New Experimental Limits on Exotic Spin-Spin-Velocity-Dependent Interactions by Using SmCo5 Spin Sources

We report the latest results of searching for possible new macro-scale spin-spin-velocity-dependent forces (SSVDFs) based on specially designed iron-shielded SmCo_5(ISSC) spin sources and a spin exchange relaxation free (SERF) co-magnetometer. The ISSCs have high net electron spin densities of about 1.7\times 10^{21}cm^{-3} which mean high detecting sensitivity; and low magnetic field leakage of about \simG level due to iron...