arXiv 2004.067402020-04hep-ph

SIDIS中$J/ψ$介子的产生：高低横动量的匹配

$J/ψ$ meson production in SIDIS: matching high and low transverse momentum

Daniël Boer, Umberto D'Alesio, Francesco Murgia, Cristian Pisano, Pieter Taels

备注：: 17 pages, 1 figure; final version to appear in JHEP

摘要：

本文研究了电子和质子非极化的半包容深度非弹性电子-质子散射中产生的$J/ψ$介子的横动量谱和$\cos 2ϕ$方位角分布。在低横动量下，我们提出了与横动量相关的胶子分布和形状函数的因式分解表达式。我们表明，我们的公式，在顺序$α_s,$正确匹配的共线因式分解结果在高横动量。后者是在非相对论QCD（NRQCD）框架下以$α_s^2$阶计算的，其中包括中间的$^3S_1^{[1]}$色单重态Fock态，以及在NRQCD速度参数$v$中被因子$v^4$相对抑制的次主导色八重态。我们发现，$^1\!S_0^{[8]}$和$^3\!P_J^{[8]}$（$J = 0,1,2$）的贡献发散在小的横向动量区域，并允许我们确定的形状函数，其中携带相同的量子数的微扰的尾巴。这些原来是相同的，除了由适当的NRQCD长距离矩阵元素给出的总幅度。

英文摘要：

We consider the transverse momentum spectrum and the $\cos 2ϕ$ azimuthal distribution of $J/ψ$ mesons produced in semi-inclusive, deep-inelastic electron-proton scattering, where the electron and the proton are unpolarized. At low transverse momentum, we propose factorized expressions in terms of transverse momentum dependent gluon distributions and shape functions. We show that our formulae, at the order $α_s,$ correctly match with the collinear factorization results at high transverse momentum. The latter are computed at the order $α_s^2$ in the framework of nonrelativistic QCD (NRQCD), with the inclusion of the intermediate $^3S_1^{[1]}$ color-singlet Fock state, as well as the subleading color-octet ones that are relatively suppressed by a factor $v^4$ in the NRQCD velocity parameter $v$. We show that the $^1\!S_0^{[8]}$ and $^3\!P_J^{[8]}$ ($J = 0,1,2$) contributions diverge in the small transverse momentum region and allow us to determine the perturbative tails of the shape functions, which carry the same quantum numbers. These turn out to be identical, except for the overall magnitude given by the appropriate NRQCD long distance matrix element.

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。

摘要：

英文摘要：

相关论文