Meson loops in the $f_0(980)$ and $a_0(980)$ radiative decays into $\rho$, $\omega$

Abstract

We calculate the radiative decay widths of the $a_0(980)$ and $f_0(980)$ scalar mesons into $\rho \gamma$ and $\omega \gamma$ considering the dynamically generated nature of these scalar resonances within the realm of the Chiral Unitary Approach. The main ingredient in the evaluation of the radiative width of the scalar mesons are the loops coming from the decay into their constituent pseudoscalar-pseudoscalar components and the subsequent radiation of the photon. The dominant diagrams with only pseudoscalar mesons in the loops are found to be convergent while the divergence of those with a vector meson in the loop are written in terms of the two meson loop function easily regularizable. We provide results for all the possible charge channels and obtain results, with uncertainties, which differ significantly from quark loops models and some version of vector meson dominance.