No Arabic abstract
Recent analyses of the diffuse TeV-PeV neutrino flux highlight a tension between different Ice-Cube data samples that strongly suggests a two-component scenario rather than a single steep power-law flux. Such a tension is further strengthened once the latest ANTARES data are also taken into account. Remarkably, both experiments show an excess in the same energy range (40-200 TeV), whose origin could intriguingly be related to dark matter. In this paper, I discuss the combined analysis of IceCube and ANTARES data, highlighting the presence of the low-energy excess. Moreover, I update the results of the angular analysis for potential dark matter signals, previously obtained with the 4-year High-Energy Starting Events data. In particular, I statistically compare the distribution of the arrival directions of 6-year IceCube events belonging to the low-energy excess with the angular distributions expected in case of different dark matter neutrino signals.
The hypothesis of two different components in the high-energy neutrino flux observed with IceCube has been proposed to solve the tension among different data-sets and to account for an excess of neutrino events at 100 TeV. In addition to a standard astrophysical power-law component, the second component might be explained by a different class of astrophysical sources, or more intriguingly, might originate from decaying or annihilating dark matter. These two scenarios can be distinguished thanks to the different expected angular distributions of neutrino events. Neutrino signals from dark matter are indeed expected to have some correlation with the extended galactic dark matter halo. In this paper, we perform angular power spectrum analyses of simulated neutrino sky maps to investigate the two-component hypothesis with a contribution from dark matter. We provide current constraints and expected sensitivity to dark matter parameters for future neutrino telescopes such as IceCube-Gen2 and KM3NeT. The latter is found to be more sensitive than IceCube-Gen2 to look for a dark matter signal at low energies towards the galactic center. Finally, we show that after 10 years of data-taking, they will firmly probe the current best-fit scenario for decaying dark matter by exploiting the angular information only.
In the next decades, ultra-high-energy neutrinos in the EeV energy range will be potentially detected by next-generation neutrino telescopes. Although their primary goals are to observe cosmogenic neutrinos and to gain insight into extreme astrophysical environments, they can also indirectly probe the nature of dark matter. In this paper, we study the projected sensitivity of up-coming neutrino radio telescopes, such as RNO-G, GRAND and IceCube-gen2 radio array, to decaying dark matter scenarios. We investigate different dark matter decaying channels and masses, from $10^7$ to $10^{15}$ GeV. By assuming the observation of cosmogenic or newborn pulsar neutrinos, we forecast conservative constraints on the lifetime of heavy dark matter particles. We find that these limits are competitive with and highly complementary to previous multi-messenger analyses.
We investigate different neutrino signals from the decay of dark matter particles to determine the prospects for their detection, and more specifically if any spectral signature can be disentangled from the background in present and future neutrino observatories. If detected, such a signal could bring an independent confirmation of the dark matter interpretation of the dramatic rise in the positron fraction above 10 GeV recently observed by the PAMELA satellite experiment and offer the possibility of distinguishing between astrophysical sources and dark matter decay or annihilation. In combination with other signals, it may also be possible to distinguish among different dark matter decay channels.
We perform a new dark matter hot spot analysis using ten years of public IceCube data. In this analysis we assume dark matter self-annihilates to neutrino pairs and treat the production sites as discrete point sources. For neutrino telescopes these sites will appear as hot spots in the sky, possibly outshining other standard model neutrino sources. Comparing to galactic center analyses, we show that this approach is a powerful tool and capable of setting the highest neutrino detector limits for dark matter masses between 10 TeV and 100 PeV. This is due to the inclusion of spatial information in addition to the typically used energy deposition in the analysis.
We explore the possibility of distinguishing neutrino mass hierarchies through the neutrino signal from dark matter annihilation at neutrino telescopes. We consider a simple extension of the standard model where the neutrino masses and mixing angles are obtained via the type-II seesaw mechanism as an explicit example. We show that future extensions of IceCube neutrino telescope may detect the neutrino signal from DM annihilation at the Galactic Center and inside the Sun, and differentiate between the normal and inverted mass hierarchies, in this model.