Observation of a Be double-Lambda hypernucleus in the J-PARC E07 experiment

• Published in: arXiv.org 2019-02
• Main Authors: Ekawa, H, Agari, K, Ahn, J K, Akaishi, T, Akazawa, Y, Ashikaga, S, Bassalleck, B, Bleser, S, Endo, Y, Fujikawa, Y, Fujioka, N, Fujita, M, Goto, R, Han, Y, Hasegawa, S, Hashimoto, T, Hayakawa, S H, Hayakawa, T, Hayata, E, Hicks, K, Hirose, E, Hirose, M, Honda, R, Hoshino, K, Hosomi, K, Hwang, S H, Ichikawa, Y, Ichikawa, M, Ieiri, M, Imai, K, Inaba, K, Ishikawa, Y, Iskendir, A, Ito, H, Ito, K, Jung, W S, Kanatsuki, S, Kanauchi, H, Kasagi, A, Kawai, T, Kim, M H, Kinbara, S, Kiuchi, R, Kobayashi, H, Kobayashi, K, Koike, T, Koshikawa, A, Lee, J Y, Lee, J W, Ma, T L, Matsumoto, S Y, Minakawa, M, Miwa, K, Moe, A T, Moon, T J, Moritsu, M, Nagase, Y, Nakada, Y, Nakagawa, M, Nakazawa, K, Nanamura, T, Naruki, M, Nyaw, A N L, Ogura, Y, Ohashi, M, Oue, K, Ozawa, S, Pochodzalla, J, Ryu, S Y, Sako, H, Sasaki, Y, Sato, S, Sato, Y, Schupp, F, Shirotori, K, Soe, M M, Soe, M K, Sohn, J Y, Sugimura, H, Suzuki, K N, Takahashi, H, Takahashi, T, Takahashi, Y, Takeda, T, Tamura, H, Tanida, K, Theint, A M M, Tint, K T, Toyama, Y, Ukai, M, Umezaki, E, Watabe, T, Watanabe, K, Yamamoto, T O, Yang, S B, Yoon, C S, Yoshida, J, Yoshimoto, M, Zhang, D H, Zhang, Z
• Format: Article
• Language: English
• Subjects: Emulsions; Hypernuclei; Hyperons; Nuclear emulsions
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1811.07726

A double-\(\Lambda\) hypernucleus, \({}_{\Lambda\Lambda}\mathrm{Be}\), was observed by the J-PARC E07 collaboration in nuclear emulsions tagged by the \((K^{-},K^{+})\) reaction. This event was interpreted as a production and decay of \( {}_{\Lambda\Lambda}^{\;10}\mathrm{Be}\), \({}_{\Lambda\Lambda}^{\;11}\mathrm{Be}\), or \({}_{\Lambda\Lambda}^{\;12}\mathrm{Be}^{*}\) via \(\Xi^{-}\) capture in \({}^{16}\mathrm{O}\). By assuming the capture in the atomic 3D state, the binding energy of two \(\Lambda\) hyperons\(\,\)(\(B_{\Lambda\Lambda}\)) of these double-\(\Lambda\) hypernuclei are obtained to be \(15.05 \pm 0.11\,\mathrm{MeV}\), \(19.07 \pm 0.11\,\mathrm{MeV}\), and \(13.68 \pm 0.11\,\mathrm{MeV}\), respectively. Based on the kinematic fitting, \({}_{\Lambda\Lambda}^{\;11}\mathrm{Be}\) is the most likely explanation for the observed event.