Constraining light dark matter in vector-scalar portals with COSI and AMEGO-X

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Dutra, Maíra, Siqueira, Clarissa, Venters, Tonia M.
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866913070113095680
author Dutra, Maíra
Siqueira, Clarissa
Venters, Tonia M.
author_facet Dutra, Maíra
Siqueira, Clarissa
Venters, Tonia M.
contents Detecting gamma-ray signals that could be due to dark matter (DM) particles would give us invaluable information about the nature of DM. In particular, gamma-ray lines could provide a way to measure the DM mass. The excellent energy resolution of the upcoming Compton Spectrometer and Imager (COSI) will allow us to probe underexplored regions of the DM parameter space while being sensitive to distinctive spectral features of potential DM signals. In this work, we consider a fermionic sub-GeV DM charged under a new U(1) gauge symmetry. Both the DM and the new gauge boson $Z'$ acquire mass from a new singlet scalar. The masses of the new particles in this class of vector-scalar portal models are naturally at the MeV scale, enabling detectable gamma-ray lines in the bandpasses of COSI and proposed missions such as the All-sky Medium Energy Gamma-ray Observatory eXplorer (AMEGO-X). We estimate the sensitivities of COSI and AMEGO-X to sub-GeV DM in this context, considering a B-L and a purely axial $Z'$ as benchmark examples. We find regions of the parameter space where COSI will provide leading constraints, beyond the strong CMB limits. On the other hand, AMEGO-X would probe most of the viable parameter space leading to continuum gamma rays. The implementation of our generic vector-scalar portal model in the Hazma toolkit is available at GitHub.
format Preprint
id arxiv_https___arxiv_org_abs_2508_15891
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Constraining light dark matter in vector-scalar portals with COSI and AMEGO-X
Dutra, Maíra
Siqueira, Clarissa
Venters, Tonia M.
High Energy Physics - Phenomenology
High Energy Astrophysical Phenomena
High Energy Physics - Theory
Detecting gamma-ray signals that could be due to dark matter (DM) particles would give us invaluable information about the nature of DM. In particular, gamma-ray lines could provide a way to measure the DM mass. The excellent energy resolution of the upcoming Compton Spectrometer and Imager (COSI) will allow us to probe underexplored regions of the DM parameter space while being sensitive to distinctive spectral features of potential DM signals. In this work, we consider a fermionic sub-GeV DM charged under a new U(1) gauge symmetry. Both the DM and the new gauge boson $Z'$ acquire mass from a new singlet scalar. The masses of the new particles in this class of vector-scalar portal models are naturally at the MeV scale, enabling detectable gamma-ray lines in the bandpasses of COSI and proposed missions such as the All-sky Medium Energy Gamma-ray Observatory eXplorer (AMEGO-X). We estimate the sensitivities of COSI and AMEGO-X to sub-GeV DM in this context, considering a B-L and a purely axial $Z'$ as benchmark examples. We find regions of the parameter space where COSI will provide leading constraints, beyond the strong CMB limits. On the other hand, AMEGO-X would probe most of the viable parameter space leading to continuum gamma rays. The implementation of our generic vector-scalar portal model in the Hazma toolkit is available at GitHub.
title Constraining light dark matter in vector-scalar portals with COSI and AMEGO-X
topic High Energy Physics - Phenomenology
High Energy Astrophysical Phenomena
High Energy Physics - Theory
url https://arxiv.org/abs/2508.15891