Precision measurement of the proton and deuteron spin structure functions g2 and asymmetries A2

P.L. Anthony(SLAC National Accelerator Laboratory), R. G. Arnold(American University), T. Averett(William & Mary), H. R. Band(University of Wisconsin–Madison), N. Benmouna(American University), W. B. Li(Florida International University), H. Borel(Commissariat à l'Énergie Atomique et aux Énergies Alternatives), P. Bosted(American University), S. Bültmann(University of Virginia), G.R. Court(University of Liverpool), Donald G. Crabb(University of Virginia), Donal B. Day(University of Virginia), P. Decowski(Smith College), P. DePietro(American University), H. Egiyan(William & Mary), R. Erbacher(SLAC National Accelerator Laboratory), R. Erickson(SLAC National Accelerator Laboratory), R. Fatemi(University of Virginia), E. Frlež(University of Virginia), K. A. Griffioen(William & Mary), C. Harris(University of Virginia), E. W. Hughes(California Institute of Technology), C. E. Hyde-Wright(Old Dominion University), G. Igo(University of California, Los Angeles), J. R. Johnson(Stanford University), P. M. King(William & Mary), K. Kramer(William & Mary), Sebastian Kühn(Old Dominion University), David Lawrence(University of Massachusetts Amherst), Y. Liang(American University), R. Lindgren(University of Virginia), R. M. Lombard-Nelsen, P. McKee(University of Virginia), D. McNulty(University of Virginia), W. Meyer(University of Virginia), Gregory S. Mitchell(University of Wisconsin–Madison), Jason W. Mitchell(Thomas Jefferson National Accelerator Facility), M. Olson(St. Norbert College), S. Penttila(Los Alamos National Laboratory), G. A. Peterson(University of Massachusetts Amherst), R. Pitthan(Stanford University), D. Počanić(University of Virginia), R. Prepost(University of Wisconsin–Madison), C. Prescott(Stanford University), B. A. Raue(Florida International University), D. Reyna(American University), P. Ryan(William & Mary), L.S. Rochester(Stanford University), S. E. Rock(American University), G. Ron(University of Virginia), F. Sabatié(Old Dominion University), T Smith(Los Alamos National Laboratory), L. Sorrell(American University), S. St. Lorant(Stanford University), Z. M. Szalata(American University), Y. Terrien(William & Mary), Aurelio Tobı́as(University of Virginia), T. Toole(American University), S. Trentalange(University of California, Los Angeles), F. R. Wesselmann(Old Dominion University), T. Wright(University of Wisconsin–Madison), M. Zeier(University of Virginia), H. Zhu(University of Virginia), B. Zihlmann(University of Virginia)
Physics Letters B
January 1, 2003
10.1016/s0370-2693(02)03015-0
Cited by 171Open Access
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Abstract

We have measured the spin structure functions g2p and g2d and the virtual photon asymmetries A2p and A2d over the kinematic range 0.02⩽x⩽0.8 and 0.7⩽Q2⩽20GeV2 by scattering 29.1 and 32.3 GeV longitudinally polarized electrons from transversely polarized NH3 and 6LiD targets. Our measured g2 approximately follows the twist-2 Wandzura–Wilczek calculation. The twist-3 reduced matrix elements d2p and d2n are less than two standard deviations from zero. The data are inconsistent with the Burkhardt–Cottingham sum rule if there is no pathological behavior as x→0. The Efremov–Leader–Teryaev integral is consistent with zero within our measured kinematic range. The absolute value of A2 is significantly smaller than the A2<R(1+A1)/2 limit.

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