Mass-varying Dark Matter from a Phase Transition
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| Format: | Preprint |
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2022
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| author | Mandal, Sayan Sehgal, Neelima |
| author_facet | Mandal, Sayan Sehgal, Neelima |
| contents | We propose a mass-varying dark matter (MVDM) model consisting of a scalar field and a fermionic field interacting via a simple Yukawa coupling, and containing an exponential self-interaction potential for the scalar field. Analyzing the evolution of this coupled scalar-fermion system in an expanding Universe, we find that it initially behaves like radiation but then undergoes a phase transition after which it behaves like pressureless dark matter. The one free parameter of this model is the temperature at which the phase transition occurs; the mass of the dark matter particle, given by the mass of the fermion, is derived from this. For a phase transition temperature between 10 MeV and $10^7$ GeV, the current dark matter relic density is achieved for a fermion mass in the range of 1 GeV to $10^9$ GeV. In this dark matter model, the scalar becomes a sub-dominant unclustered component of dark matter that can lower the amplitude of structure formation by up to a few percent. Another feature is that the mass-varying fermion component can lead to discrepant measurements of the current dark matter density of about ten percent inferred from early and late-time probes assuming LCDM. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2212_07884 |
| institution | arXiv |
| publishDate | 2022 |
| record_format | arxiv |
| spellingShingle | Mass-varying Dark Matter from a Phase Transition Mandal, Sayan Sehgal, Neelima High Energy Physics - Phenomenology Cosmology and Nongalactic Astrophysics High Energy Physics - Theory We propose a mass-varying dark matter (MVDM) model consisting of a scalar field and a fermionic field interacting via a simple Yukawa coupling, and containing an exponential self-interaction potential for the scalar field. Analyzing the evolution of this coupled scalar-fermion system in an expanding Universe, we find that it initially behaves like radiation but then undergoes a phase transition after which it behaves like pressureless dark matter. The one free parameter of this model is the temperature at which the phase transition occurs; the mass of the dark matter particle, given by the mass of the fermion, is derived from this. For a phase transition temperature between 10 MeV and $10^7$ GeV, the current dark matter relic density is achieved for a fermion mass in the range of 1 GeV to $10^9$ GeV. In this dark matter model, the scalar becomes a sub-dominant unclustered component of dark matter that can lower the amplitude of structure formation by up to a few percent. Another feature is that the mass-varying fermion component can lead to discrepant measurements of the current dark matter density of about ten percent inferred from early and late-time probes assuming LCDM. |
| title | Mass-varying Dark Matter from a Phase Transition |
| topic | High Energy Physics - Phenomenology Cosmology and Nongalactic Astrophysics High Energy Physics - Theory |
| url | https://arxiv.org/abs/2212.07884 |