Lecturer: Dr. Axel Lindner, Spokesperson of the ALPS II collaboration at DESY in Hamburg, Germany
Abstract: ALPS II at DESY in Hamburg searches for axions — hypothetical particles that could help explain
dark matter and other mysteries of modern physics. The experiment uses the “light-shining-through-awall”
technique: laser light is sent toward a light-tight barrier, while strong magnetic fields may allow a
tiny fraction of photons to convert into axions, pass through the wall, and reappear as light on the other
side.
In its first science run, ALPS II excluded photon–axion conversion probabilities down to the 1e-13 level,
improving the sensitivity to the axion–photon coupling strength by about a factor of 20 over previous
experiments of this kind. The ongoing upgrade is expected to make ALPS II the first purely laboratorybased
experiment to probe beyond existing astrophysical limits on axions.
After the search for new particles, the ALPS II infrastructure will also be used to study the quantum
vacuum through magnetic birefringence and, ultimately, to search for high-frequency gravitational waves.
Wednesday, October 21, 10:30 – Nuclear Physics Seminar