Based on a data sample of $(10087 \pm 44) \times 10^6$ $J/\psi$ events taken with the BESIII detector, we search for the flavor-changing neutral current charmonium decay $J/\psi \to D^{ 0} \mu^{ +} \mu^{ -} + \text{ c.c.}$. No significant signal above the background is observed, and the upper limit on its branching fraction is set to be $\mathcal{ B}(J/\psi \to D^{ 0}\mu^{ +}\mu^{ -} + \text{ c.c.} ) < 1.1 \times 10^{ -7}$ at the 90% confidence level. This marks the first search for a flavor-changing neutral current charmonium decay involving muons in the final state.
Categories: hep-ex