Status of superheavy dark matter

Tortorici

2008

Astroparticle Physics

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.

Section: Introductionmentioning

confidence: 85%

Super heavy dark matter and UHECR anisotropy at low energy

Tortorici

2008

Astroparticle Physics

“…The most striking signature of SHDM models is represented by the peculiar composition of UHECR at the highest energies, with a flux dominated by neutrinos and gamma-rays. This signature is a precise outcome of the sole decaying dynamics of SHDM particles [11] and it is shown in figure 8 where the ratio of neutrinos, gamma-rays and protons coming from SHDM decays is plotted.…”

Section: Super Heavy Dark Mattermentioning

confidence: 99%

“…There are several different recipes discussed in literature based on both MC and analytical computations (see [11,12] and references therein) all giving the same behaviour of the expected fluxes dN/dE ∝ E −1.9 , independently of the particle type, with a photon/nucleon fraction γ/N 2 ÷ 3 and a neutrino/nucleon fraction ν/N 3 ÷ 4, quite independent of the energy.…”

Section: Super Heavy Dark Mattermentioning

confidence: 99%

“…Following [11], on very general grounds, we can assume that SHDM decay gives rise to a quark anti-quark pair with subsequent parton cascades that, hadronizing, produce Standard Model (SM) particles. The basic signatures of these kind of decays are three: (i) SHDM (as any other DM particle) cluster gravitationally and accumulate in the halo of our Galaxy with an average density ρ halo X 0.3 GeV/cm 3 ; (ii) in the hadronic cascades the most abundant particles produced are pions, therefore UHE neutrinos and gamma-rays are the most abundant particles expected on Earth, (iii) The non-central position of the Sun in the galactic halo results in an anisotropic flux of the decay products [39].…”

Section: Super Heavy Dark Mattermentioning

confidence: 99%

“…relic particles created by rapidly varying gravitational fields during inflation (see [11] and reference therein). One of the key expectations of this kind of models is the huge amount of neutrinos (and gamma-rays) produced at energies 10 20 eV [12].…”

Section: Introductionmentioning

confidence: 99%

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Ultra High Energy Cosmic Rays and Neutrinos

Nuclear and Particle Physics Proceedings

2016

We discuss the production of ultra high energy neutrinos coming from the propagation of ultra high energy cosmic rays and in the framework of top-down models for the production of these extremely energetic particles. We show the importance of the detection of ultra high energy neutrinos that can be a fundamental diagnostic tool to solve the discrepancy in the observed chemical composition of ultra high energy cosmic rays and, at the extreme energies, can unveil new physics in connection with the recent cosmological observations of the possible presence of tensor modes in the fluctuation pattern of the cosmic microwave background.

Selected Topics in Cosmic Ray Physics

Multiple Messengers and Challenges in Astroparticle Physics

Blasi

Mitri

et al. 2018

The search for the origin of cosmic rays is as active as ever, mainly driven by new insights provided by recent pieces of observation. Much effort is being channelled in putting the so called supernova paradigm for the origin of galactic cosmic rays on firmer grounds, while at the highest energies we are trying to understand the observed cosmic ray spectra and mass composition and relating them to potential sources of extragalactic cosmic rays. Interestingly, a topic that has acquired a dignity of its own is the investigation of the transition region between the galactic and extragalactic components, once associated with the ankle and now increasingly thought to be taking place at somewhat lower energies. Here we summarize recent developments in the observation and understanding of galactic and extragalactic cosmic rays and we discuss the implications of such findings for the modelling of the transition between the two.