New Experimental Limits on Exotic Spin-Spin-Velocity-Dependent Interactions By Using SmCo$_5$ Spin Sources

TL;DR

This study sets new experimental limits on exotic spin-spin-velocity-dependent interactions using specially designed spin sources and a SERF co-magnetometer, achieving the tightest constraints in the 5 cm to 1 km range.

Contribution

The paper introduces a novel experimental setup with iron-shielded SmCo$_5$ spin sources and a SERF co-magnetometer to improve constraints on SSVDFs in a previously unexplored force range.

Findings

Established the tightest limits on SSVDFs in the 5 cm to 1 km range.

Demonstrated high sensitivity detection using ISSCs and SERF co-magnetometer.

Provided new constraints on specific force forms $V_{6+7}$, $V_8$, $V_{15}$, and $V_{16}$.

Abstract

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 $\sim$mG level due to iron shielding, which means low detecting noise. With help from the ISSCs, the high sensitivity SERF co-magnetometer, and the similarity analysis method, new constraints on SSVDFs with forms of $V_{6+7}$, $V_8$, $V_{15}$, and $V_{16}$ have been obtained, which represent the tightest limits in force range of 5 cm -- 1 km to the best of our knowledge.