Twist-4 photon helicity-flip amplitude in DVCS on a nucleon in the Wandzura-Wilczek approximation
نویسندگان
چکیده
We computed twist-4 part of the photon spin-flip amplitude in deeply virtual Compton scattering on a nucleon in the Wandzura-Wilczek approximation. We found a factorizable contribution, which arises from photon scattering on quarks with non-zero angular momentum along the collision axis. As the genuine twist-2 amplitude arises at the NLO, for moderate virtualities of the hard photon, Q2 ≤ 10 GeV2, kinematical twist-4 correction can give numerically important contribution to the photon helicityflip amplitude. on leave of absence from St.Petersburg Nuclear Physics Institute, 188350, Gatchina, Russia
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