Abstract
A measurement of the virtual-photon asymmetry A 2(x,Q 2) and of the spin-structure function g 2(x,Q 2) of the proton are presented for the kinematic range 0.004<x<0.9 and 0.18 GeV2<Q 2<20 GeV2. The data were collected by the HERMES experiment at the HERA storage ring at DESY while studying inclusive deep-inelastic scattering of 27.6 GeV longitudinally polarized leptons off a transversely polarized hydrogen gas target. The results are consistent with previous experimental data from CERN and SLAC. For the x-range covered, the measured integral of g 2(x) converges to the null result of the Burkhardt–Cottingham sum rule. The x 2 moment of the twist-3 contribution to g 2(x) is found to be compatible with zero.
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The HERMES Collaboration., Airapetian, A., Akopov, N. et al. Measurement of the virtual-photon asymmetry A 2 and the spin-structure function g 2 of the proton. Eur. Phys. J. C 72, 1921 (2012). https://doi.org/10.1140/epjc/s10052-012-1921-5
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DOI: https://doi.org/10.1140/epjc/s10052-012-1921-5