Colloquium
From Liquid Xenon to Superfluid Helium: Dark Matter Direct Detection with Noble Liquids

日期:2019-10-17 阅读:852

摘要

Noble liquids have proven high effective in the search for interactions of dark matter with ordinary matter. This is due to their intrinsic scalability, low backgrounds, straightforward purification, and copious signal carriers. The LUX (Large Underground Xenon) experiment was a dual-phase (liquid/gas) xenon time projection chamber with an active mass of 250 kg that operated at the Sanford Underground Research Facility (SURF) from 2013 until 2016. Its main objective was to look for evidence of galactic dark matter in the form of Weakly Interacting Massive Particles (WIMPs). I will report the most recent LUX results from several new data analyses such as searches for axions, axion-like particles, low-mass dark matter interactions, and rate modulation in the data. I will also present recent calibration studies of the ionization and scintillation response of liquid xenon, such as pulse shape discrimination, electronic recoil calibrations using 83mKr, 127Xe, and 14C, and nuclear recoil calibration using a pulsed D–D neutron generator. These calibrations are essential to the development of the next generation of dark matter detectors, such as the LUX-ZEPLIN (LZ) experiment which is currently being assembled at the Sanford Underground Research Facility. I will present the design, current status, and projected scientific performance of LZ, which is expected to begin underground operations in 2020.

Finally, I will describe a method to search for low-mass dark matter particles using superfluid helium., dubbed HeRALD. Because the helium nucleus is relatively low in mass, it has good kinematic matching to low-mass dark matter particles. Also, because helium is liquid down to absolute zero, this enables an easily purified target material in which extremely small energy depositions may be detected using low-temperature calorimetric devices such as transition edge sensors. This method is intrinsically scalable to large target masses, and background rejection may be achieved using information carried from the interaction site by photons, phonons, and rotons.

报告人简介

Daniel N. McKinsey joined the Physics Department faculty in July 2015. He received a B.S. in Physics with highest honors at the University of Michigan in 1995. His Ph.D. was awarded by Harvard University in 2002, with a thesis on the magnetic trapping, storage, and detection of ultracold neutrons in superfluid helium. His postdoctoral research was performed at Princeton University, and in 2003 he joined the Yale University physics department, where he was promoted to Full Professor in 2014. He was awarded a Packard Fellowship in Science and Engineering Fellowship and an Alfred P. Sloan Research Fellowship, and served on the 2013-2014 Particle Physics Project Prioritization Panel (P5).


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