7 keV Scalar Dark Matter and the Anomalous Galactic X-ray Spectrum

Abstract

We present a simple model for a 7 keV scalar dark matter particle which also explains the recently reported anomalous peak in the galactic X-ray spectrum at 3.55 keV in terms of its two photon decay. The model is arguably the simplest extension of the Standard Model, with the addition of a real scalar gauge singlet field subject to a reflection symmetry. This symmetry breaks spontaneously at an energy scale of a few MeV which triggers the decay of the dark matter particle into two photons. In this framework, the Higgs boson of the Standard Model is also the source of dark matter in the Universe. The model fits the relic dark matter abundance and the partial lifetime for two photon decay, while being consistent with constraints from domain wall formation and dark matter self-interactions. We show that all these features of the model are preserved in its natural embedding into a simple dark $U(1)$ gauge theory with a Higgs mechanism. The properties of the dark photon get determined in such a scenario. High precision cosmological measurements can potentially test these models, as there are residual effects from domain wall formation and non-negligible self-interactions of dark matter.

Improved discussion of relic density and references updated; 22 pages, 5 figures

References in corpus (15)

• Gauge Singlet Scalars as Cold Dark Matter
• LHC Phenomenology of an Extended Standard Model with a Real Scalar Singlet
• The Poker Face of the Majoron Dark Matter Model: LUX to keV Line
• Resonantly-Produced 7 keV Sterile Neutrino Dark Matter Models and the Properties of Milky Way Satellites
• The Quest for an Intermediate-Scale Accidental Axion and Further ALPs
• The 7 keV axion dark matter and the X-ray line signal
• A 3.55 keV Photon Line and its Morphology from a 3.55 keV ALP Line
• X-ray line signal from decaying axino warm dark matter
• X-ray Lines from Dark Matter: The Good, The Bad, and The Unlikely
• Anomaly-free flavor models for Nambu-Goldstone bosons and the 3.5 keV X-ray line signal
• keV Photon Emission from Light Nonthermal Dark Matter
• SUSY in the sky or a keV signature of sub-GeV gravitino dark matter
• 7 keV Dark Matter as X-ray Line Signal in Radiative Neutrino Model
• Can a millicharged dark matter particle emit an observable gamma-ray line?
• Natural $X$-ray Lines from the Low Scale Supersymmetry Breaking

Cited by in corpus (23)

• Dark matter production in the early Universe: beyond the thermal WIMP paradigm
• Generating X-ray lines from annihilating dark matter
• Freeze-in Production of Sterile Neutrino Dark Matter in U(1)${}_{\mathrm{B}-\mathrm{L}}$ Model
• Nonthermal Two Component Dark Matter Model for Fermi-LAT $\gamma$-ray excess and 3.55 keV X-ray Line
• X-ray line in Radiative Neutrino Model with Global $U(1)$ Symmetry
• Improved stellar limits on a light CP-even scalar
• A Dynamical Framework for KeV Dirac Neutrino Warm Dark Matter
• Calculation of Momentum Distribution Function of a Non-thermal Fermionic Dark Matter
• Nonabelian dark matter models for 3.5 keV X-rays
• Decaying Vector Dark Matter as an Explanation for the 3.5 keV Line from Galaxy Clusters
• THESEUS Insights into ALP, Dark Photon and Sterile Neutrino Dark Matter
• 3.5-keV X-ray line from nearly-degenerate WIMP dark matter decays
• X-ray Line from the Dark Transition Electric Dipole
• Displaced Vertices from X-ray Lines
• Non-abelian Dark Matter Solutions for Galactic Gamma-ray Excess and Perseus 3.5 keV X-ray Line
• 3.5 keV X-ray line and R-Parity Conserving Supersymmetry
• ${\nu }_R$ dark matter-philic Higgs for 3.5 keV X-ray signal
• Stellar limits on light CP-even scalar
• 3.5 keV Galactic Emission Line as a Signal from the Hidden Sector
• Roles of sterile neutrinos in particle physics and cosmology
• Warm Dark Matter in Two Higgs Doublet Models
• Supersymmetric Higgs-portal and X-ray lines
• Sterile neutrino dark matter from a TeV Scale Seesaw