Evidence for the Θ+ in the γd→K+K-pn reaction by detecting K+K- pairs

T. Nakano, N. Muramatsu, D. S. Ahn, J. K. Ahn, H. Akimune, Y. Asano, W. C. Chang, S. Daté, H. Ejiri, H. Fujimura, M. Fujiwara, S. Fukui, H. Hasegawa, K. Hicks, K. Horie, T. Hotta, K. Imai, T. Ishikawa, T. Iwata, Y. KatoH. Kawai, Z. Y. Kim, K. Kino, H. Kohri, N. Kumagai, S. Makino, T. Matsuda, N. Matsuoka, T. Matsumura, T. Mibe, M. Miyabe, Y. Miyachi, M. Niiyama, M. Nomachi, Y. Ohashi, H. Ohkuma, T. Ooba, D. S. Oshuev, C. Rangacharyulu, A. Sakaguchi, P. M. Shagin, Y. Shiino, A. Shimizu, H. Shimizu, Y. Sugaya, M. Sumihama, Y. Toi, H. Toyokawa, A. Wakai, C. W. Wang, S. C. Wang, K. Yonehara, T. Yorita, M. Yoshimura, M. Yosoi, R. G.T. Zegers

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132 Citations (Scopus)


The γd→K+K-pn reaction has been studied to search for the evidence of the Θ+ by detecting K+K- pairs at forward angles. The Fermi-motion-corrected nK+ invariant mass distribution shows a narrow peak at 1.524±0.002+0.003 GeV/c2. The statistical significance of the peak calculated from a shape analysis is 5.1 σ, and the differential cross section for the γn→K-Θ+ reaction is estimated to be 12±2 nb/sr in the photon energy range from 2.0 to 2.4 GeV in the LEPS angular range by assuming the isotropic production of the Θ+ in the γn center-of-mass system. The obtained results support the existence of the Θ+.

Original languageEnglish
Article number025210
JournalPhysical Review C - Nuclear Physics
Issue number2
Publication statusPublished - 2009 Feb 2
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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