Testing weak equivalence with the LEMING experiment – Damian Goeldi (ETHZ)
48/2-224 - Madrone
SLAC
The LEMING experiment aims to test weak equivalence in leptonic antimatter. We will employ atomic interferometry to measure the vertical deviation of a horizontal cold muonium (M = μ+ + e−) beam.
Existing muonium production schemes are unsuitable for such a precise measurement due to their large velocity and angular spread. To overcome this limitation we have demonstrated a new technique leveraging the chemical potential of superfluid helium (SFHe) to produce a cold muonium beam with a very well defined velocity and angular spectrum.
Due to the SFHe our particle detectors need to operate at temperatures below 1K. We have successfully achieved sub-kelvin operation of commercial silicon photomultipliers (SiPMs).
Furthermore, a strong background suppression is required in order to reach the intended sensitivity. This can be achieved via a reliable detection of the atomic electron from the muonium, left over after the decay of the antimuon. However, these electrons possess very low energies. Hence, a second detector is required which not only operates below 1K, but also features an energy detection threshold below 1keV. We are currently testing several candidate detectors including perovskite nanocrystals and superconducting nanowires.
This talk will give an overview of the LEMING experiment with a focus on the cold muonium beam as well as the cryogenic particle detectors.
Join from PC, Mac, Linux, iOS or Android: https://stanford.zoom.us/j/98973156241?pwd=cEU5RFdlVXoyc0JTeTlDMkozKzQ5UT09
David Goldfinger, Yifan Chen
(dgoldfin@stanford.edu, cyifan@slac)