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arXiv 2211.09435hep-ex
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利用 ATLAS 探测器在质心能量为 $\sqrt{s} = 13$ TeV 的 $pp$ 碰撞 $W^{\pm}Z$ 产生中观测规范玻色子联合极化态

Observation of gauge boson joint-polarisation states in $W^{\pm}Z$ production from $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

ATLAS Collaboration

AI总结:

本文利用 ATLAS 探测器在 $\sqrt{s}=13$ TeV 的 $pp$ 碰撞数据,首次以 $7.1$ 标准差显著观测到 $W^{\pm}Z$ 产生中纵向极化矢量玻色子的成对产生,并测量了联合与单独螺旋度分数及微分截面,结果与标准模型预测一致。

摘要:

本文报告了 $W^{\pm}Z$ 产生中 $W$ 和 $Z$ 规范玻色子联合极化态的测量结果。所用数据集对应于欧洲核子研究中心大型强子对撞机 ATLAS 探测器记录的质心能量为 $13$ TeV 的质子-质子碰撞的 $139$ fb$^{-1}$ 积分亮度。利用规范玻色子衰变为电子和缪子的轻子衰变模式重建 $W^{\pm}Z$ 候选事件。首次测量了纵向极化矢量玻色子的同时成对产生,显著性为 $7.1$ 标准差。在 fiducial 区域内积分测得的的联合螺旋度分数为 $f_{\mathrm{00}} = 0.067 \pm 0.010$、$f_{\mathrm{0T}} = 0.110 \pm 0.029$、$f_{\mathrm{T0}} = 0.179 \pm 0.023$ 和 $f_{\mathrm{TT}} = 0.644 \pm 0.032$,与次领头阶标准模型预测一致。还测量了 $W$ 和 $Z$ 玻色子的单独螺旋度分数,发现在预期相关量范围内与联合螺旋度分数一致。联合和单独螺旋度分数也在 $W^+Z$ 和 $W^-Z$ 事件中分别进行了测量。此外,还报告了几个对极化敏感的运动学观测量的包容性和微分截面。

英文摘要:

Measurements of joint-polarisation states of $W$ and $Z$ gauge bosons in $W^{\pm}Z$ production are presented. The data set used corresponds to an integrated luminosity of $139$ fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of $13$ TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. The $W^{\pm}Z$ candidate events are reconstructed using leptonic decay modes of the gauge bosons into electrons and muons. The simultaneous pair-production of longitudinally polarised vector bosons is measured for the first time with a significance of $7.1$ standard deviations. The measured joint helicity fractions integrated over the fiducial region are $f_{\mathrm{00}} = 0.067 \pm 0.010$, $f_{\mathrm{0T}} = 0.110 \pm 0.029$, $f_{\mathrm{T0}} = 0.179 \pm 0.023$ and $f_{\mathrm{TT}} = 0.644 \pm 0.032$, in agreement with the next-to-leading-order Standard Model predictions. Individual helicity fractions of the $W$ and $Z$ bosons are also measured and found to be consistent with joint helicity fractions within the expected amount of correlations. Both the joint and individual helicity fractions are also measured separately in $W^+Z$ and $W^-Z$ events. Inclusive and differential cross sections for several kinematic observables sensitive to polarisation are presented.

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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