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arXiv · 1811.07726

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

H. Ekawa·K. Agari·J. K. Ahn·T. Akaishi·Y. Akazawa·S. Ashikaga·B. Bassalleck·S. Bleser·Y. Endo·Y. Fujikawa·N. Fujioka·M. Fujita·R. Goto·Y. Han·S. Hasegawa·T. Hashimoto·S. H. Hayakawa·T. Hayakawa·E. Hayata·K. Hicks·E. Hirose·M. Hirose·R. Honda·K. Hoshino·S. Hoshino·K. Hosomi·S. H. Hwang·Y. Ichikawa·M. Ichikawa·M. Ieiri·K. Imai·K. Inaba·Y. Ishikawa·A. Iskendir·H. Ito·K. Ito·W. S. Jung·S. Kanatsuki·H. Kanauchi·A. Kasagi·T. Kawai·M. H. Kim·S. H. Kim·S. Kinbara·R. Kiuchi·H. Kobayashi·K. Kobayashi·T. Koike·A. Koshikawa·J. Y. Lee·J. W. Lee·T. L. Ma·S. Y. Matsumoto·M. Minakawa·K. Miwa·A. T. Moe·T. J. Moon·M. Moritsu·Y. Nagase·Y. Nakada·M. Nakagawa·D. Nakashima·K. Nakazawa·T. Nanamura·M. Naruki·A. N. L. Nyaw·Y. Ogura·M. Ohashi·K. Oue·S. Ozawa·J. Pochodzalla·S. Y. Ryu·H. Sako·Y. Sasaki·S. Sato·Y. Sato·F. Schupp·K. Shirotori·M. M. Soe·M. K. Soe·J. Y. Sohn·H. Sugimura·K. N. Suzuki·H. Takahashi·T. Takahashi·Y. Takahashi·T. Takeda·H. Tamura·K. Tanida·A. M. M. Theint·K. T. Tint·Y. Toyama·M. Ukai·E. Umezaki·T. Watabe·K. Watanabe·T. O. Yamamoto·S. B. Yang·C. S. Yoon·J. Yoshida
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Abstract

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.

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H. Ekawa, K. Agari, J. K. Ahn, T. Akaishi, Y. Akazawa, S. Ashikaga, B. Bassalleck, S. Bleser, Y. Endo, Y. Fujikawa, N. Fujioka, M. Fujita, R. Goto, Y. Han, S. Hasegawa, T. Hashimoto, S. H. Hayakawa, T. Hayakawa, E. Hayata, K. Hicks, E. Hirose, M. Hirose, R. Honda, K. Hoshino, S. Hoshino, K. Hosomi, S. H. Hwang, Y. Ichikawa, M. Ichikawa, M. Ieiri, K. Imai, K. Inaba, Y. Ishikawa, A. Iskendir, H. Ito, K. Ito, W. S. Jung, S. Kanatsuki, H. Kanauchi, A. Kasagi, T. Kawai, M. H. Kim, S. H. Kim, S. Kinbara, R. Kiuchi, H. Kobayashi, K. Kobayashi, T. Koike, A. Koshikawa, J. Y. Lee, J. W. Lee, T. L. Ma, S. Y. Matsumoto, M. Minakawa, K. Miwa, A. T. Moe, T. J. Moon, M. Moritsu, Y. Nagase, Y. Nakada, M. Nakagawa, D. Nakashima, K. Nakazawa, T. Nanamura, M. Naruki, A. N. L. Nyaw, Y. Ogura, M. Ohashi, K. Oue, S. Ozawa, J. Pochodzalla, S. Y. Ryu, H. Sako, Y. Sasaki, S. Sato, Y. Sato, F. Schupp, K. Shirotori, M. M. Soe, M. K. Soe, J. Y. Sohn, H. Sugimura, K. N. Suzuki, H. Takahashi, T. Takahashi, Y. Takahashi, T. Takeda, H. Tamura, K. Tanida, A. M. M. Theint, K. T. Tint, Y. Toyama, M. Ukai, E. Umezaki, T. Watabe, K. Watanabe, T. O. Yamamoto, S. B. Yang, C. S. Yoon, J. Yoshida. 2018-11-19. Observation of a Be double-Lambda hypernucleus in the J-PARC E07 experiment. https://doi.org/10.1093/ptep%2Fpty149

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