Exclusive electroproduction of φ mesons at 4.2 GeV

We studied the exclusive reaction ep-->e'p'φ using the φ-->K⁺K^- decay mode. The data were collected using a 4.2 GeV incident electron beam and the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. Our experiment covers the range in Q² from 0.7 to 2.2 GeV², and W from 2.0 to 2.6 GeV. Taken together with all previous data, we find a consistent picture of φ production on the proton. Our measurement shows the expected decrease of the t slope with the vector-meson formation time cΔτ below 2 fm. At <cΔτ>=0.6 fm, we measure b_φ=2.27+/-0.42 GeV^-2. The cross section dependence on W as W^0.2+/-0.1 at Q²=1.3 GeV² was determined by comparison with φ production at HERA after correcting for threshold effects. This is the same dependence as observed in photoproduction.