The investigation of strangeness photoproduction in the threshold region at lns-tohoku

M. Kaneta, B. Beckford, M. Ejima, T. Fujii, Y. Fujii, T. Fujibayashi, T. Gogami, K. Futatsukawa, O. Hashimoto, K. Hosomi, K. Hirose, A. Lguchi, S. Kameoka, H. Kanda, H. Kato, D. Kawama, T. Kawasaki, C. Kimura, S. Kiyokawa, T. KoikeT. Kon, Y. Ma, K. Maeda, N. Maruyama, A. Matsumura, Y. Miyagi, Y. Miura, K. Miwa, S. N. Nakamura, H. Nomura, A. Okuyama, A. Ohtani, M. Sato, A. Shichijo, K. Shirotori, T. Takahashi, H. Tamura, N. Taniya, H. Tsubota, K. Tsukada, N. Terada, M. Ukai, D. Uchida, T. Watanabe, T. O. Yamamoto, H. Yamauchi, T. Ishikawa, T. Kinoshita, H. Miyahara, T. Nakabayashi, H. Shimizu, K. Suzuki, T. Tamae, T. Terasawa, H. Yamazaki, Y. C. Han, T. S. Wang, A. Sasaki, O. Konno, P. Bydzovsky, M. Sotona

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


The strangeness photoproduction process has been intensively studied based on the high-quality data of the charged kaon channel, γ + p → K + + Λ(ε0). On the other hand, there was no reliable data for the neutral kaon channel γ+n + K 0+Λ(ε0). The theoretical investigations suffer seriously from the lack of the data. A Substantial effort has been made to measure the γ+n + K0+Λ process in the K0 s → π+π- decay channel, using a liquid deuterium target and a tagged photon beam (Eγ = 0.8-1.1 GeV ) in the threshold region at Laboratory of Nuclear Science (LNS), Tohoku University. We have taken exploratory data quite successfully with use of Neutral Kaon Spectrometer (NKS) at LNS-Tohoku in 2003 and 2004. The data is compared theoretical models and it indicates a hint that the K0 differential cross section has a backward peak in the energy region. The second generation of the experiment, named NKS2, is designed to extend the NKS experiment by considerably upgrading the original neutral kaon spectrometer, fully replacing the spectrometer magnet, tracking detectors and all the trigger counters. The new spectrometer NKS2 has significantly larger acceptance for neutral kaons compared with NKS, particularly covering forward angles and much better invariant mass resolution. The estimated acceptance of NKS2 is three (ten) times larger for K0s(Λ) than that of NKS. The spectrometer is newly constructed and installed at LNS, Tohoku University in 2005. The deuterium target data was taken with the tagged photon beam in 2006-2007. We will report recent results of NKS2 in this paper. Additionally, a status of the upgrade project that gives us larger acceptance and capability of K0 +Λ coincidence measurement will be repsented.

Original languageEnglish
Title of host publicationHadron and Nuclear Physics 2009, HNP 2009
Number of pages10
Publication statusPublished - 2010
EventHadron and Nuclear Physics 2009, HNP 2009 - Osaka, Japan
Duration: 2009 Nov 162009 Nov 19

Publication series

NameHadron and Nuclear Physics 2009, HNP 2009


ConferenceHadron and Nuclear Physics 2009, HNP 2009


  • Photoproduction
  • Strangeness


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