First results on low-mass WIMP from the CDEX-1 experiment at the China Jinping underground Laboratory

TL;DR

This paper presents the first experimental limits on low-mass WIMP dark matter using a germanium detector at the China Jinping underground Laboratory, achieving a low energy threshold and setting new constraints on WIMP interactions.

Contribution

First experimental limit on low-mass WIMP dark matter from the CDEX-1 experiment with a germanium detector at Jinping underground lab.

Findings

Set a limit of 1.75 x 10^{-40} cm^2 on WIMP-nucleon cross-section at 7 GeV

Achieved an energy threshold of 400 eVee

Collected 14.6 kg-day of data

Abstract

The China Dark matter Experiment collaboration reports the first experimental limit on WIMP dark matter from 14.6 kg-day of data taken with a 994 g p-type point-contact germanium detector at the China Jinping underground Laboratory where the rock overburden is more than 2400 m. The energy threshold achieved was 400 eVee. According to the 14.6 kg-day live data, we placed the limit of N= 1.75 * 10^{-40} cm^{2} at 90% confidence level on the spin-independent cross-section at WIMP mass of 7 GeV before differentiating bulk signals from the surface backgrounds.