Dark matter decays from non-minimal coupling to gravity

Abstract

We consider the Standard Model extended with a dark matter particle in curved spacetime, motivated by the fact that the only current evidence for dark matter is through its gravitational interactions, and we investigate the impact on the dark matter stability of terms in the Lagrangian linear in the dark matter field and proportional to the Ricci scalar. We show that this "gravity portal" induces decay even if the dark matter particle only has gravitational interactions, and that the decay branching ratios into Standard Model particles only depend on one free parameter: the dark matter mass. We study in detail the case of a singlet scalar as dark matter candidate, which is assumed to be absolutely stable in flat spacetime due to a discrete $Z_2$ symmetry, but which may decay in curved spacetimes due to a $Z_2$-breaking non-minimal coupling to gravity. We calculate the dark matter decay widths and we set conservative limits on the non-minimal coupling parameter from experiments. The limits are very stringent and suggest that there must exist an additional mechanism protecting the singlet scalar from decaying via this gravity portal.

4 pages, 2 figures

References in corpus (3)

• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• Gauge Singlet Scalars as Cold Dark Matter
• The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV

Cited by in corpus (17)

• On Thermal Gravitational Contribution to Particle Production and Dark Matter
• Sterile Neutrino portal to Dark Matter II: Exact Dark symmetry
• Lightish but clumpy: scalar dark matter from inflationary fluctuations
• From inflation to cosmological electroweak phase transition with a complex scalar singlet
• Unitary inflaton as decaying dark matter
• Dark matter production via a non-minimal coupling to gravity
• Dark matter decay through gravity portals
• Non-minimally Coupled Vector Boson Dark Matter
• Affine gravitational scenario for dark matter decay
• Sharp spectral features from light dark matter decay via gravity portals
• White dwarf cooling via gravity portals
• Dark matter annihilation into leptons through gravity portals
• Fermionic spectral action and the origin of nonzero neutrino masses
• Observational constraints on dark matter decaying via gravity portals
• No Miracle in Gravity Portals
• Particle spectra from dark matter annihilation: physics modeling and QCD uncertainties
• Self-Gravitating Static Non-Critical Black Holes in 4$D$ Einstein-Klein-Gordon System with Nonminimal Derivative Coupling