Potential of constraining the Fifth Force Using the Earth as a Spin and Mass Source from space

We explore the potential of conducting an experiment in a low Earth orbit spacecraft and using the Earth a spin and mass source to constrain beyond-the-standard-model (BSM) long-range spin- and velocity-dependent interactions, which are mediated by the exchange of an ultralight (m_Z′ < 10^-10eV) or massless intermediate vector boson. The high speed of low-Earth-orbit spacecraft can enhance sensitivity to velocity-dependent interactions. The periodicity enables efficient signal extraction from background noise, thereby improving the experiment’s accuracy. Combining these advantages, we demonstrate theoretically that the novel Spacecraft-Earth model can improve existing bounds on these exotic interactions by up to three orders of magnitude, using the China Space Station (CSS) as a representative low-Earth-orbit carrier. Such a model, if successfully implemented, may provide an innovative strategy for detecting ultralight dark matter and yield tighter constraints on certain coupling constants of exotic interactions.