Observation of $D\to {\bar{K}}_1(1270){\mu }^{+}{\nu }_{\mu }$ and test of lepton flavor universality with $D\to {\bar{K}}_1(1270){\ell }^{+}{\nu }_{\ell }$

BESIII Collaboration, M. Ablikim, M. N. Achasov +651

By analyzing 7.93 $\mathrm{f}{\mathrm{b}}^{-1}$ of $e^{+}{e}^{-}$ collision data collected at the center-of-mass energy of 3.773 GeV with the BESIII detector operated at the BEPCII collider, we report t…