论文标题
在$ \ sqrt {s} = $ 8 tev中，使用ATLAS和CMS数据在顶级夸克腐烂中的W Boson极化测量的组合
Combination of the W boson polarization measurements in top quark decays using ATLAS and CMS data at $\sqrt{s} =$ 8 TeV
论文作者
论文摘要
提出了ATLAS和CMS协作进行的顶级夸克衰变中W玻色子极化的测量结果。这些测量基于在LHC上以8 TEV为中心产生的质子 - 普罗顿碰撞数据，对应于每个实验的综合发光度约为20 fb $^{ - 1} $。测量结果使用的事件包含一个Lepton并在最终状态下具有不同的JET多重性。结果引用为具有纵向（$ f_0 $），左撇子（$ f_ \ mathrm {l} $）或右手（$ f_ \ mathrm {r} $）极化的W玻色子的分数。极化分数的结果组合测量值为$ f_0 = $ 0.693 $ \ pm $ 0.014和$ f_ \ mathrm {l} = $ 0.315 $ \ pm $ 0.011。分数$ f_ \ mathrm {r} $是从unitarity约束中计算为$ f_ \ mathrm {r} = - $ 0.008 $ \ pm $ 0.007。这些结果与扰动量子染色体动力学的近代到领先顺序的标准模型预测一致，并且相对于最精确的单个测量，对于$ f_0 $（$ f_ \ mathrm {l} $）的精度为25（29）％（29）％（$ f_ \ mathrm {l} $）。对异常的右手向量（$ v _ {\ text {r}} $）的限制，以及左右手和右手的张量（$ g _ {\ text {l}}，g _ {\ text {r}} $）在将所有其他标准模型值设置为固定所有标准模型值的同时，将其设置为fine。对于$ v _ {\ text {r}} $，[$ - $ 0.08，0.05]的允许区域为[$ - $ 0.11，0.16]，对于$ g _ {\ g _ {\ text {l}} $，[$ - $ 0.04，0.04，0.04，0.04，0.04，0.04，0.04，0.04，0.02] for $ g _ {还得出了相应的威尔逊系数的限制。
The combination of measurements of the W boson polarization in top quark decays performed by the ATLAS and CMS Collaborations is presented. The measurements are based on proton-proton collision data produced at the LHC at a centre-of-mass energy of 8 TeV, and corresponding to an integrated luminosity of about 20 fb$^{-1}$ for each experiment. The measurements used events containing one lepton and having different jet multiplicities in the final state. The results are quoted as fractions of W bosons with longitudinal ($F_0$), left-handed ($F_\mathrm{L}$), or right-handed ($F_\mathrm{R}$) polarizations. The resulting combined measurements of the polarization fractions are $F_0 =$ 0.693 $\pm$ 0.014 and $F_\mathrm{L} =$ 0.315 $\pm$ 0.011. The fraction $F_\mathrm{R}$ is calculated from the unitarity constraint to be $F_\mathrm{R} = -$0.008 $\pm$ 0.007. These results are in agreement with the standard model predictions at next-to-next-to-leading order in perturbative quantum chromodynamics and represent an improvement in precision of 25 (29)% for $F_0$ ($F_\mathrm{L}$) with respect to the most precise single measurement. A limit on anomalous right-handed vector ($V_{\text{R}}$), and left- and right-handed tensor ($g_{\text{L}},g_{\text{R}}$) tWb couplings is set while fixing all others to their standard model values. The allowed regions are [$-$0.11, 0.16] for $V_{\text{R}}$, [$-$0.08, 0.05] for $g_{\text{L}}$, and [$-$0.04, 0.02] for $g_{\text{R}}$, at 95% confidence level. Limits on the corresponding Wilson coefficients are also derived.
