Dark Matter Search in Nucleon, Pion, and Electron Channels from a Proton Beam Dump with MiniBooNE

TL;DR

This study searched for sub-GeV dark matter produced by proton beam collisions at Fermilab using the MiniBooNE detector, setting new limits on dark matter models and ruling out certain neutrino excess explanations.

Contribution

First search for sub-GeV dark matter in nucleon, pion, and electron channels using MiniBooNE with proton beam dump data, establishing new constraints on dark matter models.

Findings

No dark matter signal observed, limits set on vector portal models.

Excluded new parameter space for dark matter masses between 5 and 50 MeV/c^2.

Ruling out beam-independent models for neutrino excess at 4.6 sigma.

Abstract

A search for sub-GeV dark matter produced from collisions of the Fermilab 8 GeV Booster protons with a steel beam dump was performed by the MiniBooNE-DM Collaboration using data from $1.86 \times 10^{20}$ protons on target in a dedicated run. The MiniBooNE detector, consisting of 818 tons of mineral oil and located 490 meters downstream of the beam dump, is sensitive to a variety of dark matter initiated scattering reactions. Three dark matter interactions are considered for this analysis: elastic scattering off nucleons, inelastic neutral pion production, and elastic scattering off electrons. Multiple data sets were used to constrain flux and systematic errors, and time-of-flight information was employed to increase sensitivity to higher dark matter masses. No excess from the background predictions was observed, and 90$\%$ confidence level limits were set on the vector portal and leptophobic dark matter models. New parameter space is excluded in the vector portal dark matter model with a dark matter mass between 5 and 50$\,\mathrm{MeV}\,c^{-2}$. The reduced neutrino flux allowed to test if the MiniBooNE neutrino excess scales with the production of neutrinos. No excess of neutrino oscillation events were measured ruling out models that scale solely by number of protons on target independent of beam configuration at 4.6$\sigma$.