Chiral loops and VMD in the V->PPgamma decays

Abstract

We evaluate radiative decays of $\rho$ and $\omega$ going to two neutral mesons, ${\pi }^0{\pi }^0$ and ${\pi }^0\eta$. We use the sequential vector decay mechanisms in addition to chiral loops and $\rho$-$\omega$ mixing. The chiral loops are obtained using elements of $U\chi PT$ successfully applied in the study of meson-meson interactions up to 1.2 GeV. The chiral loops are found very important in the case of the $\rho \to {\pi }^0{\pi }^0\gamma$ decay and small in the other cases. A good agreement with present measurements of $\rho \to {\pi }^0{\pi }^0\gamma$ and $\omega \to {\pi }^0{\pi }^0\gamma$ is obtained and predictions are made for the other decays where the rates obtained are rather small.

Comments: 16 pages, 4 figures. To be published in Nucl. Phys. A