arXiv 2002.092882020-02-21hep-ex

用CMS中$\sqrt{s} = 13~\mathrm{TeV}$的顶夸克对产生探测QCD

Probing QCD using top quark pair production at $\sqrt{s} = 13~\mathrm{TeV}$ in CMS

Matteo M. Defranchis

备注：: To appear in the Proceedings of the European Physical Society Conference on High Energy Physics (EPS-HEP 2019), Ghent, Belgium, 10-17 July 2019

摘要：

顶夸克-反夸克对产生截面$σ_\mathrm{t\bar{t}}$的测量可以用来约束强耦合常数$α_{S}$、顶夸克质量$m_\mathrm{t}$和部分子分布函数（PDF）。在这张海报中，展示了CMS协作组发布的两项最新相关成果。这些分析是使用2016年CERN LHC CMS探测器记录的13 TeV质心能量的质子-质子碰撞数据进行的，对应于$35.9~\mathrm{fb^{-1}}$的积分亮度。在第一种方法中，$α_{S}$和$m_\mathrm{t}$独立地从包含性$σ_\mathrm{t\bar{t}}$的测量中提取，使用次到次到前导阶理论预测。在第二，测量的归一化三重微分$\mathrm{t\bar{t}}$横截面进行，然后使用的结果与HERA深非弹性散射数据一起进行$α_{S}$，$m_\mathrm{t}$，和PDF的同时测定，在下一个领先的顺序。结果，在高部分子动量分数下，胶子PDF的不确定性及其与$α_{S}$的相关性显著降低，这是$\mathrm{t\bar{t}}$生产探测的运动学范围。这一结果也是迄今为止对顶夸克极质量最精确的测定。

英文摘要：

Measurements of the top quark-antiquark pair production cross section, $σ_\mathrm{t\bar{t}}$, can be used to constrain the strong coupling constant, $α_{S}$, the top quark mass, $m_\mathrm{t}$, and the parton distribution functions (PDFs). In this poster, the two most recent relevant results published by the CMS Collaboration are presented. The analyses are performed using proton-proton collision data at a centre-of-mass energy of 13 TeV recorded by the CMS detector at the CERN LHC in 2016, corresponding to an integrated luminosity of $35.9~\mathrm{fb^{-1}}$. In the first one, $α_{S}$ and $m_\mathrm{t}$ are extracted independently from a measurement of the inclusive $σ_\mathrm{t\bar{t}}$, using next-to-next-to-leading order theoretical predictions. In the second, a measurement of the normalized triple-differential $\mathrm{t\bar{t}}$ cross section is performed; the result is then used together with HERA deep-inelastic scattering data to perform a simultaneous determination of $α_{S}$, $m_\mathrm{t}$, and the PDFs, at next-to-leading order. As a result, the uncertainty in the gluon PDF and its correlation with $α_{S}$ are significantly reduced at high parton momentum fraction, the kinematic range probed by $\mathrm{t\bar{t}}$ production. The result also yields the most precise determination of the top quark pole mass, to date.

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：

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