1. First observation of a nuclear $s$-state of $\Xi$ hypernucleus, $^{15}_{\Xi}{\rm C}$
- Author
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Yoshimoto, M., Ahn, J. K., Bassalleck, B., Ekawa, H., Endo, Y., Fujita, M., Han, Y., Hashimoto, T., Hayakawa, S. H., Hicks, K., Hoshino, K., Hoshino, S., Hwang, S. H., Ichikawa, Y., Ichikawa, M., Imai, K., Ishikawa, Y., Kanauchi, H., Kasagi, A., Kim, S. H., Kinbara, S., Lin, P. M., Ma, T. L., Miwa, K., Moe, A. T., Nagase, Y., Nakazawa, K., Nanamura, T., Naruki, M., Nyaw, A. N. L., Pochodzalla, J., Sako, H., Sato, S., Soe, M. M., Soe, M. K., Sohn, J. Y., Takahashi, H., Takahashi, T., Tamura, H., Tanida, K., Theint, A. M. M., Tint, K. T., Ukai, M., Yamamoto, T. O., Yang, S. B., Yoon, C. S., Yoshida, J., Zhang, D. H., and Zhang, Z.
- Subjects
Nuclear Experiment ,Nuclear Theory ,Physics - Instrumentation and Detectors - Abstract
Bound-systems of $\Xi^-$--$^{14}_{}{\rm N}$ are studied via $\Xi^-$ capture at rest followed by emission of a twin single-$\Lambda$ hypernucleus in the emulsion detectors. Two events forming extremely deep $\Xi^-$ bound states were obtained by analysis of a hybrid method in the E07 experiment at J-PARC and reanalysis of the E373 experiment at KEK-PS. The decay mode of one event was assigned as $\Xi^-+^{14}_{}{\rm N}\to^{5}_{\Lambda}{\rm He}$+$^{5}_{\Lambda}{\rm He}$+$^{4}_{}{\rm He}$+n. Since there are no excited states for daughter particles, the binding energy of the $\Xi^-$ hyperon, $B_{\Xi^-}$, in $^{14}_{}{\rm N}$ nucleus was uniquely determined to be 6.27 $\pm$ 0.27 MeV. Another $\Xi^-$--$^{14}_{}{\rm N}$ system via the decay $^{9}_{\Lambda}{\rm Be}$ + $^{5}_{\Lambda}{\rm He}$ + n brings a $B_{\Xi^-}$ value, 8.00 $\pm$ 0.77 MeV or 4.96 $\pm$ 0.77 MeV, where the two possible values of $B_{\Xi^-}$ correspond to the ground and the excited states of the daughter $^{9}_{\Lambda}{\rm Be}$ nucleus, respectively. Because the $B_{\Xi^-}$ values are larger than those of the previously reported events (KISO and IBUKI), which are both interpreted as the nuclear $1p$ state of the $\Xi^-$--$^{14}_{}{\rm N}$ system, these new events give the first indication of the nuclear $1s$ state of the $\Xi$ hypernucleus, $^{15}_{\Xi}{\rm C}$., Comment: 26 pages, 7 figures
- Published
- 2021
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