Mechanisms of nuclear reactions at interaction of cosmic rays with materials and nanostructures

The mechanism of failures of microelectronic elements, caused by ionization of atoms by recoil nuclei and secondary fragments formed at nuclear interactions of cosmic-ray protons and light ions with substance, has been analyzed. Models of nuclear physics are used to calculate the macroscopic failure cross section.     

Paleoastrophysics and cosmic rays

Summary A discussion is given of the status and potential of studying the cosmic-ray flux level over long time scales by high-precision measurement of cosmogenic isotopes content in natural archives of cosmic radiation. Invited talk given at the XXIV International Cosmic-Ray Conference, Rome, August 28–September 8, 1995.     

Solar cosmic rays

Summary This report is a brief overview of the energetic-particle phenomena related to solar activity discussed at the XXIV International Cosmic-Ray Conference. In the rapporteur's opinion, the most significant results to be highlighted are: 1) the new higher-energy measurements of the solar energetic ion charge state which seem to be consistent with the older measurements at ∼1 MeV/nucleon, and 2) the many reports of extended gamma-ray production during solar flares with multiple episodes of emission implying multiple episodes of particle acceleration. Rapporteur talk given at the XXIV International Cosmic-Ray Conference, Rome, August 28–September 8, 1995.     

Origin of cosmic rays

Cosmic rays were discovered in 1911 but it is only now that some ideas are beginning to emerge as to their origin. This paper will examine the present evidence concerning the origin question over the whole energy range, from 10⁹ eV to 10²⁰ eV. At the lowest energies, (10⁹–10¹⁰ eV), the new subject of gamma ray astronomy plays a crucial role and a galactic origin is favoured. At higher energies (10¹²–10¹⁷ eV) recent measurements of the anisotropies in arrival directions also suggest a galactic origin, although the evidence is not as strong. At the very highest energies it seems likely that some, at least, of the particles come from outside the galaxy although the non-existence of the cut-off at about 6 × 10¹⁹ eV arising from interactions with the cosmological relict radiation provides a paradox. The likely future areas of advance in this fascinating subject will be indicated. Based on the B. B. Roy memorial lectures delivered at Calcutta University, February 1–3, 1978.     

Spectrum of ultrahigh-energy cosmic rays

Detailed calculation of the energy spectra of ultrahigh-energy cosmic rays has been performed. The spectral features related to the interaction of protons with cosmic microwave background have been analyzed. The calculated spectra are compared with the experimental data obtained at the giant detectors for ultrahigh-energy cosmic rays.     

A theory of cosmic rays

We present a theory of non-solar cosmic rays (CRs) in which the bulk of their observed flux is due to a single type of CR source at all energies. The total luminosity of the Galaxy, the broken power-law spectra with their observed slopes, the position of the ‘knee(s)’ and ‘ankle’, and the CR composition and its variation with energy are all predicted in terms of very simple and completely ‘standard’ physics. The source of CRs is extremely ‘economical’: it has only one parameter to be fitted to the ensemble of all of the mentioned data. All other inputs are ‘priors’, that is, theoretical or observational items of information independent of the properties of the source of CRs, and chosen to lie in their pre-established ranges. The theory is part of a ‘unified view of high-energy astrophysics’ — based on the ‘Cannonball’ model of the relativistic ejecta of accreting black holes and neutron stars. The model has been extremely successful in predicting all the novel properties of Gamma Ray Bursts recently observed with the help of the Swift satellite. If correct, this model is only lacking a satisfactory theoretical understanding of the ‘cannon’ that emits the cannonballs in catastrophic processes of accretion.     

Ultra-high-energy cosmic rays and inflation relics

There are two processes of matter creation after inflation that may be relevant to the resolution of the puzzle of cosmic rays observed with energies beyond GZK cut-off: 1) gravitational creation of superheavy (quasi)stable particles, and 2) non-thermal phase transitions leading to the formation of topological defects. We review both possibilities.     

Spinning neutron stars and cosmic rays

Spindown of magnetic neutron stars in close binaries by the propeller mechanism, and spinup by accretion are revised. Spindown is more efficient than sometimes claimed. Cosmic rays are probably generated by the propeller mechanism rather than in (single) pulsar winds.     

Prompt-muon production in cosmic rays

Summary We discuss here the results obtained calculating the contribution of prompt muons in the vertical atmospheric muon flux, computed taking into account the up-to-date data from experiments at accelerators and the most recent theoretical achievements on charm generation in nucleon-air nucleus interactions. Our results are compared with the experimental data obtained with underground detectors.

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Riassunto Si discutono in questo lavoro i risultati ottenuti sul contributo di muoni pronti al flusso atmosferico verticale dei muoni, calcolato utilizzando i dati piú recenti di esperimenti degli acceleratori ed i risultati teorici sulla produzione di particelle charmate in interazioni nucleoni-nuclei atmosferici. I risultati ottenuti sono confrontati con i dati sperimentali forniti da esperimenti sotterranei.

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Резюме Мы обсуждаем результаты вычислений вклада мгновенных мюонов в вертикальный роток атмосферных мюонов. Вычисления учитывают данные из зкспериментов на ускорителях и недавние теоретические предсказания по рождению очарованных частиц при, взаимодействиях нуклонов с ядрами воздуха. Наши результаты сравниваются с зкспериментальными данными, полученными с помощью подземных детекторов.

     

Prompt leptons in cosmic rays

Summary Energy spectra and zenith-angle distributions of cosmic-ray muons, neutrinos and antineutrinos of prompt generation for energy interval (1÷10⁶) TeV are calculated. For calculations of differential cross-sections of D^±, D⁰, ⁰ and Λ_c production inNN and πN interactions the recombination quark-parton model (RQPM) is used. Accounting of nuclear effects is done by using the additive quark model and the optical model of nucleus. Detailed comparison of results obtained in RQPM with corresponding predictions of quark-gluon string model (MQGS) is carried out. Dynamics of semi-leptonic D- and Λ_c and energy losses of muons in the atmosphere are taken into account. Calculations of hadronic cascades in the atmosphere are done with accounting of growth with energy of total inelastic hadron-nucleus cross-sections, steepening of primary cosmic-ray spectrum and processes of pion regeneration. The comparison of our calculations with experimental data and with calculations of other authors is given.     

Ultra high energy cosmic rays

The current status of Ultra High Energy Cosmic Rays (UHECR) is reviewed, with emphasis given to theoretical interpretation of the observed events. The galactic and extragalactic origin, in case of astrophysical sources of UHE particles, have the problems either with acceleration to the observed energies or with the fluxes and spectra. Topological defects can naturally produce particles with energies as observed and much higher, but in most cases fail to produce the observed fluxes. Cosmic necklaces and monopole-antimonopole pairs are identified as most plausible sources, which can provide the observed flux and spectrum. The relic superheavy particles are shown to be clustering in the Galactic halo, producing UHECR without Greisen-Zatsepin-Kuzmin cutoff. The Lightest Supersymmetric Particles are discussed as UHE carriers in the Universe.     

Ultra high energy cosmic rays

Ultra High Energy Cosmic Rays (UHECRs) represent the most energetic source of elementary particles available to scientists. They have macroscopic energies, exceeding 5 × 10¹⁹ eV, and as yet unidentified sources. Unfortunately, their flux is as low as one particle per century per square kilometre, requiring dedicated detectors with huge apertures to obtain high-quality and statistically significant data-sets. Over the last three to four decades, a few tens of events at extreme energies were detected by ground-based cosmic ray detectors, opening a new window in the field of astroparticle physics. In this article, the physics of cosmic rays is reviewed briefly. We present a short history and the present status of the field mainly from an experimental point of view. Special attention is given to the Pierre Auger Observatory, the world's largest operating hybrid detector. The most recent and fascinating results are also presented and discussed. Finally, some attention is given to the next generation of detectors devoted to the exploration of the highest energy ranges, which is likely to dramatically increase our knowledge about UHECRs in the near future.     

Aligned interactions in cosmic rays

The first clean Centauro was found in cosmic rays years many ago at Mt Chacaltaya experiment. Since that time, many people have tried to find this type of interaction, both in cosmic rays and at accelerators. But no one has found a clean cases of this type of interaction.It happened finally in the last exposure of emulsion at Mt Chacaltaya where the second clean Centauro has been found. The experimental data for both the Centauros and STRANA will be presented and discussed in this paper. We also present our comments to the intriguing question of the existence of a type of nuclear interactions at high energy with alignment.