TeV PeV Energy Range Research Articles

Shower formation constraints on cubic Lorentz invariance violation parameters in quantum electrodynamics

We present shower formation constraints on the Lorentz invariance violation (LIV) energy scale for photons with a cubic dispersion relation from recent gamma-ray observations in the 100 TeV–PeV energy range by the Large High Altitude Air Shower Observatory (LHAASO). We assume a Myers–Pospelov effective field theory framework, and calculate the suppression for the Bethe–Heitler process which is mainly responsible for the formation of photon-initiated atmospheric showers. Comparing the high-energy photon events with the suppressed flux predictions, we obtain 95%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$95\\%$$\\end{document} CL constraints on the LIV energy scale. The obtained shower constraint ELIV≳O1020GeV\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E_\ extrm{LIV} \\gtrsim \\mathcal {O} \\left( 10^{20} \ ext{ GeV }\\right) $$\\end{document} is significantly weaker than existing birefringence constraints but is independent.

High-Energy and Ultra-High-Energy Neutrino Astrophysics

The origin of high-energy cosmic rays, and their behavior in astrophysical sources, remains an open question. Recently, new ways to address this question have been made possible by the observation of a new astrophysical messenger, namely neutrinos. The IceCube telescope has detected a diffuse flux of astrophysical neutrinos in the TeV-PeV energy range, likely produced in astrophysical sources accelerating cosmic rays, and more recently it has reported on a few candidate individual neutrino sources. Future experiments will be able to improve on these measurements quantitatively, by the detection of more events, and qualitatively, by extending the measurement into the EeV energy range. In this paper, we review the main features of the neutrino emission and sources observed by IceCube, as well as the main candidate sources that could contribute to the diffuse neutrino flux. As a parallel question, we review the status of high-energy neutrinos as a probe of Beyond the Standard Model physics coupling to the neutrino sector.

A GEANT4 based simulation framework for the large area muon telescope of the GRAPES-3 experiment

The GRAPES-3 experiment located in Ooty, India, samples the electron and muon components in extensive air showers using an array of plastic scintillator detectors and a muon telescope (G3MT) consisting of proportional counters to study the composition of primary cosmic rays (PCRs) as well as γ-ray sources in the TeV–PeV energy range. The G3MT is designed with an appropriate mass absorber to shield the electromagnetic and hadronic components in the shower and to detect muons above 1 GeV×sec(θ) energy, incident from a zenith angle θ. We developed a simulation framework based on the GEANT4 toolkit to evaluate the response of shower particles such as muons, γ-rays, electrons and hadrons in the G3MT. We discuss the geometric modeling of the G3MT using GEANT4 starting with the proportional counter. We estimated the punch-through contribution of hadrons in the G3MT. We compare the simulated muon multiplicity distributions with the observed ones assuming PCR composition from a four population supernova remnant acceleration model namely H4a.

Baikal-GVD neutrino telescope: Design reference 2022

Baikal-GVD is a large-scale Cherenkov detector designed to detect neutrinos in the TeV–PeV energy range with a goal to establish their sources. It is being deployed cluster by cluster and has been taking data since 2015. This contribution presents the telescope structure as of 2022.

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.

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.

Measuring the depth of shower maximum of extensive air showers using Cherenkov light

A method is proposed to reconstruct the depth at which showers reach the maximum number of charged particles (Xmaxcharged) using atmospheric Cherenkov telescopes. The dependence of the Cherenkov signal with telescope distance from shower core is explored and a region in which the measurement is possible is determined (150 to 200 m). A parametrization is presented to reconstruct Xmaxcharged. The resolution of the method is studied as a function of energy, for different primary particle types and for telescope fields of view ranging from 3.5∘ to 10∘. Good resolution ( ∼ 25 g/cm2) is achieved for most of the cases of primary particle type (gamma ray, proton and iron nuclei) and energy (10 TeV < E < 300 TeV). Very good resolution ( < 15 g/cm2) is achieved in the best cases and not so good resolution ( > 40 g/cm2) is seen for energies below 30 TeV. The results presented here contribute to the understanding of the development of gamma-ray showers and suggest another possibility of using atmospheric Cherenkov telescopes to study cosmic rays in the TeV-PeV energy range.

The angular resolution of GRAPES-3 EAS array after improved timing and shower front curvature correction based on age and size

The angular resolution of an extensive air shower (EAS) array plays a critical role in determining its sensitivity for the detection of point γ-ray sources in the multi-TeV energy range. The GRAPES-3, an EAS array located at Ooty in India (11.4̂N, 76.7̂E, 2200 m altitude) is designed to study γ-rays in the TeV-PeV energy range. It comprises of a dense array of 400 plastic scintillators deployed over an area of 25000 m2 and a large area (560 m2) muon telescope. The development of a new statistical method has allowed the real time determination of propagation delay of each detector in the GRAPES-3 array. The shape of the shower front is known to be curved and here the details of a new method developed for accurate measurement of the shower front curvature is presented. These two developments have led to a sizable improvement in the angular resolution of the GRAPES-3 array. It is shown that the curvature depends on the size and the age of an EAS. By employing two different techniques, namely, the odd-even and the left-right methods, independent estimates of the angular resolution are obtained. The odd-even method estimates the best achievable resolution of the array. For obtaining the angular resolution, the left-right method is used after implementing the size and age dependent curvature correction. A comparison of the angular resolution as a function of EAS energy by these two methods shows them be virtually indistinguishable. The angular resolution of the GRAPES-3 array is 47′ for energies E>5 TeV and improves to 17′ at E>100 TeV, eventually approaching 10′ at E>500 TeV.

Recent results from the ANTARES deep sea neutrino telescope

The ANTARES deep sea neutrino telescope has been continuously taking data for more than ten years. Thanks to its excellent angular resolution in both the muon channel and the cascade channel, ANTARES offers unprecedented sensitivity for neutrino source searches in the Southern sky in the TeV-PeV energy range, so that already valuable constraints have been set on the origin of the cosmic neutrino flux discovered by the IceCube detector. This document highlights recent results obtained by ANTARES in the search for high energy cosmic neutrinos coming from point or extended sources, from multi-messenger analyses of transient sources, and from indirect searches for Dark Matter.

ANTARES highlights and recent multi-messenger studies

The ANTARES deep sea neutrino telescope, installed at the bottom of the Mediterranean Sea, has been continuously taking data for more than ten years. Thanks to its excellent angular resolution in both the muon channel and the cascade channel (induced by all neutrino flavours), ANTARES offers unprecedented sensitivity for neutrino source searches in the Southern sky in the TeV–PeV energy range. In the search for a potential cosmic diffuse neutrino flux using nine years of ANTARES data a mild excess was seen, consistent with the IceCube discovery. The source of these neutrinos still remains unknown.Recent Gravitational Wave (GW) discoveries and joint efforts with other multi-messenger observatories (gamma-ray, X-ray, optical, radio) can contribute to solving the puzzle of the high energy neutrinos origin and cosmic ray acceleration sites. Antares data has been analysed in order to search a neutrino emission in correspondence of all observed GW events, including recent neutron star – neutron star merger GW170817. Moreover, this year the search for neutrino emission from Fast Radio Bursts with 2013–2017 years data was completed. Merging ANTARES and IceCube data for searches of various sources improves the sensitivity as it is demonstrated for the recent Galactic Plane analysis.

High Energy Neutrino Astronomy: Where Do We Stand, Where Do We Go?

With the identification of a diffuse flux of astrophysical ("cosmic") neutrinos in the TeV-PeV energy range, IceCube has opened a new window to the Universe. However, the corresponding cosmic landscape is still uncharted: so far, the observed flux does not show any clear association with known source classes. In the present talk, I sketch the way from Baikal-NT200 to IceCube and summarize IceCube's recent astrophysics results. Finally, I describe the present projects to build even larger detectors: GVD in Lake Baikal, KM3NeT in the Mediterranean Sea and IceCube-Gen2 at the South Pole. These detectors will allow studying the high-energy neutrino sky in much more detail than the present arrays permit.

Could a multi-PeV neutrino event have as origin the internal shocks inside the GRB progenitor star?

The IceCube Collaboration initially reported the detection of 37 extraterrestrial neutrinos in the TeV–PeV energy range. The reconstructed neutrino events were obtained during three consecutive years of data taking, from 2010 to 2013. Although these events have been discussed to have an extragalactic origin, they have not been correlated to any known source. Recently, the IceCube Collaboration reported a neutrino-induced muon event with energy of 2.6±0.3 PeV which corresponds to the highest event ever detected. Neither the reconstructed direction of this event (J2000.0), detected on June 11 2014 at R.A.=110°.34, Dec.=11°.48 matches with any familiar source. Long gamma-ray bursts (lGRBs) are usually associated with the core collapse of massive stars leading relativistic-collimated jets inside stars with high-energy neutrino production. These neutrinos have been linked to the 37 events previously detected by IceCube experiment. In this work, we explore the conditions and values of parameters so that the highest neutrino recently detected could be generated by proton–photon and proton–hadron interactions at internal shocks inside lGRB progenitor star and then detected in IceCube experiment. Considering that internal shocks take place in a relativistic collimated jet, whose (half) opening angle is θ0∼0.1, we found that lGRBs with total luminosity L≲1048 erg/s and internal shocks on the surface of progenitors such as Wolf–Rayet (WR) and blue super giant (BSG) stars favor this multi-PeV neutrino production, although this neutrino could be associated with L∼1050.5 (∼1050) erg/s provided that the internal shocks occur at ∼109(∼1010.2) cm for a WR (BSG).

Signatures of a Two Million Year Old Supernova in the Spectra of Cosmic Ray Protons, Antiprotons, and Positrons.

The locally observed cosmic ray spectrum has several puzzling features, such as the excess of positrons and antiprotons above ~20 GeV and the discrepancy in the slopes of the spectra of cosmic ray protons and heavier nuclei in the TeV-PeV energy range. We show that these features are consistently explained by a nearby source which was active approximately two million years ago and has injected (2-3)×10^{50} erg in cosmic rays. The transient nature of the source and its overall energy budget point to the supernova origin of this local cosmic ray source. The age of the supernova suggests that the local cosmic ray injection was produced by the same supernova that has deposited ^{60}Fe isotopes in the deep ocean crust.

Very high energy antineutrinos from photo-disintegration of cosmic ray nuclei

The photo-disintegration of cosmic ray nuclei by starlight leads to the production of secondary antineutrinos. We have assumed that the flux of the ultrahigh energy cosmic ray nuclei near the Galactic plane region is the same as that observed near the earth and calculated the antineutrino flux produced from their photo-disintegration. The IceCube detector has measured the neutrino/antineutrino flux in the TeV–PeV energy range. Our calculated secondary antineutrino flux in the energy range of 10–100 TeV is found to be much less compared to the flux detected by the IceCube collaboration. The upper limit on the intensity of the radiation field in the extragalactic medium is much lower than that near the Galactic center. If we extend our formalism to the extragalactic medium the contribution from the photo-disintegration of ultrahigh energy cosmic ray heavy nuclei remains insignificant due to their very low flux.

The NUCLEON space experiment for direct high energy cosmic rays investigation in TeV–PeV energy range

The NUCLEON satellite experiment is designed to investigate directly, above the atmosphere, the energy spectra of cosmic-ray nuclei and the chemical composition from 100GeV to 1000TeV as well as the cosmic-ray electron spectrum from 20GeV to 3TeV. NUCLEON is planned to be launched in 2014. This mission is aimed at clarifying the essential details of cosmic-ray origin in this energy interval: number and types of sources, identification of actual nearby sources, and the investigation of the mechanisms responsible for the knee. Specific features of the NUCLEON instrument are relatively small thickness and small weight. A special method of energy determination by the silicon tracker was developed for this case. In this paper we describe a design of the instrument and the results of accelerator beam tests in terms of charge and energy resolution. The overall evidences of the capability of the apparatus to achieve the declared aims are also presented.

Observation of TeV–PeV cosmic ray anisotropy with IceCube, IceTop and AMANDA

The study of cosmic ray anisotropy in the TeV–PeV energy range could provide clues about the origin and propagation of cosmic rays in our galactic neighborhood. Since the observed anisotropy is very small, below the per mille level, large event volumes are needed in order to characterize it in sufficient detail. The IceCube Observatory has already collected more than 150 billion cosmic ray induced muon events. This large data sample made it possible to detect anisotropies in the southern hemisphere, down to the 10−5 level, at primary energies in excess of 10TeV. The observed anisotropy is not a simple dipole, but it can be described as composed of multipole components of the spherical harmonic expansion, down to about 10°. A change in topological structure of the cosmic ray arrival distribution is observed above 100TeV. Data collected with the air shower array IceTop above 300TeV confirm the observations up to the PeV energy scale. Moreover, the addition of data collected with the AMANDA neutrino telescope, which operated between 2000 and 2007, has enabled us to search for time variability in the observed TeV anisotropy.

Anisotropy in cosmic rays from internal transitions in neutron stars

We discuss the possibility that some recently measured anisotropic cosmic ray components in the TeV–PeV energy range may be an indication of the ejection of a peculiar type of matter. We present a model where a neutron star internal transition with nuclear deconfinement of the quark content takes place. This catastrophic event may cause a mass ejection process seeding the insterstelar medium with droplets of quark matter, so called nuclearites. Neutralization of these droplets in molecular clouds may drive the anisotropy since quasi-rectilinear trajectories are allowed. Complementary information from current experimental settings on earth or magnetic spectrometers on the ISS may shed light on this exotic form of matter.

Search for neutrino point sources with the IceCube Neutrino Observatory

The IceCube Neutrino Observatory is a kilometer-scale detector located at the South Pole. The full detector comprises 5,160 photomultipliers (PMTs) deployed among 86 strings from 1.5–2.5 km deep within the ice. The constructing phase started in the austral summer of 2004 and ended in December 2010 with the deployment of the last 7 strings that make up the full detector. In this proceeding we present the results of the time integrated and time dependent point source searches corresponding to the years from April 2008 to May 2010 with two different configurations of the IceCube detector (40 and 59 strings). In the northern sky the IceCube neutrino telescope is sensitive to point sources of neutrinos with E−2 spectra mainly in the TeV–PeV energy range. In the opposite hemisphere, due to the higher contamination of high-energy atmospheric muons, the detector is most sensitive to sources with harder spectra, which produce high fluxes of PeV to EeV energies. The combined sensitivity is about a factor ∼2.5 better than the previous 1-year limit. An overview of the sensitivity and discovery potential for the time integrated searches over three years of IceCube, from April 2008 to May 2011, is also shown.

ANISOTROPY AS A PROBE OF THE GALACTIC COSMIC-RAY PROPAGATION AND HALO MAGNETIC FIELD

The anisotropy of cosmic rays (CRs) in the solar vicinity is generally at- tributed to the CR streaming due to the discrete distribution of CR sources or local magnetic field modulation. Recently, the two dimensional large scale CR anisotropy has been measured by many experiments in TeV-PeV energy range in both hemispheres. The tail-in excess along the tangential direction of the local spiral arm and the loss cone deficit pointing to the north Galactic pole direction agree with what have been obtained in tens to hundreds of GeV. The persistence of the two large scale anisotropy structures in such a wide range of energy suggests that the anisotropy might be due to a global streaming of the Galactic CRs (GCRs). This work tries to extend the observed CR anisotropy picture from solar system to the whole galaxy. In such a case, we can find a new interesting signature, a loop of GCR streaming, of the GCR propagation. We further calculate the overall GCR streaming induced magnetic field, and find a qualitative consistence with the observed structure of the halo magnetic field.

Prompt TeV-PeV atmospheric neutrino window

We discuss the possible existence of an observational window, in the TeV-PeV energy range, for the detection of prompt neutrinos from the decay of charmed particles produced in cosmic-ray interactions with the atmosphere. The flux calculations for prompt muon and tau neutrinos are subject to large uncertainties, which we quantify. We investigate the interplay of the predicted fluxes with those produced by the flavor oscillation of conventional atmospheric neutrinos, and by anticipated cosmic sources. We calculate the event rates for the detection of prompt neutrinos and argue that they may be observable in a kilometer-scale neutrino telescope.