Levitating Dark Matter

TL;DR

This paper explores how dark matter particles with a dark U(1)' charge can cause observable effects that mimic dark energy or modify mass measurements, impacting our understanding of cosmic acceleration.

Contribution

It introduces the concept that charged dark matter can lead to discrepancies in mass measurements and cosmic acceleration interpretations, suggesting new effects in cosmology.

Findings

Charged dark matter can cause a mismatch in mass estimates.

Dark gauge forces may mimic dark energy effects.

Local variations in galaxy forces could be misinterpreted as cosmic acceleration.

Abstract

A sizable fraction of the total energy density of the universe may be in heavy particles with a net dark $U(1)'$ charge comparable to its mass. When the charges have the same sign the cancellation between their gravitational and gauge forces may lead to a mismatch between different measures of masses in the universe. Measuring galactic masses by orbits of normal matter, such as galaxy rotation curves or lensing, will give the total mass, while the flows of dark matter agglomerates may yield smaller values if the gauge repulsion is not accounted for. If distant galaxies which house light beacons like SNe Ia contain such dark particles, the observations of their cosmic recession may mistake the weaker forces for an extra `antigravity', and infer an effective dark energy equation of state smaller than the real one. In some cases, including that of a cosmological constant, these effects can mimic $w<-1$. They can also lead to a {\it local} variation of galaxy-galaxy forces, yielding a larger `Hubble Flow' in those regions of space that could be taken for a dynamical dark energy, or superhorizon effects.