'$\mathbf{{\textit K^-}{\textit p}{\textit p}}$', a ${\overline{K}}$-Meson Nuclear Bound State, Observed in $^{3}{\rm He}({K^-}, {\Lambda} p)n$ Reactions
| Autor: | collaboration, J-PARC E15, Ajimura, S., Asano, H., Beer, G., Berucci, C., Bhang, H., Bragadireanu, M., Buehler, P., Busso, L., Cargnelli, M., Choi, S., Curceanu, C., Enomoto, S., Fujioka, H., Fujiwara, Y., Fukuda, T., Guaraldo, C., Hashimoto, T., Hayano, R. S., Hiraiwa, T., Iio, M., Iliescu, M., Inoue, K., Ishiguro, Y., Ishikawa, T., Ishimoto, S., Itahashi, K., Iwasaki, M., Kanno, K., Kato, K., Kato, Y., Kawasaki, S., Kienle, P., Kou, H., Ma, Y., Marton, J., Matsuda, Y., Mizoi, Y., Morra, O., Nagae, T., Noumi, H., Ohnishi, H., Okada, S., Outa, H., Piscicchia, K., Sada, Y., Sakaguchi, A., Sakuma, F., Sato, M., Scordo, A., Sekimoto, M., Shi, H., Shirotori, K., Sirghi, D., Sirghi, F., Suzuki, K., Suzuki, S., Suzuki, T., Tanida, K., Tatsuno, H., Tokuda, M., Tomono, D., Toyoda, A., Tsukada, K., Doce, O. Vazquez, Widmann, E., Yamaga, T., Yamazaki, T., Zhang, Q., Zmeskal, J. |
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| Rok vydání: | 2018 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | We observed a distinct peak in the $\Lambda p$ invariant mass spectrum of $^{3}{\rm He}(K^-, \, \Lambda p)n$, well below the mass threshold of $m_K + 2 m_p$. By selecting a relatively large momentum-transfer region $q = 350 \sim 650$ MeV/$c$, one can clearly separate the peak from the quasi-free process, $\overline{K}N \rightarrow \overline{K}N$ followed by the non-resonant absorption by the two spectator-nucleons $\overline{K}NN \rightarrow \Lambda N $. We found that the simplest fit to the observed peak gives us a Breit-Wigner pole position at $B_{\rm {\it Kpp}} = 47 \pm 3 \, (stat.) \,^{+3}_{-6} \,(sys.)$ MeV having a width $\Gamma_{\rm {\it Kpp}} = 115 \pm 7 \, (stat.) \,^{+10}_{-9} \,(sys.)$ MeV, and the $S$-wave Gaussian reaction form-factor parameter $Q_{\rm {\it Kpp}} = 381 \pm 14 \, (stat.)\,^{+57}_{-0} \,(sys.)$ MeV/$c$, as a new form of the nuclear bound system with strangeness -- "$K^-pp$". Comment: 17 pages, 4 figures |
| Databáze: | arXiv |
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