Field: Physics and Astronomy › Nuclear and High Energy PhysicsType: No effect foundArea: dark matter searchesTarget: Ultralight B–L dark matter via a magnetically levitated particleStage: exploratory
Hypothesis
A submillimetre magnet levitated in a superconducting trap would detect the oscillating force from ultralight dark matter coupled to baryon-minus-lepton number.
What failed
With a force sensitivity of 0.2 fN/√Hz, the search found no evidence of a signal in the mass range 1.10360–1.10485 × 10⁻¹³ eV/c², giving a most stringent coupling limit of g(B−L) ≲ 2.98 × 10⁻²¹.
Broken assumption
Ultralight B–L dark matter in this mass window couples strongly enough to move a levitated magnet detectably.
Why
No signal was present at this first experiment's sensitivity and narrow mass range; the authors propose staged upgrades (POLONAISE) to widen both.
From the published paper: Amaral et al. Physical Review Letters, 2025. ↗CC BY