Abstract
The STAR Collaboration reports measurements of the longitudinal double-spin asymmetry, ALL, for neutral pions produced at forward directions in polarized proton-proton collisions, at a center-of-mass energy of 510 GeV. Results are given for transverse momenta in the range 2<pT<10 GeV/c within two regions of pseudorapidity that span 2.65<η<3.9. These results are sensitive to the polarized gluon parton distribution function, Δg(x), down to the region of Bjorken x∼10-3. The asymmetries observed are less than ±5×10-3 in magnitude and will help constrain the contribution to the spin of the proton from polarized gluons at low x, when combined with other measurements as part of a global analysis.
Original language | English |
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Article number | 032013 |
Journal | Physical Review D |
Volume | 98 |
Issue number | 3 |
DOIs | |
State | Published - Aug 1 2018 |
Externally published | Yes |
Funding
We thank the RHIC Operations Group and RCF at BNL, the NERSC Center at LBNL, and the Open Science Grid consortium for providing resources and support. This work was supported in part by the Office of Nuclear Physics within the U.S. DOE Office of Science, the U.S. National Science Foundation, the Ministry of Education and Science of the Russian Federation, National Natural Science Foundation of China, Chinese Academy of Science, the Ministry of Science and Technology of China and the Chinese Ministry of Education, the National Research Foundation of Korea, Czech Science Foundation and Ministry of Education, Youth and Sports of the Czech Republic, Department of Atomic Energy and Department of Science and Technology of the Government of India, the National Science Centre of Poland, the Ministry of Science, Education and Sports of the Republic of Croatia, RosAtom of Russia and German Bundesministerium fur Bildung, Wissenschaft, Forschung and Technologie (BMBF) and the Helmholtz Association.
Funders | Funder number |
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RosAtom of Russia and German Bundesministerium fur Bildung, Wissenschaft, Forschung and Technologie | |
National Science Foundation | 1614545 |
National Science Foundation | |
Office of Science | |
Nuclear Physics | |
Department of Science and Technology, Ministry of Science and Technology, India | |
National Natural Science Foundation of China | |
Ministerstvo Školství, Mládeže a Tělovýchovy | |
Grantová Agentura České Republiky | |
Ministry of Education of the People's Republic of China | |
Bundesministerium für Bildung und Forschung | |
Chinese Academy of Sciences | |
Ministry of Science and Technology of the People's Republic of China | |
Ministarstvo Obrazovanja, Znanosti i Sporta | |
Ministry of Education and Science of the Russian Federation | |
National Research Foundation of Korea | |
Narodowe Centrum Nauki | |
Ministry of Education and Science | |
Helmholtz Association |