119832402
Deconfinement transition in anisotropic matter
Abstract Because of nuclear transparency at beam energies relevant to quark plasma formation, the extension of phase equilibrium conditions for interpenetrating pieces of matter is investigated. Applying this thermodynamical formalism to the deconfinement transition a non-trivial change is found on the phase diagram, due to the relative velocity of the interpenetrating matter elements.
16881732
Evaluation of QCD sum rules for HADES
QCD sum rules are evaluated at finite nucleon densities and temperatures to determine the change of pole mass parameters for the lightest vector mesons $\rho$, $\omega$ and $\phi$ in a strongly interacting medium at conditions relevant for the starting experiments at HADES. The role of the four-quark condensate is highlighted. A few estimates (within a fire ball model and BUU calculations) of dilepton spectra in heavy-ion collisions at 1 AGeV are presented.
118548456
Meson vacuum phenomenology in a three-flavor linear sigma model with (axial-)vector mesons
We study scalar, pseudoscalar, vector, and axial-vector mesons with non-strange and strange quantum numbers in the framework of a linear sigma model with global chiral $U(N_f)_L \times U(N_f)_R$ symmetry. We perform a global fit of meson masses, decay widths, as well as decay amplitudes. The quality of the fit is, for a hadronic model that does not consider isospin-breaking effects, surprisingly good. We also investigate the question whether the scalar $\bar{q}q$ states lie below or above 1 GeV and find the scalar states above 1 GeV to be preferred as $\bar{q}q$ states. Additionally, we also describe the axial-vector resonances as $\bar{q}q$ states.
123530530
Baryonic channels of dilepton production
A calculation of the Dalitz-decay width of baryon resonances is presented and applied to dilepton production in proton-proton collisions in the BEVALAC/SIS energy range. The results indicate, that for these energies the contribution of Dalitz decay of higher baryon resonances (i.e. other that the δ(1232)) are negligible.
15180819
From pion nucleon scattering to vector mesons in nuclear matter
Abstract We construct a relativistic and unitary approach to ‘high’ energy pion nucleon scattering taking into account the inelastic πΔ, ρ N , ω N , K Σ, K Λ and η N channels [1]. Our scheme dynamically generates the s- and d-wave nucleon and isobar resonances N *(1535), N *(1650), N *(1520), N *(1700), Δ*(1620) and Δ*(1700). We also describe the ρ- and ω-nucleon scattering amplitudes which in turn provide the leading density modification of the ρ and ω mass distribution in nuclear matter. We find repulsive mass shifts for both vector mesons at small nuclear density but predict considerable strength in low energy resonance-hole like vector meson modes.
56157029
Zero temperature properties of mesons in a vector meson extended linear sigma model
A three flavor linear sigma model with vector and axial-vector mesons is discussed. Preliminary results concerning on the symmetry breaking pattern, the question of parameterization, as well as the resulting meson masses are presented.
122292810
A total energy trigger at large angles used in a calorimetric study of 150 GeV and 300 GeV pion and proton interactions on hydrogen
Abstract Hard hadronic scattering was studied by selecting 150 GeV and 300 GeV π − p and pp events with large energy in a 240 cell calorimeter covering 45† to 135† in the c.m.s. polar angle and the full 2 π azimuth. A downstream calorimeter measured the remaining energy flow at smaller angles. For large energy deposited in the segmented calorimeter the proton induced cross section drops below the pion induced cross section, as expected in a constituent scattering picture. However, neither a simple energy scaling of the cross section nor a dominant jet structure of the events is observed. No evidence was found for recently proposed higher-twist mechanisms leading to events
123558617
A study of high transverse energy interactions of 300 GeV pions and protons on hydrogen using a streamer chamber
Abstract High transverse energy π − p and pp interactions at 300 GeV/ c have been studied using a calorimeter-triggered streamer-chamber vertex spectrometer. The data are found to have many of the qualitative features expected from hard-scattering processes, in particular charge correlations with the quark content of the incident hadrons, charge correlations between the highest- p T particles, and back-to-back correlations between the highest- p T particles. However, the data are found not to agree quantitatively with a QCD four-jet model. Nor can they be described by an extrapolation of low- p T processes.
120076725
Dependence of multiplicity and rapidity distributions on the number of projectile collisions in 200-GeV/c proton-nucleus interactions
Interactions of 200-GeV/c protons on hydrogen, neon, argon, and xenon were studied with a streamer-chamber spectrometer. The number of projectile collisions inside the nucleus and the number of secondary collisions in the intranuclear cascade were estimated. The dependence of multiplicity and rapidity distributions on the number of projectile collisions was analyzed. The predictions of the additive quark model were found to be in qualitative agreement with the results of the experiment.
123564276
Production of K∗(892) in K+N interactions at 3 GeV/c
We have studied the reactions K+d→K+π−pp,K+d→Koπopp,K+d→Koπ+pp, obtained from an exposure of the Saclay 81-cm bubble chamber filled with deuterium and exposed at CERN to a separated 3 GeV/c K+ beam. 
 
In reactions (1) and (2) there is abundant production of K∗0(892) and some production of K∗(1420). From the density matrix elements, it is found that K∗0(892) is produced mainly by pion exchange. The K∗(892) four-momentum-transfer distribution in reaction (1) agrees with the predictions of the OPE model, as modified by Durr and Pilkuhn. A marked asymmetry of the decay distribution of the K+π− system is observed and discussed in the framework of a unitarized Veneziano model. In reaction (3), on the other hand, the production of K∗+(892) and N∗+(1236) is found to proceed mainly by vector exchange.
117777421
sigma- Production and decay properties in K-p --> sigma-pi+