Precise determination of the spin structure function g{sub 1} of the proton, deuteron, and neutron

Journal Article · Mon Jan 01 04:00:00 EST 2007 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.75.012007· OSTI ID:20933200

Airapetian, A; Deconinck, W; Lorenzon, W ^[1]; Akopov, N; Akopov, Z; Avakian, R; Avetissian, A; Elbakian, G; Gharibyan, V; Marukyan, H; Taroian, S ^[2]; Andrus, A; Linden-Levy, L A; Makins, N C. R.; Rubin, J ^[3]; Aschenauer, E C; Boettcher, H; Gabbert, D; Gregor, I M; Guler, H ^[4]

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1. Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)
2. Yerevan Physics Institute, 375036 Yerevan (Armenia)
3. Department of Physics, University of Illinois, Urbana, Illinois 61801-3080 (United States)
4. DESY, 15738 Zeuthen (Germany)

Precise measurements of the spin structure functions of the proton g{sub 1}{sup p}(x,Q{sup 2}) and deuteron g{sub 1}{sup d}(x,Q{sup 2}) are presented over the kinematic range 0.0041{<=}x{<=}0.9 and 0.18 GeV{sup 2}{<=}Q{sup 2}{<=}20 GeV{sup 2}. The data were collected at the HERMES experiment at DESY, in deep-inelastic scattering of 27.6 GeV longitudinally polarized positrons off longitudinally polarized hydrogen and deuterium gas targets internal to the HERA storage ring. The neutron spin structure function g{sub 1}{sup n} is extracted by combining proton and deuteron data. The integrals of g{sub 1}{sup p,d} at Q{sup 2}=5 GeV{sup 2} are evaluated over the measured x range. Neglecting any possible contribution to the g{sub 1}{sup d} integral from the region x{<=}0.021, a value of 0.330{+-}0.011(theo){+-}0.025(exp){+-}0.028(evol) is obtained for the flavor-singlet axial charge a{sub 0} in a leading-twist next-to-next-to-leading-order analysis.

• OSTI ID: 20933200
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 1 Vol. 75; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
DEEP INELASTIC SCATTERING
DESY
DEUTERIUM
DEUTERONS
FLAVOR MODEL
GEV RANGE
HERA STORAGE RING
HYDROGEN
NEUTRONS
POSITRONS
PROTONS
SPIN
STRUCTURE FUNCTIONS