Neutron-induced nuclear recoil background in the PandaX-4T experiment

TL;DR

This study assesses neutron-induced nuclear recoil backgrounds in the PandaX-4T dark matter experiment using simulation and data-driven methods, estimating about 1.15 background events in the signal region for 0.63 tonne-year exposure.

Contribution

It introduces three methods—Monte Carlo simulation and two data-driven approaches—to evaluate neutron background in liquid xenon dark matter detectors.

Findings

Estimated neutron background of 1.15 events in the signal region.

Methods yield consistent results across different approaches.

Background contribution quantified for the PandaX-4T experiment.

Abstract

Neutron-induced nuclear recoil background is critical to the dark matter searches in the PandaX-4T liquid xenon experiment. This paper studies the feature of neutron background in liquid xenon and evaluates their contribution in the single scattering nuclear recoil events through three methods. The first method is fully Monte Carlo simulation based. The last two are data-driven methods that also use the multiple scattering signals and high energy signals in the data, respectively. In the PandaX-4T commissioning data with an exposure of 0.63 tonne-year, all these methods give a consistent result that there are $1.15\pm0.57$ neutron-induced background in dark matter signal region within an approximated nuclear recoil energy window between 5 and 100 keV.