We report on measurements of the all-particle cosmic ray energy spectrum and composition in the PeV to EeV energy range using 3 years of data from the IceCube Neutrino Observatory. The IceTop ...detector measures cosmic ray induced air showers on the surface of the ice, from which the energy spectrum of cosmic rays is determined by making additional assumptions about the mass composition. A separate measurement is performed when IceTop data are analyzed in coincidence with the high-energy muon energy loss information from the deep in-ice IceCube detector. In this measurement, both the spectrum and the mass composition of the primary cosmic rays are simultaneously reconstructed using a neural network trained on observables from both detectors. The performance and relative advantages of these two distinct analyses are discussed, including the systematic uncertainties and the dependence on the hadronic interaction models, and both all-particle spectra as well as individual spectra for elemental groups are presented.
Inelasticity, the fraction of a neutrino’s energy transferred to hadrons, is a quantity of interest in the study of astrophysical and atmospheric neutrino interactions at multi-TeV energies with ...IceCube. In this work, a sample of contained neutrino interactions in IceCube is obtained from five years of data and classified as 2650 tracks and 965 cascades. Tracks arise predominantly from charged-current νμ interactions, and we demonstrate that we can reconstruct their energy and inelasticity. The inelasticity distribution is found to be consistent with the calculation of Cooper-Sarkar et al. across the energy range from ∼1 to ∼100 TeV. Along with cascades from neutrinos of all flavors, we also perform a fit over the energy, zenith angle, and inelasticity distribution to characterize the flux of astrophysical and atmospheric neutrinos. The energy spectrum of diffuse astrophysical neutrinos is described well by a power law in both track and cascade samples, and a best-fit index γ=2.62±0.07 is found in the energy range from 3.5 TeV to 2.6 PeV. Limits are set on the astrophysical flavor composition and are compatible with a ratio of (13∶13∶13)⊕. Exploiting the distinct inelasticity distribution of νμ and ν¯μ interactions, the atmospheric νμ to ν¯μ flux ratio in the energy range from 770 GeV to 21 TeV is found to be 0.77−0.25+0.44 times the calculation by Honda et al. Lastly, the inelasticity distribution is also sensitive to neutrino charged-current charm production. The data are consistent with a leading-order calculation, with zero charm production excluded at 91% confidence level. Future analyses of inelasticity distributions may probe new physics that affects neutrino interactions both in and beyond the Standard Model.
We present a search for a light sterile neutrino using three years of atmospheric neutrino data from the DeepCore detector in the energy range of approximately 10–60 GeV. DeepCore is the low-energy ...subarray of the IceCube Neutrino Observatory. The standard three-neutrino paradigm can be probed by adding an additional light (Δm412∼1 eV2) sterile neutrino. Sterile neutrinos do not interact through the standard weak interaction and, therefore, cannot be directly detected. However, their mixing with the three active neutrino states leaves an imprint on the standard atmospheric neutrino oscillations for energies below 100 GeV. A search for such mixing via muon neutrino disappearance is presented here. The data are found to be consistent with the standard three-neutrino hypothesis. Therefore, we derive limits on the mixing matrix elements at the level of |Uμ4|2<0.11 and |Uτ4|2<0.15 (90% C.L.) for the sterile neutrino mass splitting Δm412=1.0 eV2.
A search for high-energy neutrinos interacting within the IceCube detector between 2010 and 2012 provided the first evidence for a high-energy neutrino flux of extraterrestrial origin. Results from ...an analysis using the same methods with a third year (2012-2013) of data from the complete IceCube detector are consistent with the previously reported astrophysical flux in the 100 TeV-PeV range at the level of 10(-8) GeV cm-2 s-1 sr-1 per flavor and reject a purely atmospheric explanation for the combined three-year data at 5.7σ. The data are consistent with expectations for equal fluxes of all three neutrino flavors and with isotropic arrival directions, suggesting either numerous or spatially extended sources. The three-year data set, with a live time of 988 days, contains a total of 37 neutrino candidate events with deposited energies ranging from 30 to 2000 TeV. The 2000-TeV event is the highest-energy neutrino interaction ever observed.
A diffuse flux of astrophysical neutrinos above 100 TeV has been observed at the IceCube Neutrino Observatory. Here we extend this analysis to probe the astrophysical flux down to 35 TeV and analyze ...its flavor composition by classifying events as showers or tracks. Taking advantage of lower atmospheric backgrounds for showerlike events, we obtain a shower-biased sample containing 129 showers and 8 tracks collected in three years from 2010 to 2013. We demonstrate consistency with the (fe:fμ:fτ)⊕≈(1:1:1)⊕ flavor ratio at Earth commonly expected from the averaged oscillations of neutrinos produced by pion decay in distant astrophysical sources. Limits are placed on nonstandard flavor compositions that cannot be produced by averaged neutrino oscillations but could arise in exotic physics scenarios. A maximally tracklike composition of (0:1:0)⊕ is excluded at 3.3σ, and a purely showerlike composition of (1:0:0)⊕ is excluded at 2.3σ.
The IceCube Neutrino Observatory has observed a diffuse flux of TeV-PeV astrophysical neutrinos at 5.7sigma significance from an all-flavor search. The direct detection of tau neutrinos in this flux ...has yet to occur. Tau neutrinos become distinguishable from other flavors in IceCube at energies above a few hundred TeV, when the cascade from the tau neutrino charged current interaction becomes resolvable from the cascade from the tau lepton decay. This paper presents results from the first dedicated search for tau neutrinos with energies between 214 TeV and 72 PeV in the full IceCube detector. The analysis searches for IceCube optical sensors that observe two separate pulses in a single event-one from the tau neutrino interaction and a second from the tau decay. No candidate events were observed in three years of IceCube data. For the first time, a differential upper limit on astrophysical tau neutrinos is derived around the PeV energy region, which is nearly 3 orders of magnitude lower in energy than previous limits from dedicated tau neutrino searches.
High-energy neutrino emission has been predicted for several short-lived astrophysical transients including gamma-ray bursts (GRBs), core-collapse supernovae with choked jets, and neutron star ...mergers. IceCube's optical and x-ray follow-up program searches for such transient sources by looking for two or more muon neutrino candidates in directional coincidence and arriving within 100 s. The measured rate of neutrino alerts is consistent with the expected rate of chance coincidences of atmospheric background events and no likely electromagnetic counterparts have been identified in Swift follow-up observations. Here, we calculate generic bounds on the neutrino flux of short-lived transient sources. Assuming an E^{-2.5} neutrino spectrum, we find that the neutrino flux of rare sources, like long gamma-ray bursts, is constrained to <5% of the detected astrophysical flux and the energy released in neutrinos (100 GeV to 10 PeV) by a median bright GRB-like source is <10^{52.5} erg. For a harder E^{-2.13} neutrino spectrum up to 30% of the flux could be produced by GRBs and the allowed median source energy is <10^{52} erg. A hypothetical population of transient sources has to be more common than 10^{-5} Mpc^{-3} yr^{-1} (5×10^{-8} Mpc^{-3} yr^{-1} for the E^{-2.13} spectrum) to account for the complete astrophysical neutrino flux.
In this paper, we present the physics performance of the ESSnuSB experiment in the standard three flavor scenario using the updated neutrino flux calculated specifically for the ESSnuSB configuration ...and updated migration matrices for the far detector. Taking conservative systematic uncertainties corresponding to a normalization error of Formula omitted for signal and Formula omitted for background, we find that there is Formula omitted Formula omitted CP violation discovery sensitivity for the baseline option of 540 km (360 km) at Formula omitted. The corresponding fraction of Formula omitted for which CP violation can be discovered at more than Formula omitted is Formula omitted. Regarding CP precision measurements, the Formula omitted error associated with Formula omitted is around Formula omitted and with Formula omitted is around Formula omitted Formula omitted for the baseline option of 540 km (360 km). For hierarchy sensitivity, one can have Formula omitted sensitivity for 540 km baseline except Formula omitted and Formula omitted sensitivity for 360 km baseline for all values of Formula omitted. The octant of Formula omitted can be determined at Formula omitted for the values of: Formula omitted ( Formula omitted and Formula omitted) for baseline of 540 km (360 km). Regarding measurement precision of the atmospheric mixing parameters, the allowed values at Formula omitted are: Formula omitted ( Formula omitted) and Formula omitted eV Formula omitted eV Formula omitted ( Formula omitted eV Formula omitted eV Formula omitted) for the baseline of 540 km (360 km).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Updated physics performance of the ESSnuSB experiment Alekou, A.; Baussan, E.; Blaskovic Kraljevic, N. ...
The European physical journal. C, Particles and fields,
12/2021, Letnik:
81, Številka:
12
Journal Article
Recenzirano
Odprti dostop
In this paper, we present the physics performance of the ESSnuSB experiment in the standard three flavor scenario using the updated neutrino flux calculated specifically for the ESSnuSB configuration ...and updated migration matrices for the far detector. Taking conservative systematic uncertainties corresponding to a normalization error of
5
%
for signal and
10
%
for background, we find that there is
10
σ
(
13
σ
)
CP violation discovery sensitivity for the baseline option of 540 km (360 km) at
δ
CP
=
±
90
∘
. The corresponding fraction of
δ
CP
for which CP violation can be discovered at more than
5
σ
is
70
%
. Regarding CP precision measurements, the
1
σ
error associated with
δ
CP
=
0
∘
is around
5
∘
and with
δ
CP
=
-
90
∘
is around
14
∘
(
7
∘
)
for the baseline option of 540 km (360 km). For hierarchy sensitivity, one can have
3
σ
sensitivity for 540 km baseline except
δ
CP
=
±
90
∘
and
5
σ
sensitivity for 360 km baseline for all values of
δ
CP
. The octant of
θ
23
can be determined at
3
σ
for the values of:
θ
23
>
51
∘
(
θ
23
<
42
∘
and
θ
23
>
49
∘
) for baseline of 540 km (360 km). Regarding measurement precision of the atmospheric mixing parameters, the allowed values at
3
σ
are:
40
∘
<
θ
23
<
52
∘
(
42
∘
<
θ
23
<
51
.
5
∘
) and
2.485
×
10
-
3
eV
2
<
Δ
m
31
2
<
2.545
×
10
-
3
eV
2
(
2.49
×
10
-
3
eV
2
<
Δ
m
31
2
<
2.54
×
10
-
3
eV
2
) for the baseline of 540 km (360 km).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Hands‐on dissections using cadaveric tissues for neuroanatomical education are not easily available in many educational institutions due to financial, safety, and ethical factors. Supplementary ...pedagogical tools, for instance, 3D models of anatomical specimens acquired with photogrammetry are an efficient alternative to democratize the 3D anatomical data. The aim of this study was to describe a technical guideline for acquiring realistic 3D anatomic models with photogrammetry and to improve the teaching and learning process in neuroanatomy. Seven specimens with different sizes, cadaveric tissues, and textures were used to demonstrate the step‐by‐step instructions for specimen preparation, photogrammetry setup, post‐processing, and display of the 3D model. The photogrammetry scanning consists of three cameras arranged vertically facing the specimen to be scanned. In order to optimize the scanning process and the acquisition of optimal images, high‐quality 3D models require complex and challenging adjustments in the positioning of the specimens within the scanner, as well as adjustments of the turntable, custom specimen holders, cameras, lighting, computer hardware, and its software. MeshLab® software was used for editing the 3D model before exporting it to MedReality® (Thyng, Chicago, IL) and SketchFab® (Epic, Cary, NC) platforms. Both allow manipulation of the models using various angles and magnifications and are easily accessed using mobile, immersive, and personal computer devices free of charge for viewers. Photogrammetry scans offer a 360° view of the 3D models ubiquitously accessible on any device independent of operating system and should be considered as a tool to optimize and democratize the teaching of neuroanatomy.
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