abstract

The Galactic Cosmic Rays contain a sample of matter from elsewhere in the galaxy. It is a relatively recent sample (\(\sim 10^7\) years old) and contains information on the source material and conditions of confinement and transport in the galaxy. Unraveling the astrophysics of the cosmic rays has been underway for half a century, but major progress has been made in the last decades. The current state of our astrophysical knowledge of cosmic rays is reviewed in different energy regions, with particular attention to the implication of recent isotopic composition measurements at low energy. Extrapolating to higher energy delineates some of the experimental challenges facing the field in the future.

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Some general properties of extensive air showers are discussed. The main focus is put on the longitudinal development, in particular the energy flow, and on the lateral distribution of different air shower components. The intention of the paper is to provide a basic introduction to the subject rather than a comprehensive review.

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Recent results from the KASCADE experiment on measurements of cosmic rays in the energy range of the knee are presented. Emphasis is placed on energy spectra of individual mass groups as obtained from sophisticated unfolding procedures applied to the reconstructed electron and truncated muon numbers of EAS. The data show a knee-like structure in the energy spectra of light primaries (p, He, C) and an increasing dominance of heavy ones (\(A\gt 20\)) towards higher energies. This basic result is robust against uncertainties of the applied interaction models QGSJET and SIBYLL. Slight differences observed between experimental data and EAS simulations provide important clues for improvements of the interaction models. The data are complemented by new limits on global anisotropies in the arrival directions of CRs and by upper limits on point sources. Astrophysical implications for discriminating models of maximum acceleration energy vs galactic diffusion/drift models of the knee are discussed based on this data. To improve the reconstruction quality and statistics around \(10^{17}\) eV, KASCADE has recently been extended by a factor 10 in area. The status and expected performance of the new experiment KASCADE-Grande is presented.

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The DELPHI detector located at LEP accelerator has been used also to measure multi-muon bundles originated from cosmic ray interactions. Two subdetectors — Hadron Calorimeter and Time Projection Chamber, are used for this purpose. The 1999 and 2000 data are analyzed over wide range of multiplicities. The multiplicity distribution is compared with prediction of Monte Carlo simulation based on CORSIKA/QGSJET. The Monte-Carlo does not describe the large multiplicity part of data. Even the extreme assumption on the cosmic ray composition (pure iron nuclei) hardly predicts comparable number of high-multiplicity events.

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The origin of the highest energy particles in the Universe is a mystery that persists despite experimental efforts that have intensified for 50 years. The issue has attracted keen theoretical interest in the last decade in response to evidence that the energy spectrum continues to energies above \(10^{20}\) eV without the cutoff expected from pion photoproduction. Explanations necessarily entail new fundamental physics or some unexpected astrophysics. Observations from different experiments are presently incommensurate, and more powerful observatories are under construction to discover and study the sources of the highest energy cosmic rays.

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Pulsars are considered as possible sources of high energy cosmic ray particles, in particular UHECR. We discuss physical processes in pulsar vicinity relevant to the problem of acceleration of high energy particles. Empirical information on pulsar emission is briefly reviewed. The Crab Nebula is discussed as a template for pulsar wind nebulae. The pulsar wind models are presented with particular emphasis on their acceleration capabilities. The hypothesis that a population of neutron stars with the highest magnetic fields (magnetars) in nearby galaxies are the sources of UHECR above the GZK cutoff is discussed.

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We address some current theoretical issues around ultra-high energy cosmic rays. We recall that scenarios producing more \(\gamma \)-rays than cosmic rays up to high redshift can in general only provide a sub-dominant contribution to the ultra-high energy cosmic ray flux. This includes extra-galactic top-down and the \(Z\)-burst scenarios. Finally we discuss the influence of large scale cosmic magnetic fields on ultra-high energy cosmic ray propagation which is currently hard to quantify. The views presented here represent the authors perspective.

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The High Resolution Fly’s Eye (HiRes) observatory consists of two detector sites separated by 12.6 km in the western Utah desert. These sites observe Ultra High Energy Cosmic Rays (UHECR) using the air fluorescence technique. Reconstructing the data collected at these sites, we have measured the spectrum, composition, and anisotropy in arrival direction of these cosmic rays. The spectrum is measured from \(\sim 10^{17}\) eV and shows significant structure including the “ankle” and a steep fall off which is consistent with a GZK threshold. The composition is measured using the \(X_{\rm max}\) technique. It was found to be predominantly light and unchanging over the range from 10\(^{\rm 18}\) to 3\(\times \)10\(^{19}\) eV. Finally, several different styles of searches for anisotropy in the data were performed. No significant anisotropy was found.

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The Pierre Auger Observatory is now being constructed to understand the nature and origin of cosmic rays at ultra-high energies (\(\gt 10^{19}\) eV). It will be the largest cosmic ray detector ever built, covering 3000 square kilometers in both hemispheres in its full configuration. First data show a very good performance of the apparatus.

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The hypothetical photonic origin of the most energetic air shower detected by the Fly’s Eye experiment is discussed. The method used for the analysis is based on Monte Carlo simulations including the effect of precascading of ultra-high energy (UHE) photons in the geomagnetic field. The application of this method to data expected from the Pierre Auger Observatory is discussed. The importance of complementing the southern Auger location by a northern site for UHE photon identification is pointed out.

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In this article, based on the talk given at the Cracow Epiphany Conference on Astroparticle Physics, I discuss some of the opportunities provided by high-energy and ultra-high energy neutrino astronomy in probing particle physics beyond the standard model. Following a short summary of current and next generation experiments, I review the prospects for observations of high-energy neutrino interactions, searches for particle dark matter, and measurements of absolute neutrino masses, lifetimes and pseudo-Dirac mass splittings.

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The Antarctic Muon And Neutrino Detector Array (AMANDA) is a high-energy neutrino telescope based at the geographic South Pole. It is a lattice of photo-multiplier tubes buried deep in the polar ice, which is used as interaction and detection medium. The primary goal of this detector is the observation of astronomical sources of high-energy neutrinos. This paper shows the latest results of the search for a diffuse flux of extraterrestrial \(\nu _{\mu }\)s with energies between \(10^{11}\) eV and \(10^{18}\) eV, \(\nu _{\mu }\)s emitted from point sources and \(\nu _{\mu }\)s from dark matter annihilation in the Earth and the Sun.

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The Super-Kamiokande data from the first phase of the detector activity from April 1996 to July 2001 have been recently reanalysed and the new results are reported. Solar neutrino data allowed for precision analysis of oscillation parameters. When combined with the latest results from SNO and KamLAND experiments the best fit parameters of \(\nu _{e}\leftrightarrow \nu _{\mu \tau }\) transitions are \(\delta m^2=(7.1^{+0.6}_{-0.5})\times 10^{-5}\) eV\(^2\) and \(\tan ^2 \theta =0.44\pm 0.08\). The atmospheric neutrino sample is compared with the updated simulations taking into account flux calculations based on new primary cosmic ray measurements and modifications introduced to neutrino interaction model thanks to measurements in the near detectors of the K2K experiment. The new analysis based on a subsample of higher precision events allowed to reveal a dip in the distribution of the ratio of the distance over neutrino energy, presenting thus the first oscillatory behavior in neutrino data. As a result the parameters of the transitions \(\nu _\mu \leftrightarrow \nu _\tau \) are better constrained: \(1.9\times 10^{-3} \lt \Delta m^2 \lt 3.0\times 10^{-3}\;{\rm eV}^2\) and \(\sin ^22\theta \gt 0.90\) at 90% C.L. The atmospheric neutrino oscillations have been confirmed by the first long-baseline accelerator experiment, K2K, using the neutrino beam produced at KEK and interactions recorded in the Super-Kamiokande detector. The results from the phase I as well as phase II of the experiment show a deficit of muon neutrinos consistent with the atmospheric neutrino oscillations. Finally the most recent results on searches for proton decays are presented.

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The present ICARUS detector, called T600, is ready for installation in the Gran Sasso underground laboratory. It consists of two large cryostats, each one filled with 300 tons of Liquid Argon and equipped with two Time Projection Chambers (TPCs). An overview of the T600 detector is given. Main results of the analyses of the data collected during the surface tests with cosmic rays in summer 2001 are presented. They illustrate the detector’s excellent performance. A vast physics program of the ICARUS experiment, which includes different aspects of the neutrino studies and searches for proton decays, is shortly discussed. Finally, the detector upgrade towards the total mass of 3000 tons of Liquid Argon is mentioned.

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In this paper we show that the neutrino observables, including an information about the transverse neutrino spin polarization, can be sensitive to the effects coming from the interference terms between the standard vector \(V\), axial \(A\) couplings of l-handed neutrinos and exotic scalar \(S\) coupling of r-handed ones in the differential cross section. Our analysis is based on the electron neutrino–electron elastic scattering. This reaction is considered at the level of the four-fermion point interaction. Neutrinos are assumed to be massive and to be polarized Dirac fermions coming from the Sun.

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We discuss baryogenesis via leptogenesis in seesaw models with the heaviest right-chiral neutrino effectively decoupled from the seesaw mechanism and propose a natural bottom-up parametrization, which leads to a simple formula for the CP asymmetry in the decays of the lightest right-chiral neutrino. We show that for successful leptogenesis there is a lower bound on the mass of the lightest right-chiral neutrino. If this neutrino is to be produced thermally after inflation, the bound on its mass can be translated into a lower bound on the reheating temperature of the Universe, which can be in conflict with the upper bound required to avoid the gravitino problem. We also present possible ways of circumventing this difficulty.

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Analysis of the massive star properties during C, Ne, O & Si burning i.e. the neutrino-cooled stage, leads to the simplified neutrino emission model. In the framework of this model we have simulated spectrum of the antineutrinos. Flux normalized according to the massive star model with explicitly given neutrino luminosity allow us to predict signal produced in water Cherenkov detectors. The results are discussed from the point of view of the possibility of the core-collapse supernova event prediction in advance of a few days.

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Very high energy (VHE) gamma-ray astronomy is a very young field of astronomy. The main detection techniques, the status and the near term prospects will be reviewed.

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I present the observational properties of gamma-ray burst and outline the current theoretical models of these phenomena. I review the main problems in the gamma-ray burst science and sketch the prospects for the future.