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Evolution equation for the structure function g_2(x,Q^2)

V. M. Braun·G. P. Korchemsky·A. N. Manashov
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Abstract

We perform an extensive study of the scale dependence of flavor-singlet contributions to the structure function g_2(x,Q^2) in polarized deep-inelastic scattering. We find that the mixing between quark-antiquark-gluon and three-gluon twist-3 operators only involves the three-gluon operator with the lowest anomalous dimension and is weak in other cases. This means, effectively, that only those three-gluon operators with the lowest anomalous dimension for each moment are important, and allows to formulate a simple two-component parton-like description of g_2(x,Q^2) in analogy with the conventional description of twist-2 parton distributions. The similar simplification was observed earlier for the nonsinglet distributions, although the reason is in our case different.

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V. M. Braun, G. P. Korchemsky, A. N. Manashov. 2001-02-26. Evolution equation for the structure function g_2(x,Q^2). https://doi.org/10.1016/s0550-3213(01)00165-1

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