On Dark Matter Self-interaction via Single Neutrino Exchange Potential
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arXiv
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| Format: | Preprint |
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2023
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| _version_ | 1866929235514359808 |
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| author | Zhang, Yue |
| author_facet | Zhang, Yue |
| contents | Neutrinos -- amongst the lightest known particles -- can mediate a force driving dark matter self-interaction and the small scale structure of the universe. We explore such a possibility in the simplest neutrino portal dark sector model where neutrino has a Yukawa coupling with a scalar $ϕ$ and fermion $χ$ that are degenerate in mass and together comprise 100\% of dark matter in the universe. We derive the non-relativistic potential generated by single-neutrino exchange which is of the monopole-dipole form and explore $χϕ\toχϕ$ scattering based on phase shift analysis. Our result shows that Born approximation continues to be valid in the low energy regime and the scattering cross section scales as $1/v^2$ over a wide range of dark matter velocities. Such a velocity-dependent self-interacting cross section can be large enough to explain the shallow density of dwarf galaxy cores and consistent with the upper limit from colliding galaxy clusters. The $1/v^2$ behavior persists down to rather low velocities $v\sim m_ν/m$ where $m$ is the dark matter mass, leaving the opportunity for further astrophysical probes. Through the neutrino portal, the self-interacting dark matter parameter space can be tested by searches for $Z$-boson and light mesons decaying into the dark sector, as well as low-mass dark matter direct detection experiments. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2310_10743 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | On Dark Matter Self-interaction via Single Neutrino Exchange Potential Zhang, Yue High Energy Physics - Phenomenology Cosmology and Nongalactic Astrophysics Neutrinos -- amongst the lightest known particles -- can mediate a force driving dark matter self-interaction and the small scale structure of the universe. We explore such a possibility in the simplest neutrino portal dark sector model where neutrino has a Yukawa coupling with a scalar $ϕ$ and fermion $χ$ that are degenerate in mass and together comprise 100\% of dark matter in the universe. We derive the non-relativistic potential generated by single-neutrino exchange which is of the monopole-dipole form and explore $χϕ\toχϕ$ scattering based on phase shift analysis. Our result shows that Born approximation continues to be valid in the low energy regime and the scattering cross section scales as $1/v^2$ over a wide range of dark matter velocities. Such a velocity-dependent self-interacting cross section can be large enough to explain the shallow density of dwarf galaxy cores and consistent with the upper limit from colliding galaxy clusters. The $1/v^2$ behavior persists down to rather low velocities $v\sim m_ν/m$ where $m$ is the dark matter mass, leaving the opportunity for further astrophysical probes. Through the neutrino portal, the self-interacting dark matter parameter space can be tested by searches for $Z$-boson and light mesons decaying into the dark sector, as well as low-mass dark matter direct detection experiments. |
| title | On Dark Matter Self-interaction via Single Neutrino Exchange Potential |
| topic | High Energy Physics - Phenomenology Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2310.10743 |