Search for the rare decays Bs and B0 to dimuons at the LHC with the ATLAS, CMS and LHCb experiments

A combination of the results of the search for the decay $\mathrm{B^0_{(s)}}\rightarrow \mu^+\mu^-$ is performed using about 2.4 fb$^{-1}$, 5 fb$^{-1}$ and 1 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 7~TeV, collected at the Large Hadron Collider at CERN by the ATLAS, CMS and LHCb experiments, respectively. The observed candidates in the three experiments are consistent with the expectation from the sum of background and Standard Model signal processes within $1 \sigma$. The combination results in upper limits on the branching fractions, ${\cal B}(\mathrm{B^0_s}\rightarrow \mu^+\mu^-)<4.2\times 10^{-9}$ and ${\cal B}(\mathrm{B^0}\rightarrow \mu^+\mu^-)<8.1 \times 10^{-10}$ both at 95\% confidence level.