Exclusive vector-meson production in muon-proton scattering

From a muon-proton scattering experiment with a streamer chamber at the Stanford Linear Accelerator we present results in the ranges 0.3 .. ..mu..pV where V is a vector meson (rho/sup 0/, ..omega.., or phi). It is shown that in rho production the skewing parameter and the longitudinal-transverse ratio change significantly as Q/sup 2/ increases above 1 GeV/sup 2/. The cross section for rho/sup 0/ production as a function of Q/sup 2/ falls below the vector-meson-dominance prediction. The ratio of the cross section for exclusive vector-meson production to the total cross section falls by a factor of 10 between photoproduction and a Q/sup 2/ of 2 GeV/sup 2/, yet the ratio of ..omega.. to rho production remains constant at the photoproduction value out to Q/sup 2/ > 2 GeV/sup 2/.