APS » PROLA » Phys. Rev. D » Volume 58 » Issue 11

Phys. Rev. D 58, 112003 (1998) [54 pages]

Measurements of the proton and deuteron spin structure functions g1 and g2

Download: PDF (1504 kB) or Buy this Article (Use Article Pack) Export: BibTeX or EndNote (RIS)

K. Abe et al. (E143 Collaboration)
Show All Authors/Affiliations

Received 13 February 1998; published 27 October 1998

Measurements are reported of the proton and deuteron spin structure functions g1p and g1d at beam energies of 29.1, 16.2, and 9.7 GeV, and g2p and g2d at a beam energy of 29.1 GeV. The integrals Γp=∫01g1p(x,Q2)dx and Γd=∫01g1d(x,Q2)dx were evaluated at fixed Q2=3 (GeV/c)2 using the full data set to yield Γp=0.132±0.003(stat)±0.009(syst) and Γd=0.047±0.003±0.006. The Q2 dependence of the ratio g1/F1 was studied and found to be small for Q2>1 (GeV/c)2. Within experimental precision the g2 data are well described by the twist-2 contribution, g2WW. Twist-3 matrix elements were extracted and compared to theoretical predictions. The asymmetry A2 was measured and found to be significantly smaller than the positivity limit sqrt[R] for both proton and deuteron targets. A2p is found to be positive and inconsistent with zero. Measurements of g1 in the resonance region show strong variations with x and Q2, consistent with resonant amplitudes extracted from unpolarized data. These data allow us to study the Q2 dependence of the integrals Γp and Γn below the scaling region.


©1998 The American Physical Society

URL: http://link.aps.org/abstract/PRD/v58/e112003
DOI: 10.1103/PhysRevD.58.112003
PACS: 13.60.Hb, 11.55.Hx, 13.88.+e, 25.30.Fj

* Present address: California Institute of Technology, Pasadena, CA 91125.
† Present address: University of Mississippi, University, MS 38677.
‡ Permanent address: Oliver Lodge Lab, University of Liverpool, Liverpool, U.K.
§ Permanent address: University of Bonn, D-53113 Bonn, Germany.
** Permanent address: FFIYM, P.O. Box 25, N-2007 Kjeller, Norway.
†† Permanent address: University of Bonn, D-53113 Bonn, Germany.
‡‡ Permanent address: Kent State University, Kent, Ohio 44242.
Permanent address: Florida International University, Miami, FL 33199.
a Permanent address: CERN, 1211 Geneva 23, Switzerland.

[ Abstract  |  Previous article  |  Next article  |  Issue 11 ]