Limits on dark matter, ultralight scalars, and cosmic neutrinos with gyroscope spin and precision clocks

Abstract Dark matter (DM) within the solar system induces deviations in the geodetic drift of a gyroscope spin due to its gravitational interaction. Considering a constant DM density as a minimal scenario, we constrain DM overdensity within the Gravity Probe B (GP-B) orbit around the Earth and for Earth's and Neptune's orbits around the Sun. The presence of electrons in gravitating sources and test objects introduces an electrophilic scalar-mediated Yukawa potential, which can be probed from the measurement of geodetic drift as well as using terrestrial and space-based precision clocks. We derive projected DM overdensity ( η ) limits from Sagnac time measurements using onboard satellite clocks, highlighting their dependence on the source mass and orbital radius. The strongest sensitivity, η ∼ 4.45 × 10 3 , is achieved at Neptune's orbit (∼ 30 AU), exceeding existing constraints. Correspondingly, the cosmic neutrino overdensity is ξ ∼ 5.34 × 10 10 , surpassing results from KATRIN and cosmic ray studies. The strongest sensitivity on the electrophilic scalar coupling, g ∼ 7.09 × 10 -24 , is achieved for a scalar mass m φ ≲ 1.32 × 10 -18 eV. This result, obtained from the projected precision clock studies probing non-gravitational potentials, is competitive with the leading bounds from fifth-force searches. These precision measurements offer a robust framework for testing gravity at solar system scales and probing DM in scenarios inaccessible to direct detection experiments.