Search for the decay D-0 -> pi(+)pi(-)mu(+)mu(-)

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.