ρ−ωInterference and theω−φMixing Angle

Abstract

The $\ensuremath{\omega}\ensuremath{-}\ensuremath{\varphi}$ mixing angle of $\mathrm{SU}(3)$ is usually assumed to be positive, but only its magnitude is actually determined by various models of $\mathrm{SU}(3)$ breaking. The effect of this ambiguity of the relative sign of the $\mathrm{SU}(3)$ prediction of the $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\rho}$ and $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\omega}$ coupling constants on $\ensuremath{\rho}\ensuremath{-}\ensuremath{\omega}$ interference is investigated. The interference can be "constructive" or "destructive." In photoproduction of lepton pairs, destructive interference causes the effect of $\ensuremath{\rho}\ensuremath{-}\ensuremath{\omega}$ interference to be smaller than that of previous calculations. Two new models of $\ensuremath{\rho}\ensuremath{-}\ensuremath{\omega}$ interference in the colliding-beam reaction ${e}^{+}+{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}+{\ensuremath{\pi}}^{\ensuremath{-}}$ are discussed. A measurement of the cross section for the latter reaction would make possible a determination of the sign of the $\ensuremath{\omega}\ensuremath{-}\ensuremath{\varphi}$ mixing angle.