2009/08/17 by Jean-François Fortin, Fortin, Jean-François, Jessie Shelton +6 · 1 citation
Physics and Astronomy · #Atomic and Subatomic Physics Research #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle Detector Development and Performance #hep-ph
paper · pdf · doi:10.48550/arxiv.0908.2258
38 pages, 9 figures, 8 tables
arxiv created 2009/08/17 · openalex publication_date 2009/08/17 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this paper, we study gamma ray spectra for various scenarios of dark matter annihilation and decay. We focus on processes which generate only high-energy photons or leptons and photons, but no proton-antiproton pairs, to be compatible with PAMELA's data. We investigate photons produced directly from two-body decay chains and photons produced together with charged particles. For the former case we also include the process DM(+DM) -> N phi -> 2N gamma which can arise from specific strongly-coupled dark matter scenarios. For the latter case, photons are either generated by final state radiation from high-energy leptons or are directly generated from contact interactions represented by higher-order (non-renormalizable) operators obtained after integrating out heavy modes. We compare their overall annihilation cross-sections/decay rates taking into account chiral suppression (in the s-wave approximation), dimension of operators and dark matter particle properties. A rough estimate shows that, for a dark matter particle with a mass of O(1 TeV), the hard photon spectra in direct electron-positron-photon final states arising from either scalar boson dark matter annihilation/decay or Majorana fermion dark matter annihilation are dominated by higher-order operators if the scale of the leading operator is lower than O(1000 TeV). Otherwise, all the photon spectra arising in this way are dominated by final state radiation. Among the spectra studied, the higher-order operators spectrum is the hardest while the final state radiation spectrum with an intermediate decay is the softest.