A general study of decaying scalar dark matter: existing limits and projected radio signals at the SKA

Abstract

We consider a decaying scalar dark matter (DM) with mass $m_{\chi }$ in the range 10 GeV - 10 TeV and vary the branching ratios of all possible two-body SM final states (excluding and including $\nu \bar{\nu }$) in the range $0\%-100\%$ to derive constraints on the total decay width $\Gamma$ using the data collected by several astrophysical and cosmological observations. We find that, $\Gamma \lesssim 10^{-26}-10^{-27}{\mathrm{s}}^{-1}$ (excluding $\nu \bar{\nu }$) and $\Gamma \lesssim 10^{-24}-10^{-26}{\mathrm{s}}^{-1}$ (including $\nu \bar{\nu }$) are allowed, depending on the values of $m_{\chi }$, which are most robust upper limits on $\Gamma$ for a generic decaying scalar DM. We then investigate the prospect of the upcoming Square Kilometre Array (SKA) radio telescope in detecting the DM decay induced radio signals originating inside the dwarf spheroidal (dSph) galaxies. We have classified the DM parameter space, allowed by the existing observations, independently of the branching ratio of each individual two-body SM final state, based on the detectability at the SKA. Excluding the $\nu \bar{\nu }$ decay mode, we find that, throughout the DM mass range considered, $\Gamma \gtrsim 10^{-30}{\mathrm{s}}^{-1}-10^{-29}{\mathrm{s}}^{-1}$ is detectable for all possible branching ratio combinations at the SKA (assuming 100 hours of observation time), with conservative choices for the relevant astrophysical parameters. On the other hand, when arbitrary branching ratios are allowed also for the $\nu \bar{\nu }$ decay mode, DM decays can be probed independently of the branching ratio of each SM final state for $\Gamma \gtrsim 2\times 10^{-29}{\mathrm{s}}^{-1}$, provided DM masses are greater than a few hundreds of GeV.

46 pages, 12 figures, 1 table; text modified, figures and table added; current version matches with the version accepted in JCAP

References in corpus (37)

• PYTHIA 6.4 Physics and Manual
• Observation of an anomalous positron abundance in the cosmic radiation
• Symmetries and Strings in Field Theory and Gravity
• The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV
• The Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived From First-Year Fermi Large Area Telescope Data
• A common mass scale for satellite galaxies of the Milky Way
• Searching for Dark Matter Annihilation in Recently Discovered Milky Way Satellites with Fermi-LAT
• A Tentative Gamma-Ray Line from Dark Matter Annihilation at the Fermi Large Area Telescope
• Weak Corrections are Relevant for Dark Matter Indirect Detection
• On the local dark matter density
• Cosmic-ray positron fraction measurement from 1 to 30 GeV with AMS-01
• General Constraints on Dark Matter Decay from the Cosmic Microwave Background
• Decaying Dark Matter can explain the electron/positron excesses
• Giant Magnetized Outflows from the Centre of the Milky Way
• Cosmic-ray propagation with DRAGON2: I. numerical solver and astrophysical ingredients
• Dwarf galaxy annihilation and decay emission profiles for dark matter experiments
• Precise constraints on the dark matter content of Milky Way dwarf galaxies for gamma-ray experiments
• The Most Dark Matter Dominated Galaxies: Predicted Gamma-ray Signals from the Faintest Milky Way Dwarfs
• Detecting dark matter WIMPs in the Draco dwarf: a multi-wavelength perspective
• Gamma Ray Spectrum from Gravitino Dark Matter Decay
• Gamma-Rays from Decaying Dark Matter
• Effect of turbulent diffusion on iron abundance profiles
• Constraints on decaying dark matter from the extragalactic gamma-ray background
• Strong Evidence for Gamma-ray Line Emission from the Inner Galaxy
• Probing the scotogenic FIMP at the LHC
• Axinos as Dark Matter Particles
• Searching for Dark Matter with X-ray Observations of Local Dwarf Galaxies
• Hunting for super-heavy dark matter with the highest-energy cosmic rays
• Local Group dSph radio survey with ATCA (III): Constraints on Particle Dark Matter
• Local Group dSph radio survey with ATCA (II): Non-thermal diffuse emission
• Direct constraints on diffusion models from cosmic-ray positron data: Excluding the Minimal model for dark matter searches
• Right-chiral sneutrinos and long-lived staus: event characteristics at the Large Hadron Collider
• Axino dark matter with R-parity violation and 130 GeV gamma-ray line
• Dark matter decay through gravity portals
• Right sneutrinos and the signals of a stable stop at the Large Hadron Collider
• The Cosmic-Ray Positron and Electron Excess: An Experimentalist's Point of View
• Baryogenesis and Asymmetric Dark Matter from The Left-Right Mirror Symmetric Model

Cited by in corpus (7)

• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Superhorizon entanglement from inflationary particle production
• Neutron star mass in dark matter clumps
• MeV to multi-TeV thermal WIMPs: most conservative limits
• Strong Constraints on Dark Photon and Scalar Dark Matter Decay from INTEGRAL and AMS-02 data
• Multi-Component Dark Matter from Minimal Flavor Violation
• A frequentist view on the two-body decaying dark matter model