In this article we try to answer the question whether the radar detection technique can be used for the detection of high-energy-neutrino induced particle cascades in ice. A high-energy neutrino interacting in ice will induce a particle cascade, also referred to as a particle shower, moving at approximately the speed of light. Passing through, the cascade will ionize the medium, leaving behind a plasma tube. The different properties of the plasma-tube, such as its lifetime, size and the charge-density will be used to obtain an estimate if it is possible to detect this tube by means of the radar detection technique. Next to the ionization electrons a second plasma due to mobile protons induced by the particle cascade is discussed. An energy threshold for the cascade inducing particle of 4 PeV for the electron plasma, and 20 PeV for the proton plasma is obtained. This allows the radar detection technique, if successful, to cover the energy-gap between several PeV and a few EeV in the currently operating neutrino detectors, where on the low side IceCube runs out of events, and on the high side the Askaryan radio detectors begin to have large effective volumes.
We investigate the feasibility of detecting extensive air showers by the radar technique at viewing angles smaller than $\sim 25^\circ$ to the shower axis. Considering a bistatic radar setup and shower geometries in which the receiver points into the arriving shower, we simulate reflection of radio waves off the short-lived plasma produced by the high-energy shower particles in the air. Using the Thomson cross-section for scattering of radio waves and summing coherently contributions of the reflected radio wave over the volume of the plasma disk, we obtain the time evolution of the signal. We …
We investigate the possibility of detecting extensive air showers by the radar technique. Considering a bistatic radar system and different shower geometries, we simulate reflection of radio waves off the static plasma produced by the shower in the air. Using the Thomson cross-section for radio wave reflection, we obtain the time evolution of the signal received by the antennas. The frequency upshift of the radar echo and the power received are studied to verify the feasibility of the radar detection technique.
The IceCube Neutrino Observatory at the South Pole can provide unique tests of muon production models in extensive air showers by measuring both the low-energy (GeV) and high-energy (TeV) muon components. We present here a measurement of the TeV muon content in near-vertical air showers detected with IceTop in coincidence with IceCube. The primary cosmic-ray energy is estimated from the dominant electromagnetic component of the air shower observed at the surface. The high-energy muon content of the shower is studied based on the energy losses measured in the deep detector. Using a neural netwo…
IceTop is an air shower array that is part of the IceCube Observatory currently under construction at the geographic South Pole. When completed, it will consist of 80 stations covering an area of 1 km2. Previous analyzes done with IceTop studied the events that triggered five or more stations, leading to an effective energy threshold of about 0.5 PeV. The goal of this study is to push this threshold lower, into the region where it will overlap with direct measurements of cosmic rays which currently have an upper limit around 300TeV.We select showers that trigger exactly three or exactly four a…
We present a semi-analytical method for the calculation of coherent Askaryan radiation in showers induced by neutrinos of any flavor in ice. We compare our results with those of a full Monte Carlo simulation based on the ZHAireS code. This approach is able to reproduce the vector potential and hence electric field at any experimentally relevant observer position in the time domain. This work extends published results only valid for electron-induced showers. We establish the validity of the semi-analytical calculation of the radio signal produced by all types of neutrino-induced showers in ice.…
Reflection of radio waves off the short-lived plasma produced by the high-energy shower particles in the air is simulated, considering various radar setups and shower geometries. We show that the plasma produced by air showers has to be treated always as underdense. Therefore, we use the Thomson cross-section for scattering of radio waves corrected for molecular quenching and we sum coherently contributions of the reflected radio wave over the volume of the plasma disk to obtain the time evolution of the signal arriving at the receiver antenna. The received power and the spectral power density…
Currently new radio detection techniques are being explored to detect astrophysical neutrinos beyond the PeV scale interacting in polar ice. Due to the long attenuation length of radio waves in a medium, it can be expected that such instruments will also be sensitive to the radio emission of cosmic ray air showers. Furthermore, cosmic ray air showers hitting a high-altitude layer of ice will initiate an in-ice particle cascade, also leading to radio emission. We present the first results of detailed simulations of the in-ice continuation of these cosmic-ray-induced particle cascades, using a c…
The IceCube Neutrino Observatory at the South Pole is a multi-component detector capable of measuring the cosmic ray energy spectrum and composition from PeV to EeV, the energy region typically thought to cover the transition from galactic to extragalactic sources of cosmic rays. The IceTop array at the surface is sensitive to the electromagnetic part of the air shower while the deep in-ice array detects the high-energy (TeV) muonic component of air showers. IceTop's reconstructed shower size parameter, S$_{125}$, is unfolded into a high statistics all-particle energy spectrum. Furthermore, fo…
Simulation of combined radio and radar signals at the Radar Echo Telescope for Cosmic Rays
Radboud University（拉德堡德大学）；Université libre de Bruxelles (ULB)（布鲁塞尔自由大学）；Vrije Universiteit Brussel（布鲁塞尔自由大学）；The Ohio State University（俄亥俄州立大学）；University of Kansas（堪萨斯大学）；Pennsylvania State University（宾夕法尼亚州立大学）；University of Chicago（芝加哥大学）；University of the Basque Country UPV/EHU（巴斯克大学）
In recent works we discussed the feasibility of the radar detection technique as a new method to probe high-energy cosmic-neutrino induced plasmas in ice. Using the different properties of the induced ionization plasma, an energy threshold of several PeV was derived for the over-dense scattering of a radio wave off the plasma. Next to this energy threshold the radar return power was determined for the different constituents of the plasma. It followed that the return signal should be detectable at a distance of several hundreds of meters to a few kilometers, depending on the plasma constituents…
IceTop, the surface component of the IceCube detector, has been used to measure the energy spectrum of cosmic ray primaries in the range between 1.58 PeV and 1.26 EeV. It can also be used to study the low energy muons in air showers by looking at large distances (> 300m) from the shower axis. We will show the muon lateral distribution function at large lateral distances as measured with IceTop and discuss the implications of this measurement. We also discuss the prospects for low energy muon studies with IceTop.
We discuss the radio emission from high-energy cosmic-ray induced air showers hitting Earth's surface before the cascade has died out in the atmosphere. The induced emission gives rise to a radio signal which should be detectable in the currently operating Askaryan radio detectors built to search for the GZK neutrino flux in ice. The in-air emission, the in-ice emission, as well as a new component, the coherent transition radiation when the particle bunch crosses the air-ice boundary, are included in the calculations.
Muons with a high transverse momentum (p_T) are produced in cosmic ray air showers via semileptonic decay of heavy quarks and the decay of high p_T kaons and pions. These high p_T muons have a large lateral separation from the shower core muon bundle. IceCube is well suited for the detection of high p_T muons. The surface shower array can determine the energy, core location and direction of the cosmic ray air shower while the in-ice array can reconstruct the energy and direction of the high p_T muon. This makes it possible to measure the decoherence function (lateral separation spectrum) at di…
The interaction of high energy cosmic rays with the Earth's atmosphere produces extensive air showers of secondary particles with a large muon component. By exploiting the sensitivity of neutrino telescopes to high energy muons, it is possible to use these detectors for precision cosmic ray studies. The high rate of cosmic-ray muon events provides a high-statistics data sample that can be used to look for anisotropy in the arrival directions of the parent particles at the per-mille level. This paper reports on the observation of anisotropy in the cosmic ray data collected with the IceCube neut…
The Cherenkov radio pulse emitted by hadronic showers in ice is calculated for showers of energies in the EeV range. This is obtained with three dimensional simulations of both shower development and the coherent radio pulse emitted as the excess charge develops in the shower. A Monte Carlo, ZHAireS, has been developed for this purpose combining the high energy hadronic interaction capabilities of AIRES, and the dense media propagation capabilities of TIERRAS, with the precise low energy tracking and specific algorithms developed to calculate the radio emission in ZHS. A thinning technique is …
The IceCube Neutrino Observatory is a multi-component detector at the South Pole which detects high-energy particles emerging from astrophysical events. These particles provide us with insights into the fundamental properties and behaviour of their sources. Besides its principal usage and merits in neutrino astronomy, using IceCube in conjunction with its surface array, IceTop, also makes it a unique three-dimensional cosmic-ray detector. This distinctive feature helps facilitate detailed cosmic-ray analysis in the transition region from galactic to extragalactic sources. We will present the p…
The detection of the radio emission following a neutrino interaction in ice is a promising technique to obtain significant sensitivities to neutrinos with energies above PeV. The detectable radio emission stems from particle showers in the ice. So far, detector simulations have considered only the radio emission from the primary interaction of the neutrino. For this study, existing simulation tools have been extended to cover secondary interactions from muons and taus. We find that secondary interactions of both leptons add up to 25\% to the effective volume of neutrino detectors. Also, muon a…
IceTop, the surface array of the IceCube Neutrino Observatory, consists of 162 ice-Cherenkov tanks distributed over an area of 1km$^2$. Besides being used as a veto for the in-ice neutrino detector, IceTop is a powerful cosmic-ray detector. In the upcoming years, the capabilities of the IceTop array will be enhanced by augmenting the existing ice-Cherenkov tanks with an array of elevated scintillator panels and radio antennas. Combining the data obtained from the different detectors will improve the reconstruction of cosmic-ray energy and primary mass while reducing the energy threshold and in…
We report on the measurement of the all-particle cosmic ray energy spectrum with the IceTop air shower array in the energy range from 1.58 PeV to 1.26 EeV. The IceTop air shower array is the surface component of the IceCube Neutrino Observatory at the geographical South Pole. The analysis was performed using only information from IceTop. The data used in this work were taken from June 1, 2010 to May 13, 2011. During that period the IceTop array consisted of 73 stations compared to 81 in its final configuration. The measured spectrum exhibits a clear deviation from a single power law above the …
Cosmic-Ray Physics in the PeV to EeV Energy Range with the IceCube-Gen2 Surface Array (ICRC 2025)
Bartol Research Institute, Department of Physics and Astronomy, University of Delaware（特拉华大学巴托尔物理与天文学研究所）；Institute for Astroparticle Physics, Karlsruhe Institute of Technology (KIT)（卡尔斯鲁厄理工学院高能粒子物理研究所）
IceCube is a cubic-kilometer Cherenkov detector installed in deep ice at the geographic South Pole. IceCube's surface array, IceTop, measures the electromagnetic signal and mainly low-energy muons from extensive air showers above several 100 TeV primary energy, with shower bundles and high-energy muons detected by the in-ice detector IceCube. In combination, the in-ice detector and IceTop provide unique opportunities to study cosmic rays in detail with large statistics. This contribution summarizes recent results from these studies. In addition, the IceCube-Upgrade will include a considerable …
IceCube is a 1 km^3 neutrino telescope currently under construction at the South Pole. The detector will consist of 5160 optical sensors deployed at depths between 1450 m and 2450 m in clear Antarctic ice distributed over 86 strings. An air shower array covering a surface area of 1 km2 above the in-ice detector will measure cosmic ray air showers in the energy range from 300 TeV to above 1 EeV. The detector is designed to detect neutrinos of all flavors: electron-, muon-, and tau-neutrinos. With 59 strings in operation in 2009, construction is 67% complete. Based on data taken to date, the obs…
Cosmic rays with energies up to $10^{11}\,\mathrm{GeV}$ enter the atmosphere and produce showers of secondary particles. Inside these showers muons with high transverse momentum ($p_\mathrm{T} \gtrsim 2\,\mathrm{GeV}$) are produced from the decay of heavy hadrons, or from high $p_\mathrm{T}$ pions and kaons very early in the shower development. These isolated muons can have large transverse separations from the shower core up to several hundred meters, together with the muon bundle forming a double or triple track signature in IceCube. The separation from the core is a measure of the transvers…
Data from the IceCube detector in its 22-string configuration (IC22) were used to directly measure the atmospheric muon energy spectrum near the horizon. After passage through more than 10 km of ice, muon bundles from air showers are reduced to single muons, whose energy can be estimated from the total number of photons registered in the detector. The energy distribution obtained in this way is sensitive to the cosmic ray composition around the knee and is complementary to measurements by air shower arrays. The method described extends the physics potential of neutrino telescopes and can easil…
The IceCube Neutrino Observatory provides the opportunity to perform unique measurements of cosmic-ray air showers with its combination of a surface array and a deep detector. Electromagnetic particles and low-energy muons ($\sim$GeV) are detected by IceTop, while a bundle of high-energy muons ($\gtrsim$400 GeV) can be measured in coincidence in IceCube. Predictions of air-shower observables based on simulations show a strong dependence on the choice of the high-energy hadronic interaction model. By reconstructing different composition-dependent observables, one can provide strong tests of had…
The IceCube Neutrino Detector observes tens of thousands of atmospheric neutrinos every year with its low energy extension DeepCore, covering the neutrino energy range from GeV to TeV. These neutrinos can be used to study particle interactions in conditions that are inaccessible to current accelerator-based experiments. Here, we present constraints concerning the production of light and strange mesons in atmospheric particle cascades using a dedicated analysis based on the shape of the neutrino spectrum in zenith and energy. We report the first measurement of the atmospheric K/Pi-ratio in a co…
We discuss the radar detection technique as a probe for high-energy cosmic neutrino induced particle cascades in a dense medium like ice. With the recent detection of high-energy cosmic neutrinos by the IceCube neutrino observatory the window to neutrino astronomy has been opened. We discuss a new technique to detect cosmic neutrinos at even higher energies than those covered by IceCube, but with an energy threshold below the currently operating Askaryan radio detectors. A calculation for the radar return power, as well as first experimental results will be presented.
The IceCube Neutrino Observatory with its 1-km^3 in-ice detector and the 1-km^2 surface detector (IceTop) constitutes a three-dimensional cosmic ray detector well suited for general cosmic ray physics. Various measurements of cosmic ray properties, such as energy spectra, mass composition and anisotropies, have been obtained from analyses of air showers at the surface and/or atmospheric muons in the ice.
The combined information from cosmic ray air showers that trigger both the surface and underground parts of the IceCube Neutrino Observatory allows the reconstruction of both the energy and mass of the primary particle through the knee region of the energy spectrum and above. The properties of high-energy muon bundles, created early in the formation of extensive air showers and capable of penetrating deep into the ice, are related to the primary energy and composition. New methods for reconstructing the direction and composition-sensitive properties of muon bundles are shown. Based on a likeli…
The standard neutrino oscillation paradigm predicts almost equal fractions of astrophysical neutrino flavors at Earth regardless of their production ratio at the sources. Therefore, identification of astrophysical tau neutrinos could not only reconfirm the astrophysical neutrino flux measured by IceCube, but also is essential in precisely determining the astrophysical neutrino flavor ratio at Earth, which is an important probe for physics beyond the Standard Model over astronomical baselines. A tau neutrino undergoing a charged current (CC) interaction in IceCube could produce a double deposit…
Radio detection of air showers in the current era has progressed immensely to effectively extract the properties of these air showers. Primary cosmic rays with energies of hundreds of PeV have been successfully measured with the method of radio detection. There are also attempts to observe high-energy neutrinos with this technique. Current radio experiments measuring cosmic-ray air showers mostly operate in the frequency range of 30-80 MHz. An optimization of the frequency band of operation can be done for maximizing the signal-to-noise ratio that can be achieved by an array of radio antennas …
We interpret the PeV shower events observed by the IceCube collaboration as an s-channel enhancement of neutrino-quark scattering by a leptoquark that couples to the tau-flavor and light quarks. With a leptoquark mass of ~ 0.6 TeV and a steep 1/E^{2.3} neutrino flux, charged-current scattering gives shower events at ~ 1 PeV and neutral-current scattering gives shower events at ~ 0.5 PeV. This mechanism is also consistent with the paucity of muon-track events above 100 TeV.
The Radar Echo Telescope for Cosmic Rays (RET-CR) is a recently initiated experiment designed to detect the englacial cascade of a cosmic-ray initiated air shower via in-ice radar, toward the goal of a full-scale, next-generation experiment to detect ultra high energy neutrinos in polar ice. For cosmic rays with a primary energy greater than 10 PeV, roughly 10% of an air-shower's energy reaches the surface of a high elevation ice-sheet ($\gtrsim$2 km) concentrated into a radius of roughly 10 cm. This penetrating shower core creates an in-ice cascade many orders of magnitude more dense than the…
The ARIANNA hexagonal radio array (HRA) is an experiment in its pilot phase designed to detect cosmogenic neutrinos of energies above 10^16 eV. The most neutrino-like background stems from the radio emission of air showers. This article reports on dedicated efforts of simulating and detecting the signals of cosmic rays. A description of the fully radio self-triggered data-set, the properties of the detected air shower signals in the frequency range of \unit[100-500]{MHz} and the consequences for neutrino detection are given. 38 air shower signals are identified by their distinct waveform chara…
Neutrinos are key to probing the deep structure of matter and the high-energy Universe. Yet, until recently, their interactions had only been measured at laboratory energies up to about 350 GeV. An opportunity to measure their interactions at higher energies opened up with the detection of high-energy neutrinos in IceCube, partially of astrophysical origin. Scattering off matter inside the Earth affects the distribution of their arrival directions --- from this, we extract the neutrino-nucleon cross section at energies from 18 TeV to 2 PeV, in four energy bins, in spite of uncertainties in the…
The IceCube observatory is the first cubic kilometre scale instrument in the field of high-energy neutrino astronomy and cosmic rays. In 2009, following five successful deployment seasons, IceCube consisted of 59 strings of optical modules in the South Pole ice, together with 118 air shower detectors in the IceTop surface array. The range of physics topics includes neutrino signals from astrophysical sources, dark matter, exotic particle physics, cosmic rays, and atmospheric neutrinos. The current IceCube status and selected results are described. Anticipated future developments are also discu…
