2026/02/18 by Jason Arakawa, Jack F. Doyle, Elina Fuchs +10 · 1 voice · 2 citations
Physics and Astronomy · #hep-ph #nucl-ex #physics.atom-ph
Ultralight dark matter is expected to induce oscillations of nuclear parameters. These oscillations are characterized by extremely weak couplings or high suppression scales, with the Planck scale - the characteristic scale of quantum gravity - serving as a natural benchmark. Probing this phenomenon requires systems with exceptional sensitivity to shifts in nuclear energies. The uniquely low-energy nuclear isomeric transition in 229Th provides such sensitivity: it directly probes the nuclear interaction and, owing to a near cancellation between electromagnetic and nuclear contributions, its response to changes in nuclear structure is greatly amplified. We devise and perform a new type of ultrasensitive search for dark matter which uses the precision nuclear spectroscopy at JILA to set the strongest bounds in the mass range 10-21 \rm eV \lesssim m\rm DM \lesssim 10-19 \rm eV. Our results probe effective interaction scales exceeding 106 times the Planck scale (the Mega-Planck scale) and establish the 229Th system as the leading probe of dark matter couplings to the nuclear sector.