$\rho-\phi$ Relative Production Phase Using Dimuons

The $\rho-\phi$ production phase is determined using a sample of quasielastically photoproduced $\mu^{+}\mu^{-}$ events obtained in the FOCUS experiment at Fermi National Accelerator Laboratory. The measurement is accomplished by correcting for the Bethe-Heitler dimuon production and by fitting for interference between the $\rho \rightarrow \mu^{+}\mu^{-}$ and $\phi \rightarrow \mu^{+}\mu^{-}$ final states. This result represents the first direct measurement of the $\rho-\phi$ production phase. A preliminary study of the $\omega \rightarrow \mu^{+} \mu^{-}\pi^{0}$ decay channel is also presented.