2009/06/30 by V. Barger, Yu Gao, Y. Gao +4 · 1 citation
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Particle physics theoretical and experimental studies #astro-ph.HE #hep-ex #hep-ph
paper · pdf · doi:10.1103/physrevd.80.063537
published as Phys.Rev.D80:063537,2009 · 9 pages, 4 figures. Version to appear in PRD
arxiv created 2009/09/14 · openalex publication_date 2009/09/28 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We describe a characteristic signature of dark matter (DM) annihilation or decay into gamma rays. We show that if the total angular momentum of the initial DM particle(s) vanishes, and helicity suppression operates to prevent annihilation/decay into light fermion pairs, then the amplitude for the dominant 3-body final state f+f^\ensuremath-\ensuremathγ has a unique form dictated by gauge invariance. This amplitude and the corresponding energy spectra hold for annihilation of DM Majorana fermions or self-conjugate scalars, and for decay of DM scalars, thus encompassing a variety of possibilities. Within this scenario, we analyze Fermi LAT, PAMELA, and HESS data, and predict a hint in future Fermi gamma-ray data that portends a striking signal at atmospheric Cherenkov telescopes.