Dissertation Defense: Ako Jamil, Yale University, “Rare Event Searches in Liquid Xenon with EXO-200 and nEXO”

Noble liquid time projection chambers are ubiquitously used to search for rare events such
as neutrinoless double beta decay or dark matter interactions. A detailed understanding of
light and charge transport in liquid xenon is of the utmost importance when modeling the
performance of these experiments.
In this talk I will present the design and physics reach of the proposed nEXO experiment,
searching for the neutrinoless double beta decay of Xe-136 at the 1028 year half-life sensitivity using 5 tonnes of liquid xenon. The energy resolution is one of the critical parameters
for achieving the projected sensitivity, requiring highly efficient light and charge detection
systems. I will show results for modeling the electron transport in the presence of electronegative contaminants in liquid xenon and comprehensive results for the characterization and
simulation of the light response of the Silicon Photomultipliers used in nEXO.
Additionally, I will describe a search for novel interactions of dark matter via charged current absorption on xenon using data from the EXO-200 experiment, providing leading limits for MeV-scale dark matter interacting primarily via this process. The talk will conclude by exploring the possibility of scaling the liquid xenon technology toward the kilotonne scale, covering the majority of the remaining parameter space for neutrinoless double beta decay and providing an observatory for various beyond the standard model physics searches.
Thesis Advisor: David Moore (david.c.moore@yale.edu)