Ηn scattering parameters and possible η0d bound state from η photoproduction on the deuteron

T. Ishikawa, K. Aoki, H. Fujimura, H. Fukasawa, H. Fujioka, R. Hashimoto, Q. He, Y. Honda, T. Hotta, Y. Inoue, K. Itahashi, T. Iwata, S. Kaida, H. Kanda, J. Kasagi, A. Kawano, S. Kusawaki, H. Kawai, K. Maeda, S. MasumotoY. Matsumura, M. Miyabe, F. Miyahara, K. Mochizuki, S. Miyata, N. Muramatsu, A. Nakamura, K. Nawa, T. Nishi, S. Ohgushi, Y. Okada, H. Ohnishi, Y. Onodera, K. Ozawa, Y. Sakamoto, M. Sato, H. Shimizu, H. Sugai, K. Suzuki, R. Shirai, M. Tabata, Y. Tajima, S. Takahashi, Y. Taniguchi, A. O. Tokiyasu, Y. Tsuchikawa, H. Yamazaki, R. Yamazaki, C. Yoshida, H. Y. Yoshida

Research output: Contribution to journalArticlepeer-review

Abstract

Two physics programs, determination of low-energy scattering parameters between the eta meson (η) and nucleon (N), and search for a possible bound state between the eta prime meson (η0) and deuteron, using η photoproduction from the deuteron target are conducted at the Research Center for Electron Photon Science (ELPH), Tohoku University. Among the two-body dynamics of the meson–nucleon systems, the ηN interaction is not well-known although it has been found attractive. An experiment is carried out to determine the low-energy ηN scattering parameters using a special kinematics. The energy and momentum of the emitted proton (p) are measured at 0 degrees for η photoproduction on the deuteron (d) at incident energies around 0.94 GeV, which gives the low relative momentum between η and neutron (n) in the final state. Low-energy ηn scattering is likely to take place in this condition, and the scattering parameters can be determined from the differential cross section as a function of the ηn invariant mass. The measurement is currently in progress to determine the real part of the ηn scattering length. A possible η0d bound state is theoretically predicted, and a structure corresponding to the state can be observed via the γd → ηd reaction at incident energies around 1.2 GeV. In the case of backward η emission, the structure becomes prominent because a background contribution coming from quasi-free single-step η emission is highly suppressed. The γd → ηd reaction has been also studied at ELPH below the incident energy of 1.15 GeV. The angular differential cross sections are determined at backward η emission angles. The tail of the corresponding peak is not observed, and the background level is much higher than predicted.

Original languageEnglish
Pages (from-to)27-32
Number of pages6
JournalActa Physica Polonica B
Volume51
Issue number1
DOIs
Publication statusPublished - 2020

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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