Photoproduction of $\Lambda$ and ${\Sigma }^0$ hyperons off protons with linearly polarized photons at $E_{\gamma }=1.5-3.0$ GeV

Abstract

We report the measurement of the $\gamma p\to K^{+}\Lambda$ and $\gamma p\to K^{+}{\Sigma }^0$ reactions at SPring-8. The differential cross sections and photon-beam asymmetries are measured at forward $K^{+}$ production angles using linearly polarized tagged-photon beams in the range of $E_{\gamma }=1.5$--3.0 GeV. With increasing photon energy, the cross sections for both $\gamma p\to K^{+}\Lambda$ and $\gamma p\to K^{+}{\Sigma }^0$ reactions decrease slowly. Distinct narrow structures in the production cross section have not been found at $E_{\gamma }=1.5$--3.0 GeV. The forward peaking in the angular distributions of cross sections, a characteristic feature of $t$-channel exchange, is observed for the production of $\Lambda$ in the whole observed energy range. A lack of similar feature for ${\Sigma }^0$ production reflects a less dominant role of $t$-channel contribution in this channel. The photon-beam asymmetries remain positive for both reactions, suggesting the dominance of $K^{\ast }$ exchange in the $t$ channel. These asymmetries increase gradually with the photon energy, and have a maximum value of +0.6 for both reactions. Comparison with theoretical predictions based on the Regge trajectory in the $t$ channel and the contributions of nucleon resonances indicates the major role of $t$-channel contributions as well as non-negligible effects of nucleon resonances in accounting for the reaction mechanism of hyperon photoproduction in this photon energy regime.

arXiv commentpublished version, two-column format, 10 pages, 8 figures

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Cited by in corpus (8)

• Light Baryon Spectroscopy
• Jülich-Bonn-Washington Model for Pion Electroproduction Multipoles
• $K^{+}\Lambda$ photoproduction at forward angles and low momentum transfer
• Coupled-channel analysis of pion- and eta-electroproduction with the Jülich-Bonn-Washington model
• Observation of a cusp-like structure in the $\gamma p\to K^{+}{\Sigma }^0$ cross section at forward angles and low momentum transfer
• Beam-Recoil Transferred Polarization in $K^{+}Y$ Electroproduction in the Nucleon Resonance Region with CLAS12
• Photoproduction of $K^{+}\Lambda$ with a Regge-plus-resonance model
• Differential cross section and photon-beam asymmetry for the gamma p -> pi- Delta++(1232) reaction at forward pi- angles for Egamma=1.5-2.95 GeV