Lawrence Berkeley National Laboratory

A search for the lepton-flavour violating decay D0→e±μ∓is made with a dataset corresponding to an integrated luminosity of 3.0 fb-1of proton-proton collisions at centre-of-mass energies of 7TeV and 8TeV, collected by the LHCb experiment. Candidate D0mesons are selected using the decay D*+→D0π+and the D0→e±μ∓branching fraction is measured using the decay mode D0→K-π+as a normalization channel. No significant excess of D0→e±μ∓candidates over the expected background is seen, and a limit is set on the branching fraction, B(D0→e±μ∓)<1.3×10-8, at 90% confidence level. This is an order of magnitude lower than the previous limit and it further constrains the parameter space in some leptoquark models and in supersymmetric models with R-parity violation.