Non-strange dibaryons studied in the γd → π0π0d reaction

T. Ishikawa, H. Fujimura, H. Fukasawa, R. Hashimoto, Q. He, Y. Honda, T. Iwata, S. Kaida, H. Kanda, J. Kasagi, A. Kawano, S. Kuwasaki, K. Maeda, S. Masumoto, M. Miyabe, F. Miyahara, K. Mochizuki, N. Muramatsu, A. Nakamura, K. NawaS. Ogushi, Y. Okada, K. Okamura, Y. Onodera, K. Ozawa, Y. Sakamoto, M. Sato, H. Shimizu, H. Sugai, K. Suzuki, Y. Tajima, S. Takahashi, Y. Taniguchi, Y. Tsuchikawa, H. Yamazaki, R. Yamazaki, H. Y. Yoshida

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26 Citations (Scopus)


Coherent double neutral-pion photoproduction on the deuteron, γd→π0π0d, has been experimentally studied at incident photon energies ranging from 0.75 to 1.15 GeV. The total cross section as a function of the γd center-of-mass energy shows resonance-like behavior, which peaks at approximately 2.47 and 2.63 GeV. The measured angular distribution of deuteron emission is rather flat, which cannot be reproduced by the kinematics of quasi-free π0π0 production with deuteron coalescence. In π0d invariant-mass distributions, a clear peak is observed at 2.14±0.01 GeV/c2 with a width of 0.09±0.01 GeV/c2. The spin-parity of this state is restricted to 1+, 2+ or 3 from the angular distributions of the two π0s. The present work shows strong evidence for the existence of an isovector dibaryon resonance with a mass of 2.14 GeV/c2. The 2+ assignment is consistent with the theoretically predicted D12 state, and also with the energy dependence of the πd partial-wave amplitude P23 for the π±d→π±d and π+d→pp reactions.

Original languageEnglish
Pages (from-to)413-418
Number of pages6
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Publication statusPublished - 2019 Feb 10


  • Coherent meson photoproduction
  • Dibaryon resonance


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