W/Z bremsstrahlung as the dominant annihilation channel for dark matter, revisited

2011/04/30 by Nicole F. Bell, James B. Dent, Ahmad J. Galea +5 · 3 citations
Physics and Astronomy · #Annihilation #Bremsstrahlung #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark matter #Electroweak interaction #Helicity #Lepton #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #astro-ph.HE #hep-ph

paper · pdf · doi:10.1016/j.physletb.2011.10.057

published as Phys.Lett. B706 (2011) 6-12 · 8 pages, 6 figures; replaced to match published version

openalex publication_date 2011/10/27 · arxiv created 2012/05/23 · arxiv updated 2015/03/18 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

We revisit the calculation of electroweak bremsstrahlung contributions to dark matter annihilation. Dark matter annihilation to leptons is necessarily accompanied by electroweak radiative corrections, in which a W or Z boson is also radiated. Significantly, while many dark matter models feature a helicity suppressed annihilation rate to fermions, bremsstrahlung process can remove this helicity suppression such that the branching ratios Br(ℓ νW ), Br(ℓ⁺ℓ^-Z), and Br(ννZ) dominate over Br(ℓ⁺ℓ^-) and Br(νν). We find this is most significant in the limit where the dark matter mass is nearly degenerate with the mass of the boson which mediates the annihilation process. Electroweak bremsstrahlung has important phenomenological consequences both for the magnitude of the total dark matter annihilation cross section and for the character of the astrophysical signals for indirect detection. Given that the W and Z gauge bosons decay dominantly via hadronic channels, it is impossible to produce final state leptons without accompanying protons, antiprotons, and gamma rays.

Citations

• Cosmic abundances of stable particles: Improved analysis
• Generic dark matter signature for gamma-ray telescopes
• Toward a minimum branching fraction for dark matter annihilation into electromagnetic final states
• Detection of leptonic dark matter
• W/Zbremsstrahlung as the dominant annihilation channel for dark matter
• Model-independent dark matter annihilation bound from the diffuse gamma ray flux
• Three-body annihilation of neutralinos below two-body thresholds
• TeV scale dark matter and electroweak radiative corrections

Cited by

• Collide and conquer: constraints on simplified dark matter models using mono-X collider searches
• Effective field theory interpretation of searches for dark matter annihilation in the Sun with the IceCube Neutrino Observatory
• Dark matter at the LHC: Effective field theories and gauge invariance