{"paper":{"title":"Non-strange Dibaryon Resonances Observed in the $\\gamma d\\to \\pi^0\\pi^0 d$ Reaction","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ex"],"primary_cat":"nucl-ex","authors_text":"A. Kawano, A. Nakamura, F. Miyahara, H. Fujimura, H. Fukasawa, H. Kanda, H. Shimizu, H. Sugai, H. Yamazaki, H.Y. Yoshida, J. Kasagi, K. Maeda, K. Mochizuki, K. Nawa, K. Okamura, K. Ozawa, K. Suzuki, M. Miyabe, M. Sato, N. Muramatsu, Q. He, R. Hashimoto, R. Yamazaki, S. Kaida, S. Kuwasaki, S. Masumoto, S. Ogushi, S. Takahashi, T. Ishikawa, T. Iwata, Y. Honda, Y. Okada, Y. Onodera, Y. Sakamoto, Y. Tajima, Y. Taniguchi, Y. Tsuchikawa","submitted_at":"2018-05-23T01:41:19Z","abstract_excerpt":"Coherent double neutral-pion photoproduction on the deuteron, $\\gamma{d}${$\\to$}$\\pi^0\\pi^0{d}$, 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 $\\gamma{d}$ 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 $\\pi^0\\pi^0$ production with deuteron coalescence. In $\\pi^0d $ invariant-mass distributions, a clear peak is observed at $2"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1805.08928","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}