Angular analysis of the B${}^0$ $\to$ K${}^{\ast }$(892)${}^0{\mu }^{+}{\mu }^{-}$ decay in proton-proton collisions at $\sqrt{s}$ = 13 TeV

A full set of optimized observables is measured in an angular analysis of the decay B${}^0$ $\to$ K${}^{\ast }$(892)${}^0{\mu }^{+}{\mu }^{-}$ using a sample of proton-proton collisions at $\sqrt{s}$ = 13 TeV, collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 140 fb${}^{-1}$. The analysis is performed in six bins of the squared invariant mass of the dimuon system, $q^2$, over the range 1.1 $<$ $q^2$ $<$ 16 GeV${}^2$. The results are among the most precise experimental measurements of the angular observables for this decay and are compared to a variety of predictions based on the standard model. Some of these predictions exhibit tension with the measurements.