Axion and FIMP Dark Matter in a $U(1)$ extension of the Standard Model

Abstract

In the Standard Model a Dark Matter candidate is missing, but it is relatively simple to enlarge the model including one or more suitable particles. We consider in this paper one such extension, inspired by simplicity and by the goal to solve more than just the Dark Matter issue. Indeed we consider a local $U(1)$ extension of the SM providing an axion particle to solve the strong CP problem and including RH neutrinos with appropriate mass terms. One of the latter is decoupled from the SM leptons and can constitute stable sterile neutrino DM. In this setting, the PQ symmetry arises only as an accidental symmetry but its breaking by higher order operators is sufficiently suppressed to avoid introducing a large $\theta$ contribution. The axion decay constant and the RH neutrino masses are related to the same v.e.v.s and the PQ scale and both DM densities are determined by the parameters of the axion and scalar sector. The model predicts in general a mixed Dark Matter scenario with both axion and sterile neutrino DM and is characterised by a reduced density and observational signals from each single component.

30 pages, 6 figures

References in corpus (13)

• An Improved Experimental Limit on the Electric Dipole Moment of the Neutron
• The fate of hints: updated global analysis of three-flavor neutrino oscillations
• Symmetries and Strings in Field Theory and Gravity
• The landscape of QCD axion models
• Dielectric Haloscopes: A New Way to Detect Axion Dark Matter
• More Axions from Strings
• Physics potential of the International Axion Observatory (IAXO)
• Search for "Invisible" Axion Dark Matter in the $3.3\text{-}4.2\mu$eV Mass Range
• Dark Matter from Axion Strings with Adaptive Mesh Refinement
• keV Sterile Neutrino Dark Matter from Singlet Scalar Decays: The Most General Case
• A Simple Motivated Completion of the Standard Model below the Planck Scale: Axions and Right-Handed Neutrinos
• FIMP dark matter candidate(s) in a $B-L$ model with inverse seesaw mechanism
• Exploring Supersymmetric CP Violation after LHC Run 2 with Electric Dipole Moments and B Observables