Showing papers in "Progress in Particle and Nuclear Physics in 1999"

TL;DR: In this article, the authors reviewed all existing evidence and indications in favour of neutrino oscillations that have been obtained in the atmospheric, solar and LSND experiments and investigated possibilities to test the different neutrinos mass and mixing schemes obtained in this way.

TL;DR: The application of effective field theory (EFT) to nuclear systems is reviewed in this paper, where the roles of degrees of freedom, QCD symmetries, power counting, renormalization, and potentials are discussed.

TL;DR: In this article, a self-contained introduction to the necessary mathematical tools (q-numbers, q-analysis and q-oscillators), the suq(2) rotator model and its extensions, the construction of deformed exactly soluble models (u(3)so(3), model, Interacting Boson Model, Moszkowski model), the 3-dimensional q-deformed harmonic oscillator imd its relation to the nuclear shell model, and the symmetries of the anisotropic quantum harmonic oscillators with rational ratios of frequencies.

TL;DR: In this article, the slow neutron capture ( s ) process is considered as a possibility for supernova studies, and the quantitative interpretation of the natural abundances provides an exciting possibility for exploring a variety of problems related to stellar and Galactic evolution.

TL;DR: In this paper, the current status of automatic calculation of Feynman diagrams in particle physics is reported. But the most important theoretical techniques are introduced and their usefulness is demonstrated with the help of simple examples.

TL;DR: In this article, the structure of the 8 states found in these reactions is discussed, as well as their relevance for the decay of 11Li resonances, which is of interest for the spin-orbit splitting in these light neutronrich nuclei.

TL;DR: In this article, nonequilibrium models (three-fluid hydrodynamics and UrQMD) are used to discuss the uniqueness of often proposed experimental signatures for quark matter formation in relativistic heavy ion collisions.

TL;DR: The High Acceptance DiElectron Spectrometer HADES (HADES) as mentioned in this paper was designed for an invariant mass resolution Δ M inv /M inv ≅ 1% (σ), a large signal to background ratio, and a high granularity.

TL;DR: In this article, the production yields and azimuthal anisotropies of strange particles (K +,K −,π and Φ) are measured with the FOPI detector at SIS.

TL;DR: In this article, the authors discuss predictions based on QCD sum rules and on hadronic models for the properties of vector mesons in the nuclear medium and describe possible experimental signatures and show detailed predictions for dilepton invariant mass spectra with a special emphasis on nuclear reactions involving elementary incoming beams and nuclear targets.

TL;DR: In this paper, the authors review the theoretical interpretation of experimental results on low and high spin states in some even mass A=60−80 nuclei within the complex versions of the excited vampir and Fed Vampir variational approaches and find that the coexistence of oblate and prolate deformed configurations and their mixing at low spin are responsible for the irregular sequences of states and the isomeric decays identified at low excitation energy in even even nuclei.

TL;DR: In this paper, the authors studied collective effects in medium energy heavy ion collisions with exotic beams and showed that the repulsion of the symmetry term of the nuclear equation of state above normal density is strongly dependent on the density of collective flows.

TL;DR: In this article, the reaction dynamics of central Pb+Pb collisions at 160 GeV/nucleon were analyzed in terms of hadron ratios, freeze-out distributions and a source analysis for final state pions.

TL;DR: In this article, a new era of experiments has been started with exotic nuclei separated by the FRS and stored and cooled in the experimental storage ring ESR for weakly-bound systems.

TL;DR: In this article, a self-consistent and conserving scheme for broad resonances with broad mass distribution is presented. But it does not account for the damping width of the particles.

TL;DR: In this article, an analysis from an integrated luminosity of about 150 pb−1 recorded by each experiment at LEP, taken at different center-of-mass energies within ± 3 GeV around the peak of the Z resonance during the years 1989 to 1995 are available now.

TL;DR: In this paper, the authors reexamine the production of J/ψ and other charmonium states for a variety of target-projectile choices at the SPS, in particular for the interesting comparison between S+U at 200 GeV/c and Pb+Pb at 158 GeV /c as observed in the experiments NA38 and NA50 respectively.

TL;DR: In this article, the production and propagation of kaons and antikaons has been studied in symmetric nucleus-nucleus collisions in the SIS energy range, and the ratio of the excitation functions of K+ production in Au+Au and C+C collisions increases with decreasing beam energy.

TL;DR: In this article, a tentative picture emerges in which a partonic state is indeed formed in central Pb+Pb collisions which hadronizes at about T = 185 MeV, and expands its volume more than tenfold, cooling to about 120 MeV before hadronic collisions cease.

TL;DR: In this article, the beam line of the 18 Tm synchrotron has been used to irradiate a production target of beryllium, with the resulting pion beams being transported to the nearest downstream experimental area.

TL;DR: In this article, a general survey of photon-photon luminosities in relativistic heavy ion collisions is discussed and photon-nucleus physics at various γγ-invariant mass scales is discussed.

TL;DR: In this paper, the authors review the present understanding of hadron in-medium properties and the progress made in extracting such information from available experimental data using the relativistic transport model.

TL;DR: In this paper, the authors show that vector mesons show up in the electromagnetic current current-current correlator and provide a constraint on hadronic models for this correlator for vacuum as well as for finite nuclear density.

TL;DR: In this paper, the authors discuss what they have learned from two-proton and two-neutron correlation function measurements performed in recent years at Michigan State University, with details depending on the space-time characteristics of the emitting system.

TL;DR: In this paper, the results of the two-neutron halo nuclei 6 He and 11 Li results of angular, energy and momentum correlation measurements after breakup into a core fragment and valence neutrons are given and single-particle ground-state properties and large low-lying multipole strength near the threshold for particle emission are discussed.

TL;DR: In this article, a kinetic equation which combines the quasiparticle drift of Landau's equation with a dissipation governed by a nonlocal and noninstantaneous scattering integral in the spirit of Enskog corrections is discussed, and numerical values of the off-shell contribution to the Wigner distribution, of the collision duration and of collision nonlocality are presented for different realistic potentials.

TL;DR: The influence of the chiral mean field on the collective motion of kaons in relativistic heavy ion reactions at SIS energies is investigated in this article, where three types of collective motion, i.e., the transverse flow, the out-of-plane flow (squeeze-out) and the radial flow, are considered.

TL;DR: Theoretical and experimental studies of in-medium properties of hadrons in hot and/or dense matter is one of the most active frontiers in nuclear physics as mentioned in this paper, where the authors present an overview of current experimental efforts towards the measurement of dilepton and photon spectra in heavy-ion collisions at CERN SPS energies.

TL;DR: In this paper, the basic assumptions of thermal models were studied and it was shown that at SIS energies the particles are mainly produced in a highly non-equilibrium situation, at freeze-out only nucleons are thermalized.