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arXiv 2407.04793hep-ph
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小横动量下 $J/ψ$ 轻子产生的因子化

Factorization for $J/ψ$ leptoproduction at small transverse momentum

Miguel G. Echevarria, Samuel F. Romera, Pieter Taels

AI总结:

本文结合 NRQCD 与 SCET 研究小横动量 $J/ψ$ 轻子产生,推导以 TMDShF 表示的截面因子化定理,并完成次领头阶计算、演化及与 LDME 的匹配。

摘要:

非相对论量子色动力学(NRQCD)在低横动量区域失效,在该区域中,所产生夸克偶素态的横动量对与入射强子的多重散射以及软胶子辐射十分敏感。在这一运动学区域,需要横动量依赖(TMD)因子化框架,将 NRQCD 的长程矩阵元(LDME)提升为所谓的 TMD 形状函数(TMDShF),后者同时编码软胶子辐射和重夸克束缚态的形成。在本工作中,我们将一种有效场论方法(结合 NRQCD 与 SCET)应用于遍举 $J/ψ$ 轻子产生中的光子–胶子融合过程。我们以 TMDShF 表示截面,推导了因子化定理,在次领头阶计算了这些量,建立了它们的演化,并研究了它们在高横动量区域与相应 LDME 的匹配。我们的结果与电子–离子对撞机(Electron-Ion Collider)尤其相关,在该装置上 $J/ψ$ 轻子产生可用于探测胶子横动量依赖部分子分布函数(gluon TMDPDF)。

英文摘要:

Nonrelativistic Quantum Chromodynamics (NRQCD) breaks down in the region of low transverse momentum, where the transverse momentum of the produced quarkonium state is sensitive to multiple scattering with the incoming hadron and to soft gluon radiation. In this kinematic regime, the transverse-momentum-dependent (TMD) factorization framework is required, promoting the long-distance matrix elements (LDMEs) of NRQCD to the so-called TMD shape functions (TMDShFs), which encode both the soft gluon radiation and the formation of the heavy-quark bound state. In this work, we apply an effective-field theory approach (combining NRQCD and SCET) to the photon-gluon fusion process in inclusive $J/ψ$ leptoproduction. We derive a factorization theorem for the cross section in terms of TMDShFs, compute these quantities at next-to-leading order, establish their evolution, and study their matching onto the corresponding LDMEs in the high-transverse-momentum region. Our results are particularly relevant to the Electron-Ion Collider, where $J/ψ$ leptoproduction can be used to probe gluon transverse-momentum-dependent parton distribution functions (gluon TMDPDFs).

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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