High Energy Neutrino Astronomy Research Articles

High-energy neutrino astronomy — the neutrino connections to the cosmic-ray origin: present and future

High-energy neutrino astronomy has been blooming. In addition to the possible identification of the blazar and Seyfert II galaxies as neutrino emitters, the present neutrino data has indicated some hints to characterize or constrain the origin of cosmic rays. Being motivated by the observational fact that the astrophysical neutrino background energy flux is comparable to that of ultrahigh-energy (UHE) cosmic rays, we derive the generic requirements that a major fraction of UHE cosmic ray sources must meet, if they are also responsible for the ∼ 100 TeV-energy cosmic neutrino background radiation. The source parameters characterizing the cosmic ray – neutrino unified scheme, such as the photon radiation luminosity and the cosmic ray luminosity density, suggest that the yet-unidentified cosmic ray and neutrino origins can be transient objects visible in the optical/NIR wavelength band. We propose a viable scheme of multimessenger observations to identify the sources using the neutrino multiplet detections.

Shadowing effects in the diffractive scattering of virtual photons on nuclei and its interference with the process of bremsstrahlung

In cosmic ray physics and high-energy neutrino astronomy, muons are ubiquitous. Due to their slow energy loss and consequently large range at high energies, the correct simulation of their transport through matter is especially important for underground experiments. The dominant energy loss processes are ionization and at higher energies pair production, bremsstrahlung and inelastic interaction with nuclei. A muon energy loss process, which has hitherto been neglected in such simulations, is the diffractive scattering of virtual photons on nuclei. As the elastic channel of this process has the same final state as the bremsstrahlung process (mu + A rightarrow mu + A + gamma ), an interference term arises, whose sign depends on the charge of the lepton. It is found that the contribution of this process was overestimated in earlier works and is significantly affected by shadowing.

High-Energy Extragalactic Neutrino Astrophysics

The detection of an astrophysical flux of neutrinos in the TeV–PeV energy range by the IceCube Neutrino Observatory has opened new possibilities for the study of extreme cosmic accelerators. The apparent isotropy of the neutrino arrival directions favors an extragalactic origin for this flux, potentially created by a large population of distant sources. Recent evidence for the detection of neutrino emission from extragalactic sources includes the active galaxies TXS 0506+056 and NGC 1068. We here review the current status of the search for the sources of the high-energy neutrino flux, concentrating on its extragalactic contribution. We discuss the implications of these observations for multimessenger studies of cosmic sources and present an outlook for how additional observations by current and future instruments will help address fundamental questions in the emerging field of high-energy neutrino astronomy.

Lorentz Symmetry and High-Energy Neutrino Astronomy

The search of the violation of Lorentz symmetry, or Lorentz violation (LV), is an active research field. The effects of LV are expected to be very small, and special systems are often used to search it. High-energy astrophysical neutrinos offer a unique system to search signatures of LV, due to the three factors: high neutrino energy, long propagation distance, and the presence of quantum mechanical interference. In this brief review, we introduce tests of LV and summarize existing searches of LV, using atmospheric and astrophysical neutrinos.

KM3NeT sensitivity to low energy astrophysical neutrinos

KM3NeT, a new generation of neutrino telescope, is currently being deployed in the Mediterranean Sea. While its two sites, ORCA and ARCA, were respectively designed for the determination of neutrino mass hierarchy and high-energy neutrino astronomy, this contribution presents a study of the detection potential of KM3NeT in the MeV-GeV energy range. At these low energies, the data rate is dominated by low-energy atmospheric muons and environmental noise due to bioluminescence and K-40 decay. The goal of this study is to characterize the environmental noise in order to optimize the selection of low-energy neutrino interactions and increase the sensitivity of KM3NeT to transient astrophysical phenomena, such as close-by core-collapse supernovae, solar flares, and extragalactic transients. In this contribution, we will study how using data science tools might improve the sensitivity of KM3NeT in these low-energy neutrino searches. We will first introduce the data sets and the different variables used to characterize KM3NeT’s response to the environmental noise. We will then compare the efficiency of various tools in identifying different components in the environmental noise and in disentangling low-energy neutrino interactions from the background events. We will conclude with the implication of low-energy neutrinos for future astrophysical transient searches.

High-Energy Neutrino Astronomy and the Baikal-GVD Neutrino Telescope

Neutrino astronomy offers a novel view of the non-thermal Universe and is complementary to other astronomical disciplines. The field has seen rapid progress in recent years, including the first detection of astrophysical neutrinos in the TeV-PeV energy range by IceCube and the first identified extragalactic neutrino source (TXS 0506+056). Further discoveries are aimed for with new cubic-kilometer telescopes in the Northern Hemisphere: Baikal-GVD, in Lake Baikal, and KM3NeT-ARCA, in the Mediterranean sea. The construction of Baikal-GVD proceeds as planned; the detector currently includes over 2000 optical modules arranged on 56 strings, providing an effective volume of 0.35 km$^3$. We review the scientific case for Baikal-GVD, the construction plan, and first results from the partially built array.

High-Energy Neutrino Astronomy—Baikal-GVD Neutrino Telescope in Lake Baikal

High-energy neutrino astronomy is a fascinating new field of research, rapidly developing over recent years. It opens a new observation window on the most violent processes in the universe, fitting very well to the concept of multi-messenger astronomy. This may be exemplified by the recent discovery of the high-energy neutrino emissions from the γ-ray loud blazar TXS 0506+056. Constraining astrophysical neutrino fluxes can also help to understand the long-standing mystery of the origin of the ultra-high energy cosmic rays. Astronomical studies of high-energy neutrinos are carried out by large-scale next-generation neutrino telescopes located in different regions of the world, forming a global network of complementary detectors. The Baikal-GVD, being currently the largest neutrino telescope in the Northern Hemisphere and still growing up, is an important constituent of this network. This paper briefly reviews working principles, analysis methods, and some selected results of the Baikal-GVD neutrino telescope.

High energy neutrino astronomy with KM3NeT

The KM3NeT Collaboration aims at the observation of high neutrino sources in the Universe and at the determination of the neutrino mass hierarchy. This talk is focused on ARCA. The deployment of the first Detection Units at 3500 m depth offshore CapoPassero (Italy) started and two are in operation. ARCA will made of two buildings blocks made of 115 Detection Units corresponding to an instrumented volume of about 1 km3 and will provide a very large coverage of the neutrino sky - 87% for up going muon neutrinos). The superior angular resolution, 0.1°at energy higher of 10 TeV, will be important for source search. In this talk the detector technology, status and perspectives for detection of high energy neutrinos signals from different candidate sources are discussed.

Neutrino Sources from a Multi-Messenger Perspective

The field of high-energy neutrino astronomy is undergoing a rapid evolution. After the discovery of a diffuse flux of astrophysical TeV-PeV neutrinos in 2013, the Ice-Cube observatory has recently found first compelling evidence for neutrino emission from blazars. In this brief review, I will summarize the status of these neutrino observations and highlight the strong role of multi-messenger astronomy for their interpretation.

Particle Physics with ORCA

KM3NeT is a Megaton-scale neutrino telescope currently under construction at the bottom of the Mediterranean Sea. When completed, it will consist of two separate detectors: ARCA (Astroparticle Research with Cosmics in the Abyss), optimised for high-energy neutrino astronomy, and ORCA (Oscillation Research with Cosmics in the Abyss) for neutrino oscillation studies of atmospheric neutrinos. The main goal of ORCA is the determination of the neutrino mass ordering (NMO). Nevertheless it is possible to exploit ORCA’s configuration to make other important measurements, such as sterile neutrinos, non standard interactions, tau-neutrino appearance, neutrinos from Supernovae, Dark Matter and Earth Tomography studies. Part of these analyses are summarized here.

KM3NeT: Next-generation neutrino telescope in the Mediterranean Sea

Abstract The successes of the ANTARES detector have demonstrated the feasibility and value of deep sea neutrino telescopes , as well as their versatility through Earth and Sea sciences. KM3NeT is a distributed undersea research infrastructure in the Mediterranean Sea that will host a network of next-generation neutrino telescopes. With the ORCA telescope at the KM3NeT-Fr site, the main objective is to determine the neutrinos mass hierarchy by studying atmospheric neutrino oscillations . The ARCA telescope at the KM3NeT-It site will allow for high energy neutrino astronomy . The telescopes consist of a regular 3D array of Digital Optical Modules, each composed of 31 photomultipliers, equally spaced along flexible lines anchored on the seabed. This multi-photomultipliers concept yields a factor three increase in photocathode area, compared to a design with a single 10 inch photomultiplier, leading to a significant cost reduction. Moreover, this concept allows for an accurate measurement of the light intensity and offers directional information with an almost isotropic field of view. A detailed overview of the detectors, their construction status and their physics program will be presented. The calibration techniques will be discussed, with an emphasis on time calibration, water properties and positioning measurements.

KM3NeT-ORCA: Oscillation Research with Cosmics in the Abyss

KM3NeT, currently under construction in the abysses of the Mediterranean Sea, is a distributed research infrastructure that will host a km3-scale neutrino telescope (ARCA) for high-energy neutrino astronomy, and a megaton scale detector (ORCA) for neutrino oscillation studies of atmospheric neutrinos. ORCA is optimised for a measurement of the mass hierarchy, providing a sensitivity of 3σ after 3-4 years. It will also measure the atmospheric mixing parameters Δm2atm and θ23 with a precision comparable to the NOvA and T2K experiments using both the muon neutrino disappearance and tau neutrino appearance channels. It will provide a measurement of the tau neutrino appearance rate with better than 10% precision, a crucial ingredient for tests of unitarity. It will probe the octant of the mixing angle θ23 via matter resonance effects on neutrinos and antineutrinos crossing the core and mantle, which are largely independent on the CP phase. The observation of neutrino oscillations over a wide range of baselines and energies will provide broad sensitivity to new physics such as non-standard neutrino interactions (NSI) and sterile neutrinos.

Development of the radio astronomical method of cosmic particle detection for extremely high-energy cosmic ray physics and neutrino astronomy

Development of the radio astronomical method of cosmic particle detection for extremely high-energy cosmic ray physics and neutrino astronomy

Development of the radio astronomical method of cosmic particle detection for extremely high-energy cosmic ray physics and neutrino astronomy

The proposal to use ground based radio telescopes for detection of Askaryan radio pulses from particle cascades arising when extremely high-energy (EHE > 1020 eV) cosmic rays (including neutrinos) interact with the lunar regolith of multi gigaton mass was made at the end of 1980s in the framework of the Russian (Soviet) DUMAND Program. During more than a quarter of century a number of lunar experiments were carried out mainly in the 1–3 GHz frequency range using the large radio telescopes of Australia, USA, Russia and other countries but these experiments only put upper limits to the EHE cosmic rays fluxes. For this reason, it would be of great interest to search for nanosecond radio pulses from the Moon in a wider interval of frequencies (including lower ones of 100–350 MHz) with larger radio detectors – for example the giant radio telescope SKA (Square Kilometer Array) which is constructed in Australia, New Zealand and South Africa. In this paper possibilities are discussed to use one of the most sensitive meter-wavelength (∼ 110 MHz) Large Phased Array (LPA) of 187 × 384 m2 and the wide field of view meter-wavelength array of the Pushchino Radio Astronomy Observatory as prototypes of low frequency radio detectors for lunar experiments. The new scheme for fast simulation of ultrahigh and extremely high-energy cascades in dense media is also suggested. This scheme will be used later for calculations of radio emission of cascades in the lunar regolith with energies up to 1020 eV and higher in the wide frequency band of 0.1− a few GHz.

Moon as a Giant Detector for Neutrino Streams from Pulsars

Unaddressed existence of extraterrestrial sources of high energy neutrinos was discovered in 2013y. But the most promising addition to supernovae includes objects such as pulsars and closes multiple systems. Relying mainly on its own experience in the search and registration of the seismic response at frequencies of pulsars and close binary stars on Earth and the Moon and using the results to detect solar neutrinos work on the study of modulated neutrino fluxes were continued. The study of the spectra of lunar seismic noise revealed a number of significant spectral peaks that match the frequency to 3-4 significant figures with the frequencies of sending energy pulses from pulsars. At the same time availability of registration of seismic peaks and their characteristics are strongly associated with the shape and depth of the radioactive geological structures of the lithosphere of the Moon. That is the energy of interaction modulated beam of neutrinos from the pulsar radioactive elements Moon differently converted into energy of seismic noise. There have also been recorded seismic peaks well coincides with the period of close binary stars. Some of the peaks previously were registered not only as a purely seismic frequency, but as the frequency inherent to radioactive laboratory sources. It is further confirms their astrophysical neutrino origin and similar search becomes the part of high-energy neutrino astronomy.

IceCube and the discovery of high-energy cosmic neutrinos

By transforming a cubic kilometer of natural Antarctic ice into a neutrino detector, the IceCube project created the opportunity to observe cosmic neutrinos. We describe the experiment and the complementary methods presently used to study the flux of the recently discovered cosmic neutrinos. In one method, events are selected in which neutrinos interacted inside the instrumented volume of the detector, yielding a sample of events dominated by neutrinos of electron and tau flavor. Alternatively, another method detects secondary muons produced by neutrinos selected for having traveled through the Earth to reach the detector, providing a pure sample of muon neutrinos. We will summarize the results obtained with the enlarged data set collected since the initial discovery and appraise the current status of high-energy neutrino astronomy. The large extragalactic neutrino flux observed points to a nonthermal universe with comparable energy in neutrinos, gamma rays and cosmic rays. Continued observations may be closing in on the source candidates. In this context, we highlight the potential of multimessenger analyses as well as the compelling case for constructing a next-generation detector larger in volume by one order of magnitude.

Characterization of the Astrophysical Neutrino Flux at the IceCube Neutrino Observatory

With the discovery of a high-energy astrophysical neutrino flux, the IceCube Neutrino Observatory, located at the geographical South Pole, has opened the field of high-energy neutrino astronomy. While evidence for extraterrestrial neutrinos has been found in multiple searches, it was not yet possible to identify their sources; they appear as an isotropic excess. Nevertheless, it is possible to constrain the properties of the sources by measuring the energy spectrum and the flavor composition of the flux. Here, we present the latest results from a global analysis, combining all available detection channels and energy ranges. We derive the currently most precise constraints on the energy spectrum and flavor composition of the astrophysical neutrino flux. In addition, we show projected constraints on these properties that can be obtained with additional data in the future.

The Giant Radio Array for Neutrino Detection

High-energy neutrino astronomy will probe the working of the most violent phenomena in the Universe. The Giant Radio Array for Neutrino Detection (GRAND) project consists of an array of $\sim10^5$ radio antennas deployed over $\sim$200000km$^2$ in a mountainous site. It aims at detecting high-energy neutrinos via the measurement of air showers induced by the decay in the atmosphere of $\tau$ leptons produced by the interaction of the cosmic neutrinos under the Earth surface. Our objective with GRAND is to reach a neutrino sensitivity of $3\times10^{-11}E^{-2}$GeV$^{-1}$cm$^{-2}$s$^{-1}$sr$^{-1}$ above $3 \times10^{16}$eV. This sensitivity ensures the detection of cosmogenic neutrinos in the most pessimistic source models, and about 100 events per year are expected for the standard models. GRAND would also probe the neutrino signals produced at the potential sources of UHECRs. We show how our preliminary design should enable us to reach our sensitivity goals, and present the experimental characteristics. We assess the possibility to adapt GRAND to other astrophysical radio measurements. We discuss in this token the technological options for the detector and the steps to be taken to achieve the GRAND project.

高能中微子天文观测进展

The production and propagation of cosmic rays in the universe are usually accompanied by high energy neutrino production. High energy neutrino astronomy is a unique window for high energy astrophysics. Recently, the south-pole neutrino experiment IceCube has reported the detections of 37 high energy (>TeV) events, which reject pure atmospheric origin in 5.7s confidence level. This is the first detection of extraterrestrial high energy neutrinos, opening a brand new window to observe the universe, and marking the birth of the high energy neutrino astronomy. In this paper, we briefly introduce the history of high energy neutrino astronomy, the high energy neutrino experiments, the recent results from IceCube, and then we make general discussion on the origin of IceCube detected neutrinos, and finally some prospects in high energy neutrino astronomy.

Detection of ultra-high energy neutrinos and cosmic rays with Tianshan radio array

The detection of cosmic neutrinos is opening a new window beyond the electromagnetic observable universe. However, the traditional technique for neutrino detection does not facilitate the observation of super high-energy neutrinos due to the limited effective area and duty cycle resulted from the high cost of the detectors. The radio technique is employed in the Sino-French TianShan mountain neutrino telescopes using the low-cost, all-duty cycle antenna, and this technique allows to build a large area array to achieve the desired sensitivity of super high energy neutrino astronomy. In the Key Project of Chinese National Programs for Fundamental Research and Development “cosmic detection of the first rays of dawn” funding, a prototype array has been built and important results were achieved in the years 2011-2012. Relying only unipolar antenna array, it effectively detects the air shower first in the world without traditional particle detectors. We plan to build a giant antenna array, which would be the worlds most sensitive super high-energy neutrino telescope.