Sommerfeld effect in freeze-in dark matter

If two annihilation products of dark matter particles are non-relativistic and couple to a light force mediator, their plane wave functions are modified due to multiple exchanges of the force mediators. This gives rise to the Sommerfeld effect (SE). We consider the SE on relic density in different p...

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Bibliographic Details
Published inarXiv.org
Main Authors Zhong, Fucheng, Wang, Xinyu
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 22.10.2022
Subjects
Dark matter
Density
Phase diagrams
Plane waves
Relativistic particles
Wave functions
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Summary:If two annihilation products of dark matter particles are non-relativistic and couple to a light force mediator, their plane wave functions are modified due to multiple exchanges of the force mediators. This gives rise to the Sommerfeld effect (SE). We consider the SE on relic density in different phases of freeze-in dark matter. We find that in pure freeze-in region, SE slightly increases the relic density \(< \mathcal{O}(10)\). When the dark matter reannihilation happens, SE makes dark matter number density reach its maximum then reduce by the dark sector freeze-out. During the dark sector thermalize, it will be faster with the influence of SE; if dark matter decouples at this time, SE will decrease the relic density, causing the "mesa" on the phase diagram to shift below. Then in the dark sector freeze-out region, SE will significantly affect relic abundance the same as the usual freeze-out of WIMP. Finally, we show the SE on the phase diagram by a simple model, it causes the parameter space shifts in the horizontal or vertical direction when we apply the correct relic density.
ISSN:2331-8422