Implications of a Scalar Dark Force for Terrestrial Experiments

TL;DR

This paper explores how a hypothetical long-range dark force mediated by an ultralight scalar could influence terrestrial experiments and astrophysical observations, providing constraints on dark matter models and interactions.

Contribution

It analyzes the implications of a dark force for terrestrial experiments and constrains dark matter models using astrophysical and experimental data.

Findings

Dark force effects are constrained by galactic dynamics and structure formation.

WEP tests limit scalar-mediated dark force in scalar singlet DM scenarios.

Constraints on Higgs-exchange contributions to DM detection cross-sections.

Abstract

A long range Weak Equivalence Principle (WEP) violating force between Dark Matter (DM) particles, mediated by an ultralight scalar, is tightly constrained by galactic dynamics and large scale structure formation. We examine the implications of such a "dark force" for several terrestrial experiments, including Eotvos tests of the WEP, direct-detection DM searches, and collider studies. The presence of a dark force implies a non-vanishing effect in Eotvos tests that could be probed by current and future experiments depending on the DM model. For scalar singlet DM scenarios, a dark force of astrophysically relevant magnitude is ruled out in large regions of parameter space by the DM relic density and WEP constraints. WEP tests also imply constraints on the Higgs-exchange contributions to the spin-independent (SI) DM-nucleus direct detection cross-section. For WIMP scenarios, these considerations constrain Higgs-exchange contributions to the SI cross-section to be subleading compared to gauge-boson mediated contributions. In multicomponent DM scenarios, a dark force would preclude large shifts in the rate for Higgs decay to two photons associated with DM-multiplet loops that might otherwise lead to measurable deviations at the LHC or a future linear collider. The combination of observations from galactic dynamics, large scale structure formation, Eotvos experiments, DM-direct-detection experiments, and colliders can further constrain the size of new long range forces in the dark sector.