Search for the K-pp bound state via γd→K+π-X reaction at Eγ=1.5-2.4GeV

A. O. Tokiyasu, M. Niiyama, J. D. Parker, D. S. Ahn, J. K. Ahn, S. Ajimura, H. Akimune, Y. Asano, W. C. Chang, J. Y. Chen, S. Daté, H. Ejiri, H. Fujimura, M. Fujiwara, S. Fukui, S. Hasegawa, K. Hicks, K. Horie, T. Hotta, S. H. HwangK. Imai, T. Ishikawa, T. Iwata, Y. Kato, H. Kawai, K. Kino, H. Kohri, Y. Kon, N. Kumagai, D. L. Lin, Y. Maeda, S. Makino, T. Matsuda, T. Matsumura, N. Matsuoka, T. Mibe, M. Miyabe, M. Miyachi, N. Muramatsu, R. Murayama, T. Nakano, Y. Nakatsugawa, M. Nomachi, Y. Ohashi, H. Ohkuma, T. Ohta, T. Ooba, D. S. Oshuev, C. Rangacharyulu, S. Y. Ryu, A. Sakaguchi, T. Sawada, P. M. Shagin, Y. Shiino, H. Shimizu, E. A. Strokovsky, Y. Sugaya, M. Sumihama, J. L. Tang, Y. Toi, H. Toyokawa, T. Tsunemi, M. Uchida, M. Ungaro, A. Wakai, C. W. Wang, S. C. Wang, K. Yonehara, T. Yorita, M. Yoshimura, M. Yosoi, R. G.T. Zegers

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68 Citations (Scopus)


A search for the K-pp bound state (the lightest kaonic nucleus) has been performed using the γd→K+π-X reaction at Eγ = 1.5-2.4 GeV at LEPS/SPring-8. The differential cross section of the K+π- photo-production off deuterium (d2σ/dcosθlabK+/dcosθlabπ-) has been measured for the first time in this energy region. A peak structure was searched for in the inclusive missing mass spectrum. A statistically significant peak structure was not observed in the region from 2.22 to 2.36 GeV/c2. The upper limits of the differential cross section of the K-pp bound state production were determined to be (0.17-0.55), (0.55-1.7) and (1.1-2.9) μb at 95% confidence level with the assumed widths of 20 MeV, 60 MeV and 100 MeV.

Original languageEnglish
Pages (from-to)616-621
Number of pages6
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Publication statusPublished - 2014
Externally publishedYes

Bibliographical note

Funding Information:
The authors thank the SPring-8 staff for their contributions in the operation of the LEPS experiment. This research was supported in part by the Ministry of Education, Science, Sports and Culture of Japan , by the GCOE program in Kyoto University , by the National Science Council of the Republic of China (Taiwan) , by the National Research Foundation of Korea ( 2012R1A2A1A01011926 ) and by the National Science Foundation (NSF Award PHY-0244999 ). Author J.D. Parker was supported by a Postdoctoral Fellowship for Foreign Researchers from the Japan Society for the Promotion of Science .


  • Antikaon-nucleon physics
  • Kaonic nuclei
  • Photo-production

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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