Journal Article

PUBDB-2026-01206

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Sub-GeV dark matter and nano-Hertz gravitational waves from a classically conformal dark sector

Balan, S. ; Bringmann, T. ; Kahlhoefer, F. ; Matuszak, J. (Corresponding author) ; Tasillo, C.Extern*DESY*

2025
IOP London

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Please use a persistent id in citations: doi:10.1088/1475-7516/2025/08/062  doi:10.3204/PUBDB-2026-01206

Report No.: arXiv:2502.19478

Abstract: Strong first-order phase transitions in a dark sector offer a compelling explanation for the stochastic gravitational wave background in the nano-Hertz range recently detected by pulsar timing arrays (PTAs). We explore the possibility that such a phase transition at the same time gives mass to a stable fermion that accounts for the observed dark matter abundance and leads to testable effects in laboratory experiments. Concretely, we consider a classically conformal dark sector with a hidden U(1)^' gauge symmetry that couples to the Standard Model via kinetic mixing. Since the PTA signal requires a phase transition in the MeV temperature range, spontaneous symmetry breaking gives rise to a sub-GeV dark matter candidate that couples to the Standard Model via a dark photon mediator and obtains its relic abundance via annihilations into electrons and dark Higgs bosons. Such a scenario is tightly constrained by laboratory searches for dark photons and cosmological constraints on the decays of dark Higgs bosons after the phase transition. We show that viable parameter regions can be found both for the case that the dark Higgs bosons remain in equilibrium with the Standard Model and that they decouple and only decay much later. In the latter case, the parameter regions preferred by the PTA signal and the dark matter relic abundance can be fully explored by future beam-dump experiments searching for missing energy.

Keyword(s): cosmology of theories beyond the SM ; particle physics - cosmology connection ; primordial gravitational waves (theory)

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Contributing Institute(s):

1. Theorie-Gruppe (T)

Research Program(s):

1. 611 - Fundamental Particles and Forces (POF4-611) (POF4-611)
2. DFG project G:(GEPRIS)396021762 - TRR 257: Phänomenologische Elementarteilchenphysik nach der Higgs-Entdeckung (396021762) (396021762)
3. DFG project G:(GEPRIS)390833306 - EXC 2121: Das Quantisierte Universum II (390833306) (390833306)

Experiment(s):

1. No specific instrument

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF >= 5 ; JCR ; National-Konsortium ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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Linked articles:

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Preprint Balan, S. ; Bringmann, T. ; Kahlhoefer, F. ; Matuszak, J. (Corresponding author) ; Tasillo, C.Extern*DESY*
Sub-GeV dark matter and nano-Hertz gravitational waves from a classically conformal dark sector
[10.3204/PUBDB-2026-01247]     Files  Fulltext by arXiv.org BibTeX | EndNote: XML, Text | RIS

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