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FADC traces of stations at 1 km from the shower core for two real showers of 5 EeV. (a) shower arriving in the early stages of development (“young” shower). (b) “old” extensive air shower ( θ ~ 80 ° ) .
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The observation of ultrahigh energy (UHE) neutrinos has become a priority in
experimental astroparticle physics. UHE neutrinos can be detected with a
variety of techniques. In particular, neutrinos can interact in the atmosphere
(downward-going neutrinos) or in the Earth crust (Earth-skimming neutrinos),
producing air showers that can be observed w...
Similar publications
Ultra-high-energy cosmic rays (UHECRs) are studied with giant ground-based detector systems recording extensive air showers, induced by cosmic ray particles in the atmosphere. Research at the Pierre Auger Observatory - the largest of such detectors ever built -- largely contributed to a number of breakthroughs and dramatically advanced our understa...
The observation of ultrahigh energy neutrinos (UHEνs) has become a priority in experimental astroparticle physics. UHEνs can be detected with a variety of techniques. In particular, neutrinos can interact in the atmosphere (downward-going ν) or in the Earth crust (Earth-skimming ν), producing air showers that can be observed with arrays of detector...
The present-day status of the problem of searching for primary cosmic gamma
rays at energies above 100 TeV is discussed, as well as a proposal for a new
experiment in this field. It is shown that an increase of the area of the muon
detector of the Carpet-2 air shower array up to 410 square meters, to be
realized in 2016, will make this array quite...
In this paper, ultra-high-energy cosmic rays (UHECRs) are studied with giant ground-based detector systems recording extensive air showers, induced by cosmic ray particles in the atmosphere. Research at the Pierre Auger Observatory — the largest of such detectors ever built — largely contributed to a number of breakthroughs and dramatically advance...
Proc. of the Atmospheric Monitoring for High-Energy Astroparticle Detectors (AtmoHEAD) Conference, Saclay (France), June 10-12, 2013 arXiv 1403.4816. Pas de proceedings pour cette communication au 20/03/2014
Citations
... The number of expected neutrinos could benefit from the topography surrounding the experiments, such as mountains, as suggested in [24,25]. These experiments are usually placed at high altitudes on plateaus at the foot of mountains. ...
We assess the capabilities of a ground-based gamma-ray observatory to detect astrophysical neutrinos with energies in the 100 TeV to 100 PeV range. The identification of these events is done through the measurement of very inclined extensive air showers induced by downward-going and upward-going neutrinos. The discrimination of neutrino-induced showers in the overwhelming cosmic-ray background is achieved by analyzing the balance of the total electromagnetic and muonic signals of the shower at the ground. We demonstrate that a km2-scale wide-field-of-view ground-based gamma-ray observatory could detect a couple of very-high- to ultrahigh-energy neutrino events per year with a reasonable pointing accuracy, making it an interesting facility for multimessenger studies with both photons and neutrinos.
... Furthermore, the fluxes, composition, and the production mechanisms of UHECRs sensitively depend on the origin. Thus, they still need to be clarified [10][11][12][13][14][15]. From the observation of UHECRs up to E CR ∼ 10 21 eV, we also naturally expect the guaranteed existence of ultra-high-energy (UHE) neutrinos, produced by the Greisen-Zatsepin-Kuzmin (GZK) mechanism between UHECR nuclei and the cosmic-microwave-background (CMB) photon during extragalactic propagation. ...
... These UHE neutrinos from the GZK mechanism are expected from the observations of the UHE cosmic rays by the airshower detector arrays [1,2] and the observations of diffuse photons by the gamma-ray telescopes [60], although there is no direct observation of the GZK neutrinos by the neutrino telescopes yet [10,11]. The UHE neutrinos can produce nearly horizontal and deep air showers, which correspond to X ∼ 13; 000 g=cm 2 [12]. For typical flux values and CC and NC interactions, we expect ∼ð0.9 − 2.9Þ events per year with typical choices of the acceptance values and the GZK neutrino flux models, although no neutrino-induced event candidates have been found yet [101], which provides the bound on the GZK neutrino flux. ...
Semiclassical processes such as production and decay of electroweak sphaleron in the Standard Model and also microscopic black hole in low scale gravity scenario typically involve large number of particles in final states. These large multiplicities can be distinctively seen in collisions of ultra-high-energy (UHE) neutrinos with Eν≳109 GeV and nucleons in the atmosphere of the Earth. Focusing on air-shower detector array experiments including Telescope Array Experiment (TA), Pierre-Auger Observatory (Auger), we propose strategic ways to discover and analyze such events.
... The conversion mechanisms of a neutrino into an air shower are different for DG and ES, and the requirements made on the signals to efficiently separate neutrinos from background events also call for different strategies. For optimization purposes, the DG procedure is further subdivided into two sets for Low zenith angles (DGL) [7,37], between θ = 60 • and θ = 75 • , and High zenith angles (DGH) [7,38,39], between θ = 75 • and θ = 90 • . ...
... Each neutrino flavour must be treated separately because the showers they initiate through charged-current (CC) interactions are substantially different in the fraction of energy that they carry relative to the incident neutrino [37][38][39]. For DG showers, the effective area is obtained by integrating the neutrino identification efficiency, ε i,c , and the interaction probability per unit depth 1 σ c m −1 p , where m p is the mass of a proton, and σ c the neutrino-nucleon cross-section, over the array area A, (transverse to the neutrino direction) and over the atmospheric matter depth of the neutrino trajectory X: ...
With the Surface Detector array (SD) of the Pierre Auger Observatory we can detect neutrinos with energy between 1017 eV and 1020 eV from point-like sources across the sky, from close to the Southern Celestial Pole up to 60o in declination, with peak sensitivities at declinations around ~ −53o and ~+55o, and an unmatched sensitivity for arrival directions in the Northern hemisphere. A search has been performed for highly-inclined air showers induced by neutrinos of all flavours with no candidate events found in data taken between 1 Jan 2004 and 31 Aug 2018. Upper limits on the neutrino flux from point-like steady sources have been derived as a function of source declination. An unrivaled sensitivity is achieved in searches for transient sources with emission lasting over an hour or less, if they occur within the field of view corresponding to the zenith angle range between 60o and 95o where the SD of the Pierre Auger Observatory is most sensitive to neutrinos.
... In the case of DGH showers the cuts on the properties of the signal pattern are L/W > 3, V < 0.313 m ns −1 and RMS(V )/ V < 0.08, along with a further requirement on the estimated shower zenith angle θ rec > 75 • (see table I in [33]). In contrast, in the DGL case, corresponding to 60 • < θ < 75 • , restrictions on the signal patterns have been found to be less efficient in selecting inclined events than θ rec [54], and only an angular cut 58.5 • < θ rec ≤ 76.5 • is applied, including some allowance to account for the resolution in the angular reconstruction of the simulated neutrino events [54]. In both the DGH and DGL cases, at least 4 stations (N stat ≥ 4) are required in the event. ...
... In the case of DGH showers the cuts on the properties of the signal pattern are L/W > 3, V < 0.313 m ns −1 and RMS(V )/ V < 0.08, along with a further requirement on the estimated shower zenith angle θ rec > 75 • (see table I in [33]). In contrast, in the DGL case, corresponding to 60 • < θ < 75 • , restrictions on the signal patterns have been found to be less efficient in selecting inclined events than θ rec [54], and only an angular cut 58.5 • < θ rec ≤ 76.5 • is applied, including some allowance to account for the resolution in the angular reconstruction of the simulated neutrino events [54]. In both the DGH and DGL cases, at least 4 stations (N stat ≥ 4) are required in the event. ...
... The last ones, even if they are triggered only by muons from a background cosmic-ray shower, can exhibit large values of AoP because they are far from the core where muons are known to arrive with a larger spread in time. The variables used in the Fisher discriminant analysis in the DGL channel are the individual AoP of the four (five) stations closest to the core for events with θ rec ≤ 67.5 • (θ rec > 67.5 • ) and their product [33,54]. Finally, in the DGL analysis it is also required that at least 75% of the triggered stations closest to the core have a ToT local trigger [33,54]. ...
Neutrinos with energies above 1017 eV are detectable with the Surface Detector Array of the Pierre Auger Observatory. The identification is efficiently performed for neutrinos of all flavors interacting in the atmosphere at large zenith angles, as well as for Earth-skimming τ neutrinos with nearly tangential trajectories relative to the Earth. No neutrino candidates were found in ~ 14.7 years of data taken up to 31 August 2018. This leads to restrictive upper bounds on their flux. The 90% C.L. single-flavor limit to the diffuse flux of ultra-high-energy neutrinos with an Eν−2 spectrum in the energy range 1.0 × 1017 eV –2.5 × 1019 eV is E2 dNν/dEν < 4.4 × 10−9 GeV cm−2 s−1 sr−1, placing strong constraints on several models of neutrino production at EeV energies and on the properties of the sources of ultra-high-energy cosmic rays.
... In the case of DGH showers the cuts on the properties of the signal pattern are L/W > 3, V < 0.313 m ns −1 and RMS(V )/ V < 0.08, along with a further requirement on the estimated shower zenith angle θ rec > 75 • (see table I in [33]). In contrast, in the DGL case, corresponding to 60 • < θ < 75 • , restrictions on the signal patterns have been found to be less efficient in selecting inclined events than θ rec [54], and only an angular cut 58.5 • < θ rec ≤ 76.5 • is applied, including some allowance to account for the resolution in the angular reconstruction of the simulated neutrino events [54]. In both the DGH and DGL cases, at least 4 stations (N stat ≥ 4) are required in the event. ...
... In the case of DGH showers the cuts on the properties of the signal pattern are L/W > 3, V < 0.313 m ns −1 and RMS(V )/ V < 0.08, along with a further requirement on the estimated shower zenith angle θ rec > 75 • (see table I in [33]). In contrast, in the DGL case, corresponding to 60 • < θ < 75 • , restrictions on the signal patterns have been found to be less efficient in selecting inclined events than θ rec [54], and only an angular cut 58.5 • < θ rec ≤ 76.5 • is applied, including some allowance to account for the resolution in the angular reconstruction of the simulated neutrino events [54]. In both the DGH and DGL cases, at least 4 stations (N stat ≥ 4) are required in the event. ...
... The last ones, even if they are triggered only by muons from a background cosmic-ray shower, can exhibit large values of AoP because they are far from the core where muons are known to arrive with a larger spread in time. The variables used in the Fisher discriminant analysis in the DGL channel are the individual AoP of the four (five) stations closest to the core for events with θ rec ≤ 67.5 • (θ rec > 67.5 • ) and their product [33,54]. Finally, in the DGL analysis it is also required that at least 75% of the triggered stations closest to the core have a ToT local trigger [33,54]. ...
Neutrinos with energies above eV are detectable with the Surface Detector Array of the Pierre Auger Observatory. The identification is efficiently performed for neutrinos of all flavors interacting in the atmosphere at large zenith angles, as well as for Earth-skimming neutrinos with nearly tangential trajectories relative to the earth. No neutrino candidates were found in years of data taken up to 31 August 2018. This leads to restrictive upper bounds on their flux. The C.L. single-flavor limit to the diffuse flux of ultra-high-energy neutrinos with an spectrum in the energy range is , placing strong constraints on several models of neutrino production at EeV energies and on the properties of the sources of ultra-high-energy cosmic rays.
... This is done in two steps. The differential probability of a tau lepton of given energy exiting the Earth has been calculated as a function of θ using simulations of tau neutrino interactions in rock that include regeneration [36]. The tau-exit probability must be integrated over decay distance weighted by the survival probability, the decay probability per unit distance and the probability of detection with the SD. ...
An overview of the multi-messenger capabilities of the Pierre Auger Observatory is presented. The techniques and performance of searching for Ultra-High Energy neutrinos, photons and neutrons are described. Some of the most relevant results are reviewed, such as stringent upper bounds that were placed to a flux of diffuse cosmogenic neutrinos and photons, bounds placed on neutrinos emitted from compact binary mergers that were detected by LIGO and Virgo during their first and second observing runs, as well as searches for high energy photons and neutrons from the Galactic center that constrain the properties of the putative Galactic PeVatron, observed by the H.E.S.S.\ collaboration. The observation of directional correlations between ultra-high energy cosmic rays and either high energy astrophysical neutrinos or specific source populations, weighted by their electromagnetic radiation, are also discussed. They constitute additional multi-messenger approaches aimed at identifying the sources of high energy cosmic rays.
... This is done in two steps. The differential probability of a tau lepton of given energy exiting the Earth has been calculated as a function of θ using simulations of tau neutrino interactions in rock that include regeneration (Abreu et al., 2013). The tau-exit probability must be integrated over decay distance weighted by the survival probability, the decay probability per unit distance and the probability of detection with the SD. ...
An overview of the multi-messenger capabilities of the Pierre Auger Observatory is presented. The techniques and performance of searching for Ultra-High Energy neutrinos, photons and neutrons are described. Some of the most relevant results are reviewed, such as stringent upper bounds that were placed to a flux of diffuse cosmogenic neutrinos and photons, bounds placed on neutrinos emitted from compact binary mergers that were detected by LIGO and Virgo during their first and second observing runs, as well as searches for high energy photons and neutrons from the Galactic center that constrain the properties of the putative Galactic PeVatron, observed by the H.E.S.S. collaboration. The observation of directional correlations between ultra-high energy cosmic rays and either high energy astrophysical neutrinos or specific source populations, weighted by their electromagnetic radiation, are also discussed. They constitute additional multi-messenger approaches aimed at identifying the sources of high energy cosmic rays.
... This is done in two steps. The differential probability of a tau lepton of given energy exiting the Earth has been calculated as a function of θ using simulations of tau neutrino interactions in rock that include regeneration [36]. The tau-exit probability must be integrated over decay distance weighted by the survival probability, the decay probability per unit distance and the probability of detection with the SD. ...
... Neutrinos produced through interactions with EBL, characterised by lower thresholds, have energies of the order of 10 15 eV in the case of photo-pion production and 10 14 eV in the case of neutron decay (see [240] and references therein). [300,301] and the Auger limits on neutrino fluxes [302]. ...
The search for the origin of cosmic rays is as active as ever, mainly driven by new insights provided by recent pieces of observation. Much effort is being channelled in putting the so called supernova paradigm for the origin of galactic cosmic rays on firmer grounds, while at the highest energies we are trying to understand the observed cosmic ray spectra and mass composition and relating them to potential sources of extragalactic cosmic rays. Interestingly, a topic that has acquired a dignity of its own is the investigation of the transition region between the galactic and extragalactic components, once associated with the ankle and now increasingly thought to be taking place at somewhat lower energies. Here we summarize recent developments in the observation and understanding of galactic and extragalactic cosmic rays and we discuss the implications of such findings for the modelling of the transition between the two.
... As a tradeoff between wanting to exploit the spectrum and hoping to circumvent the low statistics inherent in this endeavour, we generate P (C) in three final energy bins, with edges at [25,100,1000,5000] TeV. In the real data, there are 34 events in the 20-100 TeV bin, with a relative Poisson noise of √ 34/34 ∼ 17% only marginally larger than that of the full dataset ( √ 53/53 ∼ 15%). ...
... A perhaps more subtle distinction between the two methods is that one can model the flux distribution of many source populations in many detectors, while the specific estimator adopted in the fitting method is (at least in its current form) one-to-one. The main text illustrates the multiplicity of source populations, with different abundances, spectral indices and redshift evolutions; but besides IceCube, all instruments sensitive to high-energy neutrinos currently produce nonmeasurements [100][101][102]. And although in this study we restrict our attention to neutrino data at the highest energies, a one-point analysis can in principle be both multi-wavelength and multi-messenger, if the model M of astrophysics and of instrument responses that gives rise to the P (C|M) count distributions is sufficiently elaborate. ...
We perform the first one-point fluctuation analysis of the high-energy neutrino sky. This method reveals itself to be especially suited to contemporary neutrino data, as it allows to study the properties of the astrophysical components of the high-energy flux detected by the IceCube telescope, even with low statistics and in the absence of point source detection. Besides the veto-passing atmospheric foregrounds, we adopt a simple modeling of the high-energy neutrino background by assuming two main extra-galactic components: star-forming galaxies and blazars. By leveraging multi-wavelength data from Herschel and Fermi, we predict the spectral and anisotropic probability distributions for their expected neutrino counts in IceCube. We find that star-forming galaxies are likely to remain a diffuse background due to poor angular resolution, and determine an upper limit on the number of shower events that can reasonably be associated to blazars. We also find that upper limits on the contribution of blazars to the measured flux are unfavourably affected by the skewness of their flux distribution. Our modeling suggests that blazars and star-forming galaxies can jointly explain only ~5 events of the 53 observed in the IceCube HESE data, leaving room for other astrophysical components at greater than 5 sigma significance in a one-point fluctuation analysis.
