Search for the Rare Decay D0 → μ+ μ- in Proton-Proton Collisions at √s=13.6 TeV

Abstract

A search for the rare decay D-0 -> mu(+) mu(-) is reported using proton-proton collision events at root s = 13.6 TeV collected by the CMS detector in 2022-2023, corresponding to an integrated luminosity of 64.5 fb(-1). This is the first analysis to use a newly developed inclusive dimuon trigger, expanding the scope of the CMS flavor physics program. The search uses D-0 mesons obtained from D*(+) -> D-0 pi(+) decays. No significant excess is observed. A limit on the branching fraction of B(D-0 -> mu(+)mu(-)) < 2.4 x 10(-9) at 95% confidence level is set. This is the most stringent upper limit set on any flavor changing neutral current decay in the charm sector.