PM: Enhancing BSM Searches with Cold Atom Sources

While the Standard Model of particle physics has been remarkably successful, there are many lines of evidence, both from particle colliders and from astrophysical measurements, that suggest that there is new fundamental physics Beyond the Standard Model (BSM) that remains almost completely unknown. This research program will focus on using precision methods of atomic physics to search for new BSM particles and forces in a laboratory environment.

One research project will search for heavier versions of the lightest known particles of matter (neutrinos), which may help to explain the origin of the light neutrino masses that are currently unexplained in the Standard Model. If they are found, the so-called "heavy sterile neutrinos" may explain the existence of "dark matter" in the universe. A second research project will use a laser to directly probe the matter waves of trapped atoms, using them as ultra-precise detectors to search for new forces predicted in various models of dark matter and dark energy.

This technique could find use in compact, precision atomic-based acceleration sensors with applications including GPS-free navigation, geodesy, and geologic studies. Unlike particle physics experiments, these projects are both tabletop in scale. They will provide skills training in a variety of quantum mechanical, optical, and electrical techniques for a small team of graduate students and a postdoctoral researcher.

The heavy neutrino project will be part of the HUNTER (Heavy Unseen Neutrino Total Energy-Momentum Reconstruction) collaboration which aims to surpass present laboratory limits on the sterile neutrino mixing angle in the 30–280 keV/c2 mass range. HUNTER will increase the precision of the RIMS (recoil-ion momentum spectroscopy) techniques that have been previously used to examine atomic and molecular reactions, showing how the improvement of atomic techniques can lead to tests of the most fundamental laws of nature.

Specifically the research team will develop a system to optically polarize the Cs-131 nuclear spins enabling a search for a BSM asymmetry in electron capture decay, and work to commission the HUNTER apparatus. The atomic sensor project, BOSSY (Bloch OScillation Sensing with Ytterbium), previously demonstrated sensitivity to atomic motion over tens of nanometers and in microsecond time scales.

This research project will focus on the addition of an evaporative cooling stage of ytterbium atoms to increase the matter wave coherence length and time. Using a quantum detection method (cavity QED) to detect a quantum effect (Bloch oscillations) will provide a rich playground for quantum sensing. For example, the cavity QED platform also enables investigations into improved sensitivity using squeezing techniques and may be used for trapped atom interferometry.

Finally, measurement of unique magic and tune-out wavelengths on a narrow intercombination transition can provide inputs for atomic structure calculations of ytterbium.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.