Finite width effects in \phi radiative decays

Abstract

The decay widths \phi \to \gamma f_0(980) and \phi \to \gamma a_0(980) are calculated taking into account the finite widths of the scalar resonances f_0(980) and a_0(980). The latter are shown to be essential in order to obtain meaningful results. Simultaneously we also study the decays \phi\to \gamma \pi^0\pi^0 and \gamma \pi^0\eta where a good reproduction of the recent experimental data is obtained, pointing out the necessity of a \phi\gamma K^0\bar{K}^0 contact vertex. The calculated decay rates to \gamma f_0(980) and \gamma a_0(980) are in good agreement with the experimental ones without invoking isospin breaking in the couplings of the f_0(980) and a_0(980) resonances to the K^+ K^- and K^0 \bar{K}^0 channels, at odds with recent proposals. The derived formula for calculating these \phi radiative decay widths can be also applied in their own experimental analyses in order to obtain more precise results.