Black Holes Could Reveal New Ultralight Particles

Experiments looking for physics beyond the standard model typically hunt for relatively massive particles. However, some theories predict the existence of extremely lightweight particles not occurring in the standard model, which wouldn't show up in particle collider experiments or dark matter detectors. A new calculation by Daniel Baumann of the University of Amsterdam and colleagues suggests that clouds of ultralight bosons could be detectable in the gravitational-wave signals from merging black holes. In that sense, gravitational waves could provide an entirely novel way to detect certain particles inaccessible to ordinary experiments.