Radiativeρ-Meson Decay

Abstract

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