Observation of $D_s^{+}\to {\eta }^{\prime }{\mu }^{+}{\nu }_{\mu }$, Precision Test of Lepton Flavor Universality with $D_s^{+}\to {\eta }^{(\prime )}{\ell }^{+}{\nu }_{\ell }$, and First Measurements of $D_s^{+}\to {\eta }^{(\prime )}{\mu }^{+}{\nu }_{\mu }$ Decay Dynamics

BESIII Collaboration, M. Ablikim, M. N. Achasov +596

By analyzing 7.33 fb${}^{-1}$ of $e^{+}{e}^{-}$ annihilation data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we report the observation of th…