Low-mass dark matter search results from full exposure of PandaX-I experiment

TL;DR

This paper reports the results of a low-mass WIMP dark matter search using the PandaX-I experiment, setting new bounds and disfavoring previous positive signals, demonstrating the effectiveness of liquid xenon detectors for low-mass WIMP detection.

Contribution

First full-exposure results from PandaX-I with optimized low-mass WIMP detection, providing stringent bounds and challenging earlier positive signals in the field.

Findings

No significant excess events were observed.

The experiment set competitive bounds on WIMPs below 10 GeV/c².

Results disfavor previously reported positive signals for low-mass WIMPs.

Abstract

We report the results of a weakly-interacting massive particle (WIMP) dark matter search using the full 80.1\;live-day exposure of the first stage of the PandaX experiment (PandaX-I) located in the China Jin-Ping Underground Laboratory. The PandaX-I detector has been optimized for detecting low-mass WIMPs, achieving a photon detection efficiency of 9.6\%. With a fiducial liquid xenon target mass of 54.0\,kg, no significant excess event were found above the expected background. A profile likelihood analysis confirms our earlier finding that the PandaX-I data disfavor all positive low-mass WIMP signals reported in the literature under standard assumptions. A stringent bound on the low mass WIMP is set at WIMP mass below 10\,GeV/c$^2$, demonstrating that liquid xenon detectors can be competitive for low-mass WIMP searches.