Table of contents

Levels in ¹⁵²Ce are identified for the first time along with new high spin states in ^142-148Ba, ^144-150Ce and ^150-156Nd from X-X, gamma -X and gamma - gamma - gamma -ray coincidence measurement in spontaneous fission of ²⁵²Cf and ²⁴²Pu. The N=88, 90 Ba nuclei have very nearly identical J₁ for the yrast bands (2⁺ to 10⁺) and for the octupole bands (3^- to 15^-). The N=92, 94 Nd nuclei have essentially identical yrast J₁ (0⁺ to 16⁺).

We present a review and analysis of the experimental data on cosmic rays with energies above 10¹⁴-10¹⁵ eV and up to 10²⁰ eV. At the beginning a brief survey of the direct experimental data on the cosmic-ray energy spectrum and mass composition is given. We then consider the choice of the hadron interaction model at energies above 10¹⁵ eV that is essential for the interpretation of the experimental data on extensive air showers (EAS). Much attention is given to the well known knee in the primary energy spectrum at approximately 3*10¹⁵ eV and also to an analysis of this phenomenon in the framework of the recently developed Hall diffusion model. In doing so we use as yet scarce data on cosmic-ray anisotropy and mass composition at superhigh energies 10¹⁴-10¹⁷ eV. A considerable part of our review is concerned with cosmic rays of ultrahigh energies 10¹⁷-10²⁰ eV. Using the galactic origin model for cosmic rays with energies 10¹⁴-10²⁰ eV the possibility of explaining all the relevant data at energies above 3*10¹⁸-10¹⁹ eV is discussed: evidence of the 'ankle' in the primary energy spectrum, the upper bound of cosmic-ray anisotropy, and evidence for the increasing proton abundance. The prospects for future cosmic-ray investigations at superhigh energies are outlined and the great importance of development in the neutron and proton astronomy for energies above 10¹⁸-10¹⁹ eV is pointed out.

We show that the topological B vector-product F term in 3+1 dimensions can be generated via spontaneous symmetry breaking in a generalized Abelian Higgs model. Further, we also show that even in D dimensions (D>or=3), a B vector-product F term gives rise to the topological massive excitations of the Abelian gauge field and that such a B vector-product F term can also be generated via the Higgs mechanism.

The electroweak radiative corrections to nu _mu e scattering are calculated and the vector and axial couplings are obtained. The theoretical results are in good agreement with the experimental data.

The possibility of describing simultaneously a single nucleon and quark matter in the framework of the colour-dielectric model (CDM) with perturbative gluons is investigated. It is pointed out that including the one-gluon exchange both in the hadronized and in the deconfined phase leads to a quark-hadron phase transition at anomalously small densities. This conclusion is independent of the choice of the model parameters, once these are constrained to yield the correct static properties of the nucleon. The unrealistic deconfinement densities that we find are determined by the large effective mass of quarks in the CDM.

We study the complete process gamma gamma to bbW⁺W^- using exact matrix element computations at tree-level, at a square root s=500 GeV e⁺e^- linear collider of the next generation. Incoming photons produced via back-scattering of laser light are considered. Sizable effects due to the finite width of the top quark as well as to the irreducible background to tt production and decay are predicted.

A method to calculate the hole spectral function in the discrete part of the spectrum is suggested within the natural orbital representation of the one-body density matrix of the A-nucleon system using its relationship with the overlap functions of the eigenstates in the (A-1)-nucleon system.

The differential polarization of ground-state photoneutrons from ¹⁶O has been determined at five angles at energies below 26 MeV. The polarization was measured by observing the asymmetry in the elastic scattering of the photoneutrons from either a liquid helium or a graphite target. The neutron energies were measured with a time-of-flight spectrometer; the resolution was 300 ps m^-1. Systematic errors were minimized by using a neutron spin-precession solenoid. The values of the s-, p-, d- and f-wave amplitudes and phases of the reaction matrix elements have been deduced. The results are compared with those obtained from the ¹⁵N(p, gamma ₀)¹⁶O reaction and with the predictions of various theoretical models. The observed energy dependence of the neutron polarization, and the energy dependence of the amplitudes and phases are not well accounted for by any currently available model.

The mass asymmetry dependence of the fission process in the fusion-like deformation valley is studied within the framework of the generalized rotating liquid drop model taking into account the proximity and temperature effects. The Businaro-Gallone point is well reproduced. The rotation as well as the thermal excitation favour the symmetric splitting.

The polarization transfer coefficients K_x^x', K_y^y' and K_z^x' in the reaction ²H(p,p)²H have been measured at an incident proton energy of 22.5 MeV. The results are compared to predictions from Faddeev calculations using various nucleon-nucleon potential models. The overall agreement is rather good. The comparison in more detail shows a pronounced sensitivity of the results, especially for K_y^y', to the ³S₁-³D₁ and ¹P₁ NN force components. As in nucleon-nucleon scattering, however, these two parameters are correlated, thus hampering definite conclusions.

We have analysed the momentum spectra of the secondary particles in pp interactions predicted by different models, comparing them with accelerator data from 19.7 GeV to 1.8 TeV (CMS). All models predicting asymptotic behaviour of secondary spectra with Feynman scaling in the fragmentation region lead to a rather slow increase of multiplicity in contradiction to the accelerator data. It is shown that the pure phenomenological model, which is based on the semi-inclusive spectra from ISR and FNAL collider experiments at 19.7 GeV, and extrapolated to higher energies by assuming violated Feynman scaling in the entire phase space, describes the data well in the whole accelerator range. This model is also relevant for application in the study of cosmic rays at high energies.

The attenuation mean free path, lambda _att, of nucleons and pions in thick lead chambers is calculated assuming a simple geometrical model for hadron-nucleus interactions and also taking experimental procedure into consideration. The results are compared with experimental data of the Pamir and Chacaltaya collaboration experiment, where it is observed that lambda _att of hadrons in high-energy families is much smaller than that of ordinary hadrons. lambda _att of single-arrived hadrons, which are considered to be mostly protons, observed in the same experiment, agrees well with calculations for proton incidence. For hadrons in families, however, calculations give lambda _att not smaller than that of single-arrived hadrons and fail to explain the experimental results even when we assume hadrons are mostly nucleons in high-energy families. Fluctuations in the estimation of lambda _att are also discussed.

Measurements of the differential cross section for the ⁷Li(d, alpha alpha n) reaction have been performed at incident deuteron energy E_d=19.7 MeV. An appropriate kinematical configuration was chosen to observe the population of the second excited ⁸Be level. The values of (11.3+or-0.2) MeV for the excitation energy and of (3.7+or-0.2) MeV for the width of the above level were found. The influence of the transformation Jacobian on the determination of the two spectroscopic parameters is discussed.