Observation of D0 Meson Decays to π+π−μ+μ− and K+K−μ+μ− Final States

Abstract

The first observation of the D0→π+π-μ+μ- and D0→K+K-μ+μ- decays is reported using a sample of proton-proton collisions collected by LHCb at a center-of-mass energy of 8 TeV, and corresponding to 2 fb-1 of integrated luminosity. The corresponding branching fractions are measured using as normalization the decay D0→K-π+[μ+μ-]ρ0/ω, where the two muons are consistent with coming from the decay of a ρ0 or ω meson. The results are B (D0→π+π-μ+μ- )=(9.64 ±0.48 ±0.51 ±0.97 )×10-7 and B (D0→K+K-μ+μ- )=(1.54 ±0.27 ±0.09 ±0.16 )×10-7 , where the uncertainties are statistical, systematic, and due to the limited knowledge of the normalization branching fraction. The dependence of the branching fraction on the dimuon mass is also investigated.