Probing Spin-Independent WIMP-Nucleon Interactions with the PandaX-I Detector.

Abstract

A dark matter relic density remaining from the Big Bang is believed to be permeating our Universe in the form of dark matter particles. It is likely that these relics could be detected in Earth-based experiments, prompting a prolonged search effort by experimental groups looking for the mysterious particle. Recent dark matter searches have received much attention due to several possible positive direct detection results, with reports putting the dark matter mass near 10 GeV/c^2. This has motivated other direct detection experiments to focus their efforts in the low mass region which has resulted in several competing null results.

The PandaX-I detector, located at China JinPing Laboratory in Sichuan Province, China, is a dual-phase liquid xenon time projection chamber with three-dimensional position reconstruction capabilities. The high light yield design allows for a low energy threshold and sizable xenon mass, targeting the low mass WIMP-nucleon cross-section region of parameter space. The detector was designed, constructed, and operated by the international Particle and Astrophysical Xenon (PandaX) collaboration with the goal of probing the alluring low WIMP mass cross-section parameter space.

This dissertation outlines the operation of the deep underground, low background PandaX-I detector utilized for a rare event dark matter search. I discuss dark matter interactions rates in terrestrial detectors and the properties of liquid xenon as a suitable dark matter target. A detailed discussion of the dark matter WIMP search with liquid xenon based detectors is given, including the design, background simulation, construction and operation of the MiX (Michigan Xenon) development detector and the large scale PandaX-I (Particle and Astrophysical Xenon) detector. Finally, I discuss the outcome resulting from a dark matter search analysis of the first 17.4 live-days in the PandaX-I 37 kg fiducial volume. With this effort, the PandaX collaboration provided a deep probe of the low WIMP mass parameter space, excluding the aforementioned low mass dark matter signal reports.