=10^{-4}-10^{-6}$ depending on the substructures ($q\bar{q}$, $qq\bar{q}\bar{q}$, $K\bar{K}$, glueball). Hence, we could discriminate among various models by measuring these widths at future $\varphi$ factories. The understanding of these meson structures is valuable not only in hadron spectroscopy but also in nuclear physics in connection with the widely-used but little-understood $\sigma$ meson. We also find that the decay $\varphi \to S\gamma \to K^0{\bar{K}}^0\gamma$ is not strong enough to pose a significant background problem for studying CP violation via $\varphi \to K^0{\bar{K}}^0$ at the $\varphi$ factories.

Comments: 11 pages, LATEX file (without figures), Talk given at the International Workshop on Flavor and Spin in Hadronic and Electromagnetic Interactions Torino, Italy, September 21-23, 1992