Single photon events from neutral current interactions at MiniBooNE

TL;DR

This paper models neutral current photon emission in MiniBooNE to assess if it explains the observed low-energy excess, finding that single-nucleon processes are insufficient.

Contribution

It introduces an improved microscopic model for neutral current photon emission and compares predictions with MiniBooNE data and other theories.

Findings

Model predicts photon event rates consistent with previous estimates.

Single-nucleon current emission cannot account for the MiniBooNE excess.

Results suggest additional sources are needed to explain the excess.

Abstract

The MiniBooNE experiment has reported results from the analysis of $\nu _e$ and $\bar \nu _e$ appearance searches, which show an excess of signal-like events at low reconstructed neutrino energies, with respect to the expected background. A significant component of this background comes from photon emission induced by (anti)neutrino neutral current interactions with nucleons and nuclei. With an improved microscopic model for these reactions, we predict the number and distributions of photon events at the MiniBooNE detector. Our results are compared to the MiniBooNE in situ estimate and to other theoretical approaches. We find that, according to our model, neutral current photon emission from single-nucleon currents is insufficient to explain the events excess observed by MiniBooNE in both neutrino and antineutrino modes.