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

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 ( √ 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-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 final results are reported in 10-and mostly 30-MeV-wide √ s bins for the charged-and the neutral-modes, respectively. Possible effects from K + * 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.

Searching for the odderon in pp→ppK+K− and pp→pLebiedowicz1, Nachtmann2, Szczurek3 2020Phys. Rev. D170260View full textAdd to dashboardCite

“…In [70] no vertex form factors were taken into account for the Reggeized meson exchange contributions and instead of the f 2 ð1270Þ-exchange there one should consider f 0 2 -exchange with appropriate parameters. However, a peak in the differential cross sections ðdσ=dtÞ t¼t min at forward angles around E γ ∼ 2 GeV (W γp ∼ 2.3 GeV) observed by the LEPS [97,98] and CLAS [99] collaborations cannot be explained by the processes mentioned above. To explain the near-threshold bump structure the authors of [67,68,71] propose to include exchanges with the excitation of nucleon resonances.…”

“…[100][101][102], and [62]. The open data points are taken from [70] (data was obtained there by integrating over the differential cross sections given in [99]). The solid lines correspond to a coherent sum of Pomeron, f 2R Reggeon, pseudoscalar, and scalar exchanges.…”

ϕ(2170) production in the process γp→ηϕp

“…For instance, the strangeness φ(1019) and φ(1680) were observed in the photo-production reactions respectively in Refs. [31][32][33][34] and Refs. [35][36][37].…”

Towards a complete study of central exclusive production of K+K− pairs in proton-proton collisions within the tensor Pomeron approach

“…Thus, the pomeron exchange alone should not be expected to fit the low-energy data precisely. We refer the reader to[69,70] for measurements of the γp → φp reaction near threshold.…”