High Energy Primary Cosmic Rays Research Articles

Hadronic Interactions Studies at the LHC

The deficit of muons in the simulation of extensive air showers is a long-standing problem and the origin of large uncertainties in the reconstruction of the mass of the high-energy primary cosmic rays. Hadronic interaction models re-tuned after early LHC data have a more consistent description of the muon content among them but still disagree with the data. Furthermore, some inconsistencies are also visible in the electromagnetic component. Ten years after the first LHC-tuned model release, much more detailed data are available both from LHC, SPS and hybrid air shower measurements, allowing for the understanding of some deficiencies in the model which could lead to a change in both Xmax and the muon production by air showers. A better treatment of the core-corona approach according to LHC data has important consequences on the muon production while an update of diffraction and nuclear fragmentation is changing the Xmax distribution. An updated version of EPOS LHC will be presented addressing the main issues of this model.

Study of lateral density distributions of Cherenkov photons in extensive air showers at primary energy 50 GeV and above

An EAS (extensive air shower) refers to the cascade of secondary particles created from the interactions of high energy primary cosmic ray particles with the air nuclei and subsequent decay of the particles produced. Ultra-relativistic secondary charged particles in the atmosphere produce Cherenkov radiation, which may be detected by ground based detector array. Such an array, HAGAR (High Altitude GAmma Ray) experiment is operating at Hanle, Ladakh, at an energy threshold of about 100 GeV, which will be lowered to 50 GeV using MACE telescope. We have studied the simulations of the distribution patterns of lateral density of Cherenkov photons generated in EAS for different primary particles (γ, p) incident with the fixed primary energy 50 GeV and these are compared with those of 100 GeV showers using the standard CORSIKA code. From our study it has been found that, for all primary particles, the variation of lateral density distribution of Cherenkov photons almost obey the functional relation, ρch (r) = ρ0 e(−βr). The steepness of the lateral distribution function is found to depend on the primary mass composition. Further a prominent hump is observed in the lateral distribution for gamma shower only.

Analysis of the space-time microstructure of cosmic ray air showers using the HADES RPC TOF wall

Cosmic rays have been studied, since they were discovered one centuryago, with a very broad spectrum of detectors and techniques. However,never the properties of the extended air showers (EAS) induced by highenergy primary cosmic rays had been analysed at the Earth surface witha high granularity detector and a time resolution at the 0.1 nsscale. The commissioning of the timing RPC (Resistive Plate Chambers)time of flight wall of the HADES spectrometer with cosmic rays, at theGSI (Darmstadt, Germany), opened up that opportunity. During the lastmonths of 2009, more than 500 millions of cosmic ray events wererecorded by a stack of two RPC modules, of about 1.25 m2 each, ableto measure swarms of up to ∼ 100 particles with a time resolutionbetter than 100 ps. In this document it is demonstrated how such arelative small two-plane, high-granularity timing RPC setup mayprovide significant information about the properties of the shower andhence about the primary cosmic ray properties.

The track imaging Cherenkov experiment

We describe a dedicated cosmic-ray telescope that explores a new method for detecting Cerenkov radiation from high-energy primary cosmic rays and the large particle air shower they induce upon entering the atmosphere. Using a camera comprising 16 multi-anode photomultiplier tubes for a total of 256 pixels, the Track Imaging Cerenkov Experiment (TrICE) resolves substructures in particle air showers with 0.086 degree resolution. Cerenkov radiation is imaged using a novel two-part optical system in which a Fresnel lens provides a wide-field optical trigger and a mirror system collects delayed light with four times the magnification. TrICE records well-resolved cosmic-ray air showers at rates ranging between 0.01-0.1 Hz.

Latest results and perspectives of the KASCADE-Grande EAS Facility

KASCADE-Grande is a multi-detector experiment at KIT (Karlsruhe Institute of Technology) in Germany for measuring extensive air showers in the primary energy range of 100 TeV to 1 EeV. This paper does not provide a synopsis of all results of the KASCADE-Grande experiment. Rather it is focused on three aspects of current interests illustrating the advantages of a multi-detector facility. Results on the analysis of individual energy spectra of primary mass groups around the knee obtained by unfolding the shower size measurements of KASCADE with the help of the new hadronic interaction model EPOS and the all-particle energy spectrum at higher energies obtained by Grande measurements will be discussed. As KASCADE-Grande serves also as host of the LOPES radio detection experiment where both experiments measure the same showers, special emphasis will be given in comparing the characteristics and feasibility of both techniques in estimating the main parameters of high-energy primary cosmic rays: energy, composition, and arrival direction.

The LHCf experiment at LHC

High Energy Cosmic Ray experiments are providing useful information to understand high energy phenomena in the Universe. However, the uncertainty caused from the poor knowledge of the interaction between very high energy primary cosmic ray and the Earth’s atmosphere prevents the precise deduction of astrophysical parameters from the observational data. The Large Hadron Collider (LHC) provides the best opportunity for calibrating the hadron interaction models in the most interesting energy range, between 1015 eV and 1017 eV. To constrain the models used in the extensive air shower simulations the measurements of very forward particles are mandatory. Among the LHC experiments, the LHCf experiment has been designed to reach this goal and its capability to measure forward neutral particle produced in p-p interaction will result crucial for a better interpretation of cosmic ray studies. In this paper, the status of the LHCf experiment and preliminary results for 900 GeV data taking are discussed.

The Possibility of Using Artificial Neural Networks for the Estimation of Mass Composition of High-Energy Primary Cosmic Ray

This paper shows that the artificial neural networks (ANN) can be used for determining the type of particles of high-energy primary cosmic ray (i.e. its mass composition) initiating the EAS. The approach implemented here can be used, e.g., in the Auger experiment. We describe the details of the ANN construction and demonstrate that the program is correct and can be further used to solve physical problems. The network was taught and tested based on the data for the maximum of the EAS development (X_max) and primary energy of a particle initiating this EAS (lg(E0)). The identification of particles based on X_max and lg(E0) resulted in around 80% of correct answers for the light mass composition and 99% for the heavy one. We have a correct answer for the mass composition with domination of one type of particles, i.e. light or heavy. Otherwise, additional parameters should be included as ANN input data.

Experiment SPHERE status – 2006 and CR composition determination by means of Cherenkov light LDF

The modern status of the SPHERE experiment and the method to determine the primary energy and the kind of the primary nuclear particles is presented. The SPHERE experiment is based on A.E.Chudakov's suggestion to use a new method for investigating the ultra high energy primary cosmic ray energy spectrum [A.E. Chudakov, Trudy conf. po cosm. lutcham, (in Russian), p.69, Yakutsk, 1972]. A small device lifted above the snow surface of the Earth detects the Cherenkov light of extensive air showers reflected from the surface. The relatively simple detector SPHERE-2 (spherical mirror 1.5m diameter and retina of 100 pixels) is presented. The next plan of the SPHERE experiment is to start measurements of the cosmic ray spectrum in the energy range 10 16 – 10 18 eV above the snow surface of Lake Baikal.

Extensive air showers in the classroom

The basic properties of extensive air showers of particles produced in the interaction of a high-energy primary cosmic ray in the Earth's atmosphere are discussed in the context of educational cosmic ray projects involving undergraduate students and high-school teams. Simulation results produced by an air shower development code were made available on the Web by the use of ASCII files and EXCEL spreadsheets to allow people to carry out graphical and numerical analyses in cosmic ray physics.

Resolving electrons from protons in ATIC

The Advanced Thin Ionization Calorimeter (ATIC) experiment is designed for high energy cosmic ray ion detection. The possibility to identify high energy primary cosmic ray electrons in the presence of the ‘background’ of cosmic ray protons has been studied by simulating nuclear-electromagnetic cascade showers using the FLUKA Monte Carlo simulation code. The ATIC design, consisting of a graphite target and an energy detection device, a totally active calorimeter built up of 2.5 cm × 2.5 cm × 25.0 cm BGO scintillator bars, gives sufficient information to distinguish electrons from protons. While identifying about 80% of electrons as such, only about 2 in 10,000 protons (@ 150 GeV) will mimic electrons. In September of 1999 ATIC was exposed to high-energy electron and proton beams at the CERN H2 beam line, and this data confirmed the electron detection capabilities of ATIC. From 2000-12-28 to 2001-01-13 ATIC was flown as a long duration balloon test flight from McMurdo, Antarctica, recording over 360 h of data and allowing electron separation to be confirmed in the flight data. In addition, ATIC electron detection capabilities can be checked by atmospheric gamma-ray observations.

Trapped antiprotons produced by cosmic rays in the Earth's magnetosphere

The existence of significant fluxes of antiparticles in the Earth magnetosphere has been predicted on theoretical considerations in this article. These antiparticles (positrons or antiprotons) at several hundred kilometers of altitudes, we believe are not of direct extraterrestrial origin, but are the natural products of nuclear reactions of the high energy primary cosmic rays (CR) and trapped protons (TP) confined in the terrestrial radiation belt, with the constituents of terrestrial atmosphere. Extraterrestrial positrons and antiprotons born in nuclear reactions of the same CR particles passing through only 5–7 g/cm 2 of interstellar matter, exhibit lower fluxes compared to the antiprotons born at hundreds of g/cm 2 in the atmosphere, which when confined in the magnetic field of the Earth (in any other planet), get accumulated. We present the results of the computations of the antiproton fluxes at 10 MeV to several GeV energies due to CR particle interactions with the matter in the interstellar space, and also with the residual atmosphere at altitudes of ∼1000 km over the Earth's surface. The estimates show that the magnetospheric antiproton fluxes are greater by two orders of magnitude compared to the extraterrestrial fluxes measured at energies <1–2 GeV.

Antiprotons confined in the earth’s inner magnetosphere

The possible existence of noticeable fluxes of antiparticles in the Earth magnetosphere is considered theoretically in this article. These antiparticles (antiprotons in this paper) that are confined by geomagnetic field at the altitudes of several hundred kilometers are predominantly not of immediate extraterrestrial origin, but rather are the products of nuclear reactions of the high energy primary cosmic rays (CR) with constituents of the terrestrial atmosphere. Direct extraterrestrial antiprotons impinging upon the Earth’s magnetosphere are themselves also secondary in origin, i.e. they are born in nuclear reactions of the same CR passing through 5–7 g/cm 2 of interstellar matter. These exhibit lower fluxes compared to the magnetospheric antiprotons that are born at a pass length of hundreds g/cm 2 in the residual Earth atmosphere. Such locally generated antiprotons can be confined by the magnetic field of the Earth (or equivalently by another planet) and so accumulated in the magnetosphere. We here present the results of numerical simulation of antiproton fluxes in the energy range from 10 MeV to several GeV produced by CR in the Earth’s atmosphere at altitudes of about 1000 km, and we compare this to antiprotons born in interstellar matter. The estimates presented herein show a significant (up to two orders of magnitude) excess of magnetospheric antiproton fluxes over those formed in the interstellar media at energies <1 to 2 GeV.

The size of antimatter bodies and the primary very high energy cosmic ray flux

The consequences of antimatter bodies on the very high energy primary cosmic ray flux are considered. The effects of various models of cosmic ray origin and properties of astrophysical parameters are discussed. A simple expression for the production of antiprotons inN−N collisions as a function of energy of the incident proton is obtained by utilizing characteristics of particles produced in high energy collisions. It is assumed that sufficient time will have elapsed for all antibaryons to decay to antiprotons. It is shown that the measurement of antinuclei in the primary cosmic ray spectrum above 1017 eV could help to establish the size of antimatter bodies.

Matter traversal of high-energy primary cosmic rays from antiproton measurements

Matter traversal of high-energy primary cosmic rays from antiproton measurements

Secondary Antiprotons in Galactic Cosmic Radiation

Calculations are presented of the production of secondary antiprotons due to inelastic collisions of high-energy primary cosmic rays with interstellar gas nuclei. Cosmic-ray diffusion theory is assumed to apply in the steady-state approximation, with a constant average beam intensity taken over space. The cosmic-ray energy spectrum, production thresholds, cosmic-ray and target abundances and densities, and production and annihilation cross sections are examined and utilized. The results give a very approximate energy spectrum for the antiproton flux. Astrophysical ramifications of this collision source of antiprotons are discussed in light of the dominance of leakage over annihilation as a mechanism of antiproton loss.

A unified theory of terrestrial and solar magnetization, the outer Van Allen belt and high energy primary cosmic rays

A unified theory of terrestrial and solar magnetization, the outer Van Allen belt and high energy primary cosmic rays