Composite magnetic dark matter and the 130 GeV line
Aug, 2012Citations per year
Abstract: (arXiv)
We propose an economical model to explain the apparent 130 GeV gamma ray peak, found in the Fermi/LAT data, in terms of dark matter annihilation through a dipole moment interaction. The annihilating dark matter particles represent a subdominant component, with mass density 7-17% of the total DM density; and they only annihilate into gamma gamma, gamma Z, and ZZ, through a magnetic (or electric) dipole moment. Annihilation into other standard model particles is suppressed, due to a mass splitting in the magnetic dipole case, or to p-wave scattering in the electric dipole case. In either case, the observed signal requires a dipole moment of strength mu ~ 2/TeV. We argue that composite models are the preferred means of generating such a large dipole moment, and that the magnetic case is more natural than the electric one. We present a simple model involving a scalar and fermionic techniquark of a confining SU(2) gauge symmetry. We point out some generic challenges for getting such a model to work. The new physics leading to a sufficiently large dipole moment is below the TeV scale, indicating that the magnetic moment is not a valid effective operator for LHC physics, and that production of the strongly interacting constituents, followed by techni-hadronization, is a more likely signature than monophoton events. In particular, 4-photon events from the decays of bound state pairs are predicted.Note:
- 8 pages, 5 figures; v2. fixed typos, clarifications, added discussion of model-building challenges; v3. clarifications added, discussion improved, accepted for publication in PRD
- 98.70.Rz
- 95.35.+d
- 12.60.Rc
- moment: dipole
- dipole: electric
- dipole: magnetic
- dark matter: annihilation
- dark matter: density
- model: composite
- bound state: decay
References(67)
Figures(7)
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