EPJ Web Conf.
Volume 241, 2020The 12th International Workshop on the Physics of Excited Nucleons (NSTAR 2019)
|Number of page(s)||4|
|Published online||22 September 2020|
Recent results of charged pion and kaon photoproduction on the proton at SPring-8/LEPS
1 for LEPS Collaboration - Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 Japan
2 for LEPS Collaboration - Nagoya University, Furocho, Chikusa, Nagoya, 464-8602 Japan
* Corresponding author: firstname.lastname@example.org
Published online: 22 September 2020
We carry out photoproduction experiments by using linearly polarized photon beams with energies of 1.5-3 GeV at SPring-8/LEPS. One of our physics motivations is to understand reaction mechanisms of hadron photoproduction. We study (1) y→p→ π-Δ++, (2) y→p→ π+n, (3) y→p→ K+Λ(K+Σ0), and (4) y→p→ π+Δ0 reactions which produce (1) uu, (2) dd, (3) ss, and (4) dd quark-antiquark pairs in the final state. Differential cross sections and photon beam asymmetries have been measured at forward meson angles of 0.6 < cos θcm <1. Precise comparison between the π-Δ++ and π+Δ0 reactions plays an important role in the study of nucleon resonances. It enables to distinguish between N* and Δ* by taking the cross section ratios of the two reactions. We have measured preliminary cross section ratios dσ(π+Δ0)/dσ(π-Δ++). The ratios are found to be close to 1/3, which is expected from the exchange of isospin=1 in the t channel, for 0.966< cos θcm <1 and all the photon energies. The ratios become larger than 1/3 and close to 1 for larger angles and higher energy regions. The larger ratios might be due to A resonances, giving the ratio 4/3, excited in the intermediate state
© The Authors, published by EDP Sciences, 2020
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