Ultrahigh Energy Cosmic Ray Particles Research Articles

Simulation and Parameterization of Longitudinal Development using Different Hadronic Interaction Models

The importance of investigating ultra-high energy cosmic ray particles interactions was investigated in this work. Different hadronic interaction models such as (SIBYLL, EPOS, and QGSJET) were used air showers simulation AIRES program (version 19.04.00). Also, the shower size of Extensive Air Showers (EAS) was calculated by estimating the longitudinal development. Moreover, the longitudinal development simulation of the two primary particles (iron nuclei and proton) was performed, taking into account their primary energies effect as well the zenith angle for charged particles that produced in the EAS, with energies (1017 and 1019) eV. At such extremely high energies (1017 and 1019) eV, new parameters as a function of the primary energy were obtained by fitting the longitudinal development curves of EAS using the Lorentz function. Comparison of the results showed a good agreement between the values obtained from the parameterized longitudinal development using Lorentz function with experimental results by Pierre Auger EAS observatory as well the simulated results by Sciutto for the primaries iron nuclei as well proton, with the electrons and the charged muons secondary particles of high energies.

Determination of Zenith Angle Dependence of Incoherent Cosmic Ray Muon Flux Using Smartphones of the CREDO Project

The Cosmic-Ray Extremely Distributed Observatory (CREDO) was established to detect and study ultra high-energy cosmic ray particles. In addition to making use of traditional methods for finding rare and extended cosmic ray events such as professional-grade Extensive Air Shower (EAS) arrays, as well as educational ‘class-room’ detectors, CREDO also makes use of cameras in smartphones as particle detectors. Beyond the primary scientific goal of the CREDO project, to detect Cosmic Ray Ensembles, is the equally important educational goal of the project. To use smartphones for EAS detection, it is necessary to demonstrate that they are capable of effectively registering relativistic charged particles. In this article, we show that the events recorded in the CREDO project database are indeed tracing incoherent cosmic ray muons. The specific observed distribution of zenith angle of charged particle direction corresponds to that expected for muons. It is difficult, if not impossible, to imagine different mechanisms leading to such a distribution, and we believe it clearly demonstrates the suitability of smartphone-based detectors in supporting the more traditional cosmic ray detectors.

The first CREDO registration of extensive air shower

The Cosmic-Ray Extremely Distributed Observatory (CREDO) is the project to search and study ultra high-energy cosmic ray particles from deep space producing simultaneous extensive air showers over the entire exposed surface of the Earth. The concept of the CREDO infrastructure assumes absorbing all kinds of cosmic ray data from any apparatus all over the world, including professional instruments, educational detectors and arrays, and popular devices such as smartphones. We discuss here the usefulness and possibilities of using the last one and present the educational CREDO-Maze mini array comprised of four CosmicWatch detectors. This simple and affordable apparatus is shown to be able to register the extensive air showers and can be used to study cosmic rays much more effectively than the simple two-detector CosmicWatch muon telescope station. The further development direction is indicated.

Global Characteristics of the Medium Produced in Ultra-High Energy Cosmic Ray Collisions

Estimations of some geometrical and bulk parameters are presented for the matter produced in various type collisions with ultra-high energy cosmic ray (UHECR) particles. Results for multiplicity density at midrapidity, decoupling time, and energy density are discussed for small and larger collision systems. Based on the analytic functions suggested previously elsewhere, estimations for a wide set of space-time quantities are obtained for emission region created in various particle collisions at energies of UHECR. The space particle densities at freeze-out are derived also and allow the possibility of novel features for secondary particle production like Bose-Einstein condensation at least for nuclear interactions with UHECR particles. The estimations obtained for global and geometrical parameters indicate the creation of deconfined quark-gluon matter with large enough volume and lifetime even in light nuclear collisions at UHECR energies. These quantitative results can be important for both the future collider experiments at center-of-mass energy frontier and the improvement of the phenomenological models for development of the cosmic ray cascades in ultra-high energy domain.

LORD Space Experiment for Investigation of Ultrahigh Energy Cosmic-ray Particles

The problem of detecting cosmic rays and neutrinos of energies above the GZK cutoff is reviewed. Nowadays, it becomes clear that registration of nature's most energetic particles requires approaches based on new principles. First of all, we imply the detection of the coherent Cherenkov radio emission in cascades of ultrahigh-energy particles in radio-transparent natural dense media, i.e., ice shields of Antarctica, mineral salt, and lunar regolith. The Luna-Glob space mission planned for launching in the near future involves the Lunar Orbital Radio Detector (LORD) whose aperture for cosmic rays and neutrinos of energies E ≥ 1020 eV exceeds all existing ground-based arrays. The feasibility of LORD to detect radio signals from showers initiated by ultrahigh-energy particles interacting with the lunar regolith is examined. The design of the LORD space instrument and its scientific potentialities for registration of low-intense cosmic-ray particle fluxes above the GZK cut-off up to 1025 eV is discussed.

Testing calculation results of Cherenkov radiation flux from extensive air showers using CORSIKA

This paper presents computational results of the spatiotemporal characteristics of Cherenkov light from particles of extensive air showers (EASs) induced by ultra-high-energy cosmic rays (UHECR). These results were obtained by simulating EAS events with the CORSIKA software package. Events were induced by UHECR particles, i.e., protons and iron nuclei with energies of 1015 and 1016 eV. The computational results were compared with experimental data obtained at the Yakutsk EAS array; possible causes of the discrepancy between them are discussed.

Ultra-high energy cosmic rays threshold in Randers–Finsler space

Kinematics in Finsler space is used to study the propagation of ultra high energy cosmic rays particles through the cosmic microwave background radiation. We find that the GZK threshold is lifted dramatically in Randers–Finsler space. A tiny deformation of spacetime from Minkowskian to Finslerian allows more ultra-high energy cosmic rays particles to arrive at the earth. It is suggested that the lower bound of particle mass is related with the negative second invariant speed in Randers–Finsler space.

Jets as accelerators of ultrahigh-energy cosmic ray particles

The model of a cosmic jet that operates in the regimes of an MHD nozzle and a unipolar inductor is considered. It is shown that the “solid-body” rotation (according to Ferraro’s law) of helical magnetic field lines should lead to an acceleration of a small fraction of the plasma particles to ultrarelativistic energies with a spectrum dq/dɛ ∼ ɛ−n and an index n close to its observed value of n ≈ 2.70–2.75.

Is astronomy possible with neutral ultrahigh energy cosmic ray particles existing in the standard model?

The recently observed correlation between HiRes stereo cosmic ray events with energies E ∼ 1019 eV and BL Lacertae objects occurs at an angle that strongly suggests that the primary particles are neutral. We analyze whether this correlation, if not a statistical fluctuation, can be explained within the Standard Model, i.e., assuming only known particles and interactions. We have not found a plausible process that can account for these correlations. The mechanism that comes closest—the conversion of protons into neutrons in the IR background of our Galaxy—still underproduces the required flux of neutral particles by about two orders of magnitude. The situation is different at E ∼ 1020 eV, where the flux of cosmic rays at the Earth may contain up to a few percent of neutrons, indicating their extragalactic sources.

Composition and cross-section measurements using the HiRes detector

The HiRes stereo uorescence detector can precisely measure the profile of the extensive air showers caused by ultra-high energy cosmic ray particles. The distribution of the depth of the air shower maxima, Xmax, can serve as an indication of the atomic mass of the cosmic particles. It can also be used to measure the p-air inelastic cross-section. We discuss the consistency of the mass composition measurements done by the Fly’s Eye, the HiRes prototype/MIA and the HiRes stereo experiments. We introduce the first cross-section measurement at 1018:5 eV done using the HiRes stereo data and a newly developed deconvolution technique. The atmosphere can introduce a significant bias into these measurements. We estimate the systematic errors comparing the HiRes standard atmospheric model with the balloon data from the Salt Lake international airport.

Detection of meteors and sub-relativistic dust grains by the fluorescence detectors of ultra high energy cosmic rays

Fluorescence detectors of ultra high energy cosmic rays (UHECR) allow to record not only the extensive air showers, initiated by the UHECR particles, but also to detect light, produced by meteors and by the fast dust grains. It is shown that the fluorescence detector operated at the mountain site can register signals from meteors with kinetic energy threshold of about 25 J (meteor mass ∼ 5 × 10 −6 g, velocity ∼ 3 × 10 6 cm/s). The same detector might be used for recording of the dust grains of smaller mass (of about 10 −10 g) but with velocity 10 9 cm/s, close to the light velocity (sub-relativistic dust grains). The light signal from a sub-relativistic dust grain is expected in much shorter time scale (∼0.001 s), in comparison with the meteor signal (∼0.1–1 s), and much longer than duration of the UHECR signals (tens of μs). The fluorescence detector capable to register various phenomena: from meteors to UHECR – should have a variable pixel and selecting system integration time. A study of the new phenomenon of sub-relativistic grains will help to understand the mechanism of particle and dust grain acceleration in astrophysical objects (in SN explosions, for example).

KLYPVE/TUS space experiments for study of ultrahigh-energy cosmic rays

The KLYPVE space experiment has been proposed to study the energy spectrum, composition, and arrival direction of ultrahigh-energy cosmic rays (UHECR) by detecting from satellites the atmosphere fluorescence and scattered Cherenkov light produced by EAS, initiated by UHECR particles. The TUS setup is a prototype KLYPVE instrument. The aim of the TUS experiment is to detect dozens of UHECR events in the energy region of the GZK cutoff, to measure the light background, to test the atmosphere control methods, and to study stability of the optical materials, PMTs, and other instrumental parts in space environment.

FORTE satellite constraints on ultrahigh energy cosmic particle fluxes

The FORTE (Fast On-orbit Recording of Transient Events) satellite records bursts of electromagnetic waves arising from near the Earth's surface in the radio frequency (rf) range of 30 to 300 MHz with a dual polarization antenna. We investigate the possible rf signature of ultrahigh energy cosmic-ray particles in the form of coherent Cherenkov radiation from cascades in ice. We calculate the sensitivity of the FORTE satellite to ultrahigh energy neutrino (UHE $\ensuremath{\nu})$ fluxes at different energies beyond the Greisen-Zatsepin-Kuzmin cutoff. Some constraints on supersymmetry model parameters are also estimated due to the limits that FORTE sets on the UHE neutralino flux. The FORTE database consists of over 4 million recorded events to date, including in principle some events associated with UHE $\ensuremath{\nu}.$ We search for candidate FORTE events in the period from September 1997 to December 1999. The candidate production mechanism is via coherent VHF radiation from a UHE $\ensuremath{\nu}$ shower in the Greenland ice sheet. We demonstrate a high efficiency for selection against lightning and anthropogenic backgrounds. A single candidate out of several thousand raw triggers survives all cuts, and we set limits on the corresponding particle fluxes assuming this event represents our background level.

Ultra high energy cosmic ray sources and experimental results

Here we discuss the latest developments in the debate, where the ultrahigh energy cosmic ray particles come from. In this brief review, we emphasize the predictions that necessarily follow from the various concepts proposed. We discuss both sources and propagation, and spend some space on the by now most conservative model, giant radio galaxies and their hot spots and jets, because it allows more steps in the reasoning to be checked, and is more tightly constrained than any other model. It has survived about forty years of debate already. We summarize the task ahead of us at the end, including the development of new technologies to observe ultra high energy cosmic rays, e.g., with the radio emission of air showers, which may lead to an alternative to the fluorescence detectors with their small duty cycle. Due to HiRes, AUGER, and the plans for EUSO, the future is bright, and the ultra high energy cosmic ray particles may yet allow us to explore new physics.

Complementary research ability of ground- and space-based detectors of ultra high energy cosmic rays

In comparison of ground- and space-based optical detectors of ultra high energy cosmic rays (UHECR) the space-based detectors have the advantage of registering EAS, initiated by UHECR particles, at a much larger area of the atmosphere. They also have the advantages of observing EAS in a wide range of atmosphere depth including near-horizontal EAS, initiated by neutrino at depths >1000 g cm−2. Ground-based particle detector arrays have the advantages of taking data on EAS parameters, sensitive to a primary particle mass, not determined by space detectors. Particle detectors having 100% duty cycle observe a specific UHECR source longer than the space detector with the same geometrical factor.

Complementary research ability of ground- and space-based detectors of ultra high energy cosmic rays

In comparison of ground- and space-based optical detectors of ultra high energy cosmic rays (UHECR) the space-based detectors have the advantage of registering EAS, initiated by UHECR particles, at a much larger area of the atmosphere. They also have the advantages of observing EAS in a wide range of atmosphere depth including near-horizontal EAS, initiated by neutrino at depths >1000 g cm−2. Ground-based particle detector arrays have the advantages of taking data on EAS parameters, sensitive to a primary particle mass, not determined by space detectors. Particle detectors having 100% duty cycle observe a specific UHECR source longer than the space detector with the same geometrical factor.

Cosmic particles of the highest energies

A short review is given on our theoretical work on Ultra-High Energy Cosmic Ray Particles (UHECRP).

QSO Redshift Limit and Periodicity in a Fib Universe

The FIB cosmology was conceived half a century ago, to explain the origin and spectrum of the ultrahigh energy cosmic ray particles we observed in deep mines. It succeeded in explaining quantitatively the 3°K microwave background radiation (IAU Symposium No. 44), the redshift periodicity (PASP 1976), and the cutoff of QSO's beyond z=3.5 (AAS 1982).