Observation of $\Xi(1620)^0$ and evidence for $\Xi(1690)^0$ in $\Xi_c^+ \rightarrow \Xi^-\pi^+\pi^+$ decays

• Main Authors: Belle collaboration, Sumihama, M, Adachi, I, Aihara, H, Said, S. Al, Asner, D. M, Aushev, T, Ayad, R, Bahinipati, S, Bakich, A. M, Bansal, V, Beleno, C, Bhardwaj, V, Bonvicini, G, Bozek, A, Browder, T. E, Cervenkov, D, Chen, A, Cheon, B. G, Cho, K, Czank, S. Cunliffe, Dolezal, Z, Drasal, Z, Eidelman, S, Epifanov, D, Fulsom, B. G, Gabyshev, N, Giri, A, Goldenzweig, P, Haba, J, Hayasaka, K, Hayashii, H, Hou, W. -S, Inami, K, Inguglia, G, Ishikawa, A, Iwasaki, M, Jeon, H. B, Joo, K. K, Karyan, G, Kiesling, C, Kim, J. B, Kim, K. T, Kim, S. H, Kinoshita, K, Korpar, S, Krokovny, P, Kumar, R, Kuzmin, A, Lee, I. S, Li, Y. B, Gioi, L. Li, Libby, J, Lubej, M, Luo, T, Masuda, M, Merola, M, Miyabayashi, K, Miyata, H, Mohanty, G. B, Moon, H. K, Mussa, R, Nakano, E, Nakano, T, Nanut, T, Natkaniec, Z, Niiyama, M, Pakhlov, P, Pakhlova, G, Paul, S, Pedlar, T. K, Popov, V, Ritter, M, Russo, G, Sahoo, D, Sandilya, S, Schnell, G, Schwanda, C, Seino, Y, Sevior, M. E, Shen, C. P, Shiu, J. -G, Shwartz, B, Simon, F, Staric, M, Strube, J. F, Sumiyoshi, T, Taniguchi, N, Uchida, M, Uglov, T, Uno, S, Vahsen, S. E, Wang, M. -Z, Watanabe, M, Won, E, Ye, H, Yelton, J, Zakharov, S, Zhang, Z. P, Zhilich, V
• Format: Journal Article
• Language: English
• Published: 15.10.2018
• Subjects: Physics - High Energy Physics - Experiment; Physics - Nuclear Experiment
• DOI: 10.48550/arxiv.1810.06181

Phys. Rev. Lett. 122, 072501 (2019) We report the first observation of the doubly-strange baryon $\Xi(1620)^0$ in its decay to $\Xi^-\pi^+$ via $\Xi_c^+ \rightarrow \Xi^- \pi^+ \pi^+$ decays based on a $980\,{\rm fb}^{-1}$ data sample collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. The mass and width are measured to be 1610.4 $\pm$ 6.0 (stat) $^{+5.9}_{-3.5}$ (syst)~MeV$/c^2$ and 59.9 $\pm$ 4.8 (stat) $^{+2.8}_{-3.0}$ (syst)~MeV, respectively. We obtain 4.0$\sigma$ evidence of the $\Xi(1690)^0$ with the same data sample. These results shed light on the structure of hyperon resonances with strangeness $S=-2$.