Effects of New Forces on Scalar Dark Matter Solitons

TL;DR

This paper investigates how introducing a new force mediated by a light boson affects scalar dark matter solitons, potentially improving models of galactic cores.

Contribution

It provides a numerical analysis of scalar dark matter solitons under a new force, including multiple mediators, and assesses implications for galactic core modeling.

Findings

New force modifies core density-radius relation in dark matter solitons.

Modest improvement in fitting galactic core data at gravitational-strength couplings.

Analysis includes effects of multiple mediators on soliton profiles.

Abstract

New long range forces acting on ordinary matter are highly constrained. However it is possible such forces act on dark matter, as it is less constrained observationally. In this work, we consider dark matter to be made of light bosons, such as axions. We introduce a mediator that communicates a new force between dark matter particles, in addition to gravity. The mediator is taken to be light, but not massless, so that it can affect small scale galactic behavior, but not current cosmological behavior. As a concrete application of this idea, we analyze the effects on scalar dark matter solitons bound by gravitation, i.e., boson stars, which have been claimed to potentially provide cores of galaxies. We numerically determine the soliton's profiles in the presence of this new force. We also extend the analysis to multiple mediators. We show that this new force alters the relation between core density and core radius in a way that can provide improvement in fitting data to observed galactic cores, but for couplings of order the gravitational strength, the improvement is only modest.