The first JSNS$^2$ measurement of electron neutrino flux using $^{12}C(\nu_{e},e^{-}) ^{12}N_{g.s.}$ reaction

TL;DR

This paper reports the first measurement of electron neutrino flux at JSNS$^2$ using a specific nuclear reaction, confirming simulation predictions and improving understanding of neutrino production for sterile neutrino searches.

Contribution

The study provides the first experimental electron neutrino flux measurement at JSNS$^2$, validating hadron model predictions and aiding future sterile neutrino research.

Findings

Measured electron neutrino flux: (6.7 ± 1.6 (stat.) ± 1.7 (syst.)) × 10^{-9} cm^{-2} proton^{-1}

Flux measurement consistent with simulation predictions

Enhanced understanding of neutrino flux for sterile neutrino experiments

Abstract

JSNS$^2$ (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) is an experiment searching for sterile neutrinos through the observation of $\bar{\nu}_{\mu} \rightarrow \bar{\nu}_e$ appearance oscillations, using neutrinos produced by muon decay-at-rest. A key aspect of the experiment involves accurately understanding the neutrino flux and the quantities of pions and muons, which are progenitors of (anti-)neutrinos, given that their production rates have yet to be measured. We present the first electron-neutrino flux measurement using $^{12}\mathrm{C}(\nu_{e},e^{-}) ^{12}\mathrm{N}_{g.s.}$ reaction in JSNS$^2$, yielding a flux of (6.7 $\pm$ 1.6 (stat.) $\pm$ 1.7 (syst.)) $\times$ 10$^{-9}$ cm$^{-2}$ proton$^{-1}$ at the JSNS$^2$ detector location, located at 24 meters distance from the mercury target. This flux measurement is consistent with predictions from simulations based on hadron models.