全局拟合 $b \to cτν$ 异常 2022 年中秋
Global fit to $b \to cτν$ anomalies 2022 mid-autumn
AI总结：
基于LHCb新数据，更新b→cτν异常全局拟合，发现与标准模型4.1σ偏差，并评估轻子夸克等新物理场景及未来区分潜力。
摘要：
最近，LHCb 合作组基于 LHC Run 1 数据，公布了在 $B\to D^{(\ast)}$ 半轻子衰变中轻子普适性（LFU）检验的初步结果：$R_{D}^{\rm LHCb2022} = 0.441 \pm 0.089$ 和 $R_{D^{\ast}}^{\rm LHCb2022} = 0.281 \pm 0.030$。这是 LHCb 实验首次给出 $R_{D}$ 的测量结果，其精度与其他 $B$ 工厂数据相当。有趣的是，这些数据再次倾向于支持 LFU 的破坏。来自 BaBar、Belle 和 LHCb 合作组数据的新世界平均值分别为 $R_{D} = 0.358 \pm 0.027$ 和 $R_{D^{\ast}} = 0.285 \pm 0.013$。我们纳入这些新数据，更新了 $b \to c τ\overlineν$ 测量的现状及其对新物理的影响。结合标准模型（SM）中 $B \to D^{(\ast)}$ 形状因子的最新进展，我们观察到与 SM 预测存在 $4.1\sigma$ 的偏差。我们的更新还包括：相关可观测量模型无关的新物理（NP）公式；以及轻子夸克场景和单一 NP 算子场景的参数全局拟合。此外，我们展示了利用 Belle II 上 $B\to D^{(\ast)}τ\overlineν$ 极化可观测量的精确测量以及 LHC 上高 $p_{\rm T}$ 味尾搜索，间接区分不同新物理场景的未来潜力。我们还讨论了 LFU 破坏对 $Υ\to l^+ l^-$ 的影响。
英文摘要：
Recently, the LHCb collaboration announced a preliminary result of the test of lepton flavor universality (LFU) in $B\to D^{(\ast)}$ semi-leptonic decays: $R_{D}^{\rm LHCb2022} = 0.441 \pm 0.089$ and $R_{D^{\ast}}^{\rm LHCb2022} = 0.281 \pm 0.030$ based on the LHC Run 1 data. This is the first result of $R_{D}$ for the LHCb experiment, and its precision is comparable to the other $B$-factory data. Interestingly, those data prefer the violation of the LFU again. A new world average of the data from the BaBar, Belle, and LHCb collaborations is $R_{D} = 0.358 \pm 0.027$ and $R_{D^{\ast}} = 0.285 \pm 0.013$. Including this new data, we update a circumstance of the $b \to c τ\overlineν$ measurements and their implications for new physics. Incorporating recent developments for the $B \to D^{(\ast)}$ form factors in the Standard Model (SM), we observe a $4.1 σ$ deviation from the SM predictions. Our updates also include; model-independent new physics (NP) formulae for the related observables; and the global fittings of parameters for leptoquark scenarios as well as single NP operator scenarios. Furthermore, we show future potential to indirectly distinguish different new physics scenarios with the use of the precise measurements of the polarization observables in $B\to D^{(\ast)}τ\overlineν$ at the Belle II and the high-$p_{\rm T}$ flavored-tail searches at the LHC. We also discuss an impact on the LFU violation in $Υ\to l^+ l^-$.
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。
