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Complete angular distributions of the 12C + 18O elastic and inelastic scattering were measured at the energy E lab(18O) = 105 MeV (E c.m. = 42 MeV) . Comparison of these elastic-scattering data with those from previously measured 12C + 16O data show their large-angle cross-sections to differ by as much as a factor of 100 with the 16O data being the largest. These and the 12C + 18O scattering data taken from the literature at the energies E c.m. = 12.9-56 MeV were analysed within the optical model and coupled-reaction-channels methods. Sets of Woods-Saxon 12C + 18O optical potential parameters were obtained and their energy dependence was deduced. A similar analysis was carried out for 12C + 16O where it was shown that over a wide energy range, the primary difference in the 16O and 18O scattering potentials is in their imaginary parts. The large-angle enhancement for the 12C + 18O elastic-scattering was shown to arise from the transfer of nucleons. The inelastic-scattering data were well described over the entire angular range as arising from collective excitations of the states in the target and projectile nuclei.

The doses of gamma radiation, concentrations of radium isotopes in water and sediments, radon concentration and concentration of alpha potential energy of radon decay products in the copper ore mine and in the mining region in the vicinity of Lubin town in Poland are presented. These data served as a basis for the assessment of radiological hazard to the mine workers and general public. The results of this assessment indicate that radiological hazard in the region does not differ substantially from typical values associated with natural radiation background. The calculated average annual effective dose for copper miners is 1.48 mSv. In general, copper ore mines can be regarded as radiologically safe workplaces.

Angular distributions of the 7Li + 10B elastic and inelastic scattering were measured at the energy E lab (10B) = 51 MeV (21 MeV c.m.). These and previously measured 7Li + 10B elastic-scattering data known at the 7Li-beam energies 24 MeV (14.1 MeV c.m.) and 39 MeV (22.94 MeV c.m.) were analyzed within the optical model and coupled-reaction channels method to determine the energy dependence of the parameters of the scattering potential and find the difference of these parameters from that of 7Li + 11B scattering. It was found that the 7Li + 11B potential parameters fail to describe the 7Li + 10B scattering data. The biggest difference is observed between the depths of the imaginary potentials that describe these scatterings.

The PHOBOS collaboration has studied the pseudorapidity and transverse momentum distributions of charged particles produced in heavy ion collisions. Results from Au+Au collisions at various center-of-mass energies and over a broad range of centrality are presented here. The data are compared to Cu+Cu, p+p and d+Au collisions at corresponding energies and centralities. The data are found to exhibit simple scaling properties such as the observed factorization of collision energy and geometry dependences. The presented data help us distinguish between models of particle production in relativistic heavy ion collisions.

Angular distributions of the 12C( 11B, 15N) 8Be reaction were measured at the energy Elab(11B) = 49 MeV for the transitions to the ground and 2.94 MeV (2+) excited state of 8Be and to the ground and 5.270 MeV (5/2+) + 5.299 MeV (1/2+), 6.324 MeV (3/2-), 7.155 MeV (5/2+) + 7.301 MeV (3/2+), 7.567 MeV (7/2+) excited states of 15N. The data were analyzed by the coupled-reaction-channel method. The elastic, inelastic scattering and one- and two-step transfers were included in the coupling scheme. The data of the 12C( 11B, 8Be) 15N reaction at Ecm = 9.4-17.8 MeV known from the literature, were also included in the analysis. The mechanism of the 12C( 11B, 15N) 8Be reaction and the optical-model potential parameters for the 15N + 8Be channel were deduced. The energy dependence of the optical-model parameters for the 15N + 8Be channel was obtained.

The production of the Lambda and Sigma0 hyperons has been measured via the pp->pK+Lambda / Sigma0 reaction at the internal COSY-11 facility in the excess energy range between 14 and 60 MeV. The transition of the Lambda/Sigma0 cross section ratio from about 28 at Q

The $\eta^\prime$ -meson production in the reaction $pp\rightarrow pp\eta^\prime$ has been studied at excess energies of Q = 26.5, 32.5 and 46.6 MeV using the internal beam facility COSY-11 at the cooler synchrotron COSY. The total cross-sections as well as one angular distribution for the highest Q-value are presented. The excitation function of the near-threshold data can be described by a pure s-wave phase space distribution with the inclusion of the proton-proton final-state interaction and Coulomb effects. The obtained angular distribution of the $\eta^\prime$ -mesons is also consistent with pure s-wave production.

Particle production in Au+Au collisions has been measured in the PHOBOS experiment at RHIC for a range of collision energies for a large span of pseudorapidities, |η| 65. This scaling occurs both for the total multiplicity and for highp T particles (3

The production of eta and eta-prime mesons in elementary nucleon-nucleon collisions has been investigated at the synchrotrons CELSIUS, COSY and SATURNE. The magnitude and energy dependence of the total cross section as well as the occupation distribution of the phase space serve as observables for investigating the mechanisms underlying the production processes and the interaction of mesons with nucleons. The precise data on the eta and eta-prime creation via the pp --> pp eta(eta-prime) reactions allowed to settle the general features of the eta and eta-prime meson production and revealed the sensitivity of the mentioned observables to the nucleon-nucleon-meson final state interaction. The particular production properties, like for example the determination of the dominating exchange processes which lead to the excitation of the S_11 nucleon isobar in the case of eta creation, must be established by confrontation with other observables. The present status of this investigation with an emphasis on the results of the COSY-11 collaboration is briefly presented. The available data are interpreted in view of the production mechanism and the meson-nucleon interaction., 3 pages, 3 figures, Presented at Conference on Quarks and Nuclear Physics (QNP 2002), Julich, Germany, 9-14 Jun 2002

Total and differential cross sections for the reactions p + d → 3He + m 0 with m=π, η and p + d → 3H+π+ were measured with the GEM detector at COSY for beam momenta between threshold and the maximum of the corresponding baryon resonance. For both reactions a strong forward-backward asymmetry was found. The data were compared with model calculations. The aspect of isospin symmetry breaking is studied.

The PHOBOS experiment at the Relativistic Heavy Ion Collider (RHIC), comprising the spectrometer with multiple layers of silicon wafers, is an excellent detector for very low transverse momentum (p T ) particles. Transverse momentum distributions of π–+π+, K–+K+ and $p+\overline{p}$ produced at mid-rapidity are presented for the 15% most central Au-Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. The momentum ranges for measured particles are from 30 to 50 MeV/c for pions, 90 to 130 MeV/c for kaons and 140 to 210 MeV/c for protons and antiprotons. The measurement method is briefly described. A comparison of the p T spectra to experimental results at higher particle momenta and to model predictions is discussed. PACS: 25.75.-q

In a multidetector experiment on 26 or 30 AMeV32S+58Ni, up to four coincident heavier or intermediate-mass fragments were observed. One of these occasionally has the characteristics of a projectile-like fragment, up to three may be attributed to the decay of the heavy reaction product. Taking the velocity of the fragments as a measure of the heavy-product excitation energy, one finds evaporation, fission and multifragmentation to follow one another with rising excitation. Model simulations of sequential decay with up to two binary fissions and, alternatively, of simultaneous statistical multifragmentation were performed for comparison with experimental distributions of mass, velocity and (for events with three slow intermediate-mass fragments) relative azimuthal angle. Though in the three-fragment events indications of simultaneous multifragmentation are present, the sequential binary decay predominates. Evaporated protons and α particles detected in coincidence have a mean multiplicity growing with excitation energy, while the temperature governing the spectra has a plateau with a value of about 5.5 MeV.

At the internal facility COSY-11 a first measurement of the reaction p(pol)p -> pp eta near the production threshold has been performed. Results for the analysing power will be presented and a comparison with one meson exchange models will be discussed.

Correlations between two intermediate-mass fragments resulting from 840 MeV32S projectiles interacting with197Au were measured. The angular correlations and absolute two-fragment cross sections agree with predictions of a semi-microscopic model for direct dynamic projectile break-up. This suggests a predominantly direct mechanism for the production of intermediate-mass fragment pairs. It is argued that the intensity of such a channel which, compared to decays yieldingα particles, is much larger than observed for the sequential decay of corresponding primary excited nuclei, supports the direct-break-up interpretation. The model mechanism yields also strongly damped projectile fragments of intermediate mass.

A classical dynamical alpha-cluster model has been developed and applied in order to get inclusive energy spectra of alpha particles produced in the collision of12C +12C at the beam energy 28.7 MeV/A. Results of the calculations are compared with experimental data. The shapes of the experimental energy spectra and the absolute normalization at forward angles are approximately described without any free parameters. The model makes it possible to distinguish alpha particles originating from the compound system and from direct processes. The spectra at forward angles are dominated by projectile fragmentation processes. The cross section at larger angles is overestimated, which is partially due to emission of particles other than alpha particles in central collisions. The evaporation Hauser-Feshbach model predicts that alpha particles emitted from the compound nucleus constitute less than 26% of all emitted particles.

Within the quasi free-reaction model apart from the conventional component of direct fragmentation we include also particles coming from the interaction of the socalled participant, part of the projectile, with the target. The model takes into account the momentum distribution of clusters in the projectile, the off-energy-shell cross section for a virtual two-body reaction and the phasespace factor. The last two factors have usually been neglected in studies of heavy ion fragmentation. The model has been applied to the description of inclusive energy spectra of particles produced in the12C+12C collision, measured at the energy of 85 MeV/A by the CERN-Copenhagen-Grenoble-Lund collaboration. With two parameters adjusted to the experimental data, the model describes the energy spectra at forward angles and predicts the slope of the experimental angular distributions.

Experimental elastic-scattering angular distributions of 26.6 MeV α-particles scattered from29Si and30Si nuclei have been measured. These data together with previously measured α+28Si elastic angular distribution have been analysed using the optical model. Both the phenomenological (Woods-Saxon type with four and six parameters) and the double folding model (density-independent and density-dependent real part with squared Woods-Saxon imaginary form factor) potentials have been employed in fitting the data. The best agreement of theory with experiment has been obtained when the real part of the optical potential has been calculated with density-independent M3Y interaction of Bertschet al.

Simple model of emission of light charged polar particles accompanying fission of heavy nuclei is presented. We assume the emission from the whole surface of fragments after scission, taking into account the influence of the accompanying fragment. The initial energy and time of emission are treated phenomenologically. The motion of light particles and fission fragments are subsequently calculated in the framework of classical dynamics. We get a good agreement with experimental data if we assume a prompt emission. The possibility of the connection with giant resonances is discussed.

The triton-proton angular correlation function has been measured for the58Ni(α, t p)58Ni reaction leading to the ground state of the target nucleus. The obtained experimental data have been interpreted in terms of the direct break-up (fragmentation) of the alpha particle on the target nucleus potential. It is shown that the main features of the measured double differential cross section are well predicted by the DWBA theory of the break-up. The dependence of the elastic and inclusive break-up cross sections upon the fragment-target interaction potentials is discussed.

Correlations between emission angles and energies of coincidentα-particle projectile-fragment pairs have been measured for the20Ne+197Au system at 390 MeV beam energy. Theα-particles observed close to the direction of the projectile-like fragment were found to result essentially from sequential projectile decay. Starting from the close-geometry data, the contribution of sequentially emittedα-particles was calculated by Monte Carlo simulations for the entire angular range. For deep inelastic events, the measured angular correlations exhibit a spectacular excess over the calculated correlation. This excess is centred close to the beam direction but on the opposite side of it with respect to the detected projectile-like fragment. The correspondingα-particles have velocities around 85% of the projectile velocity indicating emission in an early reaction phase.

The first experimental evidence for GQR effects in the (α, p) reaction is presented. Shapes of angular distributions of protons from the12C(α, p)15N reaction and their energy dependence suggest virtual formation of the GQR in16O as a doorway state leading to the (3/2−, 6.328 MeV) state of nitrogen.