Data analysis techniques, differential cross sections, and spin density matrix elements for the reaction γp→ϕp

Le résumé fourni par la source

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

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.