Super heavy dark matter and UHECR anisotropy at low energy

Abstract

Super Heavy quasi-stable particles are naturally produced in the early universe and could represent a substantial fraction of the Dark Matter: the so-called Super Heavy Dark Matter (SHDM). The decay of SHDM represents also a possible source of Ultra High Energy Cosmic Rays (UHECR), with a reliably calculated spectrum of the particles produced in the decay (∝ E −1.9 ). The SHDM model for the production of UHECR can explain quantitatively only the excess of UHE events observed by AGASA. In the case of an observed spectrum not showing the AGASA excess the SHDM model can provide only a subdominant contribution to the UHECR flux. We discuss here the basic features of SHDM for the production of a subdominant UHECR flux, we refer our study to the possible signatures of the model at the Auger observatory discussing in particular the expected chemical composition and anisotropy.

Super Heavy Dark Matter in light of BICEP2, Planck and Ultra High Energy Cosmic Rays Observations

“…Following [25,27], on very general grounds, we can assume that the SHDM decay produces a pair of quark anti-quark that gives rise to a parton cascade, producing SM particles through the subsequent hadronization process. The basic signatures of the SHDM decay process are three: (i) SHDM particles (as any other DM particle) cluster gravitationally and accumulate in the halo of our Galaxy with an average density of ρ halo X ≃ 0.3 GeV/cm 3 ; (ii) in the hadronic cascades the most abundant particle produced are pions, therefore UHE neutrinos and photons are the most abundant particles expected on Earth; (iii) the noncentral position of the sun in the Galactic halo results in an anisotropic flux of the SHDM decay products [41,42].…”

LUNASKA experiments using the Australia Telescope Compact Array to search for ultrahigh energy neutrinos and develop technology for the lunar Cherenkov technique

“…The February 2008 run was tailored to ''target'' a broad ( * 20 ) region of the sky near the Galactic Center, harbouring the closest supermassive black hole to Earth, and a potential accelerator of UHE CR. The Galactic Center may also be a source of UHE CR and neutrinos through the decay of massive particles in its dark matter halo (see [37] and references therein). Preliminary calculations showed that for beam-sizes similar to that of the ATCA, the greatest total effective aperture (and hence sensitivity to an isotropic or very broadly-distributed flux) is achieved when pointing the antennas at the center of the Moon, so all the limb is at approximately the half power point of the antenna beam.…”

Supersymmetric superheavy dark matter

“…The observable consequences of meta-stable SHDM were discussed already in detail in Refs. [39,40], while the prospects to detect DM in the form of stable superheavy neutralinos despite of their small number density and annihilation cross section will be discussed in a subsequent work [31].…”