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تسجيل مستخدم جديدData analysis techniques, differential cross sections, and spin density matrix elements for the reaction $gamma p rightarrow phi p$
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High-statistics measurements of differential cross sections and spin density matrix elements for the reaction $gamma p to phi p$ 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 $phi$ production angle. The high statistics of the data sample made it necessary to carefully account for the interplay between the $phi$ natural lineshape and effects of the detector resolution, that are found to be comparable in magnitude. We study both the charged- ($phi to K^+ K^-$) and neutral- ($phi to K^0_S K^0_L$) $Koverline{K}$ decay modes of the $phi$. 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 $phi$ mass resolution. Our final results are reported in 10- and mostly 30-MeV-wide $sqrt{s}$ bins for the charged- and the neutral-mode, respectively. Possible effects from $K^+ Lambda^ast$ channels with $p Koverline{K}$ final-states are discussed. These present results constitute the most precise and extensive $phi$ photoproduction measurements to date and in conjunction with the $omega$ photoproduction results recently published by CLAS, will greatly improve our understanding of low energy vector meson photoproduction.
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