NPA Seminar: Scott Hertel, University of Massachusetts Amherst, “Superfluid 4He as a tool for sub-eV particle physics”

I will lay out the promises and challenges of a novel sensor technology, employing superfluid 4He as the active material. We are motivated by the possibility that dark matter may be hiding at low (keV-MeV) mass scales, lighter than the standard WIMP. At these lower masses, the endpoint energy of a nuclear recoil spectrum would be in the meV-eV range, and sensor threshold becomes the single dominating challenge (rather than target mass or radioactive backgrounds). If a sub-eV detector technology could be developed, then it would (even at gram-scale detector scales and even in above-ground environments) immediately probe as-yet-untested parameter space.