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Large-scale high-energy physics experiments generate scientific data at the scale of petabytes or even exabytes, requiring high-performance data IO for processing. However, in large computing centers, computing and storage devices are typically separated. Large-scale data transfer has become a bottleneck for some data-intensive computing tasks, such as data encoding and decoding, compression, sorting, etc. The time spent on data transfer can account for 50% of the entire computing task. The larger the amount of data accessed, the more significant this cost becomes. One attractive solution to address this problem is to offload a portion of data processing to the storage layer. However, modifying traditional storage systems to support computation offloading is often cumbersome and requires a broad understanding of their internal principles. Therefore, we have designed a flexible software framework called XkitS, which builds a computable storage system by extending the existing storage system EOS. This framework is deployed on the EOS FTS storage server and offloads computational tasks by invoking the computing capabilities (CPU, FPGA, etc.) on FTS. Currently, it has been tested and applied in the data processing of the Large High Altitude Air Shower Observatory (LHAASO), and the results show that the time spent on data decoding using the computable storage technology is half of that using the original method. [ABSTRACT FROM AUTHOR]

With the advancement of many large-scale high-energy physics experiments, the amount of data to be processed and analyzed has significantly increased. For example, since the start of the Large High Altitude Air Shower Observatory (LHAASO) experiment in 2020, their simulation jobs have been running on an Intel X86 cluster, producing only a fraction of the planned data for the first phase due to limited CPU resources. Therefore, it is necessary to explore and expand other computing service devices. We built an application ecosystem based on the ARM architecture to support offline data processing for high-energy physics. The main work includes porting the offline software based on LHAASO experiments to run on ARM machines, formulating data transfer and job scheduling strategies in the ARM cluster, and evaluating performance and power consumption in both Intel X86 and ARM clusters. The results show that the LHAASO simulation jobs can run correctly on the ARM computing cluster. The singlecore performance of Intel X86 CPUs is better than ARM CPUs, but for the entire server with a multicore architecture, ARM servers perform better. [ABSTRACT FROM AUTHOR]

The IceCube Neutrino Observatory is a cubic kilometer neutrino telescope located at the Geographic South Pole. For every observed neutrino event, there are over 106 background events caused by cosmic ray air shower muons. In order to properly separate signal from background, it is necessary to produce Monte Carlo simulations of these air showers. Although to-date, IceCube has produced large quantities of background simulation, these studies still remain statistics limited. The first stage of simulation requires heavy CPU usage while the second stage requires heavy GPU usage. Processing both of these stages on the same node will result in an underutilized GPU but using different nodes will encounter bandwidth bottlenecks. Furthermore, due to the power-law energy spectrum of cosmic rays, the memory footprint of the detector response often exceeded the limit in unpredictable ways. This proceeding presents new client–server code which parallelizes the first stage onto multiple CPUs on the same node and then passes it on to the GPU for photon propagation. This results in GPU utilization of greater than 90% as well as more predictable memory usage and an overall factor of 20 improvement in speed over previous techniques. [ABSTRACT FROM AUTHOR]

The IceCube experiment has substantial simulation needs and is in continuous search for the most cost-effective ways to satisfy them. The most CPU-intensive part relies on CORSIKA, a cosmic ray air shower simulation. Historically, IceCube relied exclusively on x86-based CPUs, like Intel Xeon and AMD EPYC, but recently server-class ARM-based CPUs are also becoming available, both on-prem and in the cloud. In this paper we present our experience in running a sample CORSIKA simulation on both ARM and x86 CPUs available through Google Kubernetes Engine (GKE). We used the production binaries for the x86 instances, but had to build the binaries for ARM instances from source code, which turned out to be mostly painless. Our benchmarks show that ARM-based CPUs in GKE were not only the most cost-effective but were also the fastest in absolute terms in all the tested configurations. While the advantage is not drastic, about 20% in cost-effectiveness and less than 10% in absolute terms, it is still large enough to warrant an investment in ARM support for IceCube. [ABSTRACT FROM AUTHOR]

The simulation of longitudinal development in extensive air showers (EAS) was performed with AIRES system (version 19.04.00) for vertical and inclined EAS showers at the ultrahigh energies 1019, 3×1019, 1020 and 3×1020 eV. On the basis of this simulation, a new Gaussian function was obtained by approximating the longitudinal development for primary proton and iron nuclei that produced charged and neutral pions as a function of the atmospheric depth of EAS showers. The comparison of the calculated longitudinal development with that simulated with Scuitto has shown an opportunity of primary particle identification and definition of its energy at ultrahigh energies. [ABSTRACT FROM AUTHOR]

The effect of extensive air showers (EAS) was described by estimating the longitudinal development of atmospheric cascades at high energies of different cosmic-ray particles. The longitudinal development was performed using the air shower simulation (AIRES) program (version 19.04.00) at high energies (1017, 1018,1019 and 1020) eV for created particles such as an electron, muon, and pion for various primary particles (carbon, iron, proton, and silicon) with zenith angles (0 and 30o). New parameters were obtained by fitting the longitudinal development curves of Extensive air shower using a polynomial function for created particles, initiated by primary particles at the energy 1020 eV. Good agreement was obtained by comparing the present results with results simulated by Sciutto as well as the results using CORSIKA simulation for primary proton at the energy 1020 eV. [ABSTRACT FROM AUTHOR]

The simulation analysis of the Extensive Air Showers (EAS) was executed by exploring the longitudinal development employing the AIRES system (version 19.04.00) for several hadronic interaction models (SIBYLL, QGSJET, and EPOS) for high energies. The simulation was performed for different high energies (1017, 1018, and 1019) eV and two dissimilar primary particles, proton as well iron nuclei, with several zenith angles values (0o, 10o, and 30o). The shower size of longitudinal development was parameterized using the sigmoidal function (Boltzmann model) and gave a new four parameters as functions of the primary energy between the energy extent (1017-1019) eV. The comparison among the acquired results data (the parameterized number of shower particles) along with the experimental results (Pierre Auger experiment) had offered a fascinating matching for the primary proton at the fixed primary energy 1019 eV for vertical EAS showers. [ABSTRACT FROM AUTHOR]

The CORSIKA 8 project is an international collaboration of scientists working together to deliver the most modern, flexible, robust and efficient framework for the simulation of ultra-high energy secondary particle cascades in matter. The main application is for cosmic ray air shower simulations, but it can also be applied to other problems in astro(particle)-physics, particle physics and nuclear physics. Besides a comprehensive and state-of-the-art collection of physics models as well as algorithms relevant for the field, also all possible interfaces to hardware acceleration (e.g. GPU) and parallelization (vectorization, multi-threading, multi-core) will be provided. We present the status and roadmap of this project. This code will soon be available for novel explorative studies and phenomonological research, and at the same time for massive productions runs for experiments. [ABSTRACT FROM AUTHOR]

We report briefly recent experimental studies of axial-vector weak couplings for neutrino nuclear responses (squares of nuclear matrix elements NMEs) in the wide energy (0-50 MeV) and momentum (0-100 MeV/c) regions, which are relevant to neutrinoless double beta decays (DBDs) and supernova neutrinos. High energy-resolution studies of charge exchange reactions (CERs) of (³He,t) are used for studying the τ- side NMEs, while charge exchange muon reactions (ordinary muon capture reactions OMC) are for studying the τ+ side NMEs. The experimental NMEs derived from the single β/EC NMEs and the CER NMEs show that the (J± ≤4) spin isospin (axial vector) NMEs are uniformly reduced by the coefficient geffA/gfreeA≈0.5−0.6 with respect to A pnQRPA NMEs. Then the DBD NMEs M0ν may be reduced by the coefficient around 0.5, depending on the ratio of the axial-vector to vector NMEs, with respect to the pnQRPA NMEs. [ABSTRACT FROM AUTHOR]

A surface array of radio antennas will enhance the performance of the IceTop array and enable new, complementary science goals. First, the accuracy for cosmic-ray air showers will be increased since the radio array provides a calorimetric measurement of the electromagnetic component and is sensitive to the position of the shower maximum. This enhanced accuracy can be used to better measure the mass composition, to search for possible mass-dependent anisotropies in the arrival directions of cosmic rays, and for more thorough tests of hadronic interaction models. Second, the sensitivity of the radio array to inclined showers will increase the sky coverage for cosmic-ray measurements. Third, the radio array can be used to search for PeV photons from the Galactic Center. Since IceTop is planned to be enhanced by a scintillator array in the near future, a radio extension sharing the same infrastructure can be installed with minimal additional effort and excellent scientific prospects. The combination of ice-Cherenkov, scintillation, and radio detectors at IceCube will provide unprecedented accuracy for the study of highenergy Galactic cosmic rays. [ABSTRACT FROM AUTHOR]

We propose to utilize bedrock as a medium for acoustic detection of particle showers following interactions of ultra-high energy neutrinos. With the density of rock three-times larger and the speed of sound four-times larger compared to water, the amplitude of the generated bipolar pressure pulse in rock should be larger by an order of magnitude. Our preliminary simulations confirm that prediction. Higher density of rock also guarantees higher interaction rate for neutrinos. A noticeably longer attenuation length in rock reduces signal dissipation. The Pyhäsalmi mine has a unique infrastructure and rock conditions to test this idea and, if successful, extend it to a full-size experiment. [ABSTRACT FROM AUTHOR]

The Tunka Radio Extension (Tunka-Rex) is a digital radio array operating in the frequency band of 30-80 MHz and detecting radio emission from air-showers produced by cosmic rays with energies above 100 PeV. The experimentis installed at the site of the TAIGA (Tunka Advanced Instrument for cosmic rays and Gamma Astronomy) observatory and performs joint measurements with the co-located particle and air-Cherenkov detectors in passive mode receiving a trigger from the latter. Tunka-Rex collects data since 2012, and during the last five years went throughseveral upgrades. As a result the density of the antenna field was increased by three times since its commission. In this contribution we present the latest results of Tunka-Rex experiment, particularly an updated analysis and efficiency study, which have been applied to the measurement of the mean shower maximum as a function of energy for cosmic rays of energies up to EeV. The future plans are also discussed: investigations towards an energy spectrum of cosmic rays with Tunka-Rex and their mass composition using a combination of Tunka-Rex data with muon measurements by the particle detector Tunka-Grande. [ABSTRACT FROM AUTHOR]

The Giant Radio Array for Neutrino Detection (GRAND) aims to answer one of the most pressing open questions in astrophysics: what is the origin of ultra-highenergy cosmic rays (UHECRs)?. It will do so indirectly: UHECRs make secondary UHE neutrinos which encode information about the properties of UHECRs and their sources. GRAND is designed to discover UHE neutrinos even under pessimistic predictions of their flux, reaching a sensitivity of 6x10−9GeV.cm−2.s−1.sr−1 around 109GeV. It will do so by using 20 sub-arrays of 10 000 radio antennas forming a total detector area of 200 000 km2, making it the largest air-shower detector ever built. With this sensitivity, GRAND will discover cosmogenic neutrinos in 3 years of operation, even in disfavorable scenarios. Because of its subdegree angular resolution, GRAND will also search for point sources of UHE neutrinos, both steady and transient. Moreover, GRAND will be a valuable instrument for astronomy and cosmology, allowing for the discovery and followup of large numbers of radio transients - fast radio bursts, giant radio pulses - and studies of the epoch of reionization. In this contribution we will present briefly some of the science goals, detection strategy, construction plans and current status of the GRAND project. [ABSTRACT FROM AUTHOR]

Radio detection of extensive air showers is a flourish technique, attracting more and more interest to investigate the properties of high-energy cosmic rays. Past, present, and future developments are reviewed. [ABSTRACT FROM AUTHOR]

The Fluorescence detector Array of Single-pixel Telescopes (FAST) is a proposed large-area, next-generation experiment for the detection of ultra-high energy cosmic rays via the atmospheric fluorescence technique. The telescope's large field-of-view (30 ×30) is imaged by four 200 mm photomultiplier-tubes at the focal plane of a segmented spherical mirror of 1.6 m diameter. Two prototypes are installed and taking data at the Black Rock Mesa site of the Telescope Array experiment in central Utah, USA. We present the process used for optimization of the optical performance of this compact and low-cost telescope, which is based on a simulation of the telescope's optical point spread function. [ABSTRACT FROM AUTHOR]

Knowledge of the mass composition of ultra-high-energy cosmic rays is understood to be a salient component in answering the open questions in the field. The AugerPrime upgrade of the Pierre Auger Observatory aims to enhance its surface detector with the hardware necessary to reconstruct primary mass for individual events. This involves placing a scintillation-based detector with an active area of 3.8 m2 on top of each existing water-Cherenkov detector in its surface detector array. Here, we present the methods for simulating this Scintillator Surface Detector. These simulations have and will continue to aid in the interpretation of measurements with AugerPrime as well as the development and improvement of event reconstruction algorithms including primary mass. [ABSTRACT FROM AUTHOR]

An upgrade of the present IceCube surface array (IceTop) with scintillation detectors and possibly radio antennas is foreseen. The enhanced array will calibrate the impact of snow accumulation on the reconstruction of cosmic-ray showers detected by IceTop as well as improve the veto capabilities of the surface array. In addition, such a hybrid surface array of radio antennas, scintillators and Cherenkov tanks will enable a number of complementary science targets for IceCube such as enhanced accuracy to mass composition of cosmic rays, search for PeV photons from the Galactic Center, or more thorough tests of the hadronic interaction models. Two prototype stations with 7 scintillation detectors each have been already deployed at the South Pole in January 2018. These R&D studies provide a window of opportunity to integrate radio antennas with minimal effort. [ABSTRACT FROM AUTHOR]

The Giant Array for Neutrino Detection (GRAND) is a proposal for a giant observatory of ultra-high energy cosmic particles (neutrinos, cosmic rays and gamma rays). It will be composed of twenty subarrays of 10 000 antennas each, totaling a detection area of 200 000 km2. GRAND will reach unprecedented sensitivity to neutrinos allowing to detect cosmogenic neutrinos while its sub-degree angular resolution will also make it possible to hunt for point sources and possibly start neutrino astronomy. Combined with its gigantic exposure to ultra-high energy cosmic rays and gamma rays, GRAND will be a powerful tool to solve the century-long mistery of the nature and origin of the particles with highest energy in the Universe. On the path to GRAND, the GRANDProto300 experiment will be deployed in 2020 over a total area of 200 km2. It primarly aims at validating the detection concept of GRAND, but also proposes a rich science program centered on a precise and complete measurement of the air showers initiated by cosmic rays with energies between 1016.5 and 1018 eV, a range where we expect to observe the transition between the Galactic and extra-galactic origin of cosmic rays. [ABSTRACT FROM AUTHOR]

The Pierre Auger Observatory is presently being upgraded to enlarge its detection capabilities for ultra-high-energy cosmic rays. Part of this upgrade is a radio detector array, aimed to cover a surface area of 3000 km2 to measure the properties of the highest-energy cosmic rays. The plans for this radio upgrade are outlined [ABSTRACT FROM AUTHOR]

In the future, ultra-high energy cosmic ray (UHECR) observatory will be expanded due to the small flux. Then, cost reduction is useful strategy to realize a huge scale observatory. For this purpose, we are developing a simple structure cosmic ray detector named as Cosmic Ray Air Fluorescence Fresnel-lens Telescope (CRAFFT). We deployed CRAFFT detectors at the Telescope Array site and performed a test observation. We have successfully observed UHECR air showers. We will report the status and the result of the test observation. [ABSTRACT FROM AUTHOR]

The world largest exposure to ultra-high energy cosmic rays accumulated by the Pierre Auger Observatory led to major advances in our understanding of their properties, but the many unknowns about the nature and distribution of the sources, the primary composition and the underlying hadronic interactions prevent the emergence of a uniquely consistent picture. The new perspectives opened by the current results call for an upgrade of the Observatory, whose main aim is the collection of new information about the primary mass of the highest energy cosmic rays on a shower-by-shower basis. The evaluation of the fraction of light primaries in the region of suppression of the flux will open the window to charged particle astronomy, allowing for compositionselected anisotropy searches. In addition, the properties of multiparticle production will be studied at energies not covered by man-made accelerators and new or unexpected changes of hadronic interactions will be searched for. After a discussion of the motivations for upgrading the Pierre Auger Observatory, a description of the detector upgrade is provided. We then discuss the expected performances and the improved physics sensitivity of the upgraded detectors and present the first data collected with the already running Engineering Array. [ABSTRACT FROM AUTHOR]

The fluorescence detector technique is using the atmosphere as a calorimeter. Besides the precise monitoring of the parameters of the atmosphere a proper knowledge of the optical properties in the UV range of all optical components involved in the measurements of the fluorescence light is vital. Until now, the end-to-end calibration was performed with a 4.5 m2 large, uniformly lit light source attached to the aperture of the telescopes. To improve the maintainability we propose an alternative setup where a small and lightweight light source of known optical properties re-samples the measurement of the big light source piece by piece. This will be achieved by moving the light source based on an integrating sphere in two dimensions in front of the aperture. A prototype setup has been installed and we are currently optimizing the parameters of the system and the procedures. The aim is to reduce the effort for the procedure without diminishing the quality of the measurement. First measurements with this setup have already been performed and the measurements of the geometrical and optical properties of the light source are an ongoing activity. We present our calibration scheme and the first, preliminary results. [ABSTRACT FROM AUTHOR]

The Hellenic Open University (HOU) Cosmic Ray Telescope (ASTRONEU) consists of 9 large scintillator detectors and 3 RF antennas arranged in three autonomous stations operating at the Hellenic Open University campus in the city of Patras. High energy showers that are detected simultaneously by two distant stations and in coincidence with the RF antennas are used to study the RF signature of cosmic events. In previous studies we have shown that the timing of the RF signals as well as the measured electric field at the antennas position are in very good agreement with the simulation predictions. In this work we concentrate on the transfer functions of the antennas which are strongly frequency and angular dependent. We show that the RF spectra (at frequencies 30-80 MHz) of the detected showers are exhibiting features of the antenna response as predicted by detailed Monte Carlo simulation suggesting that a single antenna RF spectrum gives access to the cosmic ray arrival direction. [ABSTRACT FROM AUTHOR]

The Auger Engineering Radio Array (AERA) complements the Pierre Auger Observatory with 150 radio-antenna stations measuring in the frequency range from 30 to 80 MHz. With an instrumented area of 17 km2, the array constitutes the largest cosmic-ray radio detector built to date, allowing us to do multi-hybrid measurements of cosmic rays in the energy range of 1017 eV up to several 1018 eV. We give an overview of AERA results and discuss the significance of radio detection for the validation of the energy scale of cosmicray detectors as well as for mass-composition measurements. [ABSTRACT FROM AUTHOR]

EUSO-SPB1 was a balloon-borne mission of the JEM-EUSO (Joint Experiment Missions for Extreme Universe Space Observatory) Program aiming at the ultra-high energy cosmic ray (UHECR) observations from space. We operated the EUSO-SPB1 telescope consisting of 1 m2 Fresnel refractive optics and multi-anode photomultiplier tubes. With a total of 2304 channels, each performed the photon counting every 2.5 µs, allowing for spatiotemporal imaging of the air shower events in an ~ 11°× 11° field of view. EUSO-SPB1 was the first balloon-borne fluorescence detector with a potential to detect air shower events initiated by the EeV energy cosmic rays. On 24 April 2017 UTC, EUSO-SPB1 was launched on the NASA's Super Pressure Balloon that flew at ~16 – 33 km flight height for ~12 days. Before the flight was terminated, ~27 hours of data acquired in the air shower detection mode were transmitted to the ground. In the present work, we aim at evaluating the role of the clouds during the operation of EUSO-SPB1. We employ the WRF (Weather Research and Forecasting) model to numerically simulate the cloud distribution below EUSO-SPB1. We discuss the key results of the WRF model and the impact of the clouds on the air shower measurement and the efficiency of the cosmic ray observation. The present work is a part of the collaborative effort to estimate the exposure for air shower detections. [ABSTRACT FROM AUTHOR]

The atmospheric aerosol monitoring system of the Pierre Auger Observatory has been operating smoothly since 2004. Two laser facilities (Central Laser Facility, CLF and eXtreme Laser Facility, XLF) fire sets of 50 shots four times per hour during FD shifts to measure the highly variable hourly aerosol attenuation to correct the longitudinal UV light profiles of the Extensive Air Showers detected by the Fluorescence Detector. Hourly aerosol attenuation loads (Vertical Aerosol Optical Depth) are used to correct the measured profiles. Two techniques are used to determine the aerosol profiles, which have been proven to be fully compatible. The uncertainty in the VAOD profiles measured consequently leads to an uncertainty on the energy and on the estimation of the depth at the maximum development of a shower (Xmax) of the event in analysis. To prove the validity of the aerosol attenuation measurements used in FD event analysis, the flatness of the ratio of reconstructed SD to FD energy as a function of the aerosol transmission to the depth of shower maximum has been verified. [ABSTRACT FROM AUTHOR]

The research horizons of the Pierre Auger Cosmic-Ray Observatory widened when the collaboration found exotic (atmospheric) phenomena in both its Fluorescence Detector (FD) and Surface Detector (SD). The Cosmology and Geophysics task force of the Auger Collaboration focused some of its attention on these highly energetic events, which are correlated to some of the most intense convective thunderstorm systems in the world. In this proceeding, we compare the signal of these exotic events and the signal of cosmic rays, as seen in the FD and the SD. The FD has triggered on numerous transient luminous events, dubbed "elves" since their first observation in 2005. The SD observed peculiar events with radially expanding footprints, which are correlated with lightning strikes reconstructed by the World Wide Lightning Location Network (WWLLN). The traced signals of both of these atmospheric events last longer in time than cosmic ray signals. The footprints are much larger; typically more SD stations (or more FD pixels) contribute to the observations. [ABSTRACT FROM AUTHOR]

EUSO-TA is a cosmic ray detector developed by the JEM-EUSO (Joint Experiment Missions for Extreme Universe Space Observatory) Collaboration, observing during nighttime the fluorescence light emitted along the path of extensive air showers in the atmosphere. It is installed at the Telescope Array site in Utah, USA, in front of the fluorescence detector station at Black Rock Mesa. It serves as a ground-based pathfinder experiment for future space-based missions. EUSO-TA has an optical system with two Fresnel lenses and a focal surface with 6 × 6 multi-anode photomultiplier tubes with 64 channels each, for a total of 2304 channels. The overall field of view is ∼10.6°× 10.6°. This detector technology allows the detection of cosmic ray events with high spatial resolution, having each channel a field of view of about ∼0.2° × 0.2° and a temporal resolution of 2.5 µs. First observations of ultra-high energy cosmic rays revealed the cosmic ray detection capability of EUSO-TA. The foreseen upgrade of EUSO-TA will improve the efficiency of the detector and will increase the statistics of detected events. In this work we present recent results of the detection capability of EUSO-TA and its limits. Moreover, other results about the analysis of laser pulses, stars and meteors will be discussed. [ABSTRACT FROM AUTHOR]

The Auger@TA project is a combined effort involving members of both the Pierre Auger Observatory and the Telescope Array experiment (TA) to cross-calibrate detectors and compare results on air showers detected at one location. We have recently reported results from Phase I of the project, during which we collected and presented data from two Auger water Cherenkov surface detector stations deployed into the TA experiment near the Central Laser Facility. For Phase II, we will deploy a micro-array of six or seven single-PMT Auger surface detector stations co-located with TA scintillator surface detector stations. The Auger micro-array will trigger and collect data independently from the TA allowing for a complete end-to-end comparison of detector data, calibration, and reconstructed event quantities on a shower-by-shower basis between the TA and Auger detector systems. We describe progress towards development of the micro-array for Phase II including the preparation of surface detector water tanks, station electronics, wireless communications, triggers, and data acquisition. We also outline plans for deploying the Auger@TA micro-array into the TA experiment in 2019 with preliminary estimates for coincident air-shower rates. [ABSTRACT FROM AUTHOR]

Since 2003, significant efforts have been devoted to the understanding of the radio emission of extensive air shower in the range [20-200] MHz. Despite some studies led until the early nineties, the [1-10] MHz band has remained unused for 20 years. However, it has been measured by some pioneering experiments that extensive air shower emit a strong electric field in this band and that there is evidence of a large increase in the amplitude of the radio pulse at lower frequencies. The EXTASIS experiment, located within the Nançay Radioastronomy Observatory and supported by the CODALEMA experiment, aims to reinvestigate the [1-10] MHz band, and especially to study the so-called "Sudden Death" contribution, the expected electric field emitted by shower front when hitting the ground level. Currently, EXTASIS has confirmed some results obtained by the pioneering experiments, and tends to bring explanations to the other ones, for instance the role of the underlying atmospheric electric field. Moreover, CODALEMA has demonstrated that in the most commonly used frequency band ([20-80] MHz) the electric field profile of EAS can be well sampled, and contains all the information needed for the reconstruction of EAS: an automatic comparison between the SELFAS3 simulations and data has been developed, allowing us to reconstruct in an almost real time the primary cosmic ray characteristics. [ABSTRACT FROM AUTHOR]

We report on the first results of a unique in-situ experimental cross-calibration effort of the surface detector of the Pierre Auger Observatory and of the Telescope Array experiment (Auger@TA). In the first phase of Auger@TA, we performed surface detector station-to-station comparisons for a collection of extensive air showers landing near the experimental setup and detected by Telescope Array. Beyond the deduced cross-calibration curve between the Water-Cherenkov-based Auger and Scintillator-based TA Surface Detector stations, we also investigate the consistency of their response for individual reconstructed showers. The dataset is currently too small to draw firm conclusions as-of-yet. Hence, phase I data taking will continue even as we gear up for the deployment of an Auger micro-array within Telescope Array as part of Phase II of this work. [ABSTRACT FROM AUTHOR]

The origin of ultrahigh energy cosmic rays (UHECRs) is an open question. In this proceeding, we first review the general physical requirements that a source must meet for acceleration to 10-100 EeV, including the consideration that the shock is not highly relativistic. We show that shocks in the backflows of radio galaxies can meet these requirements. We discuss a model in which giant-lobed radio galaxies such as Centaurus A and Fornax A act as slowly-leaking UHECR reservoirs, with the UHECRs being accelerated during a more powerful past episode. We also show that Centaurus A, Fornax A and other radio galaxies may explain the observed anisotropies in data from the Pierre Auger Observatory, before examining some of the difficulties in associating UHECR anisotropies with astrophysical sources. [ABSTRACT FROM AUTHOR]

The IceCube Neutrino Observatory at the geographic South Pole, with its surface array IceTop, detects three different components of extensive air showers: the total signal at the surface, low energy muons on the periphery of the showers, and high energy muons in the deep In Ice array of IceCube. These measurements enable determination of the energy spectrum and composition of cosmic rays from PeV to EeV energies, the anisotropy in the distribution of cosmic ray arrival directions, the muon density of cosmic ray air showers, and the PeV gamma-ray flux. Furthermore, IceTop can be used as a veto for the neutrino measurements. The latest results from these IceTop analyses will be presented along with future plans. [ABSTRACT FROM AUTHOR]

High-energy neutrinos are expected to be produced by the interaction of accelerated particles near the acceleration sites. For this reason, it is intresting to search for correlation in the arrival directions of ultra–high energy cosmic rays (UHECRs) and HE neutrinos. We present here the results of a search for correlations between UHECR events measured by the Pierre Auger Observatory and Telescope Array and high-energy neutrino candidate events from IceCube and ANTARES. We perform a cross-correlation analysis, where the angular separation between the arrival directions of UHECRs and neutrinos is scanned. When comparing the results with the expectations from a null hypothesis contemplating an isotropic distribution of neutrinos or of UHECR we obtain post-trial p-values of the order of ~ 10 2. [ABSTRACT FROM AUTHOR]

The study of correlations between observations of fundamentally different nature from extreme cosmic sources promises extraordinary physical insights into the Universe. With the Pierre Auger Observatory, we can significantly contribute to multi-messenger astrophysics by searching for ultra-high energy particles, particularly neutrinos and photons which, being electrically neutral, point back to their origin. Using Pierre Auger Observatory data, stringent limits at EeV energies have been established on the photon and neutrino fluxes from a large fraction of the sky, probing the production mechanisms of ultra-high energy cosmic rays. The good angular resolution and the neutrino identification capabilities of the Observatory at EeV energies allow the follow-up of events detected in gravitational waves, such as the binary mergers observed with the Advanced LIGO/Virgo detectors, or from other energetic sources of particles. [ABSTRACT FROM AUTHOR]

The Auger Muons and Infill for the Ground Array (AMIGA) aims to both extend the detection range of the Pierre Auger Observatory down to energies ~ 1016.5 eV and to measure the muon content of extensive air showers. To accomplish these goals, its detection system is composed of an array of coupled water-Cherenkov and scintillation detectors deployed in a graded triangular grid of 433 and 750 m spacings. At each position, the scintillation detector is buried 2.3 m deep so as to shield it from the air shower electromagnetic component and thus only measure the muon component. These muon detectors have 30 m2 area split into modules, each of them highly segmented in 64 plastic-scintillator strips with an embedded wavelength-shifter optical fiber to transport light to an optical sensor located at the center of the module. During the engineering array phase (finished in November 2017) two module areas (5 m2 and 10 m2) and two optical sensors (photo-multiplier tubes and silicon-photomultipliers) were tested. In this work, we present the final performance of the muon detectors equipped with silicon-photomultipliers which were thereafter selected as the baseline design for the AMIGA production phase. Analyses and results are based both on laboratory and field measurements. [ABSTRACT FROM AUTHOR]

The average profiles of cosmic ray shower development as a function of atmospheric depth are measured for the first time with the Fluorescence Detectors at the Pierre Auger Observatory. The profile shapes are well reproduced by the Gaisser-Hillas parametrization at the 1% level in a 500 g/cm2 interval around the shower maximum, for cosmic rays with log(E/eV) > 17.8. The results are quantified with two shape parameters, measured as a function of energy. The average profiles carry information on the primary cosmic ray and its high energy hadronic interactions. The shape parameters predicted by the commonly used models are compatible with the measured ones within experimental uncertainties. Those uncertainties are dominated by systematics which, at present, prevent a detailed composition analysis. [ABSTRACT FROM AUTHOR]

The study of correlations between observations of different messengers from extreme sources of the Universe has emerged as an outstanding way to make progress in astrophysics. The Pierre Auger Observatory is capable of significant contributions as an ultra-high energy particle detector, particularly through its capability to search for inclined showers produced by neutrinos. We describe the neutrino searches made with the Observatory with particular emphasis on the recent results following the detections of gravitational waves from binary mergers with Advanced LIGO and VIRGO, leading to competitive limits. [ABSTRACT FROM AUTHOR]

Silicon Photomultipliers (SiPMs) are excellent devices to detect the faint and short Cherenkov light emitted in high energy atmospheric showers, and therefore suitable for use in imaging air Cherenkov Telescopes. The high density Near Ultraviolet Violet SiPMs (NUV-HD3) produced by Fondazione Bruno Kessler (FBK) in collaboration with INFN were used to equip optical modules for a possible upgrade of the Schwarzschild-Couder Telescope camera prototype, in the framework of the Cherenkov Telescope Array project. SiPMs are 6×6 mm2 devices based on 40×40 μm2 microcells optimized for photo-detection at the NUV wavelengths. More than 40 optical modules, each composed by a 4×4 array of SiPMs, were assembled. In this contribution we report on the development and on the assembly of the optical modules, their validation and integration in the camera. [ABSTRACT FROM AUTHOR]

Status and perspectives of the radio detection of high-energy cosmic rays are discussed with emphasis on recent developments at the LOFAR radio telescope and the Pierre Auger Observatory. [ABSTRACT FROM AUTHOR]

MAGIC, a system of two Cherenkov telescopes located at the Roque de los Muchachos Observatory (2200 a.s.l.) in the Canary Island of La Palma, has lately been engaged in an unconventional task: the search for a signature of particle showers induced by earth-skimming cosmic tau neutrinos arising from the ocean, in the PeV to EeV energy range. When pointing at the sea, the MAGIC telescopes can collect data in a range of about 5 deg in zenith and 80 deg in azimuth: the analysis of the shower images from ~30 hours of data, together with the simulations of upward-going tau neutrino showers, shows that the air showers induced by tau neutrinos can be discriminated from the hadronic background coming from a similar direction. We have calculated the point source acceptance and the expected event rates, assuming an incoming v flux consistent with IceCube measurements, and for a sample of generic neutrino fluxes from photohadronic interactions in AGNs and GRBs. A 90% C.L. upper limit on the tau-neutrino point source flux of 2.0 × 10–4 GeV cm–2 s–1 has been obtained. The presented results can also be important for future Cherenkov experiments such as the Cherenkov Telescope Array. This next generation ground-based observatory can have a much better possibility to detect v, given its larger FOV and much larger effective area. [ABSTRACT FROM AUTHOR]

One of the main objectives of cosmic-ray studies are precise measurements of the energy and chemical composition of particles with extreme energies. Large and sophisticated detectors are used to find events seen as showers starting in the Earth's atmosphere with recorded energies larger than 100 EeV. However, a Cosmic-Ray Ensemble (CRE) developing before reaching the Earth as a bunch of correlated particles may spread over larger areas and requires an extended set of detectors to be discovered. The Cosmic-Ray Extremely Distributed Observatory (CREDO) is a solution to find such phenomena. Even simple detectors measuring the particle arrival time only are useful in this approach, as they are sufficient both to provide candidate CRE events and to determine the direction from which they are arriving. [ABSTRACT FROM AUTHOR]

The LHCb experiment is designed to study flavor physics of b and c quarks. The detector is optimized for the study of identified hadrons produced in the forward direction, which also makes LHCb very interesting for the understanding of cosmic-ray induced air showers. LHCb is analysing proton-proton, protonlead, and lead-lead collisions. As a unique feature, LHCb is also studying beam interactions with noble gases using its SMOG system. We present recent measurements of charmed mesons, which are used to obtain production cross-sections, to constrain the parton PDF, to test pomeron and multi-particle interactions, nuclear and collective effects. These mostly have an indirect impact on the modeling of hadronic interactions. Finally, we present a direct measurement of the anti-proton production in proton collisions with helium gas, which are important for the understanding of AMS-02 and PAMELA data. [ABSTRACT FROM AUTHOR]

The Carpet air shower array of the Baksan Neutrino Observatory is in operation for a long time, and it was modernized more than once. A short review of important results obtained with this array is given, as well as future prospects, since at the moment the new project called Carpet-3 is in progress, using the old array as its basis. The purpose of the new project is to substantially increase the muon detector area (quite soon up to 400 m2 and later up to 600 m2). This improvement will allow one to reach a very good sensitivity to diffuse cosmic photons by selecting muon-poor showers. The energy range where the new experiment will be competitive with other experiments of gamma-ray astronomy is near and below 100 TeV. [ABSTRACT FROM AUTHOR]

Antenna arrays are beginning to make important contributions to high energy astroparticle physics supported by recent progress in the radio technique for air showers. This article provides an update to my more extensive review published in Prog. Part. Nucl. Phys. 93 (2017) 1. It focuses on current and planned radio arrays for atmospheric particle cascades, and briefly references to a number of evolving prototype experiments in other media, such as ice. While becoming a standard technique for cosmic-ray nuclei today, in future radio detection may drive the field for all type of primary messengers at PeV and EeV energies, including photons and neutrinos. In cosmic-ray physics accuracy becomes increasingly important in addition to high statistics. Various antenna arrays have demonstrated that they can compete in accuracy for the arrival direction, energy and position of the shower maximum with traditional techniques. The combination of antennas and particles detectors in one array is a straightforward way to push the total accuracy for high-energy cosmic rays for low additional cost. In particular the combination of radio and muon detectors will not only enhance the accuracy for the cosmic-ray mass composition, but also increase the gamma-hadron separation and facilitate the search for PeV and EeV photons. Finally, the radio technique can be scaled to large areas providing the huge apertures needed for ultra-high-energy neutrino astronomy. [ABSTRACT FROM AUTHOR]

Cygnus X-3 binary system is a famous object studied over the wide range of electromagnetic spectrum. Early detections of ultra-high energy gamma-rays from Cygnus X-3 by Kiel, Havera Park and then by Akeno triggered the construction of several large air shower detectors. Also, Cygnus X-3 has been proposed to be one of the most powerful sources of charged cosmic ray particles in the Galaxy. The results of twenty-year observations of the Cyg X-3 binary at energies 800 GeV - 85 TeV are presented with images, spectra during periods of flaring activity and at low flux periods. The correlation of TeV flux increases with flaring activity at the lower energy range of X-ray and radio emission from the relativistic jets of Cygnus X-3 is found as well as 4.8-hour orbital modulation of TeV γ-ray intensity. Detected modulation of TeV γ-ray emission with orbit and important characteristics of Cyg X-3 such as the high luminosity of the companion star and the close orbit leads to an efficient generation of γ-ray emission through inverse Compton scattering in this object. The different type variability of very high-energy γ-emission and correlation of radiation activity in the wide energy range can provide essential information on the mechanism of particle production up to very high energies. [ABSTRACT FROM AUTHOR]

The Large High Altitude Air Shower Observatory (LHAASO) is a new hybrid array for very high energy gamma ray astronomy and cosmic ray physics. The KM2A array, one of the main parts of LHAASO, covers an area of 1.3 km2 to observe gamma rays above 10 TeV up to 1 PeV for many sources. A prototype with 1% the size of the whole KM2A has been in stable operation for more than two years. A Monte Carlo simulation program named G4KM2A was developed; based on this work, the trigger rate, hit multiplicity, angular and core reconstruction are compared with KM2A prototype data. Finally, the moon shadow with -6.5 significance was obtained. The G4KM2A simulation results are consistent with KM2A prototype data and can be used for the whole KM2A array in future. [ABSTRACT FROM AUTHOR]

Measuring the knees of the cosmic ray spectra for individual species is a very important approach to solve the problem of the origin of ultra high energy galactic cosmic rays. The knee of the iron spectrum is implied to be above 10 PeV from previous experiments, such as ARGO-YBJ and LHAASO-WFCTA. LHAASO is a suitable size for measurements with the required precision. The key is to separate iron nuclei from all cosmic ray samples. In this paper, we identify a couple of variables that are sensitive to the composition of showers recorded by the detector arrays in LHAASO. A multi variate analysis is proposed for the separation. The efficiency and purity of the selection for demanded species are optimized by well configuring the LHAASO array using the LHAASO simulation tools. [ABSTRACT FROM AUTHOR]

The HAWC (High Altitude Water Cherenkov) observatory, located on the slopes of the Sierra Negra volcano in the state of Puebla, Mexico, was designed with the goal of detecting gamma-rays in the Teraelectron- volt energy range. However, most of the air showers that are detected with the observatory, with a rate of ≈ 27 kHz, are of hadronic origin. This makes that, after three years of operations, HAWC has accumulated a very large data set that allows to perform cosmic-ray analysis of high precision. The details of the observatory operation, as well as a selection of recent results in cosmic-ray physics are discussed in this work. [ABSTRACT FROM AUTHOR]

The paper presents results on the longitudinal development of air showers of ultra-high energies obtained from radio emission measurements at the Yakutsk array. The energy, the depth of maximum development of individual showers are determined and a statistical analysis of Xmax in order to estimate the fluctuation of air shower development σ(Xmax) in the energy region 1017-1018 eV is performed. It is shown that σ(Xmax) in the energy region 1017-1018 eV is equal to 50-60 g·cm-2, which doesn't contradict with a mixed composition of cosmic rays - protons and helium nuclei. This is also indicated by data of the Xmax value dependence on energy. [ABSTRACT FROM AUTHOR]