Improved Limits on Spin-Mass Interactions

作者：Junyi Lee, Attaallah Almasi, Michael Romalis · 发表于：Physical Review Letters · 年份：2018 · 被引用次数：158 · 研究领域：Atomic and Subatomic Physics Research、Dark Matter and Cosmic Phenomena、Quantum, superfluid, helium dynamics

Very light particles with $CP$-violating couplings to ordinary matter, such as axions or axionlike particles, can mediate long-range forces between polarized and unpolarized fermions. We describe a new experimental search for such forces between unpolarized nucleons in two 250 kg Pb weights and polarized neutrons and electrons in a $^{3}\mathrm{He}\text{\ensuremath{-}}\mathrm{K}$ comagnetometer located about 15 cm away. We place improved constraints on the products of scalar and pseudoscalar coupling constants, ${g}_{p}^{n}{g}_{s}^{N}<4.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}30}$ and ${g}_{p}^{e}{g}_{s}^{N}<1.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}30}$ (95% C.L.) for axionlike particle masses less than ${10}^{\ensuremath{-}6}\text{ }\text{ }\mathrm{eV}$, which represents an order of magnitude improvement over the best previous neutron laboratory limit.