High-resolution search for the Θ+ pentaquark via a pion-induced reaction at J-PARC

M. Moritsu, S. Adachi, M. Agnello, S. Ajimura, K. Aoki, H. C. Bhang, B. Bassalleck, E. Botta, S. Bufalino, N. Chiga, H. Ekawa, P. Evtoukhovitch, A. Feliciello, H. Fujioka, S. Hayakawa, F. Hiruma, R. Honda, K. Hosomi, Y. Ichikawa, M. IeiriY. Igarashi, K. Imai, N. Ishibashi, S. Ishimoto, K. Itahashi, R. Iwasaki, C. W. Joo, S. Kanatsuki, M. J. Kim, S. J. Kim, R. Kiuchi, T. Koike, Y. Komatsu, V. V. Kulikov, S. Marcello, S. Masumoto, Y. Matsumoto, K. Matsuoka, K. Miwa, T. Nagae, M. Naruki, M. Niiyama, H. Noumi, Y. Nozawa, R. Ota, K. Ozawa, N. Saito, A. Sakaguchi, H. Sako, V. Samoilov, M. Sato, S. Sato, Y. Sato, S. Sawada, M. Sekimoto, K. Shirotori, H. Sugimura, S. Suzuki, H. Takahashi, T. Takahashi, T. N. Takahashi, H. Tamura, T. Tanaka, K. Tanida, A. O. Tokiyasu, N. Tomida, Z. Tsamalaidze, M. Ukai, K. Yagi, T. O. Yamamoto, S. B. Yang, Y. Yonemoto, C. J. Yoon, K. Yoshida

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16 Citations (Scopus)


The pentaquark Θ+ has been searched for via the π-p→K-X reaction with beam momenta of 1.92 and 2.01 GeV/c at J-PARC. A missing mass resolution of 2 MeV (FWHM) was achieved but no sharp peak structure was observed. The upper limits on the production cross section averaged over the scattering angle from 2 to 15in the laboratory frame were found to be less than 0.28 μb/sr at the 90% confidence level for both the 1.92- and 2.01-GeV/c data. The systematic uncertainty of the upper limits was controlled within 10%. Constraints on the Θ+ decay width were also evaluated with a theoretical calculation using an effective Lagrangian. The present result implies that the width should be less than 0.36 and 1.9 MeV for the spin-parity of 1/2+ and 1/2-, respectively.

Original languageEnglish
Article number035205
JournalPhysical Review C - Nuclear Physics
Issue number3
Publication statusPublished - Sept 22 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics


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