1. Home
  2. Research
  3. Centers & Labs
  4. RIKEN Nishina Center for Accelerator-Based Science

RIKEN Nishina Center for Accelerator-Based Science Meson Science Laboratory

Director: Masahiko Iwasaki (D.Sc.)

Research Summary

Masahiko  Iwasaki

Particles like muons, pions, and kaons have finite life times, so they do not exist in natural nuclei or matters. In our research, we introduce different kind of impurities into nuclei/matters, and study new states of matter, new phenomena, or the object properties.
Implanting these particles into nuclei/matters, exotic phenomena in varieties of objects can be studied from a new point of view. Kaon is a second lightest meson which has strange-quark as a constituent quark. It is expected that if one embed a kaon into nuclei, the sizes of the nuclei become smaller and forms a high-density object beyond the normal nuclear density. Study of this object could lead better understanding of the origin of the mass of the matter, and may reveal the quark degree of freedom beyond the quark-confinement. Those properties can be studied by precise heavy pionic atom research in different angle. The other example is the weak interaction in nuclear matter. It can only be studied by the weak decay of hypernuclei, which have Lambda particle in the nuclei.
Muon provides even wider variety of study from nuclear reaction to magnetism in matter. For instance, stopping positively charged muon in a material, we obtain information on the magnetic properties or the local field at the trapped-site (muon-spin-relaxation method). Ultra-slow muon beam can be used for the material surface studies and also as a source of ultra-cold muon beam for precise muon g-2 measurement.

Main Research Fields

  • Interdisciplinary Science & Engineering

Related Research Fields

  • Complex Systems


  • Meson
  • muon
  • hadron
  • mass

Selected Publications

  • 1.M. Iwasaki, H. Bhang, J. Chiba, Choi Seonho, Y. Fukuda, T. Hanaki, R.S. Hayano, M. Iio, T. Ishikawa, S. Ishimoto, T. Ishiwatari, K. Itahashi, M. Iwai, P. Kienle, J.H. Kim, Y. Matsuda, H. Ohnishi, S. Okada, H. Outa, M. Sato, S. Suzuki, T. Suzuki, D. Tomono.:
    "Search for strange tribaryon states in the inclusive He-4 (K-(stopped), p) reaction"
    Nucl. Phys. A804, 186-196 (2008)
  • 2.S. Okada, G. Beer, H. Bhang, M. Cargnelli, J. Chiba, Seonho Choi, C. Curceanu, Y. Fukuda, T. Hanaki, R.S. Hayano, M. Iio, T. Ishikawa, S. Ishimoto, T. Ishiwatari, K. Itahashi, M. Iwai, M. Iwasaki, B. Juhasz, P. Kienle, J. Marton, Y. Matsuda, H. Ohnishi, H.:
    "Precision measurement of the 3d ---> 2p x-ray energy in kaonic He-4"
    Physics Letters B 653, 387-391 (2007).
  • 3.T. Suzuki, H. Bhang, J. Chiba, S. Choi, Y. Fukuda, T. Hanaki, R. S. Hayano, M. Iio, T. Ishikawa, S. Ishimoto, T. Ishiwatari, K. Itahashi, M. Iwai, M. Iwasaki, P. Kienle, J. H. Kim, Y. Matsuda, H. Ohnishi, S. Okada, H. Outa, M. Sato, S. Suzuki, D. Tomono.:
    "Lambda d correlation from He-4(stopped K-, d) reaction"
    Physicl Review C76, 068202 (2007)
  • 4.Y. Tanabe, T. Adachi, K. Suzuki, Y. Koike, T. Kawamata1, Risdiana, T. Suzuki1, and I. Watanabe.:
    "Similarity between Ni- and Zn-Impurity Effects on the Superconductivity and Cu-spin Correlation in La-214 High-TC Cuprates: Review Based on the Hole Trapping by Ni"
    Phys. Rev. B 83, 144521-1-6 (2011)
  • 5.F.L. Pratt, P.J. Baker, S.J. Blundell, T. Lancaster, S. Ohira-Kawamura, C. Baines, Y. Shimizu, K. Kanoda, and I. Watanabe.:
    "Magnatic-Field-Induced Quantum-Phase-Transition in the Spin-Liquid Phase of a Frustrated Magnet"
    Nature 471, 612-616 (2011)
  • 6.T. Lancaster, F.L. Pratt, S.J. Blundell, A.J. Steele, P.J. Baker, J.D. Wright, I. Watanabe, R.S. Fishman, and J.S. Miller.:
    "Local Magnetism in the Molecule-Based Metamagnet [Ru2(O2CMe)4]3[Cr(CN)6] Probed with Implanted Muons"
    Phys. Rev. B 84, 092405-1-4 (2011)
  • 7.Imao, H., Ishida, K., Kawamura, N., Matsuzaki, T., Matsuda, Y., Toyoda, A., Strasser, P., Iwasaki, M. and Nagamine, K.:
    "Density effect in d-d muon-catalyzed fusion with ortho- and para-enriched D2"
    Phys. Lett. B 658, 120-124 (2008)
  • 8.P. Bakule, D.G. Fleming, O. Sukhorukov, K. Ishida, F. Pratt, T. Momose, E. Torikai, B.G. garrett, K.A. Peterson, G.C. Schatz and D.G. Truhlar:
    "State-selected reaction of muonium with vibrationally excited H2"
    J. Phys. Chem. Lett. 3, 2755-2760 (2012)
  • 9.Bakule, P., Matsuda, Y., Miyake, Y., Nagamine, K., Iwasaki, M., Ikedo, Y., Shimomura, K., Strasser, P., and Makimura, S.:
    "Pulsed source of ultra low energy positive muons for near-surface mSR studies"
    Nuclear Instruments and Methods in Physical Research B 266, 335-346 (2008)
  • 10.T.Hashimoto et al.:
    "Search for the deeply bound K−pp state from the semi-inclusive forward-neutron spectrum in the in-flight K− reaction on helium-3"
    Prog. Theor. Exp. Phys. (2015) 061D01.

Recent Research Results

Related Links

Lab Members

Principal investigator

Masahiko Iwasaki

Core members

Haruhiko Outa
Senior Research Scientist
Isao Watanabe
Senior Research Scientist
Kenta Itahashi
Senior Research Scientist
Fuminori Sakuma
Senior Research Scientist
Yue Ma
Senior Research Scientist
Katsuhiko Ishida
Contract Researcher
Muhamad Umar
Junior Research Associate
Shun Seo
Junior Research Associate
Harison Binti Rozak
International Program Associate
Suti Winarsih
International Program Associate
Utami Widyaiswari
International Program Associate
Muhammad Hanif Bin Che Lah
International Program Associate

Contact Information

2-1 Hirosawa,
Wako, Saitama
351-0198, Japan
Email: advanced_meson [at] riken.jp