1. Determination of the neutron spin structure function
- Author
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H. Fonvieille, E. W. Hughes, Y. Terrien, Sayed Rokni, Thomas E. Smith, P. E. Bosted, J. Xu, H. Borel, F. S. Dietrich, R. A. Gearhart, J. Fellbaum, P.L. Anthony, S. E. Rock, H. Middleton, M. Spengos, F. Staley, Nathan R. Newbury, R. G. Arnold, Vincent Breton, H. R. Band, Gordon D. Cates, R. Prepost, S. E. Kuhn, R. Erbacher, Gilbert Shapiro, J. A. Dunne, James L. White, M. Woods, Z. E. Meziani, G. G. Petratos, W. Meyer, Timothy Chupp, R. Holmes, G. H. Zapalac, J. Marroncle, J.R. Johnson, Z. M. Szalata, Paul Souder, C. E. Keppel, C. C. Young, R. Pitthan, R. M. Lombard-Nelsen, L. M. Stuart, D. Kawall, J. Morgenstern, T. Maruyama, Alan K. Thompson, Y. Roblin, Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), E142, and Hughes V.W. Cavata C.
- Subjects
Physics ,Nuclear reaction ,Particle physics ,Proton ,010308 nuclear & particles physics ,Hadron ,General Physics and Astronomy ,Elementary particle ,Inelastic scattering ,01 natural sciences ,7. Clean energy ,0103 physical sciences ,Proton spin crisis ,[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex] ,Sum rule in quantum mechanics ,010306 general physics ,Nucleon - Abstract
The authors report the results of the experiment E142 which measured the spin dependent structure function of the neutron, g{sub 1}{sup n}(x, Q{sup 2}). The experiment was carried out at the Stanford Linear Accelerator Center by measuring an asymmetry in the deep inelastic scattering of polarized electrons from a polarized {sup 3}He target, at electron energies from 19 to 26 GeV. The structure function was determined over the kinematic range 0.03 < BJorken x < 0.6 and 1.0 < Q{sup 2} < 5.5 (GeV/c){sup 2}. An evaluation of the integral {integral}{sub 0}{sup 1} g{sub 1}{sup n}(x,Q{sup 2})dx at fixed Q{sup 2} = 2 (GeV/c){sup 2} yields the final result {Lambda}{sub 1}{sup n} = -0.032 {+-} 0.006 (stat.) {+-} 0.009 (syst.). This result, when combined with the integral of the proton spin structure function measured in other experiments, confirms the fundamental Bjorken sum rule with O({alpha}{sub s}{sup 3}) corrections to within one standard deviation. This is a major success for perturbative Quantum Chromodynamics. Some ancillary results include the findings that the Ellis-Jaffe sum rule for the neutron is violated at the 2 {sigma} level, and that the total contribution of the quarks to the helicity of the nucleon is 0.36 {+-}more » 0.10. The strange sea polarization is estimated to be small and negative, {Delta}s = -0.07 {+-} 0.04.« less
- Published
- 1993
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