04/11/2025
By Amanda Vozzo
Date: Wednesday, April 16, 2025
Time: 4 – 5 p.m.
Location: Olsen Hall, Room 503
Kyle Leach, Associate Professor, Departments of Physics, Nuclear Engineering, and Quantum Engineering, Colorado School of Mines with give a talk on “Hunting for Ghosts using Rare-Isotope Doped Superconducting and Optomechanical Sensors”
Abstract: Nuclear beta and electron capture (EC) decay serve as sensitive probes of the structure and symmetries at the microscopic scale of our Universe. As such, precision measurements of the final-state products in these processes can be used as powerful laboratories to search for new physics from the meV to TeV scale, as well as addressing fundamental questions of quantum mechanics at the subatomic scale. Significant advances in “rare isotope” availability and quality, coupled with decades of sensing technique development from the AMO community have led us into a new era of fundamental tests of nature using unstable nuclei. For the past few years, we have taken the approach of embedding radioisotopes in thin-film superconducting tunnel junctions (STJs) to precisely measure the recoiling atom that gets an eV-scale “kick” from the neutrino following EC decay. These recoils are encoded with the fundamental quantum information of the neutrino and decay process, as well as carrying unique signatures of weakly coupled beyond standard model (BSM) physics; including neutrino mass, exotic weak currents, and potential “dark” particles created within the energy-window of the decay. These measurements provide a complimentary and (crucially) model-independent portal to the dark sector with sensitivities that push towards synergy between laboratory and cosmological probes. In this talk, I will discuss the broad program we have developed to provide leading limits in these areas as well as the technological advances across several sub-disciplines of science required to enable this work, including subatomic physics, quantum engineering, atomic theory, and materials science. Finally, I will discuss future prospects of extending this work using macroscopic amounts of harvested exotic atoms from the Facility for Rare Isotope Beams (FRIB) in optically levitated nanospheres for direct momentum measurements of the
decay recoils.
Bio: Kyle Leach is an experimental subatomic physicist and Associate Professor in Physics, Nuclear Engineering, and Quantum Engineering at the Colorado School of Mines. Kyle received his PhD from the University of Guelph (Canada) and performed postdoctoral work in radioactive ion trapping at TRIUMF (Canada). His group works at the precision frontier between nuclear and particle physics using rare isotope doped advanced sensors. He is the spokesperson of the international BeEST collaboration and leads several other major experiments in the US and Canada to provide world-leading searches for physics beyond the standard model. Kyle has won several awards including the APS Francis M Pipkin Award, the DOE Early Career Award, and is a Moore Foundation Experimental Physics Investigator. Kyle currently serves as the Science Director of the new Colorado Underground Research Institute (CURIE) in Idaho Springs, CO and holds an affiliate Professor position at the Facility for Rare Isotope Beams at Michigan State University.