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RIKEN Nishina Center for Accelerator-Based Science Radiation Laboratory

Director: Hideto Enyo (D.Sci.)

Research Summary

Hideto  Enyo(D.Sci.)

Nucleons, such as protons and neutrons, are a bound state of constituent quarks glued together with gluons. The detail structure of nucleons, however, is not well understood yet. Especially the mechanism to build up the spin of proton, which is 1/2, is a major problem in physics of the strong force. The research goal of Radiation Laboratory is to solve this fundamental question using the world first polarized-proton collider, realized at RHIC in Brookhaven National Laboratory (BNL) in USA. RHIC stands for Relativistic Heavy Ion Collider, aiming also to create Quark Gluon Plasma, the state of Universe just after the Big Bang. RIKEN-BNL Research Center (RBRC) carries our core team at BNL for those exciting researches using the PHENIX detector. We have measured fractions of the proton spin carried by gluons and anti-quarks in the proton. Other than the activities at RHIC we are performing new experiments at J-PARC and Fermilab to study the nature of hadron. We are also performing technical developments such as novel ion sources and fine-pitch silicon pixel detectors.

Main Research Fields

  • Mathematical & Physical Sciences


  • Hadron physics
  • Chiral symmetry
  • Nucleon structure
  • quark gluon plasma

Selected Publications

  • 1.PHENIX Collaboration (A. Adare (Colorado U.) et al.).:
    "Inclusive cross section and double-helicity asymmetry for π0 production at midrapidity in p+p collisions at√s =510 GeV"
    Phys.Rev. D93 (2016) 1, 011501
  • 2.PHENIX Collaboration (A. Adare et al.).:
    "Charged-pion cross sections and double-helicity asymmetries in polarized p+p collisions at √s =200  GeV"
    Phys.Rev. D91 (2015) 3, 032001
  • 3.PHENIX Collaboration (A. Adare et al.).:
    "Measurement of transverse-single-spin asymmetries for midrapidity and forward-rapidity production of hadrons in polarized p+p collisions at s√=200 and 62.4 GeV"
    Phys.Rev. D90 (2014) 1, 012006
  • 4.PHENIX Collaboration (A. Adare et al.).:
    "Inclusive cross section and single transverse spin asymmetry for very forward neutron production in polarized p+p collisions at sqrt{s}=200  GeV"
    Phys.Rev. D88 (2013) 3, 032006
  • 5.PHENIX Collaboration (A. Adare et al.).:
    "Cross sections and double-helicity asymmetries of midrapidity inclusive charged hadrons in p+p collisions at sqrt{s}=62.4 GeV"
    Phys.Rev. D86 (2012) 092006
  • 6.PHENIX Collaboration (A. Adare et al.).:
    "Observation of direct-photon collective flow in sqrt{s_{NN}}=200 GeV Au+Au collisions"
    Phys.Rev.Lett. 109 (2012) 122302
  • 7.PHENIX Collaboration (A. Adare et al.).:
    "Cross section and double helicity asymmetry for eta mesons and their comparison to neutral pion production in p+p collisions at sqrt(s)=200 GeV"
    Phys.Rev. D83 (2011) 032001.
  • 8.PHENIX Collaboration (A. Adare et al.).:
    "Measurement of Transverse Single-Spin Asymmetries for J/psi Production in Polarized p+p Collisions at sqrt{s} = 200 GeV"
    Phys.Rev. D82 (2010) 112008, Erratum-ibid. D86 (2012) 099904.
  • 9.PHENIX Collaboration (A. Adare et al.).:
    "Event Structure and Double Helicity Asymmetry in Jet Production from Polarized p+p Collisions at sqrt{s} = 200GeV"
    Phys.Rev. D84 (2011) 01200
  • 10.PHENIX Collaboration (A. Adare et al.).:
    "Cross Section and Parity-Violating Spin Asymmetries of W+- Boson Production in Polarized p+p Collisions at sqrt(s)=500 GeV"
    Phys. Rev. Lett. 106, 062001 (2011)

Related Links

Lab Members

Principal investigator

Hideto Enyo

Core members

Yasuyuki Akiba
Vice Chief Scientist
Satoshi Yokkaichi
Senior Research Scientist
Itaru Nakagawa
Senior Research Scientist
Ralf Seidl
Postdoctoral Researcher
Yasushi Watanabe
Senior Research Scientist
Yuji Goto
Senior Research Scientist
Koki Kanno
Special Postdoctoral Researcher
Wataru Nakai
Research Associate
Minho Kim
International Program Associate

Contact Information

2-1 Hirosawa,
Wako, Saitama
351-0198, Japan

Email: enyo [at] riken.jp