Search for flavor-changing-neutral-current D meson decays

Abstract

We study the flavor-changing-neutral-current process c→uμ⁺μ ^- using 1.3 fb^-1 of pp‾ collisions at √s=1.96 TeV recorded by the D0 detector operating at the Fermilab Tevatron Collider. We see clear indications of the charged-current mediated D_s⁺ and D⁺→Φπ ⁺→μ⁺μ^-π ⁺ final states with significance greater than 4 standard deviations above background for the D⁺ state. We search for the continuum neutral-current decay of D⁺→π⁺μ⁺μ^- in the dimuon invariant mass spectrum away from the Φ resonance. We see no evidence of signal above background and set a limit of B(D⁺→π⁺μ⁺μ^-)< 3.9×10^-6 at the 90% C.L. This limit places the most stringent constraint on new phenomena in the c→uμ⁺μ^- transition.