Observational Constraints on Decoupled Hidden Sectors

Abstract

We consider an extension of the Standard Model with a singlet sector consisting of a real (pseudo)scalar and a Dirac fermion coupled with the Standard Model only via the scalar portal. We assume that the portal coupling is weak enough for the singlet sector not to thermalize with the Standard Model allowing the production of singlet particles via the freeze-in mechanism. If the singlet sector interacts with itself sufficiently strongly, it may thermalize within itself, resulting in dark matter abundance determined by the freeze-out mechanism operating within the singlet sector. We investigate this scenario in detail. In particular, we show that requiring the absence of inflationary isocurvature fluctuations provides lower bounds on the magnitude of the dark sector self-interactions and in parts of the parameter space favors sufficiently large self-couplings, supported also by the features observed in the small-scale structure formation.

10 pages, 6 figures. v2; References added. v3; Corrected typographical errors on equations (10) and (15), results unchanged

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Cited by in corpus (27)

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• The Dark Side of the Littlest Seesaw: freeze-in, the two right-handed neutrino portal and leptogenesis-friendly fimpzillas
• Scalar correlation functions in de Sitter space from the stochastic spectral expansion
• Connecting CMB anisotropy and cold dark matter phenomenology via reheating
• Impact of Higgs portal on gravity-mediated production of superheavy dark matter
• Dark Matter and Gravity Waves from a Dark Big Bang
• Charged Planckian Interacting Dark Matter
• The case for decaying spin-3/2 dark matter
• Hidden strongly interacting massive particles
• Two Component Feebly Interacting Massive Particle (FIMP) Dark Matter
• Prospects for indirect detection of frozen-in dark matter
• Disformal Dark Matter
• Freeze-In Dark Matter from a sub-Higgs Mass Clockwork Sector via the Higgs Portal
• A Model of Metastable EeV Dark Matter
• Astrophysical Tests of Dark Matter Self-Interactions
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• A new mechanism of sterile neutrino dark matter production
• Standard model Higgs field and hidden sector cosmology
• Conformal Portal to Dark Matter
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• Spectator dark matter in non-standard cosmologies
• Cosmological implications of inflaton-mediated dark and visible matter scatterings after reheating
• Asymmetric Reheating by Primordial Black Holes