Study of the X±(5568) state with semileptonic decays of the B_s⁰ meson

Here, we present a study of the X^±(5568) using semileptonic decays of the B_s⁰ meson using the full run II integrated luminosity of 10.4 fb^-1 in proton-antiproton collisions at a center of mass energy of 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. We report evidence for a narrow structure, X^±(5568), in the decay sequence X^±(5568) → B_s⁰π^± where B_s⁰ → μ^∓D_s ^±X, D_s^± → Φπ^± which is consistent with the previous measurement by the D0 Collaboration in the hadronic decay mode, X^±(5568) → B_s⁰π^± where B_s⁰ → J/ψΦ. The mass and width of this state are measured using a combined fit of the hadronic and semileptonic data, yielding m = 5566.9_-3.1^+3.2(stat)_-1.2^+0.6(syst) MeV/c², Γ = 18.6_-6.1^+7.9(stat)_-3.8^+3.5(syst) MeV/c² with a significance of 6.7σ.