Radiativeρ-Meson Decay

The radiative decays of the charged and neutral $\rho$ meson are discussed assuming that the decay vertices are dominated by the low-mass $\pi \pi$ and $\omega \pi$ intermediate states. The transitions $\rho \to \pi +\gamma$, ${\rho }^0\to {\pi }^{+}+{\pi }^{-}+\gamma$, ${\rho }^0\to {\pi }^0+{\pi }^0+\gamma$, ${\rho }^{+,-}\to {\pi }^{+,-}+{\pi }^0+\gamma$ and ${\rho }^0\to \eta +\gamma$ are considered in detail. The probability for the emission of a photon with energy exceeding 15 MeV in the process ${\rho }^0\to {\pi }^{+}+{\pi }^{-}+\gamma$ relative to the $2\pi$ decay is found to be 1.7×${10}^{-2\mathrm{}}$, indicating that the ($2\pi +\gamma$) decay width is comparable or greater than the ($\pi +\gamma$) one. The internal bremsstrahlung and direct emission processes are included in the calculation of the various partial widths.