2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/206043We report on a search for the flavor-changing neutral current decays $\Dz\to e^+e^-$ and $\Dz\toμ^+μ^-$, and the lepton-flavor violating decay $\Dz\to e^\pmμ^\mp$. The measurement is based on $122 {fb}^{-1}$ of data collected by the \babar detector at the PEP-II asymmetric $e^+e^-$ collider. No evidence is found for any of the decays. The upper limits on the branching fractions, at the 90 % confidence level, are $1.2\times 10^{-6}$ for $\Dz\to e^+e^-$, $1.3\times 10^{-6}$ for $\Dz\toμ^+μ^-$, and $8.1\times 10^{-7}$ for $\Dz\to e^\pmμ^\mp$.Minor changes of the text and reference for the publicationHigh Energy Physics - Experimenttext