Phi meson production in near threshold proton-nucleus collisions

The cross section for production of Phi mesons in proton-nucleus reactions is calculated as a function of the target mass. The decay width of the Phi meson is affected by the change of the masses of the Phi, K+ and K- mesons in the medium. A strong attractive K- potential leads to a measurable change of the behavior of the cross section as a function of of the target mass. Comparison between the kaon and electron decay modes are made.Comment: 4 pages, 1figure, new figure, new reference

Angular distribution and azimuthal asymmetry for pentaquark production in proton-proton collisions

Angular distributions for production of the $\Theta^+$ pentaquark are calculated for the collisions of polarized protons with polarized target protons. We compare calculations based on different assumptions concerning spin and parity ($J=1/2^\pm,3/2^\pm$) of the $\Theta^+$ state. For a wide class of interactions the spin correlation parameters describing the asymmetric angular distributions are calculated up to 250 MeV above production threshold. The deviations from the near threshold behavior are investigated.Comment: 8 pages, 5 figure

Calculations of K+, K- and phi Production in Near-Threshold Proton-Nucleus Collisions

K+, K- and \phi meson production in proton-nucleus (pA) collisions has been calculated within a BUU transport model. It is shown that the nucleon-hyperon strangeness transfer channel is essential. The role of three-body reactions has been investigated within the medium. The targetmass dependence of $\phi$ production is predicted to give important information on the in-medium properties of all three mesons.Comment: Talk presented by H.W.B. at the Budapest 2004 workshop on 'Hot and Dense Matter in Relativistic Heavy Ion Collisions', March 24-27, 2004, Budapest, Hungar

Radial flow has little effect on clusterization at intermediate energies in the framework of the Lattice Gas Model

The Lattice Gas Model was extended to incorporate the effect of radial flow. Contrary to popular belief, radial flow has little effect on the clusterization process in intermediate energy heavy-ion collisions except adding an ordered motion to the particles in the fragmentation source. We compared the results from the lattice gas model with and without radial flow to experimental data. We found that charge yields from central collisions are not significantly affected by inclusion of any reasonable radial flow.Comment: 8 pages, 2 figures, submitted to PRC; Minor update and resubmitted to PR

Production of phi mesons in subthreshold heavy-ion collisions

Within a BUU type transport model we study $\phi$ meson production in subthreshold Ni+Ni and Ru+Ru reactions. For the first time we included in our model the elementary reaction channels $\rho+N,\Delta \to \phi+N$, $\pi+N(1520) \to \phi+N$ and $\pi \rho$ $\to$ $\phi$. In spite of a substantial increase of the $\phi$ multiplicities by these channels our results stay significantly below the preliminary experimental data.Comment: 4 pages, 2 figures, version to be published in the proceedings of the SQM2001 Conference (Frankfurt, Germany, 25-29 Sep 2001

Collective flow in central Au-Au collisions at 150, 250 and 400 A MeV

Radial collective flow and thermalization are studied in gold on gold collisions at 150, 250 and 400 A MeV bombarding energies with a relativistically covariant formulation of a QMD code. We find that radial flow and "thermal" energies calculated for all the charged fragments agree reasonably with the experimental values. The experimental hardware filter at small angles used in the FOPI experiments at higher energies selects mainly the thermalized particles.Comment: 4 pages with 4 EPS figures included. Version accepted for publication in Phys. Rev.