Probing Light Dark Matter with Cosmic Gravitational Focusing

Fuente: arXiv
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Main Authors: Ge, Shao-Feng, Tan, Liang
Format: Preprint
Published: 2025
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author Ge, Shao-Feng
Tan, Liang
author_facet Ge, Shao-Feng
Tan, Liang
contents We investigate the possibility of using the cosmic gravitational focusing (CGF) to probe the minor light dark matter (DM) component whose mass is in the range of $(0.1 \sim 100)$\,eV. Being a purely gravitational effect, the CGF offers a mode-independent probe that is complementary to the existing ways such as Lyman-$α$ and $ΔN_{\rm eff}$. Such effect finally leads to a dipole density distribution that would affect the galaxy formation and hence can be reconstructed with galaxy surveys such as DESI. Both the free-streaming and clustering limits have been studied with analytical formulas while the region in between is bridged with interpolation. We show the projected sensitivity at DESI with the typical phase space distribution of a freeze-in DM scenario as illustration.
format Preprint
id arxiv_https___arxiv_org_abs_2509_21213
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Probing Light Dark Matter with Cosmic Gravitational Focusing
Ge, Shao-Feng
Tan, Liang
High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
We investigate the possibility of using the cosmic gravitational focusing (CGF) to probe the minor light dark matter (DM) component whose mass is in the range of $(0.1 \sim 100)$\,eV. Being a purely gravitational effect, the CGF offers a mode-independent probe that is complementary to the existing ways such as Lyman-$α$ and $ΔN_{\rm eff}$. Such effect finally leads to a dipole density distribution that would affect the galaxy formation and hence can be reconstructed with galaxy surveys such as DESI. Both the free-streaming and clustering limits have been studied with analytical formulas while the region in between is bridged with interpolation. We show the projected sensitivity at DESI with the typical phase space distribution of a freeze-in DM scenario as illustration.
title Probing Light Dark Matter with Cosmic Gravitational Focusing
topic High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2509.21213