Flavour changing neutral currents are suppressed in the Standard Model, making them a prime avenue to search for new physics. Over the past decade a consistent set of discrepancies between experimental measurements and theoretical expectations in $b\to{}s\mu^+\mu^-$ decays has emerged. The flagship $b\to{}s\mu^+\mu^-$ mode is the decay $B^{0}\to K^{\ast 0}\mu^{+}\mu^{-}$, where discrepancies have been observed in angular observables, such as $P_{5}^{\prime}$ and in the differential branching fraction.

 

In this seminar, a new comprehensive analysis of the $B^{0}\to K^{\ast 0}\mu^{+}\mu^{-}$ decay will be presented, made with $8.4\,\rm{fb}^{-1}$ of LHCb $pp$ collision data collected in 2011-2012 and 2016-2018. Results will be shown for the angular observables of the decay, which for the first time will include considerations for the effect of the muon mass. Furthermore, the differential branching fraction in $q^{2}$ will be presented, as well as the complete set of $CP$-asymmetry observables. Finally, this measurement accounts fully for the contributions of S-wave decays and their interference, from which the complete set of observables will be shown.