Sommerfeld Enhancement from Background Force and the Galactic Center GeV Excess

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Autori principali: Cheng, Yu, Ge, Shuailiang
Natura: Preprint
Pubblicazione: 2025
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author Cheng, Yu
Ge, Shuailiang
author_facet Cheng, Yu
Ge, Shuailiang
contents We study the impact of background-induced forces on dark matter (DM) annihilation and their implications for indirect detection. In the presence of a finite number density of background particles, loop-level interactions can generate an effective force that is significantly enhanced relative to the vacuum case. We construct a two-component DM model in which the dominant component is a fermionic particle $χ$ and the subdominant component is an ultralight pseudoscalar particle $ϕ$. The annihilation of $χ$ proceeds through the p-wave channel and produces gamma-ray emission. The finite density of $ϕ$ particles induces a background-enhanced force between $χ$ particles, leading to a sizable Sommerfeld enhancement of the annihilation. We show that a viable region of parameter space in this model can account for the gamma-ray excess observed in the Galactic Center using Fermi-LAT data. The background-induced force substantially amplifies the Sommerfeld enhancement and thus enlarges the parameter space capable of explaining the excess, highlighting the importance of background effects in astrophysical environments.
format Preprint
id arxiv_https___arxiv_org_abs_2512_24188
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Sommerfeld Enhancement from Background Force and the Galactic Center GeV Excess
Cheng, Yu
Ge, Shuailiang
High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
High Energy Astrophysical Phenomena
We study the impact of background-induced forces on dark matter (DM) annihilation and their implications for indirect detection. In the presence of a finite number density of background particles, loop-level interactions can generate an effective force that is significantly enhanced relative to the vacuum case. We construct a two-component DM model in which the dominant component is a fermionic particle $χ$ and the subdominant component is an ultralight pseudoscalar particle $ϕ$. The annihilation of $χ$ proceeds through the p-wave channel and produces gamma-ray emission. The finite density of $ϕ$ particles induces a background-enhanced force between $χ$ particles, leading to a sizable Sommerfeld enhancement of the annihilation. We show that a viable region of parameter space in this model can account for the gamma-ray excess observed in the Galactic Center using Fermi-LAT data. The background-induced force substantially amplifies the Sommerfeld enhancement and thus enlarges the parameter space capable of explaining the excess, highlighting the importance of background effects in astrophysical environments.
title Sommerfeld Enhancement from Background Force and the Galactic Center GeV Excess
topic High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2512.24188