High Energy Physics Seminar
We live immersed in a bath of particles beyond the standard model. I will describe several efforts to detect interactions between these ghostly particles and standard nuclear targets, efforts that may in time reveal the more fundamental 'standard' model we know is waiting. Liquefied noble element targets are increasingly the standard-bearers of this direct detection effort; their advantages over other materials include high radio-purity, high background rejection, and relatively simple scaling to larger targets. I will give an overview of two xenon-based efforts, the ongoing LUX experiment and its successor LZ, emphasizing our recently-improved world-leading sensitivity and my personal efforts to better calibrate such detectors by mixing radioactive isotopes into the liquid xenon itself. Light-mass dark matter models are very difficult to probe using liquid xenon technology, motivating detector development in the lightest noble: helium. Its superfluid phase supports unique low-energy excitations, and mK-scale temperatures allow excitation detection through ultra-sensitive Transition Edge Sensor calorimetry. I will discuss a recent demonstration of this technology, along with a general outlook for the field as a whole.