Applying superfluid ⁴He to the search for low-mass dark matter

Scott Hertel (University of Massachusetts, USA) talks about “Applying superfluid ⁴He to the search for low-mass dark matter” at 4pm UK time.

We report on recent R&D work towards “HeRALD”, a search for low-mass dark matter using a superfluid ⁴He target. Dark matter scatters within the 4He target may produce atomic recoils, detectable via roton quantum evaporation at the liquid surface. Recent work has demonstrated a recoil energy threshold of ~200eV, which we expect to reduce dramatically to the eV or sub-eV scale in the coming year. Although the long term goal of the project is to test dark matter models, our near-term efforts are focused on better understanding and optimizing the signal pathway: roton production, propagation, reflection, and evaporation.