Neutron detection and application with a novel 3D-projection scintillator tracker in the future long-baseline neutrino oscillation experiments

TL;DR

This paper introduces a novel 3D-projection scintillator tracker capable of measuring neutron energy and direction, improving neutrino energy reconstruction in long-baseline neutrino oscillation experiments.

Contribution

The paper presents a new detector design that enables event-by-event neutron kinematic measurement using time-of-flight, enhancing neutrino energy accuracy.

Findings

Successful neutron kinetic energy reconstruction demonstrated.

Improved $ar{ u}_{ ext{mu}}$ flux constraint achieved.

Enhanced neutrino energy measurement precision.

Abstract

Neutrino oscillation experiments require a precise measurement of the neutrino energy. However, the kinematic detection of the final-state neutron in the neutrino interaction is missing in current neutrino oscillation experiments. The missing neutron kinematic detection results in a feed-down of the detected neutrino energy compared to the true neutrino energy. A novel 3D\textcolor{black}{-}projection scintillator tracker, which consists of roughly ten million active cubes covered with an optical reflector, is capable of measuring the neutron kinetic energy and direction on an event-by-event basis using the time-of-flight technique thanks to the fast timing, fine granularity, and high light yield. The $\bar{\nu}_{\mu}$ interactions tend to produce neutrons in the final state. By inferring the neutron kinetic energy, the $\bar{\nu}_{\mu}$ energy can be reconstructed better, allowing a tighter incoming neutrino flux constraint. This paper shows the detector's ability to reconstruct neutron kinetic energy and the $\bar{\nu}_{\mu}$ flux constraint achieved by selecting the charged-current interactions without mesons or protons in the final state.