We studied the exclusive reaction ep⃗ e′p′φ using the φ⃗ 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 bφ=2.27±0.42 GeV-2. The cross section dependence on W as W0.2±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.
Physical Review C
Lukashin, K.; Biselli, Angela; and CLAS Collaboration, "Exclusive electroproduction of φ mesons at 4.2 GeV" (2001). Physics Faculty Publications. 107.
K. Lukashin et al. [CLAS Collaboration], "Exclusive electroproduction of φ mesons at 4.2 GeV", Physical Review C 63.6 (2001) **Corrected Article: [Phys. Rev. C 63, 065205 (2001)], Phys. Rev. C 64, 059901 (2001). ** DOI: 10.1103/PhysRevC.63.065205