Probing the structure of $f_0(980)$ through radiative $\varphi$ decays

Abstract

We consider the radiative transition $\varphi \to f_0\gamma$, which is a sensitive probe of the nature of the $f_0(980)$ particle. Using the QCD sum-rule technique, we estimate the branching ratio of such decay mode to be: $\mathcal{B}(\varphi \to f_0\gamma )=(2.7\pm 1.1)10^{-4}$, in fair agreement with present experimental data. As for the structure of the $f_0$, the result suggests a sizeable $s\bar{s}$ component; however, this result does not exclude the possibility of further components and allows a more complex structure than indicated by the naive quark model.

Comments: Latex, 11 pages, 2 eps figures. Final version to apper in Physics Letters B