Table of contents

We show how a recent modified version of the MIT bag model explains static baryon properties when quarks and pions are massive. The model is not chiral invariant and gives results consistent with observations. The quark and pion masses can be related through a continuity assumption for the divergence of the axial current across the bag surface.

Relativistic heavy ion collisions are treated analytically within a hydrodynamical (participant-spectator) model under the assumption of partial nuclear transparency. For the fragmentation regions the parameter free relation T_spec = 42 MeV (v_part/c) is derived in the target (projectile) frame and relates the temperature of the spectators to the velocity of the participants. Combining this relation with the experimental observation of a 10 MeV temperature in the fragmentation region allows one to estimate within this model the magnitude of nuclear transparency and the energy density of the participant sources.

The normalized created-charged-particle multiplicity ratio (R₃) in hadron-nucleus collisions has been observed to be dependent on the projectile, for a given number of the effective projectile encounters computed by using the additive quark model. Thus, leading to the failure of a new kind of scaling recently proposed by Kumar et al. In fact, it has been found that the charged particle multiplicity ratio R is reasonably projectile independent for a given number of collisions (ν).

Nuclear fusion by muon catalysis is dependent on the muon lifetime. We report here the first theoretical investigation of the decay of the negative muon bound in the (dμ^-d)⁺ molecular ion. The results are consistent with physical expectations.

We measured the elastic scattering of 5 GeV/c negative pions by helium nuclei in the range 0.12 < |t| < 0.90 (GeV/c)². The differential cross section exhibits a diffractive structure with a forward maximum, a minimum (at t ∼ 0.28 (GeV/c)²) and a secondary maximu. To describe the data we used the Glauber model and employed several forms of the elastic π-N amplitude and helium matter density functions. The model is unable to reproduce the shape of the measured cross section irrespective of the experimental normalisation error. Possible explanations of the discrepancy are discussed.

The spectrum of zinc was photographed in the 200-500 Å wavelength region on a 6.65 m grazing incidence spectrograph using a sliding spark and a triggered spark as light sources. On the basis of these measurements the 3d⁹-3d⁸np (n = 4, 5, 6) + nf (n = 4, 5) transitions of Zn IV have been studied. The earlier analysis of the 3d⁸4p configuration has been confirmed and extended. Thirty-six (36) levels of the 3d⁸5p, 15 of the 3d⁷6p, 44 levels of the 3d⁸4f and 28 levels of the 3d⁸5f configurations have been established. Least-squares-fit energy level calculations confirm the analysis. From the levels of the 3d⁸np (n = 4 → 6) and 3d⁸nf (n = 4, 5) configurations, the ionization potential has been calculated as Zn V ³F₄ = 480 490 cm^-1 (59.56 eV). One hundred eighty-one (181) lines have been classified in the Zn IV spectrum in the 225-500 Å region, in this region are classified fifty (50) lines in the 3d⁸-3d⁷4p transition array of Zn I.

The beam-foil excitation technique has been applied to determine lifetimes of the 3p²P_1/2, ²P_3/2 and 3d²D_3/2, ²D_5/2 levels in Na-like Cl VII. Using the ANDC method accurate values have been obtained which confirm recent theoretical values and explain some previously noted differences between theoretical and experimental oscillator strengths for transitions in multiply ionized Na-like ions.

In the independent electron approximation, an expression has been obtained for the probability of excitation of parity-unfavored autoionizing states of He atoms bombarded by protons as a function of impact parameter. It is shown that substates with M_L = 0 (M_L being the projection of the total orbital angular momentum of the final-state electrons) remain unexcited in proton-induced excitation of parity-unfavored autoionizing states of helium. Calculations have been made of the cross sections for excitation of the 2p3p¹P, 2p3d¹D, and 3p3d¹D autoionizing states of He atoms for proton energies E_p varying from 0.01 to 2.0 MeV. The results of the calculations show that:

(1) the dipole-dipole transitions resulting in the 2p3p¹P state are strongly suppressed due to interference;

(2) the main contribution to the cross sections for excitation of the 2p3d¹D and 3p3d¹D autoionizing states comes from states with |M_L| = 1; this is explained by the predominant role of single-electron transitions 1s → nlm to states with m = -l, - (l - 2),..., + (l - 2), + l.

Nonlinear coupling factors for low frequency modes in inhomogeneous plasmas are derived by the method of integration along unperturbed orbits. The results are found to agree with those of previous theory in appropriate limits. It is also found that the diamagnetic drift terms may significantly modify the nonlinear cascade processes.

The formation of ion phase space vortexes in the ion two stream region behind electrostatic ion acoustic shocks are observed in a laboratory experiment. A detailed analysis demonstrates that the evolution of such vortexes is associated with ion-ion beam instabilities and a nonlinear equation for their initial evolution is derived. The results are supported by a numerical particle simulation. Also the possibility of vortex excitation by ion bursts and coalescence of two vortexes are demonstrated. The effects of finite ion temperature, particle trapping and charge exchange collisions are discussed and the results related to ionospheric observations.

Photoluminescence (PL) spectra (excitation by UV (320 nm) at R.T. of BaS phosphors, activated by rare earth (RE) impurities like Ce and Sm, are presented in this paper. The emission bands, in general, are broad in nature. While characteristic Ce emission bands around 2.40 and 2.08 eV are observed in the case of BaS:Ce phosphors, BaS:Sm and BaS:Ce, Sm Phosphors have exhibited entirely different features in the luminescence spectra. The results are discussed considering the role of impurities, flux and native defects of this system of phosphors.

Experiments concerning large V-V_xO_y-Pb Josephson junctions have been performed. Structures having an overlap-type geometry have been considered. Preliminary experimental results are justified in the framework of the linearized current-phase model.

The Lagrangian (free energy) of the model with a complex scalar order parameter in which the phase transition to an inhomogeneous condensate state exists is constructed in the coordinate representation. In the case of condensation of charged particles (for example paired electrons) interaction with the electromagnetic field is included. The excitation spectrum in the presence of the condensate is found. The oscilations are strongly anisotropic. It is shown that superfluidity is absent for an uncharged system but that the charged one has the property of superconductivity. The important role of thermal fluctuations is demonstrated. They drastically change the behaviour of the condensate system. The condensation in a finite system is considered. A study is carried out for the behaviour of an inhomogeneous condensate in magnetic field. It is shown that the inhomogeneous condensate is a type II superconductor with Ginzburg-Landau paramerter κ ≫ 1, but that the structure of the mixed state of the system is unusual - consisting of plane layers of the normal phase, when H_c1 < H < H'_c2. The distribution of condensate in the strong magnetic field H'_c2 < H < H_c2 is also studied.

An exact solution of Maxwell's equations is found, corresponding to a p-polarized nonlinear surface wave propagating in a symmetric layered structure. The system under consideration consists of a layer with a linear dielectric constant ₁ bounded at two sides by a nonlinear medium characterized by the diagonal dielectric tensor ₁₁ = ₂₂ = _⊥ + α(|E₁|² +|E₂|²), ₃₃ = _||.

It is shown that besides symmetric and antisymmetric modes there exist asymmetric modes at power flows exceeding some certain minimal value. We have found also bistable states of p-polarized nonlinear surface waves provided that the power flow in the wave is the control parameter.

The effect of metal admixtures on the structure and imperfections of chalcogenide glassy semiconductors is investigated for Ga admixture in GeSe₄ glass. Information is obtained by the positron annihilation technique.

A microcrystalline phase in glass under doping at low admixture concentrations (about 0.01 at %) is indicated. The characteristic sizes of microinclusions and the amount of admixture atoms they contain are estimated. New aspects of the earlier interpretation (on the basis of the "induction effect") of the doping effect on electrophysical properties of glass are found.

The formulism of soliton analysis is used to study the conditions for initiating a Davydov soliton on alpha-helix in protein. The value of the exciton-phonon coupling parameter that is required for soliton formation is calculated. This calculation is in approximate agreement with an independent determination of the coupling parameter for real alpha-helix.

Results are presented from a series of numerical calculations on a physically reasonable model of alpha-helix protein. These calculations indicate that the exciton-phonon coupling parameter in alpha-helix is large enough to support the formation of Davydov solitons under normal physiological conditions.

Corrections to Physica Scripta Vol. T2/1, pp. 252-261 (1982)