[en] Theoretical and experimental papers are presented on the following subjects: nuclear interactions, heavy ion collisions, quarks, quark-gluon plasma, and hadron interactions

[en] Theoretical and experimental papers are presented in these proceedings on the following subjects: nuclear interactions, heavy ion interactions, quarks, quark-gluon plasma, and field theory

[en] In this work, we show that in the hadron-hadron collisions the effective string constant can be much greater than that of the elementary q q-bar string. We calculate the production of different hadrons (including strange and charmed particles) in proton-proton collisions and show that the results are quite consistent with the experimental data. In particular, the non-perturbative production of strange and charmed particles via Schwinger mechanism, is found to be in good agreement with the observed data. A simple and straightforward extension of the model to the case of nuclear targets can be made by assuming that the incident hadron and the nucleons which interact with it form a unique fire tube. It is found that the production rate of charmed particles by a nuclear target has a linear dependence in A if we restrict to the positive x_F region. However, for negative s_F, the production cross section increases more rapidly than linearly in A, which is not the case in perturbative QCD (P QCD) models

[en] The collective rotation of the Skyrmion in two-dimensional space is considered. In contradistinction to the three-dimensional case, inertial effects do not spoil the hedgehog form, so that a quantization limited to rotations and fluctuations of the profile function is compatible with the original field theory. We discuss the influence of the rotation on the profile function and other soliton properties. the results differ significantly from those obtained with the usual treatment. (author)

[en] Continuous particle emission during the whole expansion of thermalized matter is studied and a new formula for the observed transverse mass spectrum is derived. In some limit, the usual emission at freeze out scenario (Cooper-Frye formula) may be recovered. In a simplified description of expansion, we show that continuous particle emission can lead to a sizeable curvature in the pion transverse mass spectrum and parallel slopes for the various particles. These results are compared to experimental data. (author) various particles. These results are compared to experimental data. (author)

[en] The internal configuration of the color-carrying degrees of freedom of an ultrarelativistic hadron is frozen by Lorentz time dilation. When the spatial extent of the configuration is small, the hadron interacts weakly with other hadrons - the phenomenon of color transparency - since the color fields generated by the overall color neutral components nearly cancel. The hadron experiences only weak color-dipole interactions for small configurations. similarly, when the color configuration of the hadron is large it interacts more strongly than average - a color opacity. Such varying interactions are described by fluctuations in the interaction cross-sections of hadrons, which are intimately related of the phenomena of inelastic shadowing and diffractive dissociation. This connection allows on the deduce information on cross-section fluctuations from measurements of these phenomena. Cross-section fluctuations give rise to important fluctuations in observed quantities, such as multiplicity and transverse energy, produced in ultrarelativistic heavy-ion collisions. (author)

[en] Extending the relativistic mean-field theory of Walecka the p p-bar annihilation cross-sections into various pions are obtained through a fully relativistic first order calculation of p p-bar annihilation into two meson (π, σ,ρ and ω), simulating the decay into 2 and 3 pions by the width of the corresponding resonances. Assuming a mean distribution with a Breit-Wigner profile the results obtained for the main annihilation channel into 5 pions (from the combinations ρ ω and σ ω) are in very good agreement with the experimental data, if the mesons coupling constants are slightly reduced. (author)

[en] We present two-pion as well as two-proton correlation functions in proton-induced and in heavy ion reactions at intermediate and relativistic energies. To do this, we use the nuclear Boltzmann-Uehling-Uhlenbeck transport theory as a basis to generate single particle phase space distribution functions and obtain the interferometry information via a formalism introduced by Koonin. We compare our calculations o experimental data for 1.6 GeV proton-induced reactions, compiled by the DIOGENE collaboration at SATURNE, and to impact parameter selected heavy ion data at intermediate energies, obtained at the NSCL. We find that one can extract valuable information on the space time history of nuclear collisions by examining two-particle correlation functions. Our main result from our pion correlation study is that the nuclear shadowing effect due to rescattering and reabsorption of pions and delta resonances in the spectator mater has a sizeable influence on the two-pion correlation function and cannot be neglected when analyzing experimental data. (author)

[en] The existence of a non-trivial vacuum has influences on bound states. We calculate its effects on heavy pseudoscalar mesons parameterizing the non-perturbative properties by gluon condensates and using a non-relativistic approximation. We derive and effective Hamiltonian taking into account the interaction with the gluonic vacuum. The background gauge formalism used preserves gauge invariance. Non-perturbative effects are shown to be more important in higher excited states. (author)

[en] The proposition of Dalarsson of a simplified Skyrme model, where the quartic term is absent and a phase is added to the soliton field is tested to estimate the N N interaction as compared to results of the literature for the usual SU(2) Skyrme model in the product approximation. (author)