Self-Interacting Fermionic Dark Matter with a Scalar Mediator

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  • Recent observations of galaxy cluster Abell 3827 reveal a spatial offset between the galaxies and their associated dark matter haloes. It has been suggested that dark matter self-interactions of strength 1.0cm^2 /g<~σ/m<~1.5cm^2 /g could be responsible for the observed discrepancies. We propose a simple model for the dark sector consisting of a Dirac fermion and a scalar mediator. This dark sector is allowed to communicate with the Standard Model through mixing of the scalar mediator with the Higgs. Examination of the dark matter’s thermal freeze-out from p-wave annihilation, in combination with a theoretical upper bound placed on the mediator-fermion coupling strength, indicates that in order to satisfy the observations of Abell 3827, the mediator must be extremely light—between 0.69MeV and 100MeV—whereas the dark matter fermion could have a mass from 0.35GeV to 8200GeV. Analysis of the Higgs-mediator mixing reveals an allowed range of mediator lifetimes, from 3.2×10^(-10)s to 10^(-2)s.

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  • Copyright © 2017 the author(s). Theses may be used for non-commercial research, educational, or related academic purposes only. Such uses include personal study, research, scholarship, and teaching. Theses may only be shared by linking to Carleton University Institutional Repository and no part may be used without proper attribution to the author. No part may be used for commercial purposes directly or indirectly via a for-profit platform; no adaptation or derivative works are permitted without consent from the copyright owner.
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  • 2017


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