FIG 12 - uploaded by Samvel Ter-Antonyan
Content may be subject to copyright.
![Prompt atmospheric νµ + νµ neutrino fluxes in comparison to the expected flux of conventional atmospheric neutrinos (Honda et al. + H3a). Model predictions are represented by thin lines [8, 13, 14]. The red shaped area marks the theoretical uncertainty on the prediction of ERS08. Limits for each model are shown as thick lines in the corresponding line style and color in the valid energy range between 2.3 TeV and 360 TeV (see Tab. VI). The baseline model used here is the model ERS08 modified with the cosmic-ray parameterization by Gaisser et al. and is represented by the thick orange line. Other models are shown as published.](profile/Samvel-Ter-Antonyan/publication/258939231/figure/fig5/AS:667809847717893@1536229683967/Prompt-atmospheric-nm-nm-neutrino-fluxes-in-comparison-to-the-expected-flux-of.png)
Prompt atmospheric νµ + νµ neutrino fluxes in comparison to the expected flux of conventional atmospheric neutrinos (Honda et al. + H3a). Model predictions are represented by thin lines [8, 13, 14]. The red shaped area marks the theoretical uncertainty on the prediction of ERS08. Limits for each model are shown as thick lines in the corresponding line style and color in the valid energy range between 2.3 TeV and 360 TeV (see Tab. VI). The baseline model used here is the model ERS08 modified with the cosmic-ray parameterization by Gaisser et al. and is represented by the thick orange line. Other models are shown as published.
Source publication
A search for high-energy neutrinos was performed using data collected by the IceCube Neutrino Observatory from May 2009 to May 2010, when the array was running in its 59-string configuration. The data sample was optimized to contain muon neutrino induced events with a background contamination of atmospheric muons of less than 1%. These data, which...
Similar publications
The IceCube Neutrino Observatory is a cubic-kilometer detector at the geographic South Pole searching for astrophysical neutrinos. The main background for astrophysical neutrinos is leptons produced by cosmic ray air showers: neutrinos from the northern hemisphere and muons from the southern hemisphere. These atmospheric backgrounds are reduced usi...
A search for high-energy neutrinos was performed using data collected by the IceCube Neutrino Observatory from May 2009 to May 2010, when the array was running in its 59-string configuration. The data sample was optimized to contain muon neutrino induced events with a background contamination of atmospheric muons of less than 1%. These data, which...
On 2019 October 1, the IceCube Collaboration detected a muon track neutrino with a high probability of being of astrophysical origin, IC191001A. After a few hours, the tidal disruption event (TDE) AT2019dsg, observed by the Zwicky Transient Facility (ZTF), was indicated as the most likely counterpart of the IceCube track. More recently, the follow-...
Neutrino flares in the sky are searched for in data collected by IceCube between 2011 and 2021 May. This data set contains cascade-like events originating from charged-current electron neutrino and tau neutrino interactions and all-flavor neutral-current interactions. IceCube’s previous all-sky searches for neutrino flares used data sets consisting...
Citations
... This suppression, confirmed by multiple studies [20][21][22][23], suggests a transition from lighter to heavier particles as energies increase, hinting at profound processes occurring over cosmological distances. Such observations, including the setting of upper limits on the presence of photons [20,24,25], neutrinos [20,26,27], and neutrons [20,28] among these UHECRs, have been crucial in our quest to understand the universe. The observations of a shift in composition at energies beyond 3 × 10 18 eV [29,30] and a suppression in the flux above 4 × 10 19 eV, which could be indicative of the GZK cutoff-a theoretical prediction of energy loss over vast intergalactic travels, were made nearly sixty years ago [18,19]. ...
We investigate the effects of magnetic diffusion on the spectrum of ultra-high energy cosmic rays (UHECRs) from a cosmological perspective. To this end, we consider two modified theories of gravity (MTGs), namely, the f(R) gravity and a symmetric teleparallel gravity, also known as f(Q) gravity. Utilizing these two MTGs, we calculate the suppression in the flux of UHECRs for a collection of sources. Non-evolution (NE) and cosmic star formation rate (SFR) scenarios have been considered in our calculation of the suppression factor. This study also includes a mixed composition scenario involving the nuclei upto iron (Fe). Furthermore, we provide a parameterization of the suppression factor for the proton and also for the mixed compositions within the f(R) and f(Q) theories, considering both NE and SFR scenarios. The influence of the turbulent magnetic field on the suppression factor is also incorporated in our work. Comparative analysis of all our results with the standard CDM model reveals significant effects of MTGs on the suppression factor that the f(R) power-law model predicts the lowest suppression factor, while the f(Q) model predicts the highest, and interestingly the results from the standard model fall within the range predicted by these two cosmological models.
... This suppression has been confirmed by multiple studies [17][18][19][20]. Researchers have also set upper limits on the presence of photons [17,21,22], neutrinos [17,23,24], and neutrons [17,25] among the UHECRs. Evidence from the Pierre Auger Observatory suggests a shift from a lighter to a heavier composition as the energy of CRs increases beyond ∼ 3 × 10 18 eV [26,27]. ...
Anisotropy study of cosmic rays in the light of f(R) gravity.
... The values of the flux normalization and the spectral index, γ, are allowed to float and are fixed in a fit to data that contrasts predicted event rates vs. observed ones. Numerous analyses using IceCube data have used this procedure to measure the diffuse flux of astrophysical and atmospheric neutrinos [3,4,39,[77][78][79][80][81][82][83][84][85]. ...
Soon, a new generation of neutrino telescopes, presently under planning, will target the discovery of ultra-high-energy (UHE) neutrinos of cosmic origin, with energies higher than 100 PeV, that promise unique insight into astrophysics and particle physics. Yet, predictions of the UHE neutrino flux and interaction cross section -- whose measurement is co-dependent -- are laden with significant uncertainty that, if unaddressed, could misrepresent the capabilities to measure one or the other. To address this, we advocate for the joint measurement of the UHE neutrino spectrum and neutrino-nucleon cross section, including of their energy dependence, without assuming prior knowledge of either. We illustrate our methods by adopting empirical parametrizations of the neutrino spectrum, in forecasts geared to the planned radio array of the IceCube-Gen2 neutrino telescope. We warn against using simple parametrizations -- a simple power law or one augmented with an exponential cut-off -- that might fail to capture features of the spectrum that are commonplace in the predictions. We argue instead for the use of flexible parametrizations -- a piecewise power law or an interpolating polynomial -- that ensure accuracy. We report loose design targets for the detector energy and angular resolution that are compatible with those under present consideration.
... The IceCube Collaboration has observed high-energy astrophysical neutrinos since 2013 [82]. Two measurements of neutrino-nucleon cross sections have been reported. ...
We present a state-of-the-art prediction for cross sections of neutrino deeply inelastic scattering (DIS) from nucleon at high neutrino energies, , from 100 GeV to 1000 EeV ( GeV). Our calculations are based on the latest CT18 NNLO parton distribution functions (PDFs) and their associated uncertainties. In order to make predictions for the highest energies, we extrapolate the PDFs to small x according to several procedures and assumptions, thus affecting the uncertainties at ultra-high ; we quantify the uncertainties corresponding to these choices. Similarly, we quantify the uncertainties introduced by the nuclear corrections which are required to evaluate neutrino-nuclear cross sections for neutrino telescopes. These results can be applied to currently-running astrophysical neutrino observatories, such as IceCube, as well as various future experiments which have been proposed.
... The former has a harder spectrum than the latter and dominates at high-energy region. Below 100 TeV, however, atmospheric flux is three to four orders larger than the astrophysical flux [56]. Given the linear proportionality of neutrino-nucleon cross-section to neutrino energy E, spectral index 3.7 and 2 for atmospheric and astrophysical flux, respectively, the DIS event rate of atmospheric neutrinos in this energy range is three orders of magnitude larger than their astrophysical counterpart. ...
... The atmospheric neutrino flux below 10 TeV is taken from HKKM15 [63], and is extrapolated up to 1 PeV by fitting a standard parameterization in [56]. To reduce atmospheric muon background, only up-going neutrinos (zenith angle larger than 90 • ) are kept. ...
Dimuon events induced by charm-quark productions from neutrino deep inelastic scattering (DIS) processes have been studied in traditional DIS experiments for decades. The recent progress in neutrino telescopes makes it possible to search such dimuon events at energies far beyond laboratory scale. In this paper, we construct a simulation framework to calculate yields and distributions of dimuon signals in an IceCube-like km3 scale neutrino telescope. Due to experimental limitation in the resolution of double-track lateral distance, only dimuon produced outside the detector volume are considered. Detailed information about simulation results for ten years exposure is demonstrated. Both an earlier work [1] and our work study a similar situation, we therefore use that paper as a baseline to conduct comparisons. We then estimate the impacts of different calculation methods of muon energy losses, and find that, the average energy loss formula used in that work results in more events by contrast with Monte Carlo simulation. Finally, we study the experimental potential of dimuon searches under the hypothesis of single-muon background-only. Our results based on a simplified double-track reconstruction indicate a moderate sensitivity especially with the ORCA configuration. Further developments on both the reconstruction algorithm and possible detector designs are thus required, and are under investigation.
... By the time, when detector AMANDA at the South Pole was constructed, the Monte Carlo calculations of the atmospheric neutrinos (AN) spectra had been performed for the neutrino energies of no more than 10 TeV [12][13][14]. Later, these results were used to reconstruct the events in the IceCube [15] and Super-Kamiokande experiments. ...
Statistical analysis is performed of the atmospheric neutrino flux models as compared with the data of Frejus, AMANDA-II, IceCube, ANTARES, and Super-Kamiokande experiments. The analysis enables the evaluation of the confidence level of the flux models in comparison with atmospheric neutrino flux measurements. The flux calculations were performed in the framework of single computational scheme using a set of hadronic models combined with parameterizations of the cosmic rays spectrum by Zatsepin & Sokolskaya, and Hillas & Gaisser. The analysis showed satisfactory agreement of the conventional flux models with the measurements. The prompt neutrinos conrtibution obtained with a set of charm production models (QGSM, SIBYLL 2.3c, PROSA, GRRST, BEJKRSS, and GM-VFNS) is statistically negligible in the energy range covered by the neutrino telescopes.
... The atmospheric only hypothesis is disfavored by greater than 5σ in comparison to the single power-law astrophysical plus atmospheric flux hypothesis. Compared to constraints on the prompt normalization from other IceCube samples, the best-fit prompt normalization obtained in the background-only fit is in tension with these results [57,62,193]. Some constraints have been obtained when considering a single-power-law astrophysical component, and are thus dependent on this model assumption. ...
... Some constraints have been obtained when considering a single-power-law astrophysical component, and are thus dependent on this model assumption. However, the constraints from [193] predate the observation of high-energy extraterrestrial neutrinos and are conservative because this scenario is equivalent to zero contribution from the astrophysical flux. The latter results in a constraint of the prompt normalization of 3.80 times the ERS calculation [189] at 90 % C.L.; a model which is approximately 2.5 times larger than the benchmark model used in this analysis. ...
... Thus, e.g. we do not test cosmogenic [194] neutrino flux models, which predict neutrinos from cosmic rays interacting with the Northern sky muons IC59 [193] 3.80 × φERS -Northern sky muons IC86 [57] 1.06 × φERS -All-sky medium-energy starting cascades [62] 1.52 × φERS -HESE 7.5 years (this work) 9.82 × φBERSS 13.29 × φBERSS cosmic microwave background since they are expected to contribute at higher energies where dedicated IceCube searches exist [195]; see [196] for a recent discussion on the expected rate of cosmogenic flux in this analysis energy range. ...
The IceCube Neutrino Observatory has established the existence of a high-energy all-sky neutrino flux of astrophysical origin. This discovery was made using events interacting within a fiducial region of the detector surrounded by an active veto and with reconstructed energy above 60 TeV, commonly known as the high-energy starting event sample, or HESE. We revisit the analysis of the HESE sample with an additional 4.5 years of data, newer glacial ice models, and improved systematics treatment. This paper describes the sample in detail, reports on the latest astrophysical neutrino flux measurements, and presents a source search for astrophysical neutrinos. We give the compatibility of these observations with specific isotropic flux models proposed in the literature as well as generic power-law-like scenarios. Assuming , and an equal flux of neutrinos and antineutrinos, we find that the astrophysical neutrino spectrum is compatible with an unbroken power law, with a preferred spectral index of for the confidence interval.
... The QGSM flux [15] performed for α ψ (0) = 0 and the NSU spectrum was considered by IceCube collaborators as too optimistic prediction [57,58]. At the energies E ν > 10 6 GeV it exceeds the ERS result [22] by about 30%; however, part of this excess is related to the difference of the cosmic-ray spectra used. ...
We calculate the atmospheric flux of prompt neutrinos, produced in decays of the charmed particles at energies beyond 1 TeV. Cross sections of the D mesons and Λc+ baryons production in pA and πA collisions are calculated in the phenomenological quark–gluon string model (QGSM) which is updated using recent measurements of cross sections of the charmed meson production in the LHC experiments. A new estimate of the prompt atmospheric neutrino flux is obtained and compared with the limit from the IceCube experiment, and with predictions of other charm production models.
... The interesting feature of the Anisimov operator is that in addition to allow the production of a decoupled RH neutrino playing the role of DM particle, it also predicts a contribution, from RH neutrino DM decays, to the flux of very high energy neutrinos detectable at neutrino telescopes [1]. Therefore, the recent IceCube neutrino telescope discovery of a very high energy neutrino component in excess of the well known atmospheric contribution [6,7,8,9,10], prompts the question whether, in addition to an expected, though yet largely undetermined, astrophysical component, the IceCube signal might also receive a contribution of cosmological origin from DM decays. Initial analyses mainly focused on a scenario where heavy DM decays can explain the whole signal and in particular an excess of PeV neutrinos in early data [11,12,13]. ...
We present new results on the calculation of the dark matter relic abundance within the Higgs induced right-handed neutrino mixing model, solving density matrix equation. For a benchmark value of the dark matter mass , we show the evolution of the abundance and how this depends on reheat temperature, dark matter lifetime and source right-handed neutrino mass , with the assumption . We compare the results with those obtained within the Landau-Zener approximation showing that the latter largely overestimates the final dark matter abundance. However, we also notice that since in the density matrix formalism the production is non-resonant, this allows source right-handed neutrino masses below the W boson mass, making dark matter more stable at large values of its mass and this still allows an allowed region in the case of initial vanishing source right-handed neutrino abundance. For example, for , we find . Otherwise, for , one has to assume a thermalisation of the source right-handed neutrinos prior to the freeze-in of the dark matter abundance. In this case one has a large allowed range for the dark matter mass, depending on . For example, imposing , allowing also successful leptogenesis from decays, we find . We also comment on how an initial thermal source right-handed neutrino abundance can be justified and notice that our results suggest that also the interesting case , embaddable in usual high scale two right-handed neutrino seesaw models, might be viable.
... Following the same table the background associated to prompt neutrinos should be N prompt s ≤ 20 at 90% C.L. in 7.5 years. On the other hand that limit was derived based on [32], in which the upper limit on prompt neutrinos was 3.8×φ ERS , where φ ERS is the theoretical flux of prompt neutrinos calculated in [33]. Recently the upper limit on prompt neutrinos has been improved, reaching the level of 1.06 × φ ERS in [14]. ...
In this work we present an updated study of the flavor composition suggested by astrophysical neutrinos observed by IceCube. The main novelties compared to previous studies are the following: (1) we use the most recent measurements, namely 8 years of throughgoing muons and 7.5 years of High Energy Starting Events (HESE); (2) we consider a broken power law spectrum, in order to be consistent with the observations between 30 TeV and few PeV; (3) we use the throughgoing muon flux to predict the number of astrophysical HESE tracks. We show that accounting for the three previous elements, the result favors surprisingly the hypothesis of neutrinos produced by neutron decay, disfavoring the standard picture of neutrinos from pion decay at 2.0 and the damped muons regime at , once the atmospheric background is considered. Although the conventional scenario is not yet completely ruled out in the statistically and alternative interpretations are also plausible, such as an energy spectrum characterized by a non trivial shape, this intriguing result may suggest new directions for both theoretical interpretation and experimental search strategies.
