Model-independent indirect detection constraints on hidden sector dark matter

Abstract

If dark matter inhabits an expanded "hidden sector", annihilations may\nproceed through sequential decays or multi-body final states. We map out the\npotential signals and current constraints on such a framework in indirect\nsearches, using a model-independent setup based on multi-step hierarchical\ncascade decays. While remaining agnostic to the details of the hidden sector\nmodel, our framework captures the generic broadening of the spectrum of\nsecondary particles (photons, neutrinos, e+e- and antiprotons) relative to the\ncase of direct annihilation to Standard Model particles. We explore how\nindirect constraints on dark matter annihilation limit the parameter space for\nsuch cascade/multi-particle decays. We investigate limits from the cosmic\nmicrowave background by Planck, the Fermi measurement of photons from the dwarf\ngalaxies, and positron data from AMS-02. The presence of a hidden sector can\nchange the constraints on the dark matter annihilation cross section by up to\nan order of magnitude in either direction (although the effect can be much\nsmaller). We find that generally the bound from the Fermi dwarfs is most\nconstraining for annihilations to photon-rich final states, while AMS-02 is\nmost constraining for electron and muon final states; however in certain\ninstances the CMB bounds overtake both, due to their approximate independence\nof the details of the hidden sector cascade. We provide the full set of cascade\nspectra considered here as publicly available code with examples at\nhttp://web.mit.edu/lns/research/CascadeSpectra.html.\n