About us

Research Group for Quark Nuclear Physics

Takahiro Iwata (Professor) [Home] [Mail]
Yoshiyuki Miyachi (Professor) [Home] [Mail]
Hiroshi Yoshida (Professor, Institure of Art and Science; Networking and Computing Service Center) [Home] [Mail]
Yasuhisa Tajima (Professor, Institute of Art and Science; Networking and Computing Service Center) [Home] [Mail]
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We have activities in experimental nuclear and particle physics around strong interaction and hadronic matter. The followings are our main experimantal projects.

  1. KEK E391a and J-Parc E14 (KOTO) "Search for CP violating decay KL −> π0νν"

    The KL −> π0νν decay is a direct CP violation process. Since the theoretical ambiguity due to the QCD correction is very small, a measurement of the KL −> π0νν decay branching ratio is uniquely valuable in a search for new physics through the unitarity triangle and crucial for a profound understanding of the CP violation phenomena. A series of experiments has been planned at KEK to measure the branching ratio of KL −> π0νν; one is a kind of pilot experiment using the present 12 GeV Proton Synchrotron(PS) and the second a high sensitivity experiment using the J-Parc 50 GeV PS.

    Schedule (FY: Foundation Year)
    2002-2003FY Construction
    2004-2006FY Experimental Run at KEK
    2007-2010FY Construction for J-Parc
    2011FY- Experimental Run at 50 GeV PS

    An endcap part of the vacuum vessel
    The whole detector system of KEK E391a is planned to be put in the large vacuum chamber.

    Young physicists of Yamagata Univ. in an experiment at KEK


    - Study of Nucleon Spin Structure -
    The origin of the nucleon spin may be quark spin, gluon spin and anglular momenta of them. The SMC experiment at CERN and other related experiments have revieled in the past 10 years that the contribution of the qurak spin to the nucleon spin is small(20%). The COMPASS experiment at CERN aims at studying the gluon spin contribution. It is currently running at CERN with the world largest polarized target and the polarized muon beam at 200GeV.

    Polarized Target and COMPASS spectrometer
    An polarized target colored beige is seen in front of a spectrometer. The spectrometer consists of magnets, cherenkov counters, calorimeters, drift chambers, and the other detectors and machines.

  3. GDH-SP8 and other experiments using tagged photon beam

    The Gerasimov-Drell-Hearn(GDH) sum rule is a foundamental sum rule which describes the relation between the anomalous magnetic moment of the nucleon and its helicity dependent photo-absorption crosssection. Although it was formulated in 1966, experimental verification has not been completed. The GDH-SP8 experiment intends to measure the helicity dependent photo-absorption crosssection using the highly polarized photon beam at a few GeV energies provided in the SPring-8 LEP facility and with a polarized target. A combination of the polarized photon beam and the polarized target allows various interesting experiments.

    An experimantal setup for the (γ, η) reaction at LNS, Tohoku University. Many CsI scintillation detectors surround a solid hydrogen target seen in the center.