First Search for Dark Sector e^{+}e^{-} Explanations of the MiniBooNE Anomaly at MicroBooNE.

Area of Science:

• Particle Physics
• Dark Sector Physics
• Neutrino Physics

Background:

• The MiniBooNE anomaly, a persistent excess of electron-like events, has remained unexplained for 20 years.
• Previous investigations by MicroBooNE explored electron and photon excesses without resolving the anomaly.
• Dark sector models propose dark neutrinos decaying into visible electron-positron pairs as a potential explanation.

Purpose of the Study:

• To perform the first direct search for dark sector models explaining the MiniBooNE anomaly.
• To test specific dark neutrino models that decay into electron-positron pairs.
• To set direct limits on these dark sector models.

Main Methods:

• Utilized an exposure of 6.87×10^20 protons-on-target from the Booster Neutrino Beam.
• Implemented a selection strategy targeting forward-going, coherently produced electron-positron events.
• Compared observed events with background predictions to constrain dark sector models.

Main Results:

• Observed 95 electron-positron events, compared to a background prediction of 69.7±17.3.
• Set the world's first direct limits on dark sector models.
• Excluded the entire parameter space for single dark neutrino models and the majority for dual dark neutrino models.

Conclusions:

• The MicroBooNE search provides the first direct experimental constraints on dark sector explanations for the MiniBooNE anomaly.
• The results exclude a significant portion of parameter space for dark neutrino models proposed as solutions.
• This analysis significantly impacts the viability of dark sector models in explaining the MiniBooNE anomaly.