Table of contents

The status of the field of ultrahigh energy cosmic-ray physics is summarized, from the point of view of the latest results of the High-Resolution Fly's Eye (HiRes) Experiment. HiRes results are presented, and compared with those of the Akeno Giant Air Shower Array (AGASA), plus the Telescope Array and Pierre Auger experiments. The HiRes measurement of the cosmic-ray spectrum and the observation of the GZK cutoff are presented. HiRes results on composition, searches for anisotropy, measurement of the proton-air total cross-section and shapes of shower profiles are presented.

The interacting boson model (IBM) has been widely used for describing the quadrupole collective states of the medium-heavy nuclei and no distinction is made between proton and neutron variables when the first version of the model is applied. However, the neutrons' and protons' degrees of freedom are described explicitly in the second version of the model (IBM-2). Moreover, the microscopic foundations certainly state that it is very important to describe the proton and neutron variables explicitly and this is also the generalized definition of the second version of the IBA model (IBM-2 model). So, triaxiality can be described explicitly through the introduction of cubic terms in the boson operators. Using the best-fitted values of parameters in the Hamiltonian of the IBM-2, we have calculated energy levels and B(E2) values for a number of transitions in ^{122,124,126,128,130,132,134}Xe. The results were compared with the previous experimental and theoretical data and it has been observed that they are in good agreement. Many B(E2) values that are still not known so far are stated and the set of parameters used in these calculations is the best approximation that has been carried out so far. It has also turned out that the IBA and Bohr–Mottelson Hamiltonian with Davidson potential are fairly reliable models for the calculation of spectra in the entire set of ^{122,124,126,128,130,132,134}Xe isotopes.

We present hydrodynamic predictions for the charged pion HBT radii for a range of initial conditions covering those presumably reached in Pb+Pb collisions at the LHC. We study central (b = 0) and semi-central (b = 7 fm) collisions and show the expected increase of the HBT radii and their azimuthal oscillations. The predicted trends in the oscillation amplitudes reflect a change of the final source shape from out-of-plane to in-plane deformation as the initial entropy density is increased.

The fusion reaction may be significantly changed in a solid target due to electron screening on target nuclei while the projectile energy is very low. The electron screening effect of the D(d, p)T reaction in the deuterated metal Sm at low target temperature (T ∼ 133.2 K) has been studied in a deuteron energy region from 10 to 20 keV. The thick target yields of protons emitted in the D(d, p)T reaction were measured and compared with those data extrapolated from cross sections and stopping power data at higher energies. It is found that the reaction rates in Sm are enhanced over those of the bare nuclei. The screening potential in Sm under cooled conditions is deduced to be 520 ± 56 eV, which cannot be simply interpreted by the electron screening. The enhanced screening potential might be roughly interpreted with the classical plasma model of Debye, in which the screening potential decreases with increasing temperature while quasi-free metallic electrons are applied.

The dynamics of heavy-ion low-energy damped collisions is studied within the model based on the Langevin-type equations. Shell effects on the multi-dimensional potential energy surface play an important role in these reactions. An enhanced yield of nuclides far from the projectile and target masses was found in multi-nucleon transfer reactions due to the shell effects. Our theoretical predictions need experimental confirmation.

The γ/hadron separation in the imaging air Cherenkov telescope technique is based on differences between images of a hadronic shower and a γ induced electromagnetic cascade. One may expect for a large telescope that a detection of hadronic events containing Cherenkov light from one γ subcascade only is possible. In fact, simulations show that for the MAGIC telescope their fraction in the total protonic background is about 1.5% to 5.2% depending on the trigger threshold. It has been found that such images have small sizes (mainly below 400 photoelectrons) which correspond to the low energy primary γ's (below 100 GeV). It is shown that parameters describing shapes of images from one subcascade have similar distributions to primary γ events, so those parameters are not efficient in all methods of γ selection. Similar studies based on MC simulations are presented also for the images from 2γ subcascades which are products of the same π⁰ decay. The ratio of the number of the expected background from false γ and one π⁰ to the number of the triggered high energy photons from the Crab direction has been estimated for images with a small alpha parameter to show that the occurrence of this type of protonic shower is the reason for the difficulties with true γ selection at low energies.

We consider simple models of tunneling of an object with intrinsic degrees of freedom. This important problem was not extensively studied until now, in spite of numerous applications in various areas of physics and astrophysics. We show possibilities of enhancement for the probability of tunneling due to the presence of intrinsic degrees of freedom split by weak external fields or by polarizability of the slow composite object.

Excitation functions and isomeric cross-section ratios have been measured for the isomeric pairs ^198m,gTl, ^196m,gTl, ^198m,gAu and ^196m,gAu, formed in fusion–evaporation and transfer processes in reactions of ⁶He with ¹⁹⁷Au in the energy range 7–60 MeV. The population probability of high- and low-spin states in the fusion reaction with the formation of ¹⁹⁸Tl and ¹⁹⁶Tl (J^π_m = 7⁺, J^π_g = 2⁻), as well as of the transfer products ¹⁹⁸Au and ¹⁹⁶Au (J^π_m = 12⁻, J^π_g = 2⁻) is compared with calculations within the statistical model and with similar results, obtained in reactions induced by other nuclei.

This report presents the capabilities of the CMS experiment to explore the rich heavy-ion physics programme offered by the CERN Large Hadron Collider (LHC). The collisions of lead nuclei at energies , will probe quark and gluon matter at unprecedented values of energy density. The prime goal of this research is to study the fundamental theory of the strong interaction — Quantum Chromodynamics (QCD) — in extreme conditions of temperature, density and parton momentum fraction (low-x).

This report covers in detail the potential of CMS to carry out a series of representative Pb-Pb measurements. These include "bulk" observables, (charged hadron multiplicity, low p_T inclusive hadron identified spectra and elliptic flow) which provide information on the collective properties of the system, as well as perturbative probes such as quarkonia, heavy-quarks, jets and high p_T hadrons which yield "tomographic" information of the hottest and densest phases of the reaction.