Search for Dark Matter with Xenon-based Technology

University Of Chicago, Chicago IL

Investigators

Abstract

Multiple astronomical observations have established that about 85% of the matter in the universe is not made of normal atoms, but must be otherwise undetected elementary "dark matter" particles that do not emit or absorb light. Deciphering the nature of this so-called Dark Matter is of fundamental importance to cosmology, astrophysics, and high-energy particle physics. A leading hypothesis is that it is comprised of Weakly Interacting Massive Particles, or WIMPs, that were produced moments after the Big Bang. If WIMPs are the dark matter, then their presence in our galaxy may be detectable via scattering from atomic nuclei in detectors located deep underground to help reject backgrounds due to cosmic rays. Direct detection of WIMP dark matter would solve a fundamental mystery in particle physics and cosmology, providing a unique window to learning about the primary matter constituent of the Universe and of physics beyond the Standard Model of particle physics. This award will fund an integrated research and educational program centered on the search for dark matter. Partnerships with a local minority public high school and the Adler Planetarium will genuinely engage students, educators, and the broader public in the mystery of dark matter and the status of current research, via regular classroom visits, field trips, mentoring, teacher immersion experiences, and in-the-museum programming. This will have a deep and broad impact, directly reaching teachers, planetarium staff, hundreds of URM students, and thousands of museum visitors (hundreds of thousands indirectly). The research program offers excellent opportunities for training undergraduate and graduate students, making them part of a cutting edge project in fundamental science. This award will allow the PI to contribute to XENON1T, a direct detection WIMP experiment deployed at the Gran Sasso laboratory built underneath the Apennine Mountains in Italy (LNGS), in the assembly, commissioning and early operations of the detector, scheduled for summer 2015. The PI also plans to develop refined analysis strategies which are expected to enhance the performance of the ionization/scintillation identification methods that are exploited in XENON1T to suppress the dominant ã/â background. To achieve this goal, the PI will make a series of dedicated measurements with a small-scale xenon detector designed to collect pure samples of nuclear and electron recoils. This will permit an exhaustive investigation of the ionization and scintillation processes that govern low-energy interactions in liquid xenon. These data, which are not easily extractable from XENON1T directly, will then be used to increase the sensitivity to WIMPs through improvements in the calibration and rejection of backgrounds.