arXiv 1810.094242018-10hep-phhep-ex

LHC顶衰变弱标度下确定$|V_{cb}|$的一种方法

A Method to Determine $|V_{cb}|$ at the Weak Scale in Top Decays at the LHC

P. F. Harrison, V. E. Vladimirov

备注：: 15 pages, 1 figures. Changes for V3: removed earlier Fig. 1, associated text and citations, added one new citation
DOI：: 10.1007/JHEP01(2019)191

摘要：

到目前为止，Cabibbo Kobayashi Maskawa矩阵元，$|V_{cb}|$，一直是在$B$衰变中测量的，即~能量标度为$q_b\sim \frac{m_b}{2}$，远低于弱标度。在这里，我们考虑在大型强子对撞机（LHC）的顶部衰变中，在$q_W\sim m_W$测量它接近弱标度的可能性。我们提出的方法将使用强子顶衰变$t\rightarrow bW\rightarrow b\overline{b} c$的LHC实验数据，标记为相关顶的半轻子衰变。我们估计了这种测量的不确定性，作为当前和未来潜在的实验喷气式飞机味道标记性能的函数，并得出结论，使用2016 - 2018年期间收集的数据进行的首次测量可能会在\Vcb上产生分数误差，每次实验为7\%。我们还给出了在更高光度下的预测性能，这可能会产生对任何标准模型运行的\Vcb \低于弱标度的灵敏度，如果存在的话。

英文摘要：

Until now, the Cabibbo Kobayashi Maskawa matrix element, $|V_{cb}|$, has always been measured in $B$ decays, i.e.~at an energy scale $q_b\sim \frac{m_b}{2}$, far below the weak scale. We consider here the possibility of measuring it close to the weak scale, at $q_W\sim m_W$, in top decays at the Large Hadron Collider (LHC). Our proposed method would use data from the LHC experiments in hadronic top decays $t\rightarrow bW\rightarrow b\overline{b} c$, tagged by the semileptonic decay of the associated top. We estimate the uncertainty of such a measurement, as a function of present and potential future experimental jet flavour-tagging performances, and conclude that first measurements using the data collected during 2016 - 2018 could yield a fractional error on \Vcb\ of order 7\% per experiment. We also give projected performances at higher luminosities, which could yield sensitivity to any Standard Model running of \Vcb\ below the weak scale, if present.

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摘要：

英文摘要：

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