Cosmic Rays from Heavy Dark Matter from the Galactic Center

Cosmic Rays from Heavy Dark Matter from the Galactic Center

Departamento de Física Teórica I, Universidad Complutense de Madrid, E-28040 Madrid, Spain
   Viviana GAMMALDI
Departamento de Física Teórica I, Universidad Complutense de Madrid, E-28040 Madrid, Spain
   Antonio L. MAROTO
Departamento de Física Teórica I, Universidad Complutense de Madrid, E-28040 Madrid, Spain

The gamma-ray fluxes observed by the High Energy Stereoscopic System (HESS) from the J1745-290 Galactic Center source is well fitted by the secondary photons coming from Dark Matter (DM) annihilation in particle-antiparticle standard model pairs over a diffuse power-law background. The spectral features of the signal are consistent with different channels: light quarks, electro-weak gauge bosons and top-antitop production. The amount of photons and morphology of the signal localized within a region of few parsecs, require compressed DM profiles as those resulting from baryonic contraction, which offer large enhancements in the signal over DM alone simulations. The fits return a heavy WIMP, with a mass above 10 TeV, but well below the unitarity limit for thermal relic annihilation. The fitted background spectral index is compatible with the Fermi-Large Area Telescope (LAT) data from the same region. This possibility can be potentially tested with the observations of other high energy cosmic rays.

Cosmic Rays from Heavy Dark Matter from the Galactic Center


Antonio L. MAROTO

Departamento de Física Teórica I, Universidad Complutense de Madrid, E-28040 Madrid, Spain



The European Physical Society Conference on High Energy Physics 18-24 July, 2013 Stockholm, Sweden

1 Gamma rays from the galactic center and the dark matter hypothesis

We have studied the possibility of explaining the gamma ray data [1] observed by the High Energy Stereoscopic System (HESS) from the central part of our galaxy by being partially produced by Dark Matter (DM) annihilations or decays [2, 3]. The complexity of the region and the amount of delocalized emitting sources justifies the hypothesis of a non-negligible background. DM annihilations or decays into single standard model particle-antiparticle channels provide good fits if the DM signal is complemented with such a background, that it is consistent with Fermi-LAT measurements [4].

The fits return a DM mass between and depending on the studied channel [5]. Leptonic channels are clearly disfavored, but hadronic channels such us the , or electroweak channels such as the and channels, offer very good consistency with , and respectively [2]. The morphology of the signal requires compressed dark halos as the ones that take into account baryonic dissipation [6].

A motivated DM candidate which could have high enough masses and account for the right abundance of DM as a thermal relic, is the branon field [7, 8], which corresponds to brane fluctuations in flexible brane-world models. We have proved that a branon mass of TeV provides a good fit to the mentioned HESS data [2].

2 Conclusions and future work

The heavy DM masses required for fitting the HESS data are practically unconstrained by direct detection searches or colliders experiments [9]. On the contrary, this possibility can be tested with the observations of other cosmic-rays [10] from the GC and from other astrophysical objects. For example, high energy neutrinos could confirm this hypothesis at IceCube or ANTARES for angular resolutions below one degree.


This work has been supported by MICINN (Spain) project numbers FIS2011-23000, FPA2011-27853-01 and Consolider-Ingenio MULTIDARK CSD2009-00064.


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