$R(η_c)$的模型无关预测
Model-Independent Prediction of $R(η_c)$
摘要：
我们提出了一个独立于模型的预测$R(η_c) \! \equiv \! \mathcal{BR} (B_c \rightarrow η_c \, τ^+ν_τ)/ \mathcal{BR} (B_c \rightarrow η_c \, μ^+ν_μ)$。这种预测是通过色散关系、零反冲重夸克关系和格点量子色动力学有限的现有确定的组合，从形状因子得到的。由此产生的预测，$R(η_c)=0.29(5)$，同意以前的模型预测的加权平均值，但减少了不确定性。
英文摘要：
We present a model-independent prediction for $R(η_c) \! \equiv \! \mathcal{BR} (B_c \rightarrow η_c \, τ^+ν_τ)/ \mathcal{BR} (B_c \rightarrow η_c \, μ^+ν_μ)$. This prediction is obtained from the form factors through a combination of dispersive relations, heavy-quark relations at zero-recoil, and the limited existing determinations from lattice QCD. The resulting prediction, $R(η_c)=0.29(5)$, agrees with the weighted average of previous model predictions, but with reduced uncertainties.
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。
