Producing baryons from neutralinos in small H2 clumps over cosmological ages

TL;DR

This paper explores how neutralino WIMPs can be captured by dense H2 clumps, potentially enriching baryons and affecting dark matter profiles over cosmological timescales.

Contribution

It introduces a phenomenological model of mixed H2 and WIMP clumps, suggesting a mechanism for WIMP baryon enrichment and impact on galaxy structure.

Findings

WIMP density can increase by 10^6 during infall

Mixed clumps can migrate from halo to galaxy disk

H2-WIMP interactions may produce observable HI

Abstract

Extreme scattering events in quasars suggest the existence of dark $\rm H_2 $ clumps of mass $\rm \sim 10^{-3} M_\odot$ and size $\rm \sim 10 AU$. Such clumps are extremely dense compared to WIMPs clumps of the same mass obtained by N-body simulations. A WIMP clump gravitationally attracted by a central $\rm H_2 $ clump would experience a first infall during which its density increases by $\rm 10^6$ in $\rm \sim 1 Myr$. In this poster I begin to explore the phenomenology of mixed clumps made with $\rm H_2 $ and WIMPs. Molecular clouds built with clumps are efficient machines to transform smooth distributions of WIMPs into concentrated networks. If WIMPs are neutralinos gravitationally attracted in clumps of such molecular clouds, they may either enrich the baryon sector over cosmological ages, or remain mixed with cold $\rm H_2 $ clouds until the clumps evaporate either by collision or by stellar UV heating. A phenomenological model based on an hypothetic dark baryonic component (DBC) that was invoked in the past to explain one of the main drawbacks of CDM profiles, their overly dense cores, is briefly revisited in this context. The DBC is replaced by a mix of $\rm H_2 $ and WIMPs, with a small fraction of HI produced by internal $\rm H_2 $ collisions, in slightly dispersive clumpy clouds that may migrate from the halo towards inner parts of a galaxy and disk.