Search for the lepton-flavor-violating decays Bs0→e ^±μ and B0→e^±μ

A search for the lepton-flavor-violating decays Bs0→e ^±μ and B0→e ^±μ is performed with a data sample, corresponding to an integrated luminosity of 1.0 fb ^-1 of pp collisions at √s=7 TeV, collected by the LHCb experiment. The observed number of Bs0→e ^±μ and B0→e ^±μ candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be B(Bs0→e ^±μ)<1.1(1.4)×10 ^-8 and B(B0→e ^±μ)<2.8(3.7)×10 ^-9 at 90% (95%) confidence level (C.L.). These limits are a factor of 20 lower than those set by previous experiments. Lower bounds on the Pati-Salam leptoquark masses are also calculated, M _LQ(Bs0→e ^±μ)>101 TeV/c2 and M _LQ(B0→e ^±μ)>126 TeV/c2 at 95% C.L., and are a factor of 2 higher than the previous bounds.