# First observation of the decay D0→K−π+μ+μ− in the ρ0-ω region of the dimuon mass spectrum

Abstract : A study of the decay D0→K−π+μ+μ− is performed using data collected by the LHCb detector in proton-proton collisions at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 2.0 fb−1. Decay candidates with muon pairs that have an invariant mass in the range 675--875 MeV/c2 are considered. This region is dominated by the ρ0 and ω resonances. The branching fraction in this range is measured to be B(D0→K−π+μ+μ− ) = (4.17±0.12(stat)±0.40(syst))×10−6. This is the first observation of the decay D0→K−π+μ+μ−. Its branching fraction is consistent with the value expected in the Standard Model.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-01222150
Contributor : Claudine Bombar <>
Submitted on : Thursday, October 29, 2015 - 12:05:56 PM
Last modification on : Wednesday, September 16, 2020 - 4:29:39 PM

### Citation

R. Aaij, L. Beaucourt, M. Chefdeville, D. Decamp, N. Déléage, et al.. First observation of the decay D0→K−π+μ+μ− in the ρ0-ω region of the dimuon mass spectrum. Physics Letters B, Elsevier, 2016, 757, pp.558-567. ⟨10.1016/j.physletb.2016.04.029⟩. ⟨in2p3-01222150⟩

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