Reacceleration of charged dark matter

TL;DR

This paper explores how charged dark matter particles can be reaccelerated through interactions with magnetic turbulence, affecting their detectability and constraining their possible mass-to-charge ratios.

Contribution

It introduces a mechanism of reacceleration of charged dark matter via second-order Fermi processes, linking magnetic turbulence dynamics to dark matter detection constraints.

Findings

Charged dark matter with certain mass-to-charge ratios is excluded by terrestrial detection limits.

Reacceleration impacts the magnetic turbulence spectrum, influencing dark matter diffusion.

The study constrains charged dark matter to specific mass-to-charge ranges based on turbulence and detection data.

Abstract

Charged particles scattering on moving inhomogenities of the magnetised interstellar medium can gain energy through the process of second-order Fermi acceleration. This energy gain depletes in turn the magnetic wave spectrum around the resonance wave-vector $k\sim 1/R_L$, where $R_L$ is the Larmor radius of the charged particle. This energy transfer can prohibit the cascading of magnetic turbulence to smaller scales, leading to a drop in the diffusion coefficient and allowing the efficient exchange of charged dark matter particles in the disk and the halo. As a result, terrestial limits from direct detection experiments apply to charged dark matter. Together with the no-observation of a drop in the diffusion coefficient, this excludes charged dark matter for $10^3 GeV\lesssim m/q \lesssim 10^{11} GeV$, even if the charged dark matter abundance is only a small part of the total relic abundance.