Projected WIMP sensitivity of the CDEX-50 dark matter experiment

TL;DR

The CDEX-50 experiment aims to detect low-mass WIMPs with a 50-kg germanium detector, projecting unprecedented sensitivity levels for dark matter detection in the 2.2--8 GeV/c² mass range.

Contribution

This paper provides a comprehensive background model and sensitivity projection for the CDEX-50 dark matter search, highlighting its potential to improve WIMP detection limits.

Findings

Projected sensitivity to WIMP-nucleon cross-section of 5.1×10⁻⁴⁵ cm² at 5 GeV/c²

Expected background level of ~0.01 counts/keVee/kg/day

Most sensitive results for WIMPs with mass 2.2--8 GeV/c²

Abstract

CDEX-50 is a next-generation project of the China Dark Matter Experiment (CDEX) that aims to search for dark matter using a 50-kg germanium detector array. This paper comprises a thorough summary of the CDEX-50 dark matter experiment, including an investigation of potential background sources and the development of a background model. Based on the baseline model, the projected sensitivity of weakly interacting massive particle (WIMP) is also presented. The expected background level within the energy region of interest, set to 2--2.5 keVee, is $\sim$0.01 counts keVee$^{-1}$ kg$^{-1}$ day$^{-1}$. At 90\% confidence level, the expected sensitivity to spin-independent WIMP-nucleon couplings is estimated to reach a cross-section of 5.1 $\times$ 10$^{-45}$ cm$^{2}$ for a WIMP mass of 5 GeV/c$^{2}$ with an exposure objective of 150 kg$\cdot$year and an analysis threshold of 160 eVee. This science goal will correspond to the most sensitive results for WIMPs with a mass of 2.2--8 GeV/c$^{2}$.