Studies of the Earth shielding effect to direct dark matter searches at the China Jinping Underground Laboratory

TL;DR

This paper investigates how the Earth's shielding impacts direct dark matter detection experiments at CJPL, using simulations to refine constraints on dark matter interactions with nucleons.

Contribution

It introduces the CJPL Earth Shielding Simulation code (CJPL_ESS) and applies it to analyze Earth shielding effects, providing new constraints on dark matter-nucleon cross sections.

Findings

Earth shielding significantly affects dark matter detection sensitivity.

Simulation results refine exclusion regions for dark matter-nucleon cross sections.

The methodology can be applied to other underground laboratories.

Abstract

Dark matter direct detection experiments mostly operate at deep underground laboratories. It is necessary to consider shielding effect of the Earth, especially for dark matter particles interacting with a large cross section. We analyzed and simulated the Earth shielding effect for dark matter at the China Jinping Underground Laboratory (CJPL) with a simulation package, CJPL Earth Shielding Simulation code (CJPL\_ESS), which is applicable to other underground locations. The further constraints on the $\chi$-N cross section exclusion regions are derived based on the studies with CDEX experiment data.