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arXiv 2307.08014hep-phhep-ex
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在未来轻子对撞机 Z 极点探测 $Zb\ar{b}$ 耦合

Probing the $Zb\bar{b}$ coupling at the $Z$-pole of future lepton colliders

Bin Yan, C. -P. Yuan, Shu-Run Yuan

AI总结:

针对 LEP 遗留的 $Zb\ar{b}$ 耦合双解简并问题,本文提出在未来轻子对撞机 Z 极点利用带硬光子或轻喷注辐射过程的 $A_{\ m FB}^b$ 分布,并结合 CEPC 测量实现唯一测定。

摘要:

实验上测定 $Zb\ar{b}$ 耦合长期以来一直是一项挑战,因为 LEP 在偏离 Z 极点测量中的精度有限,导致仍有两个简并解有待分辨。本文提出一种探测 $Zb\ar{b}$ 耦合的新方法:在未来轻子对撞机的 Z 极点,通过测量 $e^+ e^- \ o b \ar{b} γ$ 和/或 $e^+ e^- \ o b \ar{b} g$ 过程的 $b\ar{b}$ 系统中底夸克的前后不对称性 $A^{b}_\ ext{FB}$ 来实现。额外的硬光子或轻喷注辐射可以模拟 $e^+e^-\ o b\ar{b}$ 过程的能量扫描,而来自 γ-Z 干涉过程的 $A_{\ m FB}^b$ 分布对 $Zb\ar{b}$ 耦合具有线性敏感性。通过结合 CEPC 在 Z 极点对 $R^0_b$ 和 $A^{0,b}_\ ext{FB}$ 的预期测量,$A^{b}_\ ext{FB}$ 分布能够打破 LEP 观测到的简并,从而仅通过 Z 极点运行即可唯一测定 $Zb\ar{b}$ 耦合。

英文摘要:

The determination of the $Zb\bar{b}$ coupling in experiments has been a long-standing challenge, as the limited precision of off $Z$-pole measurements at the LEP has resulted in two degenerate solutions remained to be resolved. In this paper, we propose a novel method to probe the $Zb\bar{b}$ coupling by measuring the forward-backward asymmetry of the bottom quark, $A^{b}_\text{FB}$, in the $b\bar{b}$ system of the $e^+ e^- \to b \bar{b} γ$ and/or $e^+ e^- \to b \bar{b} g$ processes at the $Z$-pole of future lepton colliders. The additional hard photon or light jet radiation can mimic the energy scanning of the $e^+e^-\to b\bar{b}$ process, and the $A_{\rm FB}^b$ distribution from the $γ$-$Z$ interference process is linearly sensitive to the $Zb\bar{b}$ coupling. By combining the expected measurements of $R^0_b$ and $A^{0,b}_\text{FB}$ at the $Z$-pole at the CEPC, the $A^{b}_\text{FB}$ distributions can break the degeneracy observed at the LEP, leading to a unique determination of the $Zb\bar{b}$ coupling through $Z$-pole running alone.

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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