54 research outputs found
A novel method to extract dark matter parameters from neutrino telescope data
Recently it has been shown that when the Dark Matter (DM) particles captured
in the Sun directly annihilate into neutrino pairs, the oscillatory terms in
the oscillation probability do not average to zero and can lead to a seasonal
variation as the distance between the Sun and Earth changes in time. In this
paper, we explore this feature as a novel method to extract information on the
properties of dark matter. We show that by studying the variation of the flux
over a few months, it would in principle be possible to derive the DM mass as
well as new information on the flavor structure of the DM annihilation modes.
In addition to analytic analysis, we present the results of our numerical
calculations that take into account scattering and regeneration of neutrinos
traversing the Sun.Comment: 18 pages, 2 figures, 3 tables; comments and 1 figure added,
acknowledgment added, published versio
On the robustness of IceCube's bound on sterile neutrinos in the presence of non-standard interactions
The mixing parameters of sterile neutrino(s) preferred by the MiniBooNE and
LNSD experiments are in strong tension with the exclusion limit from the
IceCube experiment. Recently it has been claimed that by considering the
non-standard neutrino interactions (NSI) in addition to the sterile neutrino,
the IceCube's limit can be relaxed and the tension can be reconciled; a baroque
scenario as it has been called. We will show that this claim is just an
artifact originating from the energy cuts of the chosen datasets. Contrary to
the claim, by turning on the NSI and fixing the NSI parameters to the proposed
values, not only the IceCube's limit on sterile neutrino cannot be alleviated,
but in fact the tension will be aggravated. The reconciliation, more
appropriately, can be called surreal.Comment: 15 pages, 4 figures; v2: a few clarifications have been adde
Implications of the Pseudo-Dirac Scenario for Ultra High Energy Neutrinos from GRBs
The source of Ultra High Energy Cosmic Rays (UHECR) is still an unresolved
mystery. Up until recently, sources of Gamma Ray Bursts (GRBs) had been
considered as a suitable source for UHECR. Within the fireball model, the UHECR
produced at GRBs should be accompanied with a neutrino flux detectable at the
neutrino telescope such as IceCube. Recently, IceCube has set an upper bound on
the neutrino flux accompanied by GRBs about 3.7 times below the prediction. We
investigate whether this deficit can be explained by the oscillation of the
active neutrinos to sterile neutrinos en route from the source to the detectors
within the pseudo-Dirac scenario. We then discuss the implication of this
scenario for diffuse supernova relic neutrinos.Comment: 14 pages, 5 figures; v2: figures added, discussion improved, matches
the version published in JCA
Gamma-ray bounds from EAS detectors and heavy decaying dark matter constraints
The very high energy Galactic -ray sky is partially opaque in the
() PeV energy range. In the light of the recently detected high energy
neutrino flux by IceCube, a comparable very high energy -ray flux is
expected in any scenario with a sizable Galactic contribution to the neutrino
flux. Here we elaborate on the peculiar energy and anisotropy features imposed
upon these very high energy -rays by the absorption on the cosmic
microwave background photons and Galactic interstellar light. As a notable
application of our considerations, we study the prospects of probing the
PeV-scale decaying DM scenario, proposed as a possible source of IceCube
neutrinos, by extensive air shower (EAS) cosmic ray experiments. In particular,
we show that anisotropy measurements at EAS experiments are already sensitive
to ~s and future measurements, using
better gamma/hadron separation, can improve the limit significantly.Comment: 23 pages, 9 figures; v2: the discussion of anisotropy in section 4
improved, matches the version published at JCA
Are IceCube neutrinos unveiling PeV-scale decaying dark matter?
Recent observations by IceCube, notably two PeV cascades accompanied by
events at energies ~ (30-400) TeV, are clearly in excess over atmospheric
background fluxes and beg for an astroparticle physics explanation. Although
some models of astrophysical accelerators can account for the observations
within current statistics, intriguing features in the energy and possibly
angular distributions of the events make worth exploring alternatives. Here, we
entertain the possibility of interpreting the data with a few PeV mass scale
decaying Dark Matter, with lifetime of the order of 10^27 s. We discuss generic
signatures of this scenario, including its unique energy spectrum distortion
with respect to the benchmark expectation for astrophysical
sources, as well as peculiar anisotropies. A direct comparison with the data
show a good match with the above-mentioned features. We further discuss
possible future checks of this scenario.Comment: 7 pages, 3 figures; v2: discussion improved, reference added, matches
the version published in JCA
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