Isospin Symmetry Breaking in ρ\toπγDecay

Abstract

In terms of effective field theory and mixed propagator approach, we show that there is a larger hidden effect of isospin breaking in ${\rho }^0\to {\pi }^0\gamma$ decay due to an $\omega$ exchange, ${\rho }^0\to \omega \to {\pi }^0\gamma$. The branching ratio is predicted as $B({\rho }^0\to {\pi }^0\gamma )=(11.67\pm 2.0)\times 10^{-4}$, which is much larger than Partcile Data Group's datum $(6.8\pm 1.7)\times 10^{-4}$ and one of charged mode, $B({\rho }^{\pm }\to {\pi }^{\pm }\gamma )=(4.5\pm 0.5)\times 10^{-4}$.

8 page, revtex, 3 figures, to appear EPJA