[en] The contributions of the CORINNE II conference cover a wide range topics in the fields of particle-particle correlations, particle properties and production, and multifragmentation in heavy ion collisions. 40 items are indexed separately for INIS database. (K.A.)

[en] The PINOT collaboration has carried out an experimental study on η production in proton-nucleon and proton-nucleus interactions at SATURNE synchrotron. Results on differential and total cross sections for the pp → ppη reaction in the proton energy region from threshold to 1.5 GeV allow to test the proposed theoretical models, which emphasize the role played by N*(1535). A parallel study of pd → ηX reaction, at the same incident proton energies, has shown that η production in the pn channel is strongly enhanced with respect to the pp one. Finally η production has been studied on several nuclei with A ranging from 6 to 197 and at various incident proton energies, both below and above the pp → ppη threshold. A-dependence and T_p-dependence of η production cross sections have been measured. The comparison with the prediction of the theoretical models allows to obtain information on reaction mechanisms and on the role of η reabsorption in the nuclear medium. (authors). 15 refs., 3 figs

[en] Various methods to characterize the fragment size distributions in nuclear multifragmentation are discussed. The goal is to find the best signals of a phase transition associated to multifragmentation. The concepts of scaling and critical exponents are reviewed and the possibility to determine them in finite nuclei is examined. The fluctuations of the fragment size distribution and a possible signal of intermittency are also discussed. (authors). 29 refs., 4 figs., 1 tab

[en] During the past years artificial neural networks (ANN) have gained increasing interest not only in the regime of financial forecast and data mining, but also in the field of particle physics. Up to now artificial neural networks have mostly been applied in high energy physics trigger studies. The use of ANNs in medium energy physics data analysis is summarized. (author). 21 refs., 9 figs

[en] A new hadronization scenario is discussed where a central role is played by the chiral symmetry break-down in the expanding Quark-Gluon Plasma. The transition from the chiral-symmetric to broken state proceeds through the formation of multi-quark-antiquark clusters which later on split into hadrons. This transition is accompanied by the generation of long-lived coherent pion field which can be observed through multi-pion correlations. Time scales and spatial characteristics of chiral-symmetry breaking instabilities are estimated on the basis of an effective field-theoretical model. These results may impact significantly the strategy for searching Quark-Gluon Plasma in high-energy heavy-ion collisions at SPS, RHIC and LHC energies. (authors). 35 refs

[en] Bose effects are reviewed as a tool for recreating the space-time evolution of a reaction. The same formulation used in the two-particle interferometric phenomenology can be extended to the case of many-boson symmetrization. Opportunities for novel Bose-Einstein behavior are discussed. (author). 20 refs., 2 figs

[en] Characterization of the nature of the deexcitation of highly excited nuclei through multi-fragment or particle emission requires the use of powerful multidetectors. In this spirit a broad program was undertaken examining the multiple facets of multi-fragment emission with the multidetector INDRA. Results on the Ar+Ni system between 32 and 95 MeV/nucleon are presented, which evidence the production of a large number of fragments (up to 7) in central collisions, at all energies. Ultimately, the threshold for complete vaporization of the system into H and He isotopes is determined. (authors). 18 refs., 9 figs

[en] Physics of central symmetric reactions of heavy nuclei, in the beam energy range from few tens of MeV to a couple of GeV per nucleon, is discussed. Within transport simulations, it is shown that shock fronts perpendicular to the beam axis form in the head-on reactions. The fronts propagate into projectile and target and they separate hot compressed matter from normal matter. With an increase of the impact parameter, the angle of inclination of fronts relative to the beam axis decreases, and in-between the fronts a weak tangential discontinuity develops. Hot matter exposed to the vacuum in directions perpendicular to the shock motion (and parallel to fronts), starts to expand sideways, early within reactions. Expansion in the direction of shock motion follows, after the shocks traverse nuclei, but due to the delay does not acquire same strength. Expansion affects angular distributions and mean-energy components, and further shapes of spectra and mean energies of different particles emitted into any one direction, and also particle yields. Both the anisotropy in the expansion and a collective motion associated with the weak discontinuity, affect the magnitude of side ward flow within reaction plane. Differences in mean particle energy components in and out of the reaction plane in semi central collisions, depend sensitively on the relative magnitude of shock speed in normal matter and speed of sound in hot matter. The missing energy, considered in the past in association with low measured pion-multiplicity in central reactions, may be identified with the energy of collective expansion. (author). 17 refs., 11 figs

[en] Heavy ion collisions at very high energies provide an opportunity to recreate in the laboratory the conditions which existed in the very early universe. Matter is prepared at high energy density and evidence that the quarks and gluons are deconfined are searched for. To do this, the hadronic system giving rise to the observed particles is to be characterized. Two-particle correlations reflect the size and shape of the hadronic system when the particles cease to interact, and also carry information about the dynamics of the evolution. Recent results are presented from experiments at 200 GeV/nucleon at CERN, and novel methods are discussed to interpret the results using the RQMD event generator. (author). 18 refs., 5 figs

[en] The results on p-p and p-d correlation functions measured in recent experiments at GANIL are presented. The contribution of both preequilibrium and equilibrium protons is observed for the first time in the same experiment (ORION) and a strong dependence of the correlation function on impact parameter selection and directional cuts is seen. A shorter emission time of deuterons compared to that of protons is observed using the new method based on the directional dependence of the correlation function of non identical particles. The two-proton correlation function is measured in previously unaccessible region of very small relative momenta 1-10 MeV/c especially suited to extract with high accuracy the lifetime value of an equilibrated long-lived source. The Coulomb directional effect in p-p correlations is observed for the first time, giving the additional information on lifetime and kinematic characteristics of the emitter. (authors). 18 refs., 11 figs