UC Davis

The DarkSide-50 experiment uses an argon two-phase time projection chamber to directly search for dark matter interactions. While DarkSide-50 is optimized to detect interactions of GeV∕c2 to TeV∕c2-scale dark matter particles with nuclei, it is also sensitive to dark matter interactions with electrons. This dissertation presents the results of a search for leptophilic dark matter candidates, specifically light dark matter, dark photons, and axion-like particles, using data collected by the DarkSide-50 experiment. The inclusion of S2-only events in the dataset lowered the detector energy threshold, resulting in a total exposure of 12 306 kg d. This work produced world-leading constraints on the light dark matter-electron coupling. New parameter space has also been excluded for the dark photon kinetic mixing parameter as well as the axioelectric coupling.

The DarkSide-20k experiment will continue the search for dark matter using a 49.7 t argon target. Efforts presented here were directed towards developing event simulation and data reconstruction algorithms, including the proposal of an event data model and a study of energy reconstruction for S1 and S2 signals. The sensitivity of DarkSide-20k to dark matter interactions with electron final states was also studied. DarkSide-20k is expected to improve upon the physics reach of DarkSide-50 for leptophilic dark matter interactions by up to two orders of magnitude.

To better understand and model low-energy electronic recoils for experiments like DarkSide-20k, the ARIS-ER experiment at UC Davis will use the Compton coincidence technique to measure the response of liquid argon. Simulations optimized the experimental design and established baseline requirements such as the source activity. Also contained in this dissertation is the development of the ARIS-ER data acquisition system.