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Precision Measurement of the Proton and Deuteron Spin Structure Functions g2 and Asymmetries A2

SLAC E155 Collaboration·P. L. Anthony·R. G. Arnold·T. Averett
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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 < Q^2 < 20 GeV^2 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 sqrt[R(1+A1)/2] limit.

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SLAC E155 Collaboration, P. L. Anthony, R. G. Arnold, T. Averett. 2002-04-22. Precision Measurement of the Proton and Deuteron Spin Structure Functions g2 and Asymmetries A2. https://doi.org/10.1016/s0370-2693(02)03015-0

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