Radiation Laboratory
Research Areas
| 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 first polarized-proton collider, realized at RHIC, 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) directed by N. Samios carries our core team at BNL for those exciting researches. Recent data analysis has shown that the proton spin carried by gluons is indeed small, which is a very striking finding beyond our expectations. We have been doing other pioneering researches at the domestic accelerators at SPring-8 and High Energy Accelerator Research Organization (KEK) which is now proceeded to the new experiment at J-PARC. We are also performing technical developments such as novel ion sources, super conducting detectors, fine pitch pixel detectors and neutron optical devices. |  Chief Scientist Hideto EN'YO (D.Sci.)  |
Research Subjects
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List of Selected Publications
| (1) | PHENIX Collaboration (Adare, A., et al.): "Inclusive cross-section and double helicity asymmetry for pi0 production in p + p collisions at s**(1/2) = 200-GeV: Implications for the polarized gluon distribution in the proton." Phys.Rev.D76:051106 (2007) |
| (2) | Bazilevsky, A., et al.: "Single Transverse-Spin Asymmetry in Very Forward and Very Backward Neutral Particle Production for Polarized Proton Collisions at s**(1/2) = 200-GeV." Phys.Lett.B650:325-330 (2007) |
| (3) | PHENIX Collaboration (Adler, S.S., et al.): "Measurement of direct photon production in p + p collisions at s**(1/2) = 200-GeV." Phys.Rev.Lett.98:012002 (2007) |
| (4) | Huang, H., et al.: "Overcoming depolarizing resonances with dual helical partial siberian snakes." Phys.Rev.Lett.99:154801 (2007) |
| (5) | PHENIX Collaboration (Adler, S.S., et al.): "Measurement of density correlations in pseudorapidity via charged particle multiplicity fluctuations in Au+Au collisions at s(NN)**(1/2) = 200-GeV." Published in Phys.Rev.C76:034903(2007) |
| (6) | Okamura, M., et al.: "Direct Plasma injection scheme for accelerators." Rev. Sci. Instrum. 79, 02B314 (2008) |
| (7) | KEK-PS-E325 Collaboration (Sakuma, F., et al.): "Study of nuclear matter modification of decay widths in phi ---> e+ e- and phi ---> K+ K- channels." Phys.Rev.Lett.98:152302 (2007) |
| (8) | KEK-PS-E325 Collaboration (Muto, R., et al.): "Evidence for in-medium modification of the phi meson at normal nuclear density." Phys.Rev.Lett.98:042501 (2007) |
| (9) | KEK-PS E325 Coolaboration (Naruki, M. et al.): "Experimental signature of the medium modification for rho and omega mesons in 12-GeV p + A reactions." Phys.Rev.Lett., 96, 092301 (2006) |
| (10) | PHENIX Collaboration (Adler, S.S., et al.): "DOUBLE HELICITY ASYMMETRY IN INCLUSIVE MID-RAPIDITY PI0 PRODUCTION FOR POLARIZED P +P COLLISIONS AT S**(1/2) = 200-GEV." Phys. Rev. Lett. 93, 202002 (2004). |