https://doi.org/10.1140/epjp/s13360-025-06621-5
Regular Article
Unveiling a natural multicomponent dark sector: an inert doublet guided by Peccei–Quinn
Department of Physics, Indian Institute of Technology Guwahati, Amingaon, 781039, Guwahati, Assam, India
Received:
21
March
2025
Accepted:
4
July
2025
Published online:
22
July
2025
The Inert SU(2) Higgs doublet model (IDM) with Peccei–Quinn (PQ) symmetry offers a natural dark sector framework, incorporating both Weakly interacting massive particle (WIMP) and axion as prospective dark matter candidates. The spontaneous breaking of PQ symmetry, originally proposed to solve the strong CP problem, ensures the stability of WIMP dark matter through a residual 
symmetry. The axion arises from the phase of a complex scalar field whose vacuum expectation value breaks PQ symmetry. Interestingly, PQ symmetry also introduces a vector-like quark (VLQ), linking the dark and visible sectors via Yukawa interactions, enabling rich phenomenology with additional annihilation, coannihilation, and direct detection processes. This setup matches the observed dark matter relic density and opens up the additional IDM parameter space for WIMP masses between the GeV-TeV range. We investigate VLQ pair production at the LHC, including next-to-leading order QCD corrections. Each VLQ decays into a Standard Model quark and an inert scalar, preserving the symmetry. Using leptonic search channels and multivariate analysis, we demonstrate that the current luminosity of the 14 TeV LHC can significantly constrain the parameter space.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
