A Search for Neutral Current Single Gamma with ND280 at T2K

TL;DR

This paper presents a methodology and preliminary results for searching for single photons from neutral current neutrino interactions at T2K's ND280 detector, aiming to set the first limit below 1 GeV.

Contribution

It introduces a novel search method for single-photon production in neutrino interactions and provides initial constraints on the process at low energies.

Findings

Developed a new analysis technique for single-photon detection.

Set preliminary upper limits on neutrino-induced single-photon production.

Identified main background sources and estimation methods.

Abstract

The methodology and preliminary results for the search of single photons initiated by Neutral Current neutrino interactions with the ND280 detector at the T2K experiment are presented. This measurement aims to set the first limit on single-photon neutrino production below 1~GeV. Neutrino production of single photon is a subdominant process in neutrino interactions. Because photons and electrons have very similar signatures in neutrino detectors, careful estimations need to be made not to bias the \nue appearance oscillation results of accelerator neutrino experiments. The single photons are created by a nuclear resonance (typically $\Delta$(1232)) after interaction of the neutrino. The cross section is expected to be of the order of $10^{-42} cm^{2}$. The main background is composed of $\pi^{0}$ decaying into two photons, where only one photon is detected, and $\pi^{0}$ events creating photons from outside of the fiducial volume.