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Updated: Dec 22, 2025

Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
Rapid Bound State Formation of Dark Matter in the Early Universe
Tobias Binder1, Kyohei Mukaida2, Kalliopi Petraki3,4
1Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583, Japan.
Abstract:
The formation and decay of dark matter (DM) bound states deplete the thermal relic density during the chemical decoupling process, allowing for larger DM masses. While so far the bound state formation (BSF) has been described via the emission of an on-shell mediator, we point out that this particular process does not have to be the dominant one in general. If the mediator is coupled in a direct way to any relativistic species present in the early Universe, we demonstrate that BSF can much more efficiently occur through particle scattering. Consequently, DM can be heavier than previously expected.
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