Big Bang Darkleosynthesis

TL;DR

This paper explores a dark-sector nucleosynthesis process where dark matter forms complex composite particles through a mechanism similar to big-bang nucleosynthesis, enabled by a light mediator and resulting in potentially high-spin dark matter.

Contribution

It introduces a novel dark-sector nucleosynthesis model with a light mediator, leading to efficient formation of complex dark nuclei with high spin, distinct from previous dark matter models.

Findings

Dark matter can form complex nuclei via darkleosynthesis.

Weak mediator coupling allows formation of high-mass dark nuclei.

Dark nuclei are easier to produce and more stable than standard nuclei.

Abstract

In a popular class of models, dark matter comprises an asymmetric population of composite particles with short range interactions arising from a confined nonabelian gauge group. We show that coupling this sector to a well-motivated light mediator particle yields efficient darkleosynthesis, a dark-sector version of big-bang nucleosynthesis (BBN), in generic regions of parameter space. Dark matter self-interaction bounds typically require the confinement scale to be above \Lambda_{QCD}, which generically yields large (>>MeV/dark-nucleon) binding energies. These bounds further suggest the mediator is relatively weakly coupled, so repulsive forces between dark-sector nuclei are much weaker than coulomb repulsion between standard-model nuclei, which results in an exponential barrier-tunneling enhancement over standard BBN. Thus, dark nuclei are easier to make and harder to break than visible species with comparable mass numbers. This process can efficiently yield a dominant population of states with masses significantly greater than the confinement scale and, in contrast to dark matter that is a fundamental particle, may allow the dominant form of dark matter to have high spin > 3/2.