Statistical analysis of the azimuthal asymmetry in the $J/psi$ leptoproduction in unpolarized $ep$ collisions
Statistical analysis of the azimuthal asymmetry in the $J/psi$ leptoproduction in unpolarized $ep$ collisions
复制标题
非极化 $ep$ 碰撞中 $J/psi$ 轻子产生的方位不对称性的统计分析
DOI：
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发表时间：
2019
影响因子：
5.4
通讯作者：
Yu-Peng Yan
中科院分区：
文献类型：
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作者：
Hong-Fei Zhang;Wen-Long Sang;Yu-Peng Yan
本文研究了非极化ep碰撞中J/π超产生的方位不对称性。有两个独立的方位不对称调制，即cos（θ）和cos（2 θ），其中θ是轻子散射平面相对于强子相互作用平面的方位角。我们计算了这两个调制作为四个运动学变量的函数，发现它们提供了一个很好的实验室来区分描述重夸克偶素产生的几个模型，包括色单态（CS）模型，非相对论QCD（NRQCD）。此外，这个过程可以用来测试1 S [8] 0长距离矩阵元的大小，这是非常大的从各种唯象提取。为了得出明确的结论，我们将我们的计算限制在一个特定的运动学区域，其中CS和CO机制可以通过仔细检查cos（2 π）调制的值来区分，而1 S [8] 0优势图像可以通过测量cos（2 π）调制的值来测试。计算它们的值并进行细致的统计分析，我们发现在积分光度L = 1000 pb −1时，这两个量的统计不确定性足够小，可以区分这三个模型。当这个实验在未来的ep对撞机（如EIC）上实施时，可能会发现J/O2产生机制的关键信息。
In this paper, we study the azimuthal asymmetry in the J/ψ leptoproduction in unpolarized ep collisions. There are two independent azimuthal asymmetry modulations, namely cos(ψ) and cos(2ψ), where ψ is the azimuthal angle of the lepton scattering plane with respect to the hadron-interacting plane. We calculate the two modulations as functions of four kinematic variables, and find that they provide a very good laboratory to distinguish several models describing the heavy quarkonium production, including the color-singlet (CS) model, the nonrelativistic QCD (NRQCD). In addition, this process can be used to test the magnitude of the 1S[8] 0 long-distance matrix element, which is extraordinarily large from various phenomenological extraction. In order to make definite conclusions, we restrict our calculation in a specific kinematic region, where the CS and CO mechanisms can be distinguished by scrutinizing the values of the cos(ψ) modulation, while the 1S[8] 0 dominance picture can be tested by measuring the values of the cos(2ψ) modulation. Calculating their values and carrying out a meticulous statistical analysis, we find that at an integrated luminosity L = 1000pb−1, the statistical uncertainties of the two quantities are small enough to tell the three models apart. When this experiment is implemented at the future ep colliders such as the EIC, crucial information for the J/ψ production mechanism might be discovered..