Measurement of the Z-boson mass

The first dedicated $Z$-boson mass measurement at the LHC with $Z\to {\mu }^{+}{\mu }^{-}$ decays is reported. The dataset uses proton-proton collisions at a centre-of-mass energy of $13$ TeV, recorded in 2016 by the LHCb experiment, and corresponds to an integrated luminosity of $1.7$ fb${}^{-1}$. A template fit to the ${\mu }^{+}{\mu }^{-}$ mass distribution yields the following result for the $Z$-boson mass, \begin{equation*} m_{Z} = 91185.7 \pm 8.3 \pm 3.9 \rm{MeV}, \end{equation*} where the first uncertainty is statistical and the second systematic. This result is consistent with previous measurements and predictions from global electroweak fits.