Operator product expansion in QCD in off-forward kinematics: separation of kinematic and dynamical contributions
Operator product expansion in QCD in off-forward kinematics: separation of kinematic and dynamical contributions
复制标题
偏向运动学中 QCD 的算子乘积扩展：运动学和动力学贡献的分离
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
A. Manashov
中科院分区：
文献类型：
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作者：
V. Braun;A. Manashov
本文发展了一种计算硬过程中的靶质量和有限t =（p′-p）2修正的一般方法，这种硬过程可以在算符乘积展开的框架下进行研究，并涉及到从强子初态到末态的动量转移。这样的修正，通常被称为运动学的，可以被定义为所有扭转的算子的贡献，可以减少到总的领导扭转算子的导数。作为主要的结果，我们提供了一组投影算子，拿起“运动”的一部分，一个任意的味道非单扭四QCD运营商。一个完整的表达式推导出的两个电磁电流的时间顺序的产品，包括所有的运动学修正扭曲四精度。所得结果可直接应用于深虚康普顿散射、γ* → Mγ跃迁形状因子及相关过程的研究。作为这项研究的副产品，我们发现了一系列“真正的”扭曲四味非单线态夸克-反夸克-胶子运营商具有相同的反常尺寸的领导扭曲夸克-反夸克运营商。
A bstractWe develop a general approach to the calculation of target mass and finite t = (p′ − p)2 corrections in hard processes which can be studied in the framework of the operator product expansion and involve momentum transfer from the initial to the final hadron state. Such corrections, which are usually referred to as kinematic, can be defined as contributions of operators of all twists that can be reduced to total derivatives of the leading twist operators. As the principal result, we provide a set of projection operators that pick up the “kinematic” part of an arbitrary flavor-nonsinglet twist-four operator in QCD. A complete expression is derived for the time-ordered product of two electromagnetic currents that includes all kinematic corrections to twist-four accuracy. The results are immediately applicable to the studies of deeply-virtual Compton scattering, transition γ* → Mγ form factors and related processes. As a byproduct of this study, we find a series of “genuine” twist-four flavor-nonsinglet quark-antiquark-gluon operators which have the same anomalous dimensions as the leading twist quark-antiquark operators.