Search for Rare Decays of D^{0} Mesons into Two Muons

Area of Science:

• Particle Physics
• High Energy Physics
• Standard Model Physics

Background:

• The Standard Model of particle physics predicts rare decays.
• The decay D^{0}→μ^{+}μ^{-} is highly suppressed.
• Searches for such decays probe new physics beyond the Standard Model.

Purpose of the Study:

• To search for the rare decay D^{0}→μ^{+}μ^{-}.
• To set stringent limits on the branching fraction of this decay.
• To constrain new physics models.

Main Methods:

• Utilized data from LHCb experiment in proton-proton collisions at 7, 8, and 13 TeV.
• Analyzed integrated luminosity of 9 fb^{-1}.
• Optimized search for D^{0} mesons from D^{*+}→D^{0}π^{+} decays.

Main Results:

• No evidence for an excess of events over the expected background was observed.
• An upper limit on the branching fraction was set at B(D^{0}→μ^{+}μ^{-})<3.1×10^{-9} at 90% C.L.
• This is the world's most stringent limit to date.

Conclusions:

• The search places strong constraints on the branching fraction of the D^{0}→μ^{+}μ^{-} decay.
• The results constrain theoretical models of physics beyond the Standard Model.
• Further searches may improve sensitivity to this rare decay.