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 · Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRevD.75.012007· OSTI ID:940204

Airapetian, A; Akopov, N; Akopov, Z; Andrus, A; Aschenauer, E C; El Alaoui, M A; Jackson, H E; Reimer, P E; Sanjiev, I

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.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: USDOE; FOR; NSF
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 940204
• Report Number(s): ANL/PHY/JA-57155
• Journal Information: Phys. Rev. D, Journal Name: Phys. Rev. D Journal Issue: Jan. 1, 2007 Vol. 75; ISSN 1550-7998
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

08 HYDROGEN
43 PARTICLE ACCELERATORS
DEUTERIUM
DEUTERONS
HERA STORAGE RING
HYDROGEN
NEUTRONS
POSITRONS
PROTONS
SCATTERING
SPIN
STRUCTURE FUNCTIONS
TARGETS