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Title: Spin physics at RHIC

Journal Article · · AIP Conference Proceedings
DOI:https://doi.org/10.1063/1.3442577· OSTI ID:21361999
 [1]
  1. RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198 (Japan) and RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973 (United States)

Polarized-proton collisions at a collision energy 200 GeV started in 2001 at RHIC in BNL. We have investigated a polarized structure of the proton to understand the origin of the nucleon spin 1/2 with polarized-proton collisions. The first goal of spin physics at RHIC is determination of the gluon-spin contribution to the proton spin. The PHENIX and STAR experiments have investigated the gluon-spin contribution by measuring longitudinal-spin asymmetries of neutral pion and jet produced in longitudinally-polarized proton collisions. Experimental results have shown that these asymmetries are small and strong constraints have been given for the gluon-spin contribution. From 2009, polarized-proton collisions at a collision energy 500 GeV started and we have investigated flavor-sorted contribution of the quark spin to the proton spin with weak-boson production. The final remaining piece of information to understand the proton spin is orbital-angular momenta of quarks and gluons. Multi-dimensional structure of the nucleon which includes information of the orbital-angular motion inside the nucleon has been investigated with transverse-spin asymmetry measurements.

OSTI ID:
21361999
Journal Information:
AIP Conference Proceedings, Vol. 1235, Issue 1; Conference: 7. Japan-China joint nuclear physics symposium, Tsukuba (Japan), 9-13 Nov 2009; Other Information: DOI: 10.1063/1.3442577; (c) 2010 American Institute of Physics; ISSN 0094-243X
Country of Publication:
United States
Language:
English