Spokesperson

Curtis A. Meyer

Abstract

High-statistics measurements of differential cross sections and spin density matrix elements for the reaction γp -> φp have been made using the CLAS detector at Jefferson Lab. We cover center-of-mass energies (sqrt(s)) from 1.97 to 2.84 GeV, with an extensive coverage in the φ production angle. The high statistics of the data sample made it necessary to carefully account for the interplay between the φ natural lineshape and effects of the detector resolution, that are found to be comparable in magnitude. We study both the charged- (φ -> K⁺K^-) and neutral- (φ -> K⁰_SK⁰_L) KK decay modes of the φ. Further, for the charged mode, we differentiate between the cases where the final K^- track is directly detected or its momentum reconstructed as the total missing momentum in the event. The two charged-mode topologies and the neutral-mode have different resolutions and are calibrated against each other. Extensive usage is made of kinematic fitting to improve the reconstructed φ mass resolution. Our nal results are reported in 10- and mostly 30-MeV-wide sqrt(s) bins for the charged- and the neutral-mode, respectively. Possible eects from K+Λ^* channels with pKK final-states are discussed. These present results constitute the most precise and extensive φ photoproduction measurements to date and in conjunction with the ω photoproduction results recently published by CLAS, will greatly improve our understanding of low energy vector meson photoproduction.

Comment

The data were obtained using real photons produced via bremsstrahlung from a 4.023-GeV electron beam

Publication

1. B.Dey, C.A.Meyer, M.Bellis, M.Williams, and CLAS Collaboration Data analysis techniques, differential cross sections, and spin density matrix elements for the reaction γp -> φp // arXiv:1403.2110v2 [nucl-ex]

Quantities

dσ/dcos(θ)   ρ⁰_0,0   ρ⁰_1,0   ρ⁰_1,-1

Measurements