First Search for Neutral Current Coherent Single-Photon Production in MicroBooNE

TL;DR

This paper reports the first search for neutrino-induced neutral current coherent single-photon production using MicroBooNE data, setting the world's first upper limit on the process's cross section at 0.8 GeV neutrino energy.

Contribution

It introduces a novel search method for NC coherent 1γ production in liquid argon detectors and provides the first experimental upper limit for this process.

Findings

Set the first upper limit on the cross section of NC coherent 1γ production.

Developed a targeted selection method for single-photon events.

Constrained the dominant background from NCπ0 production.

Abstract

This article presents the first search for neutrino-induced neutral current coherent single-photon production (NC coherent 1$\gamma$). The search makes use of data from the MicroBooNE 85-tonne active volume liquid argon time projection chamber detector, situated in the Fermilab Booster Neutrino Beam (BNB), with an average neutrino energy of $\langle E_{\nu}\rangle \sim 0.8$ GeV. A targeted selection of candidate neutrino interactions with a single photon-like electromagnetic shower in the final state and no visible vertex activity was developed to search for the NC coherent 1$\gamma$ process, along with two auxiliary selections used to constrain the dominant background from NC$\pi^0$ production. With an integrated exposure of $6.87 \times 10^{20}$ protons on target delivered by the BNB, we set the world's first limit for this rare process, corresponding to an upper limit on the flux-averaged cross section of $\sigma<1.49 \times 10^{-41}\text{cm}^2$ at 90\% C.L.