Lawrence Berkeley National Laboratory

A search for the non-resonant decays Bs0 → μ+μ−μ+μ− and B0 → μ+μ−μ+μ− is presented. The measurement is performed using the full Run 1 data set collected in proton-proton collisions by the LHCb experiment at the LHC. The data correspond to integrated luminosities of 1 and 2 fb−1 collected at centre-of-mass energies of 7 and 8 TeV, respectively. No signal is observed and upper limits on the branching fractions of the non-resonant decays at 95% confidence level are determined to be ℬBs0→μ+μ−μ+μ−<2.5×10−9,$$ \mathrm{\mathcal{B}}\left({B}_s^0\to {\mu}^{+}{\mu}^{-}{\mu}^{+}{\mu}^{-}\right)<2.5\times 1{0}^{-9}, $$ℬB0→μ+μ−μ+μ−<6.9×10−10.$$ \mathrm{\mathcal{B}}\left({B}^0\to {\mu}^{+}{\mu}^{-}{\mu}^{+}{\mu}^{-}\right)<6.9\times 1{0}^{-10}. $$