Wandzura-Wilczek approximation for the twist-3 DVCS amplitude

被引：66
作者：
Kivel, N [1 ]
Polyakov, MV
Schäfer, A
Teryaev, OV
机构：
[1] Univ Regensburg, Inst Theoret Phys, D-93040 Regensburg, Germany
[2] Petersburg Nucl Phys Inst, Gatchina 188350, Russia
[3] Ruhr Univ Bochum, Inst Theoret Phys 2, D-44780 Bochum, Germany
[4] Joint Inst Nucl Res, Bogoliubov Lab Theoret Phys, Dubna 141980, Russia
来源：
PHYSICS LETTERS B | 2001年 / 497卷 / 1-2期
关键词：
D O I：
10.1016/S0370-2693(00)01313-7
中图分类号：
P1 [天文学];
学科分类号：
0704 ;
摘要：
We present a derivation of Wandzura-Wilczek (WW) like relations for skewed parton distributions. It is demonstrated for photon-pion scattering that the skewed twist-3 parton distributions contributing to the DVCS amplitude have discontinuities at the points x = +/-xi in the WW approximation. This may lead to a violation of factorisation for the twist-3 DVCS amplitude with transverse polarization of the virtual photon. We show, however, that the contribution of the divergencies to the scattering of a transversely polarized virtual photon affects DVCS observables only at order 1/Q(2) and can be neglected at twist-3 accuracy. For the scattering of a longitudinally polarized photon the twist-3 amplitude is free of such divergencies. (C) 2001 Published by Elsevier Science B.V.
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页码：73 / 79
页数：7
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