Signals of a light dark force in the galactic center

Jia Liu, Neal Weiner, Wei Xue

    Research output: Contribution to journalArticlepeer-review


    Abstract: Recent evidence for an excess of gamma rays in the GeV energy range about the Galactic Center have refocused attention on models of dark matter in the low mass regime (mχ ≲ mZ/2). Because this is an experimentally well-trod energy range, it can be a challenge to develop simple models that explain this excess, consistent with other experimental constraints. We reconsider models where the dark matter couples to dark photon, which has a weak kinetic mixing to the Standard Model photon, or scalars with a weak mixing with the Higgs boson. We focus on the light (≲1.5 GeV) dark mediator mass regime. Annihilations into the dark mediators can produce observable gamma rays through decays to π0, through radiative processes when decaying to charged particles (e+e, μ+μ,..), and subsequent interactions of high energy e+e with gas and light. However, these models have no signals of p¯$$ \overline{p} $$ production, which is kinematically forbidden. We find that in these models, the shape of resulting gamma-ray spectrum can provide a good fit to the excess at Galactic Center. We discuss further constraints from AMS-02 and the CMB, and find regions of compatibility.

    Original languageEnglish (US)
    Article number50
    JournalJournal of High Energy Physics
    Issue number8
    StatePublished - Aug 17 2015


    • Beyond Standard Model
    • Electromagnetic Processes and Properties

    ASJC Scopus subject areas

    • Nuclear and High Energy Physics


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