Photoproduction of Λ and Σ0 hyperons off protons with linearly polarized photons at Eγ=1.5–3.0 GeV
| Autor: | Y. Nakatsugawa, Joseph D. Parker, Yusuke T. Maeda, T. Sawada, Manabu Miyabe, K Mizutani, S. H. Shiu, Takatsugu Ishikawa, Chary Rangacharyulu, T. Tsunemi, K. Imai, S. Y. Ryu, Hajime Shimizu, H. Ejiri, M. Uchida, M. Sumihama, T. Nakano, M. Ungaro, J. K. Ahn, Y. Kato, Shuji Fukui, Yuhei Morino, W. Gohn, H. Fujimura, W. C. Chang, K. Hicks, M. Fujiwara, M. Yosoi, S. Daté, Hyomin Lee, D. S. Ahn, K. Joo, Hiroyuki Noumi, Yorihito Sugaya, Tomoaki Hotta, Norihito Muramatsu, Makoto Oka, Y. Kon, T. Ohta, S. H. Hwang, Tsutomu Mibe, M. Niiyama, J. Y. Chen, Yoji Ohashi, H. Kohri |
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| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | Physical Review C. 97 |
| ISSN: | 2469-9993 2469-9985 |
| DOI: | 10.1103/physrevc.97.015208 |
| Popis: | We report the measurement of the $\gamma p \rightarrow K^{+}\Lambda$ and $\gamma p \rightarrow K^{+}\Sigma^{0}$ 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 $\gamma p \rightarrow K^{+}\Lambda$ and $\gamma p \rightarrow K^{+}\Sigma^{0}$ 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 $K^{*}$ 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. |
| Databáze: | OpenAIRE |
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