13276917
Probing in-medium vector meson decays by
double-differential di-electron spectra
in heavy-ion collisions at SIS energies
Abstract.Within a transport code simulation for heavy-ion collisions
at bombarding energies around 1 AGeV, we demonstrate that
double-differential di-electron spectra with suitable
kinematical cuts are useful to isolate
(i) the ρ meson peak even in case of strong broadening, and
(ii) the in-medium ω decay contribution.
The expected in-medium modifications of 
the vector meson spectral densities can thus be probed
in this energy range via the di-electron channel.
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.
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.
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.
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.
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.
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.
117090913
sigma+/- lifetimes and longitudinal acceleration
122039401
Long-range correlations in hadron-nucleus interactions
An analysis of correlations in rapidity of charged particles produced in proton and antiproton interactions on hydrogen, argon and xenon at 200 GeV is presented. Positive long-range correlations are observed in interactions on heavy targets. The dependence of rapidity correlations between the forward and backward hemisphere on the number of projectile collisions is discussed.
188188770
The reaction k+ d ---> k0 p p at 4.6 gev/c
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.