Search for the Lepton-Flavor-Violating Decays B-s(0) -> e(+/-)mu(-/+) and B-0 -> e(+/-)mu(-/+)

A search for the lepton-flavor-violating decays B-s(0) -> e(+/-)mu(-/+) and B-0 -> e(+/-)mu(-/+) is performed with a data sample, corresponding to an integrated luminosity of 1.0 fb(-1) of pp collisions at root s = 7 TeV, collected by the LHCb experiment. The observed number of B-s(0) -> e(+/-)mu(-/+) and B-0 -> e(+/-)mu(-/+) candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be B(B-s(0) -> e(+/-)mu(-/+)) < 1.1(1.4) x 10(-8) and B(B-0 -> e(+/-)mu(-/+)) < 2.8(3.7) x 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(B-s(0) -> e(+/-)mu(-/+)) > 101 TeV/c(2) and M-LQ(B-0 -> e(+/-)mu -/+) > 126 TeV/c(2) at 95% C.L., and are a factor of 2 higher than the previous bounds.