3.5-keV X-ray line from nearly-degenerate WIMP dark matter decays

Abstract

The unidentified emission line at the energy of $\sim$3.5~keV observed in X-rays from galaxy clusters may originate from a process involving a dark matter particle. On the other hand, a weakly interacting massive particle (WIMP) has been an attractive dark matter candidate, due to its well-understood thermal production mechanism and its connection to physics at the TeV scale. In this paper, we pursue the possibility that the 3.5-keV X-ray arises from a late time decay of a WIMP dark matter into another WIMP dark matter, both of which have the mass of $O(100)$~GeV and whose mass splitting is about 3.5~keV. We focus on the simplest case where there are two Majorana dark matter particles and two charged scalars that couple with a standard model matter particle. By assuming a hierarchical structure in the couplings of the two dark matter particles and two charged scalars, it is possible to explain the 3.5-keV line and realize the WIMP dark matter scenario at the same time. Since the effective coupling of the two different Majorana dark matter particles and one photon violates CP symmetry, the model always contains a new source of CP violation, so the model's connection to the physics of electric dipole moments is discussed. The model's peculiar signatures at the LHC are also studied. We show the prospect of detecting the charged scalars through a detailed collider simulation.

References in corpus (29)

• PYTHIA 6.4 Physics and Manual
• Search for direct production of charginos, neutralinos and sleptons in final states with two leptons and missing transverse momentum in pp collisions at sqrt(s) = 8 TeV with the ATLAS detector
• Searches for electroweak production of charginos, neutralinos, and sleptons decaying to leptons and W, Z, and Higgs bosons in pp collisions at 8 TeV
• 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
• Dipolar Dark Matter
• 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
• Generating X-ray lines from annihilating dark matter
• X-ray Lines from Dark Matter: The Good, The Bad, and The Unlikely
• Relic Gravity Waves and 7 keV Dark Matter from a GeV scale inflaton
• 3.5 keV X-rays as the "21 cm line" of dark atoms, and a link to light sterile neutrinos
• 3.55 keV photon lines from axion to photon conversion in the Milky Way and M31
• 7 keV Scalar Dark Matter and the Anomalous Galactic X-ray Spectrum
• keV Photon Emission from Light Nonthermal Dark Matter
• A Dynamical Framework for KeV Dirac Neutrino Warm Dark Matter
• 3.55 keV X-ray Line Signal from Excited Dark Matter in Radiative Neutrino Model
• The 3.5 keV X-ray line signal from decaying moduli with low cutoff scale
• 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?
• X-ray Line from the Dark Transition Electric Dipole
• Natural $X$-ray Lines from the Low Scale Supersymmetry Breaking
• The 3.5 keV X-ray line signature from annihilating and decaying dark matter in Weinberg model
• Testing the Minimal Direct Gauge Mediation at the LHC
• Extra light fermions in $E_6$-inspired models and the 3.5 keV X-ray line signal
• 3.5 keV Galactic Emission Line as a Signal from the Hidden Sector
• 3.55 keV X-ray Line Interpretation in Radiative Neutrino Model

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• Nonthermal Two Component Dark Matter Model for Fermi-LAT $\gamma$-ray excess and 3.55 keV X-ray Line
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• X-ray line in Radiative Neutrino Model with Global $U(1)$ Symmetry
• Decaying Vector Dark Matter as an Explanation for the 3.5 keV Line from Galaxy Clusters
• Exploring X-Ray Lines as Scotogenic Signals
• Non-abelian Dark Matter Solutions for Galactic Gamma-ray Excess and Perseus 3.5 keV X-ray Line
• Displaced Vertices from X-ray Lines
• A 3.55 keV Line from Exciting Dark Matter without a Hidden Sector
• Supersymmetric Higgs-portal and X-ray lines
• Cosmic Birefringence as a probe of dark matter nature: Sterile neutrino and dipolar dark matter