Abstract-The origin of cosmic rays can be deciphered by accurately measuring the components and energy spectrum in the knee region. Extensive air shower (EAS) studies rely on information provided by secondary high energy hadrons, which generate evaporation neutrons when they interact with matter in the environment. In the early 21st century, the electron-neutron detector (EN-detector) was...
As part of the high-altitude LHAASO project, ENDA (Electron Neutron Detector Array) is being created in China. The concept of the ENDA consists in simultaneous registration of the electromagnetic and thermal neutron components (being a part of hadronic component) of the EAS. The report provides a brief overview of analytical and ML (Machine Learning) methods for shower and primary particle...
Currently, the deployment of the Baikal-GVD neutrino telescope is successfully underway in Lake Baikal. Baikal-GVD now comprises 96 strings with 3456 optical modules. We present the current status and plans for further deployment of the Baikal-GVD telescope and discuss issues related to the creation of a next-generation neutrino telescope in Lake Baikal.
Neutrino radio detectors are designed to target the first measurement of neutrinos beyond energies of ∼10 PeV. Several such radio detectors operate in Antarctica. They are scanning the ice sheet in search of Askaryan radio emission from neutrino induced showers. The Radio Neutrino Observatory in Greenland (RNO-G), designed to monitor ultra-high-energy neutrinos in the northern hemisphere, is...
We analyze neutrino fluxes near the surface of a protoneutron star in type II supernova explosions at core-collapse regime. For dynamoactive supernovae it is shown that effective neutrino collisions in a magnetized nucleon gas caused by the neutral current Gamow-Teller component lead to neutrino acceleration. Such an effect originates from spin-projection asymmetry in phase space volume of...
The TAIGA experiment in Tunka valley is expanding the present scintillation detector array with new TAIGA-Muon detector stations. A simulation model was developed for the new stations optimization and study of the identification performance of the array together with HiScore optical stations system. The extensive air showers (EASs) were simulated with the CORSIKA simulation tool, and the...
The High-Energy Ray Observatory (HERO) is a space experiment based on a heavy ionization calorimeter for direct study of cosmic rays. The effective geometric factor of the apparatus is not less than 12m2sr for protons and not less than 18m2sr for nuclei and electrons. During the exposure for ∼5-7 years this mission will make it possible to measure energy spectra of all abundant cosmic ray...
Paper contains the first results of our attempts in the development of a model of SPHERE-3 telescope for the primary cosmic ray studies in 1-1000 PeV energy range with reflected and direct Cherenkov light generated by extensive air showers (EAS).
The aim of the work is to develop an automated method for the design of SPHERE-3 telescope, which, on one hand, will enable it to obtain the best...
Acceleration of cosmic rays in astrophysical jets is investigated. Particles are
accelerated at the outer bow shock and by shear flows in the jet cocoon.
Applications for the origin and chemical composition of
ultra high energy cosmic rays are discussed.
The paper discusses an approach that made it possible to estimate the distance to the nearest pevatrons, which form a break in the spectrum of the cosmic ray nucleon component of about 4 PeV. It is based on the spectra of nucleons and electrons obtained by the authors in the framework of the superdiffusion model of nonclassical CR diffusion, which have a break, on the assumption that nucleons...
The commonly accepted CR transport theory is based on the diffusion equation, which in turn follows from the Boltzmann kinetic equation. The latter was derived for multiple collisions of particles with local formations (atoms, molecules) under the assumption of their statistical independence, more precisely, of the Poisson nature of the ISM ensemble. It is this property that is responsible for...
A set of eight scintillators with the reduced to (50-70)ns width of their output pulse signals is applied for determination of the arrival directions of extensive air showers which are effectively detected by the Tien Shan shower installation in the energy range between 1 and 100 PeV. Up to the present time, about ~$10^6$ shower events applicable for deducing their directional angles were...
The TUS experiment was the first detector to measure the fluorescence and Cherenkov radiation of extensive air showers (EAS) in the Earth's atmosphere from space orbit. The main goal of the TUS experiment was to search for and study ultra high-energy cosmic rays with energies E > 70 EeV. The TUS detector registered a number of unusual events, the origin of which is unclearwith an anomalously...
The Experimental Complex (EC) NEVOD (MEPhI, Moscow) includes the NEVOD-EAS array, detecting electron-photon component of extensive air showers (EAS), and the Cherenkov water calorimeter (CWC), measuring energy deposit of particles passing through its operating volume.
Reconstruction of main EAS parameters (axis position, arrival direction, age and size) is performed according to the data of...
CMS measurementsm valuable for tuning CR generators are discussed.
Collisions of cosmic ray particles with ultra-high initial energies larger than 0.1–1 EeV with nuclei in the atmosphere lead to creation a strongly interacting matter under extreme conditions and open a wide room for appearing of the novel dynamical features for production of secondary particles. In particular, the estimations obtained for the space density of charged particles at freeze-out...
The excess of muons in ultra-high energy cosmic rays (UHECR) in comparison with the results of Monte-Carlo simulations that grows with the primary particle energy is known as the muon puzzle. Since the LHC data became available, many improvements have been done to the models of hadronic interactions used in extensive air showers (EAS) simulation tools. Yet the noticeable deviation from...
The report is devoted to the geometric and kinematic description of the azimuthal correlation of photon and hadron families, which was observed by the Pamir collaboration in emulsion experiments with cosmic rays. This effect is called «alignment», because quantitatively this feature demonstrates a deviation from the straight line of points on the emulsion film plane used for particles...
At National Research Nuclear University MEPhI, a large-scale coordinate-tracking detector TREK for the study of muon bundles at large zenith angles is under construction. The detector has an area of 250 $m^2$ and consists of two planes of multi-wire drift chambers.
In joint operation with the Cherenkov water detector of 2000 tons of distillated water, the TREK detector will provide on...
Recent experimental data from space-based instruments of the DAMPE and CALET collaborations have shown that the energy spectrum of protons has a new feature, a break in the $\sim 10$ TeV region. In this energy range, the spectrum index of the observed particles varies from $-2.6$ to $-2.9$.
The purpose of this work is to establish the location zone of the sources that determine this break,...
NEVOD-DECOR is the unique experiment where systematic studies of cosmic ray muon bundles in a wide range of zenith angles and, accordingly, the energies of primary cosmic rays are carried out. Impressive experimental material (more than 100 thousand events) has been accumulated over a long time period from May 2012 to December 2022. The earlier developed method of local muon density spectra...
The results of direct measurements of the muon density in extensive air showers (EAS) with zenith angles $\theta \leq 45^\circ$ and energies $Е_0\geq 10^{17}$ eV obtained in the Auger experiment and at the Yakutsk array are considered. In both cases muons were registered by underground scintillation detectors with the same threshold energy $Е_{\mu}\approx 1.0 \times \sec \theta$ GeV. The...
Systematic uncertainties in the energy estimation of EAS primaries are a source of headache for physicists and lead to elusive discrepancies in the energy spectra of cosmic rays measured with different arrays. We have found the zenith angle distribution of EAS event rate to be sensitive to these systematic uncertainties. It gives an opportunity to test different algorithms for the primary...
Since 1986, regular measurements of radio emission generated by air shower relativistic particles have been started at the Yakutsk array. As a result of studying the noise background on the array region, a frequency of 30-35 MHz was chosen with minimal radio noise. Showers with energies greater than 10 EeV were registered at the array. For the first time, radio emission in showers with...
The Carpet-2 collaboration reports on the observation and analysis of an event with a low muon content coincident with the gamma-ray burst GRB 221009A and the transient Swift J1913.1+1946. This bright transient was observed by numerous instruments in the optical, X-ray and gamma-ray energy ranges. The redshift of this GRB is z=0.1505 (measured from afterglow observations).
The Carpet-2 array...
Search for gamma rays with energies ≥ 300 TeV was being performed at the Carpet-2 array at the INR RAS Baksan Neutrino Observatory from 2018 to 2022. We analyzed the spectra of gamma-like events from the Milky Way region and compared it with the rest of the sky. In addition, we studied several Galactic point sources, in particular those detected by LHAASO. The results of the searches will be...
