arXiv 2004.023232020-04-05hep-ph

在NNLO改进介质诱导胶子辐射的不透明度膨胀

Improved opacity expansion at NNLO for medium induced gluon radiation

João Barata, Yacine Mehtar-Tani

备注：: 27 pages, 5 figures, submitted to JHEP
DOI：: 10.1007/JHEP10(2020)176

摘要：

当高能部分子在热而致密的QCD介质中传播时，它通过弹性散射或介质诱导的胶子辐射而损失能量。由于LPM效应，胶子辐射谱在高频下被抑制，并包含两个解析已知的区域：在高频下$ω>ω_c = \hat q L^2$，其中$\hat q $是喷流猝灭输运系数，$L$是介质的长度，谱由单个硬散射主导，而区域$ω<ω_c$由多个低动量转移主导。在本文中，我们扩展了最近的方法（被称为改进的不透明度扩展（IOE）），它允许分析（和系统）的治疗超出了多个软散射近似，匹配这个结果与单一的硬发射光谱。我们计算特别是NNLO校正分析和数值，并表明，它是强烈抑制相比，非线性光学表示IOE计划的快速收敛，因此，我们得出结论，这是足够的截断系列在非线性光学。我们还提出了一个比较GW和HTL势的处方，并将它们的参数与未来的唯象工作联系起来。

英文摘要：

When an energetic parton propagates in a hot and dense QCD medium it loses energy by elastic scatterings or by medium-induced gluon radiation. The gluon radiation spectrum is suppressed at high frequency due to the LPM effect and encompasses two regimes that are known analytically: at high frequencies $ω>ω_c = \hat q L^2$, where $\hat q $ is the jet quenching transport coefficient and $L$ the length of the medium, the spectrum is dominated by a single hard scattering, whereas the regime $ω<ω_c$ is dominated by multiple low momentum transfers. In this paper, we extend a recent approach (dubbed the Improved Opacity Expansion (IOE)), which allows an analytic (and systematic) treatment beyond the multiple soft scattering approximation, matching this result with the single hard emission spectrum. We calculate in particular the NNLO correction analytically and numerically and show that it is strongly suppressed compared to the NLO indicating a fast convergence of the IOE scheme and thus, we conclude that it is sufficient to truncate the series at NLO. We also propose a prescription to compare the GW and the HTL potentials and relate their parameters for future phenomenological works.

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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