Characterization of the correlated background for a sterile neutrino search using the first dataset of the JSNS $$^2$$ 2 experiment

Abstract

Abstract JSNS

$$^2$$

2

(J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) is an experiment that is searching for sterile neutrinos via the observation of

$${\bar{\nu }}_{\mu } \rightarrow {\bar{\nu }}_{e}$$

ν

¯

μ

→

ν

¯

e

appearance oscillations using muon decay-at-rest neutrinos. Before dedicated data taking in the first-half of 2021, we performed a commissioning run for 10 days in June 2020. Using the data obtained in this commissioning run, in this paper, we present an estimate of the correlated background which imitates the

$${\bar{\nu }}_{e}$$

ν

¯

e

signal in a sterile neutrino search. In addition, in order to demonstrate future prospects of the JSNS

$$^2$$

2

experiment, possible pulse shape discrimination improvements towards reducing cosmic ray induced fast neutron background are described.