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Physics Colloquium: “Taming the BeEST: Rare-Isotopes, Quantum Sensors, & Our Quest for the New Standard Model”
September 14, 2021 @ 3:00 pm - 4:00 pm
Colorado School of Mines, Department of Physics
Abstract: The search for sterile neutrinos is among the brightest possibilities in our quest for understanding the microscopic nature of dark matter in our universe. Experiments that hunt for these particles using large-volume direct-detection methods, however, have an inherent disadvantage in these searches since sterile neutrinos are predicted to have much weaker couplings to the Standard Model (SM) than the active neutrinos. As a result, the existence of these elusive particles are best probed indirectly via momentum conservation with SM particles during their creation in weak-interaction processes. One way to observe these momentum recoil effects experimentally is through high-precision measurements of nuclear electron-capture (EC) decay, where the final state only contains the neutrino and a recoiling atom. This approach is a powerful method in our search for beyond Standard Model (BSM) physics since it relies only on the existence of a heavy neutrino admixture to the active neutrinos and not on the model-dependent details of their interactions. In this talk, I will describe our Beryllium Electron capture in Superconducting Tunnel junctions (BeEST) experiment that uses the decay-momentum reconstruction technique to precisely measure the 7Li recoil spectrum following 7Be decay in sensitive superconducting tunnel junctions (STJ). I will also present our ongoing work for dramatically increasing the sensitivity of the BeEST, which includes scaling the experiment to thousand-pixel arrays and generating an atom-by-atom map of the rare-isotopes in our sensors using state-of-the-art material characterization methods combined with theoretical quantum simulations.
Bio: After completing his PhD at the University of Guelph (Canada) in 2013, Dr. Leach accepted a Post-Doctoral Research Fellowship at the TRIUMF facility in Vancouver (Canada) performing novel in-trap decay spectroscopy studies on highly charged radioactive ions. Dr. Leach joined Mines in 2015 and is currently an Associate Professor in the Department of Physics, and Faculty in both the Nuclear Engineering and Quantum Engineering Programs. Dr. Leach’s research focuses on using novel, high-precision experimental techniques to search for dark matter and other physics beyond the Standard Model that are created during nuclear decay. In addition to his involvement in major international research collaborations, Dr. Leach is the Spokesperson of the BeEST experiment to search for sterile neutrinos using superconducting quantum sensors. Related to this research direction, Dr. Leach was recently awarded the 2020 U.S. Department of Energy Early Career Research Award and named a 2019 FRIB Visiting Scholar.
Unless otherwise specified, all lectures will take place in CoorsTek 140/150, located at 1523 Illinois Street, Golden, CO