Using the Sun and the Moon as Source masses and the Earth's Rotation as a Modulation to Search for Exotic Spin-Dependent Interactions at Astronomical Distances

TL;DR

This paper uses the Sun and Moon as sources to set new experimental limits on exotic spin-dependent interactions at astronomical distances, surpassing previous astrophysical constraints through analysis of existing laboratory data.

Contribution

It introduces a novel method leveraging celestial bodies and Earth's rotation to constrain exotic interactions, achieving the most stringent laboratory limits at these scales.

Findings

Set new upper limits on scalar-pseudoscalar interactions at 2×10^{10}m to 10^{14}m ranges.

Laboratory limits now surpass astrophysical bounds for certain interactions.

Improved constraints on vector-axial-vector interactions by up to 12 orders of magnitude.

Abstract

Exotic spin-dependent interactions mediated by new light particles led to solutions to several important questions in modern physics. Such interactions involving a scalar coupling $g_S^N$ at one vertex and a pseudo-scalar coupling $g_P^n$ at the polarized neutron vertex can be induced by the exchange of spin-0 bosons, or a vector/axial-vector coupling $g_V^N$/$g_A^N$ at one vertex and an axial-vector coupling $g_A^n$ at the polarized neutron vertex can be induced by the exchange of spin-1 bosons. If such new interactions exist, the Sun and the Moon can induce sidereal variations of effective fields along the direction perpendicular to the Earth's rotation axis. We derived new experimental upper limits on such exotic spin-dependent interactions at astronomical interaction ranges by analyzing existing data from laboratory measurements on the Lorentz and CPT violation. We set the most stringent experimental limits on $g_S^Ng_P^n$ ranging from $\sim 2\times 10^{10}$m to $\sim 10^{14}$m. Previously, the best limit on $g_S^Ng_P^n$ at this range is from astrophysics. The result is the first time laboratory limits surpass the astrophysical ones on the scalar-pseudoscalar type interaction, to our best knowledge. We report new constraints on vector-axial-vector and axial-axial-vector type interaction at the range of astronomical scales. The new limits on vector-axial-vector are improved by as much as $\sim$12 orders of magnitude. We also apply the analysis to the Hari-Dass interactions and obtain corresponding new constraints on the interactions. We discuss the possibilities of using the beam method to further search the interaction involving other particles, such as electrons, muons, etc., based on the same idea.