论文标题
深层虚拟康普顿的理论散射了质子
Theory of Deeply Virtual Compton Scattering off the Unpolarized Proton
论文作者
论文摘要
使用螺旋性振幅形式主义，我们通过在固定目标设置中进行了一系列的运动学设置，研究了一个非极化核子目标，即$ ep \ rightarrow e'p'γ$，深入研究了虚拟的独家电子照片生产。我们重新制定了横截面的最前沿，$ ep \ rightarrowe'p'γ$工艺的定义特征，在该特征中，可观测值表示为独立螺旋性振幅的双线性产物，这些振幅是用核子的电气，磁性和轴向电流来完全描述的。 ％这种结构在横截面的深层虚拟康普顿散射和伯特·霍特勒的部分中以不同的方式反映出来。 ％ 这些贡献与基于傅立叶谐波的形式主义进行了检查，该形式迄今为止提供了基本的数学框架，以研究深度虚拟的康普顿散射和相关实验。使用Twist-Two通用Parton发行版的理论模型计算，$ h $，$ e $，$ \ widetilde {h} $和$ \ widetilde {e} $，我们发现了Harmonic系列和我们建议的框架之间的巨大差异。最重要的是，这些数值差异出现在中级$ Q^2 $范围中，这代表了从数据中提取广义的Parton分布的最佳位置。 ％ 我们提供了一个理想的框架，以研究和比较可用于描述QCD中DVC的主要订单贡献的不同惯例，而另一方面，它促进了从实验中从实验中进行定量提取物理有意义的信息，以通过中等中间的$ Q^2 $ Q^2 $ Q^2 $ Q^2 $ Q^2 $。
Using the helicity amplitudes formalism, we study deeply virtual exclusive electron photo-production off an unpolarized nucleon target, $ep \rightarrow e' p' γ$, through a range of kinematics both in the fixed target setting with initial electron energies of 6 GeV, 11 GeV and 24 GeV, and for an electron ion collider. We reformulate the cross section bringing to the forefront the defining features of the $ep \rightarrow e'p'γ$ process, where the observables are expressed as bilinear products of the independent helicity amplitudes which completely describe it in terms of the electric, magnetic and axial currents of the nucleon. %This structure is reflected in different ways in the Deeply virtual Compton scattering and Bethe-Heitler parts of the cross section. % These contributions are checked against the Fourier harmonics-based formalism which has provided so far the underlying mathematical framework to study Deeply virtual Compton scattering and related experiments. Using theoretical model calculations of the twist-two generalized parton distributions, $ H$, $E$, $\widetilde{H}$ and $\widetilde{E}$, we uncover large discrepancies between the harmonic series and our proposed framework. Most importantly, these numerical differences appear in the intermediate $Q^2$ range which represents a sweet spot for extracting generalized parton distributions from data. % We provide a framework that is ideal, on one side, to study and compare the different conventions that can be used to describe the leading order contribution to DVCS in QCD, while on the other, it facilitates a quantitative extraction of physically meaningful information from experiment through traceable and controllable approximations in the intermediate $Q^2$ region.
