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arXiv 2101.06261hep-phhep-ex
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异常$Zb\bar{b}$耦合:从LEP到LHC

The anomalous $Zb\bar{b}$ couplings: From LEP to LHC

Bin Yan, C. -P. Yuan

摘要:

LEP的底夸克前后不对称($A_{FB}^b$)数据与标准模型的预测长期存在差异。我们提出了一种新的方法来探测$Zb\bar{b}$的相互作用,通过$gg\to Zh$生产在大型强子对撞机,这是敏感的轴向矢量分量的$Zb\bar{b}$耦合。我们表明,在13 TeV的LHC收集的$Zh$数据已经可以解决的LEP精密电弱测量所隐含的异常$Zb\bar{b}$耦合的明显简并,与观测到的$Z$玻色子横动量分布的强烈依赖。通过测量HL-LHC上的$Zh$产生率,我们还发现了HL-LHC验证或排除LEP上观测到的异常$Zb\bar{b}$耦合的可能性,这一结论对环中顶夸克或希格斯玻色子异常耦合可能产生的新物理贡献并不敏感.

英文摘要:

The bottom quark forward-backward asymmetry ($A_{FB}^b$) data at LEP exhibits a long-standing discrepancy with the standard model prediction. We propose a novel method to probe the $Zb\bar{b}$ interactions through $gg\to Zh$ production at the LHC, which is sensitive to the axial-vector component of the $Zb\bar{b}$ couplings. We demonstrate that the $Zh$ data collected at the 13 TeV LHC can already resolve the apparent degeneracy of the anomalous $Zb\bar{b}$ couplings implied by the LEP precision electroweak measurements, with a strong dependence on the observed distribution of the $Z$ boson transverse momentum. We also show the potential of the HL-LHC to either verify or exclude the anomalous $Zb\bar{b}$ couplings observed at LEP through measuring the $Zh$ production rate at the HL-LHC, and this conclusion is not sensitive to possible new physics contribution induced by top quark or Higgs boson anomalous couplings in the loop.

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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