Search for flavor-changing neutral current and lepton-flavor violating decays of D0->l+l-

TL;DR

This study searches for rare D0 meson decays involving flavor-changing neutral currents and lepton-flavor violation, setting new upper limits on their branching fractions using data from the BaBar detector.

Contribution

It provides the first comprehensive search for these specific rare decays and establishes upper limits on their branching fractions at the 90% confidence level.

Findings

No evidence of the decays was observed.

Upper limits on branching fractions are set at 1.2×10⁻⁶, 1.3×10⁻⁶, and 8.1×10⁻⁷.

Results constrain new physics models predicting such decays.

Abstract

We report on a search for the flavor-changing neutral current decays $\Dz\to e^+e^-$ and $\Dz\to\mu^+\mu^-$, and the lepton-flavor violating decay $\Dz\to e^\pm\mu^\mp$. 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 $\Dz\to\mu^+\mu^-$, and $8.1\times 10^{-7}$ for $\Dz\to e^\pm\mu^\mp$.