Research
Only 15% of the mass density of the known universe is comprised of ordinary, baryonic matter. Measurements from astrophysics, including of galaxy rotation curves and the velocity dispersions of galaxies in clusters, indicate that there is a large, unseen, nonbaryonic mass component surrounding most galaxies throughout the known universe. Measurements of the cosmic microwave background provide indications that this invisible mass component has important implications for cosmology, particularly in the early universe. Diverse anomalies in nuclear and particle physics, such as the apparently vanishing neutron EDM and the existence of nonzero neutrino masses, indicate that current models, though extremely successful, are still incomplete. Extensions to the standard model of particle physics often predict the existence of new particles with extremely weak couplings to normal matter and which are often produced in significant abundance, making many of these new particles excellent candidates for what is now known far and wide as “dark matter”.
Even within the realm of “normal” matter, the various anomalies in tension with the standard model may provide clues to a new understanding of baryonic matter and interactions. While the magnitudes of the mass splittings between the neutrino flavors have been measured in several oscillation experiments, the absolute scale of the neutrino masses, the ordering of the masses, and the nature of neutrinos as Dirac or Majorana particles are all important outstanding questions. Measurements of previously unobserved processes, such as the breaking of lepton number symmetry, would be an important step toward a much deeper understanding of current models, provide guidance on the extension of these models, and a path forward in the search for new physics.
Dr. Speller’s primary research interest is in the search for physics beyond the standard model. In particular, she focuses on searches for new particles and rare events from theories that seek to build a unified picture of fundamental physics, using clues from particle physics, astrophysics, and cosmology. As a Ph.D. student, she searched for annually modulating signals of WIMP dark matter interactions using cryogenic bolometric detectors deep underground with the SuperCDMS experiment. She now uses similar techniques with the CUORE experiment to search for lepton number violation through neutrinoless double-beta decay, while continuing the search for dark matter through a different candidate: the axion. With HAYSTAC, her search techniques are expanding into the use of tunable microwave cavities and low-noise systems. Ultimately, her goal is to develop a program of low-energy and quantum measurement techniques that can be applied to a broad range of experimental approaches in the quest for new physics.
Current Projects:
Searching for neutrinoless double-beta decay with the Cryogenic Underground Observatory for Rare Events (CUORE):
Searching for axion dark matter with the HAYSTAC experiment:
