New era in dark matter phenomenology, the dawn of the nuclear clocks

ongoing

What is the nature of dark matter (DM)? This central question in physics could be soon addressed thanks to the unprecedented sensitivity of nuclear clocks. These Th-229-base clocks are set to overcome the inherent limitations of atomic and molecular clocks, which are less sensitive to the nuclear parameters, which dominate almost all motivated models of ultralight DM (ULDM) . Laser excitation of Th-229 has just reached 1:10^11 sensitivity. Given that a precision of 1:10^8 suffices to probe DM-models with world record reach (even before nuclear clocks are actually constructed), it implies that the era of nuclear clock supremacy has begun! We propose three thrusts that harness this revolutionary advancement to search for ULDM. The first is driven by our joint theory-experiment demonstration that the line shape analysis of the Th-229 isomeric state excitation may potentially lead to 1:10^21 effective sensitivity to ULDM, due to the direct-enhanced dependence on the strong interaction parameters. The second is theoretical and experimental exploration of the enhancement factor of O(10^5), that is currently uncertain, and cannot be robustly established. The third focus on studying the formal implications of the era of nuclear-clock supremacy. We provide projection for the reach of nuclear clocks for axion and scalar ULDM. We also demonstrate that a nuclear clock can be used as a QCDometer sensing spatially-dependent couplings, due to artificial source, or from super-Planckian-based physics via couplings to moduli-remnants. We further introduce a new class of non-axion ULDM models, that address the strong CP problem, where the Cabibbo–Kobayashi–Maskawa elements vary in time, in addition to the nuclear parameters. It could be tested, thus, at accelerators as well as clocks, which leads to a novel synergy between different frontiers of physics. The proposal transforms future technologies into a concrete search for DM and beyond, ushering us into the era of nuclear clocks.