ρ−ωInterference and theω−φMixing Angle

Abstract

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