Ultra High Energy Tau Neutrinos Research Articles

Design and initial performance of the prototype for the BEACON instrument for detection of ultrahigh energy particles

The Beamforming Elevated Array for COsmic Neutrinos (BEACON) is a planned neutrino telescope designed to detect radio emission from upgoing air showers generated by ultrahigh energy tau neutrino interactions in the Earth. This detection mechanism provides a measurement of the tau flux of cosmic neutrinos. We have installed an 8-channel prototype instrument at high elevation at Barcroft Field Station, which has been running since 2018, and consists of 4 dual-polarized antennas sensitive between 30–80 MHz, whose signals are filtered, amplified, digitized, and saved to disk using a custom data acquisition system (DAQ). The BEACON prototype is at high elevation to maximize effective volume and uses a directional beamforming trigger to improve rejection of anthropogenic background noise at the trigger level. Here we discuss the design, construction, and calibration of the BEACON prototype instrument. We also discuss the radio frequency environment observed by the instrument, and categorize the types of events seen by the instrument, including a likely cosmic ray candidate event.

Earth-Skimming Ultrahigh Energy Tau Neutrinos Simulated with Monte Carlo Method and CONEX Code

This paper is aimed at studying the feasibility of building an Earth-skimming cosmic tau neutrinos detector, with the aim of eventually identifying the ideal dimensions of a natural site mountain-valley for the detection of very high energy neutrinos tau range from 1 0 16 eV to 1 0 20 eV , as well as possibly locate one such site in Algeria. First, a Monte Carlo simulation of the neutrino-[mountain] matter interaction as well as the resulting decay of the tau lepton is conducted to determine the optimal dimensions of the mountain as well as the location of the tau decay in the valley. Second, a CORSIKA (COsmic Ray Simulation for KAscade) simulation with the CONEX option is conducted to track the evolution of the almost horizontal air shower initiated by the tau lepton. Many particles are produced, which are part of the shower components: electrons, muons, gammas, pions, etc. The study of the spatial distribution of these particles enables the discovery of the optimal width of the valley, and consequently, the distance at which to lay the detection network.

Study of a Large Array to Detect Ultra-high Energy Tau Neutrino

The $PeV$ cosmogenic neutrino is still interesting argument. Since cosmogenic neutrinos interact weakly with matter, the detection of their direction will precisely point out the source in the space. In this paper, we show the results of the simulation of tau lepton air showers induced by high energy neutrinos detected by an array of stations designed to use the Earth Skimming method improved by the "mountain chain screen" strategy. Both track time stamp and position information of the stations on the array are used to reconstruct the shower to estimate the direction and the number of events. The array studied consists of 640 stations ($40 \times 16$) spread over an area of $0.6\,km^2$ starting from $1500\,m$ above the sea level (a.s.l.) on $30^{o}$ inclined plane of the mountain. When we extrapolate to 3 years and 10 $km^2$ we estimate 13 tau lepton events in energy interval of 10 PeV to 1000 PeV detected using the present upper limits of tau neutrino flux.

Ultrahigh-energy tau neutrino cross sections with GRAND and POEMMA

Next generation neutrino experiments will push the limits in our understanding of astroparticle physics in the neutrino sector to energies orders of magnitude higher than the current state-of-the-art high-energy neutrino experiment, IceCube. These experiments will use neutrinos to tell us about the most extreme environments in the universe, while simultaneously leveraging these extreme environments as probes of neutrino properties at the highest energies accessible in the foreseeable future: $E\sim10^9$ GeV. At these energies neutrinos are readily absorbed in the Earth. Assuming an isotropic distribution, by looking at how the flux varies as a function of angle through the Earth, we show that it is possible to extract the $\nu_\tau$-$N$ cross section with precision at the $\sim20\%$ level ($1\sigma$ assuming Wilks' theorem) given $N_{\rm events}\sim100$ events.

Studies of an air-shower imaging system for the detection of ultrahigh-energy neutrinos

We discuss the acceptance and sensitivity of a small air-shower imaging system to detect earth-skimming ultrahigh-energy tau neutrinos. The instrument we study is located on top of a mountain and has an azimuthal field of view of $360^\circ$. We find that the acceptance and sensitivity of such a system is close to maximal if it is located about 2 km above ground, has a vertical field of view of $5^\circ$, allows the reconstruction of an at least $0.3^\circ$ long air-shower image, and features an effective light-collection area of $10$ m$^2$ in any direction. After three years of operation, an imaging system with these features achieves an all-flavor neutrino flux sensitivity of $5\times10^{-9}$ GeV cm$^{-2}$ s$^{-1}$ sr$^{-1}$ at $2\times10^8$ GeV.

Search for Ultra-High Energy Tau Neutrinos in IceCube

The IceCube Neutrino Observatory at the geographic South Pole was designed with the primary goal of discovering high energy neutrinos from astrophysical objects such as active galactic nuclei and gamma ray bursts. IceCube completed construction in 2010 and has been collecting data throughout the construction phase. IceCube is sensitive to all three flavors of neutrinos, each of which has a distinct topological signature within the detector. At sufficiently high energies, the tau neutrino signature is a “double bang” from the charged current interaction of the neutrino and the decay of the tau lepton. At high energies, the tau neutrino has negligible background and would be an intriguing astrophysical signature. A dedicated search for ultra-high energy tau neutrinos (340 TeV–200 PeV) was performed using data from the partial IceCube detector, yielding a 90% CL upper limit of Eν2Φ90(νx)<16.3×10−8GeVcm−2sr−1s−1 on a diffuse astrophysical flux of UHE neutrinos.

Search for ultrahigh-energy tau neutrinos with IceCube

The first dedicated search for ultra-high energy (UHE) tau neutrinos of astrophysical origin was performed using the IceCube detector in its 22-string configuration with an instrumented volume of roughly 0.25 km^3. The search also had sensitivity to UHE electron and muon neutrinos. After application of all selection criteria to approximately 200 live-days of data, we expect a background of 0.60 +/- 0.19 (stat.) $^{+0.56}_{-0.58}$ (syst.) events and observe three events, which after inspection emerge as being compatible with background but are kept in the final sample. Therefore, we set an upper limit on neutrinos of all-flavors from UHE astrophysical sources at 90% CL of $E^{2} \Phi(\nu_{x}) < 16.3 * 10^-8 GeV cm^-2 sr^-1 s^-1 over an estimated primary neutrino energy range of 340 TeV to 200 PeV.

Electron–muon identification by atmospheric shower in a new concept of an EAS detector

We show the test results for TOF resolution and μ/e separation capabilities of a prototype element (Iori and Sergi, 2008 [1]), intended for deployment in an array capable of measuring large zenith angle cosmic rays as well as detecting the signature of Ultra High Energy tau neutrino interactions using the Earth skimming strategy (Fargion et al., 2004 [2], Feng et al., 2002 [3], Beacom et al., 2003 [4], Zas, 2005 [5]). The module was designed to recognize single particles and determine the direction of motion (up/down) and measure the trajectory angles. It uses two pairs of scintillator counters, named towers, each composed by two tiles (20×20cm2, 1.4cm thick), separated by 160cm. Each tile is read by one low voltage R5783 Hamamatsu photomultiplier (PMT). Two PMT boxes are attached to a metal structure that defines the axis of the array. Each tile is embedded in a PVC box which also contains the PMT. The PMT has excellent time resolution (≈400ps) for good TOF precision. The PMT signal was digitized by the MATAQ board in coincidence with KASCADE-GRANDE (KG) shower Delagnes and Breton, 2001 [6].

Limit on the diffuse flux of ultrahigh energy tau neutrinos with the surface detector of the Pierre Auger Observatory

Data collected at the Pierre Auger Observatory are used to establish an upper limit on the diffuse flux of tau neutrinos in the cosmic radiation. Earth-skimming ντ may interact in the Earth’s crust and produce a τ lepton by means of charged-current interactions. The τ lepton may emerge from the Earth and decay in the atmosphere to produce a nearly horizontal shower with a typical signature, a persistent electromagnetic component even at very large atmospheric depths. The search procedure to select events induced by τ decays against the background of normal showers induced by cosmic rays is described. The method used to compute the exposure for a detector continuously growing with time is detailed. Systematic uncertainties in the exposure from the detector, the analysis, and the involved physics are discussed. No τ neutrino candidates have been found. For neutrinos in the energy range 2×1017 eV<Eν<2×1019 eV, assuming a diffuse spectrum of the form Eν−2, data collected between 1 January 2004 and 30 April 2008 yield a 90% confidence-level upper limit of Eν2dNντ/dEν<9×10−8 GeV cm−2 s−1 sr−1.2 MoreReceived 2 March 2009DOI:https://doi.org/10.1103/PhysRevD.79.102001©2009 American Physical Society

Detection of ultra high-energy tau-neutrinos with fluorescence detectors

We calculate the possible number of Extensive Air Showers originated by tau neutrinos in Fluorescence Detectors like the ones of the Pierre Auger Observatory. We consider models of production of electron and muon neutrinos in extra galactic objects and Topological Defects, as well as the possibility of neutrino flavor change in the propagation of the neutrinos between the source and the Earth. The neutrino cross section was calculated by the extrapolation of the standard model parton distribution functions until energies of the order of 10 21 eV. However, due to uncertainties in the extrapolation for energies higher than 10 12 eV the results are not robust. We conclude that, depending on the relation between flux and cross section, there is a strict range of energy for the tau neutrinos to generate double extensive air showers detectable in Fluorescence Detectors. The tau neutrino energy must be approximately 10 18 eV and the event rate can vary some orders of magnitude around one event per year, depending on the flux-cross section relation and detector characteristics.

UHE Cosmic Rays and Neutrinos Showering on Planet Edges

Ultra High Energy (UHE) Cosmic Rays, UHECR, may graze high altitude atmosphere leading to horizontal upward air-showers. Also PeVs ν e ¯ hitting electron in atmosphere may air-shower at W− boson resonant mass. On the other side ultra high energy muon and electron neutrinos may also lead, by UHE neutrinos mass state mixing, to the rise of a corresponding UHE Tau neutrino flavor; the consequent UHE tau neutrinos, via charge current interactions in matter, may create UHE taus at horizons (Earth skimming neutrinos or Hor-taus) whose escape in atmosphere and whose consequent decay in flight, may be later amplified by upward showering on terrestrial, planetary atmospheres. Indeed because of the finite terrestrial radius R ⊕ , its thin atmosphere size ( h 0 ≃ 10 ) km, its dense crust, the UHE tau cannot extend much more than ∼ R ⊕ h 0 π / 2 ≃ 360 kilometers in air, corresponding to an energy E τ ⊕ ≃ 7.2 EeV , near but below GZK cut-off ones; on the contrary Jupiter (or even Saturn) may offer a wider, less dense and thicker gaseous layer at the horizons where Tau may loose little energy, travel longer before decay and rise and shower at E ν τ ≃ 4 − 6 ⋅ 10 19 eV or ZeV extreme energy. Also solar atmosphere may play a role, but unfortunately tau-showers secondaries maybe are too noisy to be disentangled, while Jupiter atmosphere, or better, Saturn one, may offer a clearer imprint for GZK (and higher Z-Burst) Tau showering, well below the horizons edges.

Charged Higgs boson contribution toντN→τ−Xfor very largetanβin the two Higgs doublet model with ultrahigh energy neutrinos

We study the deep inelastic process $\nu_{\tau} + {\cal N} \to \tau^{-} + X$ (with ${\cal N} \equiv (n+p)/2$ an isoscalar nucleon), in the context of the two Higgs doublet model {\it type two} (2HDM(II)). In particular, we discuss the contribution to the total cross section of diagrams, in which a charged Higgs boson is exchanged. We show that for large values of $\tan\beta$ such contribution for an inclusive dispersion generated through the collision of an ultrahigh energy tau-neutrino on a target nucleon can reach up to 57% of the value of the contribution of the $W^+$ exchange diagrams (i.e. can reach up to 57% of the standard model (SM) prediction) and could permit to distinguish between the SM and the 2HDM(II) predictions at the Pierre Auger Observatory.

Ultra high energy tau-neutrinos and fluorescence detectors: A phenomenological approach

We investigate the possibility of detecting ultra-high energy cosmic tau-neutrinos by means of a process involving a double extensive air shower, the so-called double-bang phenomenon. In this process a primary tau-neutrino interacts with an atmospheric quark creating a hadronic extensive air shower that contains a tau which subsequently decays creating a second extensive air shower. The number of these events strongly depends on the cross section and on the flux of ultra-high energy tau-neutrinos arriving at the Earth’s atmosphere. We estimate the potential of optical detectors to observe double-bang events induced by tau-neutrinos with energies of about 1 EeV whose detection may confirm the maximal mixing observed in the atmospheric neutrinos also for ultra-high energy neutrinos, and give information on the neutrino flux and cross-section. For neutrino–nucleon standard model extrapolated cross-section and thick source model of flux (MPR), we estimate an event rate of 0.48 y −1 for an observatory with two fluorescence detectors with 90% efficiency in the neutrino energy range 0.5 < E ν < 5 EeV.