Search for the decay D0→π+π-μ+μ-

A search for the D0→π+π-μ+μ- decay, where the muon pair does not originate from a resonance, is performed using proton-proton collision data corresponding to an integrated luminosity of 1.0 fb-1 recorded by the LHCb experiment at a centre-of-mass energy of 7 TeV. No signal is observed and an upper limit on the relative branching fraction with respect to the resonant decay mode D0→π+π-Φ(→μ+μ-) under the assumption of a phase-space model, is found to be B(D0→π+π-μ+μ-)/BD0→π+π-Φ(→μ+μ-)) < 0.96 at 90% confidence level. The upper limit on the absolute branching fraction is evaluated to be B(D0→π+π-μ+μ-) < 5.5 × 10-7 at 90% confidence level. This is the most stringent to date. © 2013 The Authors.