Constraints on Spin-Spin Velocity-Dependent Interactions

The existence of exotic spin-dependent forces may shine light on new physics beyond the standard model. We utilize two iron shielded SmCo5 electron-spin sources and two optically pumped magnetom-eters to search for exotic long-range spin-spin velocity-dependent force. The orientations of spin sources and magnetometers are optimized such that the exotic force is enhanced and common-mode noise is effectively subtracted. We set direct limit on proton-electron interaction in the force range from 1 cm to 1 km. Our experiment represents more than 10 orders of magnitude improvement than previous works.

Automated summary

The search for exotic long-range spin-spin velocity-dependent force using two iron shielded SmCo5 electron-spin sources and two optically pumped magnetometers has led to significant improvement in our understanding of physics beyond the standard model. By optimizing the orientations of the spin sources and magnetometers, we enhanced the exotic force and effectively subtracted common-mode noise. Our experiment set a direct limit on proton-electron interaction in a wide force range, with more than 10 orders of magnitude improvement compared to previous works.