Precision measurement of the ratio $\mathcal{B}$$\left({\rm Y}(3S)\to {\tau }^{+}{\tau }^{-}\right)/\mathcal{B}$$\left({\rm Y}(3S)\to {\mu }^{+}{\mu }^{-}\right)$

Caleb Miller

The BaBar collaboration has measured the ratio $R_{\tau \mu }^{{\rm Y}(3S)}=\mathcal{B}({\rm Y}(3S)\to {\tau }^{+}{\tau }^{-})/\mathcal{B}({\rm Y}(3S)\to {\mu }^{+}{\mu }^{-})$ with a high level of precision. This measure…