Search results for " Neutrino"
showing 10 items of 727 documents
Analysis of the 4-year IceCube high-energy starting events
2016
After four years of data taking, the IceCube neutrino telescope has detected 54 high-energy starting events (HESE, or contained-vertex events) with deposited energies above 20TeV. They represent the first ever detection of high-energy extraterrestrial neutrinos and therefore, the first step in neutrino astronomy. In order to study the energy, flavor and isotropy of the astrophysical neutrino flux arriving at Earth, we perform different analyses of two different deposited energy intervals, [10 TeV $-$ 10 PeV] and [60 TeV $-$ 10 PeV]. We first consider an isotropic unbroken power-law spectrum and constrain its shape, normalization and flavor composition. Our results are in agreement with the …
Fuzzy Dark Matter and Non-Standard Neutrino Interactions
2018
We discuss novel ways in which neutrino oscillation experiments can probe dark matter. In particular, we focus on interactions between neutrinos and ultra-light ("fuzzy") dark matter particles with masses of order $10^{-22}$ eV. It has been shown previously that such dark matter candidates are phenomenologically successful and might help ameliorate the tension between predicted and observed small scale structures in the Universe. We argue that coherent forward scattering of neutrinos on fuzzy dark matter particles can significantly alter neutrino oscillation probabilities. These effects could be observable in current and future experiments. We set new limits on fuzzy dark matter interacting…
Update on decaying and annihilating heavy dark matter with the 6-year IceCube HESE data
2019
In view of the IceCube's 6-year high-energy starting events (HESE) sample, we revisit the possibility that the updated data may be better explained by a combination of neutrino fluxes from dark matter decay and an isotropic astrophysical power-law than purely by the latter. We find that the combined two-component flux qualitatively improves the fit to the observed data over a purely astrophysical one, and discuss how these updated fits compare against a similar analysis done with the 4-year HESE data. We also update fits involving dark matter decay via multiple channels, without any contribution from the astrophysical flux. We find that a DM-only explanation is not excluded by neutrino data…
Neutrinos confronting large extra dimensions
2001
We study neutrino physics in a model with one large extra dimension. We assume the existence of two four-dimensional branes in the five-dimensional space-time, one for the ordinary particles and the other one for mirror particles, and we investigate neutrino masses and mixings in this scheme. Comparison of experimental neutrino data with the predictions of the model leads to various restrictions on the parameters of the model. For instance, the size of the extra dimension, R, turns out to be bounded from below. Cosmological considerations seem to favor a large R. The usual mixing schemes proposed as solutions to the solar and atmospheric neutrino anomalies are compatible with our model.
Neutrinos properties beyond the Standard Model
1997
The present observational status of neutrino physics is sketched, with emphasis on the hints that follow from solar and atmospheric neutrino observations, as well as dark matter. I also briefly review the ways to account for the observed anomalies and some of their implications
Constraints on light asymmetric dark matter from solar neutrinos
2010
We study the effect of dark matter (DM) particles in the Sun, focusing in particular on the possible reduction of the solar neutrinos flux due to the energy carried away by DM particles from the innermost regions of the Sun, and to the consequent reduction of the temperature of the solar core. In the very low-mass range between 4 and 10 GeV, recently advocated to explain the findings of the DAMA and CoGent experiments, the effects on neutrino fluxes are detectable only for DM models with very small, or vanishing, self-annihilation cross section, such as the so-called asymmetric DM models, and we study the combination of DM masses and Spin Dependent cross sections which can be excluded with …
Summary of Working Group 4: High Energy Neutrino Telescopes
2007
The field of high-energy neutrino astronomy is rapidly developing. A number of new experiments are currently being deployed and developed. Additionally, the recent successes of TeV gamma-ray astronomy have exciting implications for future neutrino telescopes. Here we will summarize these and other issues as they were discussed in the TeV II workshop's neutrino astronomy working group.
Implications of new generations on neutrino masses
2011
We explore the possible implications that new families, that are being searched for at the LHC, would have on neutrino masses. In particular, we have explored the possibility that the smallness of the observed neutrino masses is naturally understood in a modified version of the Standard Model (SM) with complete extra generations of fermions, i.e., that have right-handed neutrinos, in which neutrino masses are generated at two loops. With one extra family it is not possible to fit the observed spectrum of masses and mixings. However, the radiative mass generated provides an important constraint in these kind of models, so the neutrino masses do not exceed their cosmological bound. Within the…
Nuclear and weak interaction aspects of neutrinoless double beta decay: Recent results
2012
The determination of the value of the light neutrino mass, as well as the determination of the nature of the neutrino, are two of the fundamental questions which motivate the experimental search of signals of neutrinoless double beta decay transitions. Here, we shall review some of the the essentials of the theory, based on both nuclear structure and elementary particle physics, relevant for the understanding of the problem.
Results and status from the HARP and MIPP hadron production experiments
2008
Recent results and status from the HARP and MIPP hadron production experiments are reviewed. After a brief description of the experimental setups and the large amounts of data collected with those, we emphasize the relevance of precision hadron production measurements for neutrino physics. Three types of neutrino sources are discussed: conventional accelerator-based neutrino beams, advanced neutrino sources, and atmospheric neutrinos. We conclude by discussing prospects from additional hadron production measurements to be expected in the near future.