Wandzura-Wilczek approximation from generalized rotational invariance
نویسنده
چکیده
We present the alternative way of derivation of the Wandzura-Wilczek relations between the kinematical twist-3 and twist-2 functions, parameterizing hadronic matrix element in two-photon processes γπ → γπ and γγ → ππ. The new equations, providing the independence of the physical cross-sections on the choice of the light-cone direction, are suggested and explored. The amplitude of γγ → ππ up to genuine twist-3 accuracy is found.
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تاریخ انتشار 2001