Comprehensive measurement of $η^\prime$ photoproduction off the proton at $E_γ< 2.4$ $\mathrm{GeV}$
nucl-ex
/ Authors
N. Muramatsu, J. K. Ahn, W. C. Chang, J. Y. Chen, M. L. Chu, S. Daté, T. Gogami, H. Hamano, T. Hashimoto, Q. H. He
and 54 more authors
K. Hicks, T. Hiraiwa, Y. Honda, T. Hotta, Y. Inoue, T. Ishikawa, I. Jaegle, Y. Kasamatsu, V. L. Kashevarov, H. Katsuragawa, S. Kido, R. Kobayakawa, Y. Kon, S. Masumoto, Y. Matsumura, M. Miyabe, K. Mizutani, T. Z. Mo, T. Nakamura, T. Nakano, T. Nam, M. Niiyama, K. V. Nikonov, Y. Nozawa
/ Abstract
For the spectroscopy of nucleon resonances at the total energies from the $η^\prime$-meson production threshold to $2.32$ $\mathrm{GeV}$, photon beam asymmetries of the reaction $γp \to η^\prime p$ were measured together with total and differential cross sections by analyzing the two decay modes $η^\prime \to γγ$ and $π^0 π^0 η$. New constraints for amplitude decomposition were given by the first-time result of photon beam asymmetries at $E_γ> 1.84$ $\mathrm{GeV}$ and the most precise data of differential cross sections to date at extremely backward $η^\prime$ angles. The possibility of a larger coupling constant of the $η^\prime$-nucleon system to the $N(2250)$ resonance was implied in the partial wave analyses using the present data.