Severe Constraints on New Physics Explanations of the MiniBooNE Excess

TL;DR

This paper analyzes the MiniBooNE excess and demonstrates that various new physics explanations, including decays and scattering of hypothetical particles, are strongly constrained or ruled out by the data.

Contribution

The study extends existing analyses by exhaustively constraining a wide range of new physics scenarios explaining the MiniBooNE excess using full data-set kinematic distributions.

Findings

New physics scenarios involving particle decay are disfavored.

Elastic scattering explanations are strongly constrained.

MiniBooNE data limits a broad class of beyond Standard Model explanations.

Abstract

The MiniBooNE experiment has recently reported an anomalous 4.5$\sigma$ excess of electron-like events consistent with $\nu_e$ appearance from a $\nu_\mu$ beam at short-baseline. Given the lack of corresponding $\nu_\mu$ disappearance observations, required in the case of oscillations involving a sterile flavor, there is strong motivation for alternative explanations of this anomaly. We consider the possibility that the observed electron-like signal may actually be due to hypothetical new particles,which do not involve new sources of neutrino production or oscillations. We find that the electron-like event energy and angular distributions in the full MiniBooNE data-set, including neutrino mode, antineutrino mode, and beam dump mode, severely limit, and in some cases rule out, new physics scenarios as an explanation for the observed neutrino and antineutrino mode excesses. Specifically, scenarios in which the new particle decays (visibly or semi-visibly) or scatters elastically in the detector are strongly disfavored. Using generic kinematic arguments, this paper extends the existing MiniBooNE results and interpretations to exhaustively constrain previously unconsidered new physics signatures and emphasizes the power of the MiniBooNE beam dump search to further constrain models for the excess.