论文标题
在$ \ sqrt {s} = $ 13 TEV中，单夸克$ t $ channel collisions中CKM矩阵元素的测量
Measurement of CKM matrix elements in single top quark $t$-channel production in proton-proton collisions at $\sqrt{s} = $ 13 TeV
论文作者
论文摘要
第一个直接的，独立于模型的测量是通过Cabibbo-Kobayashi-Maskawa（CKM）矩阵元素$ | V_ \ MATHRM {TB} | $，$ | V_ \ MATHRM {TD} |事件。该分析使用CMS实验在2016年收集的LHC的质子 - 普罗顿碰撞数据，以13 TEV的中心能量收集，对应于35.9 fb $^{ - 1} $的综合发光度。在顶部夸克的生产和衰减顶点都考虑了对这些矩阵元素直接敏感的过程。在CKM Unitarity的标准模型假设中，在95％的置信度下测量了$ | V_ \ Mathrm {TB} | $ $> 0.970的下限。考虑了标准模型之外的几种理论，并通过在涉及参数之间释放所有约束，值$ | v_ \ mathrm {tb} | = $ 0.988 $ \ pm $ 0.024，$ | v_ \ mathrm {td} |^2 + | v_ \ mathrm {ts} |^2 = $ 0.06 $ \ pm $ 0.06，其中不确定性包括统计和系统组件，衡量。
The first direct, model-independent measurement is presented of the modulus of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements $|V_\mathrm{tb}|$, $|V_\mathrm{td}|$, and $|V_\mathrm{ts}|$, in final states enriched in single top quark $t$-channel events. The analysis uses proton-proton collision data from the LHC, collected during 2016 by the CMS experiment, at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. Processes directly sensitive to these matrix elements are considered at both the production and decay vertices of the top quark. In the standard model hypothesis of CKM unitarity, a lower limit of $|V_\mathrm{tb}|$ $>$ 0.970 is measured at the 95% confidence level. Several theories beyond the standard model are considered, and by releasing all constraints among the involved parameters, the values $|V_\mathrm{tb}| =$ 0.988 $\pm$ 0.024, and $|V_\mathrm{td}|^2 + |V_\mathrm{ts}|^2 =$ 0.06 $\pm$ 0.06, where the uncertainties include both statistical and systematic components, are measured.
