Gamma-ray lines may reveal the CP nature of the dark matter particle

Abstract

Determining the fundamental properties of the dark matter is one of the most important open problems in particle physics today. If the dark matter particle has spin zero, one of these properties is its CP nature. That is, whether it is CP-even (scalar), CP-odd (pseudoscalar), or if its interactions violate CP. In this paper, we show that the observation of $\gamma$-ray lines arising from the decay of a spin-zero dark matter particle could be used to discriminate among these possibilities. We consider a general setup where dark matter decay is induced by effective operators and demonstrate that, due to gauge invariance, there exists correlations among the branching ratios into gauge boson final states ($\gamma \gamma$, $\gamma Z$, $W^{+}{W}^{-}$, $ZZ$) that depend on the mass and the CP properties of the dark matter. Consequently, the future observation of $\gamma$-ray lines may in principle be used to establish the CP nature of the dark matter particle.

6 pages, 5 figures

References in corpus (15)

• Dark Matter Search Results from a One Tonne$\times$Year Exposure of XENON1T
• A Tentative Gamma-Ray Line from Dark Matter Annihilation at the Fermi Large Area Telescope
• A Tale of Tails: Dark Matter Interpretations of the Fermi GeV Excess in Light of Background Model Systematics
• Search for dark matter and other new phenomena in events with an energetic jet and large missing transverse momentum using the ATLAS detector
• Review of LHC Dark Matter Searches
• General Constraints on Dark Matter Decay from the Cosmic Microwave Background
• Gamma Ray Signals from Dark Matter: Concepts, Status and Prospects
• Gamma-Rays from Decaying Dark Matter
• Identifying WIMP dark matter from particle and astroparticle data
• Is the dark matter particle its own antiparticle?
• Direct detection of fermionic and vector dark matter with polarised targets
• Multi-Dimensional Effective Field Theory Analysis for Direct Detection of Dark Matter
• Dark matter spin determination with directional direct detection experiments
• Prospects for determining the particle/antiparticle nature of WIMP dark matter with direct detection experiments
• Compatibility of a dark matter discovery at XENONnT/LZ with the WIMP thermal production mechanism

Cited by in corpus (3)

• Reconstructing Non-standard Cosmologies with Dark Matter
• Recurrent Axinovae and their Cosmological Constraints
• Detecting Bosonic Dark Matter with Neutron Stars