The latest and improved measurements in $B^0_{ (s)}\rightarrow\mu^+ \mu^-$ processes have been performed by LHCb using full Run 1 and Run 2 data. The measurement of the branching fraction of $B^0_{ s}\rightarrow\mu^+ \mu^-$ is presented as the most precise single experiment measurement of such a rare process. While no significant excess is found for $B^0\rightarrow\mu^+ \mu^-$, an stringent upper limit is set for its braching fraction. Both results are in agreement with SM predictions and with previous results.
Categories: hep-ex