Measurement of the photon beam asymmetry in γ⃗p→K+Σ0 at Eγ

Abstract

We report measurements of the photon beam asymmetry ⌃ for the reaction~ p ! K + ⌃ 0 (1193) using the GlueX spectrometer in Hall D at Je↵erson Lab. Data were collected using a linearly polarized photon beam in the energy range of 8.2-8.8 GeV incident on a liquid hydrogen target. The

Physics with CEBAF at 12 GeV and Future Opportunities

“…Innovations that exploited existing equipment including the latest additions have also yielded ground breaking Nuclear Physics results. A few among these include imaging the nucleon in three dimensions via the extraction of Generalized Parton Distributions (GPDs) using Deeply Virtual Compton Scattering (DVCS) and the Transverse Momentum Dependent Parton Distribution Functions (TMD-PDFs) from Semi-Inclusive Deep Inelastic Scattering (SIDIS); isospin decomposition of nucleon structure functions using a tritium gas target; observation of J/ψ photoproduction from the proton near the threshold, limits on the photo-coupling of the uudcc pentaquark, the resolution of the "Proton Radius Puzzle" through the PRad experiment with a major impact on atomic physics; and new information on neutron matter from parity violating electron scattering on 208 Pb (PREX-II) and 48 Ca (CREX) with implications for the structure of neutron stars.…”

“…Parity violating elastic electron scattering provides a model-independent way of determining these neutron radii, because the value of the weak mixing angle sin 2 θ W fortuitously leads to a coupling to neutrons that is much larger than that for protons. The high-quality polarized electron beams from CEBAF were used by the PREX-II and CREX experiments to determine the neutron radii of 208 Pb and 48 Ca, respectively. See Section 5.2 for details.…”

“…Thus, early measurements from GlueX have focused on a quantitative understanding of the meson photoproduction mechanism in this energy regime. Utilizing the linearly-polarized photon beam, beam asymmetries Σ have been measured for several single pseudoscalar mesons including the π 0 , π − , K + , η, and η over a broad range of momentum transfer, −t [207,205,206,208]. As demonstrated in Fig.…”

“…The PREX-II collaboration recently published a new measurement [271] of the "neutron skin thickness" of 208 208 Pb. Also shown in Fig.…”

Measurement of beam asymmetry for π−Δ++ photoproduction on the proton at Eγ=8.5Adhikari1, Akondi2, Ali3 et al. 2021Phys. Rev. CSelf Cite6030View full textAdd to dashboardCite

“…Measurements that constrain production mechanisms at photon beam energies relevant for the GlueX experiment are sparse. Recent measurements on the photoproduction of pseudoscalar mesons [5][6][7] have begun to provide insight into into production mechanisms. In this paper, we seek to extend this understanding by measuring the beam asymmetry ⌃ for the charge-exchange re-action~ p !…”