Search for Θ+ via π-p→K-X reaction near production threshold

K. Miwa, J. K. Ahn, K. Aoki, B. H. Choi, Y. Fukao, H. Funahashi, T. Hayakawa, M. Hayata, T. Hibi, M. Ieiri, K. Imai, S. J. Kim, K. Nakazawa, H. Nishikawa, H. Okada, N. Saito, H. D. Sato, K. Shoji, H. Takahashi, K. TaketaniK. Yamamoto, C. J. Yoon

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)


We have searched for Θ+ via π-p→K -X reaction using 1.87 and 1.92 GeV/c π- beam at the K2 beam line of the KEK 12 GeV proton synchrotron. In the missing mass spectrum at beam momentum of 1.92 GeV/c, a bump has been found at 1530 MeV/c2 which is consistent with the mass reported by several experiments. The statistical significance of this bump, however, is only 2.5-2.7σ. Therefore we have derived the upper limit of Θ+ production cross section via π-p→K-Θ+ reaction which is 3.9 μb at 90% confidence level assuming that Θ+ is produced isotropically in the center of mass system.

Original languageEnglish
Pages (from-to)72-79
Number of pages8
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number2-3
Publication statusPublished - 2006 Apr 6
Externally publishedYes

Bibliographical note

Funding Information:
We would like to express our thanks to staffs of KEK PS and beam channel group for their support to provide beam with the excellent condition during the experiment. We also acknowledge to T. Hyodo for the theoretical discussion. One of the authors (K.M.) thanks to the Japan Society for the Promotion of Science (JSPS) for support. The work of J.K. Ahn was supported by a Korea Research Foundation grant (KRF-2003-015-C00130). This work was supported by the Grant-in-Aid for Specially Promoted Research (No. 15001001) from the Ministry of Education, Culture, Science and Technology, Japan.


  • Baryons
  • Glueball and nonstandard multi-quark/gluon states
  • Hadron-induced low- and intermediate-energy reaction and scattering
  • Pion-baryon interactions

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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