948 research outputs found
Wide or Narrow? The Phenomenology of 750 GeV Diphotons
I perform a combined analysis of the ATLAS and CMS diphoton data, using both
Run-I and Run-II results, including those released at the 2016 Moriond
conference. I find combining the ATLAS and CMS results from Run-II increases
the statistical significance of the reported 750 GeV anomaly, assuming a spin-0
mediator coupling to gluons or heavy quarks with a width much smaller than the
detector resolution. This significance does not decrease when the 8 TeV data is
included. A spin-2 mediator is disfavored compared to the spin-0 case. The
cross section required to fit the ATLAS anomaly is in tension with the
aggregate data, all of which prefers a smaller value. The best fit for all
models I consider is a local significance for a 750 GeV spin-0
mediator coupling to gluons with a cross section of 4 fb at 13 TeV (assuming
narrow width) or 10~fb (assuming GeV).Comment: 16 pages, 11 figures v2 includes updated statistical tests including
data released at 2016 Moriond conferenc
Xogenesis
We present a new paradigm for dark matter in which a dark matter asymmetry is
established in the early universe that is then transferred to ordinary matter.
We show this scenario can fit naturally into weak scale physics models, with a
dark matter candidate mass of this order. We present several natural
suppression mechanisms, including bleeding dark matter number density into
lepton number, which occurs naturally in models with lepton-violating operators
transferring the asymmetry.Comment: 11 pages, 4 figure
Dark Matter Subhalos In the Fermi First Source Catalog
The Milky Way's dark matter halo is thought to contain large numbers of
smaller subhalos. These objects can contain very high densities of dark matter,
and produce potentially observable fluxes of gamma rays. In this article, we
study the gamma ray sources in the Fermi Gamma Ray Space Telescope's recently
published First Source Catalog, and attempt to determine whether this catalog
might contain a population of dark matter subhalos. We find that, while
approximately 20-60 of the catalog's unidentified sources could plausibly be
dark matter subhalos, such a population cannot be clearly identified as such at
this time. From the properties of the sources in the First Source Catalog, we
derive limits on the dark matter's annihilation cross section that are
comparably stringent to those derived from recent observations of dwarf
spheroidal galaxies.Comment: 11 pages, 9 figures V2: Minor errors in Figure 3 correcte
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