AI 中文总结
研究重夸克对从核子的专属电产生，基于胶子GTMDs框架，短程部分按微扰量子色动力学主导阶和共线展开一阶处理，扩展文献结果，引入胶子 - 胶子关联矩阵分解，明确非极化核子束下相关贡献。
AI 中文摘要
我们在胶子的广义横向动量依赖部分子分布（GTMDs）框架下研究重夸克 - 反夸克对从核子的专属电产生。过程的短程部分在微扰量子色动力学的主导阶和共线展开的一阶进行处理，这使得能与广义部分子分布（GPDs）描述相联系。对于基于GTMDs和GPDs的结构函数结果，我们仅考虑非极化（自旋平均）核子，但包含所有可能出现的方位调制。给出的结果扩展了文献中的已知表达式，对未来电子 - 离子对撞机上该专属过程的实验研究有意义。此外，我们引入了基于GTMDs的胶子 - 胶子关联矩阵的便利分解，在从部分子动量$k_T$和动量转移$\Delta_T$得到的对称无迹张量的洛伦兹基中展开。所采用的GTMDs记号与振幅水平的核子螺旋度态相关，而非与入射核子或胶子的极化态相关，这使得用非极化核子束能更清楚地获取螺旋度差和螺旋度翻转矩阵元的贡献。
英文摘要
We study exclusive electroproduction of heavy quark-antiquark pairs off nucleons in the framework of generalized transverse momentum dependent parton distributions (GTMDs) for gluons. The short-distance part of the process is treated at leading order in perturbative Quantum Chromodynamics and in first order in a collinear expansion, which allows identification with the description in terms of Generalized Parton Distributions (GPDs). For the results for the structure functions in terms of GTMDs and GPDs we consider only unpolarized (spin-averaged) nucleons, but include all possible azimuthal modulations that can arise. The presented results extend known expressions in the literature and are relevant for experimental studies of this exclusive process at the future Electron Ion Collider. Furthermore, we introduce a convenient decomposition of the gluon-gluon correlation matrix in terms of GTMDs, expanded in a Lorentz basis of symmetric traceless tensors obtained from the partonic momentum $k_T$ and the momentum transfer $Δ_T$. The adopted notation for the GTMDs relates to the nucleon helicity states at the amplitude level, rather than to polarization states of the incoming nucleon or of the gluons, which makes it more transparent which contributions from helicity difference and helicity flip matrix elements can be accessed with unpolarized nucleon beams.
Comments23 pages,3 figures
