Experimental searches for new, "fifth" forces are attracting a lot of attention because they allow to test theoretical extensions to the standard model. Here, we report a new experimental search for possible fifth forces, specifically spin-and-velocity dependent forces, by using a K-Rb-21Ne co-magnetometer and a tungsten ring featuring a high nucleon density. Taking advantage of the high sensitivity of the co-magnetometer, the pseudomagnetic field from the fifth force is measured to be <7\,aT. This sets new limits on coupling constants for the neutron-nucleon and proton-nucleon interactions in the range of ≥0.1 m. The coupling constant limits are established to be ∣gVn∣<6.6×10−11 and ∣gVp∣<3.0×10−10, which are more than one order of magnitude tighter than astronomical and cosmological limits on the coupling between the new gauge boson such as Z′ and standard model particles.
@article{arxiv.2203.07050,
title = {New Constraints on Exotic Spin-Velocity-Dependent Interactions},
author = {Kai Wei and Wei Ji and Changbo Fu and Arne Wickenbrock and Jiancheng Fang and Victor Flambaum and Dmitry Budker},
journal= {arXiv preprint arXiv:2203.07050},
year = {2022}
}