1. Observation of the '$K^-pp$'-like structure in the $d(\pi^+, K^+)$ reaction at 1.69 GeV/$c$
- Author
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Ichikawa, Yudai, Nagae, Tomofumi, Fujioka, Hiroyuki, Bhang, Hyoungchan, Bufalino, Stefania, Ekawa, Hiroyuki, Evtoukhovitch, Petr, Feliciello, Alessandro, Hasegawa, Shoichi, Hayakawa, Shuhei, Honda, Ryotaro, Hosomi, Kenji, Imai, Kenichi, Ishimoto, Shigeru, Joo, Changwoo, Kanatsuki, Shunsuke, Kiuchi, Ryuta, Koike, Takeshi, Kumawat, Harphool, Matsumoto, Yuki, Miwa, Koji, Moritsu, Manabu, Naruki, Megumi, Niiyama, Masayuki, Nozawa, Yuki, Ota, Ryosuke, Sakaguchi, Atsushi, Sako, Hiroyuki, Samoilov, Valentin, Sato, Susumu, Shirotori, Kotaro, Sugimura, Hitoshi, Suzuki, Shoji, Takahashi, Toshiyuki, Takahashi, Tomonori, Tamura, Hirokazu, Tanaka, Toshiyuki, Tanida, Kiyoshi, Tokiyasu, Atsushi, Tsamalaidze, Zviadi, Roy, Bidyut, Ukai, Mifuyu, Yamamoto, Takeshi, and Yang, Seongbae
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Nuclear Experiment - Abstract
We have observed a "$K^-pp$"-like structure in the $d(\pi^+,K^+)$ reaction at 1.69 GeV/$c$. In this reaction $\Lambda(1405)$ hyperon resonance is expected to be produced as a doorway to form the $K^-pp$ through the $\Lambda^*p\rightarrow K^-pp$ process. However, most of the produced $\Lambda(1405)$'s would escape from deuteron without secondary reactions. Therefore, coincidence of high-momentum ($>$ 250~MeV/$c$) proton(s) in large emission angles ($39^\circ<\theta_{lab.}<122^\circ$) was requested to enhance the signal-to-background ratio. A broad enhancement in the proton coincidence spectra are observed around the missing-mass of 2.27 GeV/$c^2$, which corresponds to the $K^-pp$ binding energy of 95 $^{+18}_{-17}$ (stat.) $^{+30}_{-21}$ (syst.) MeV and the width of 162 $^{+87}_{-45}$ (stat.) $^{+66}_{-78}$ (syst.) MeV., Comment: 8 pages, 4 figures, submitted to PTEP
- Published
- 2014
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