Constraints on the $K^0_{mathrm{S}}rightarrowmu^{+}mu^{-}$ branching fraction

A search for the decay $K^0_{mathrm{S}}rightarrowmu^{+}mu^{-}$ is performed using proton-proton collision data, corresponding to an integrated luminosity of $5.6,text{fb}^{-1}$ and collected with the LHCb experiment during 2016, 2017 and 2018 at a center-of-mass energy of $13,mathrm{TeV}$. The observed signal yield is consistent with zero, yielding an upper limit of ${cal B}(K^0_{mathrm{S}}rightarrowmu^{+}mu^{-}) < 2.2 times 10^{-10}$ at 90% CL. The limit reduces to ${cal B}(K^0_{mathrm{S}}rightarrowmu^{+}mu^{-}) < 2.1 times 10^{-10}$ at 90% CL once combined with the result from data taken in 2011 and 2012.