${\rm Y}$ and $\psi$ leptonic decays as probes of solutions to the $R_D^{(\ast )}$ puzzle

Daniel Aloni, Aielet Efrati, Yuval Grossman +1

Experimental measurements of the ratios $R(D^{(\ast )})\equiv \frac{\Gamma (B\to D^{(\ast )}\tau \nu )}{\Gamma (B\to D^{(\ast )}\ell \nu )}$ ($\ell =e,\mu$) show a $3.9\sigma$ deviation from the Standard Model prediction. In…