Model-Independent Prediction of $R({\eta }_c)$

Anson Berns, Henry Lamm

We present a model-independent prediction for $R({\eta }_c)\equiv \mathcal{B}\mathcal{R}(B_c\to {\eta }_c{\tau }^{+}{\nu }_{\tau })/\mathcal{B}\mathcal{R}(B_c\to {\eta }_c{\mu }^{+}{\nu }_{\mu })$. This prediction is o…