J. Schaffner

Kaon effective mass and energy in dense nuclear matter

Abstract Within the framework of the relativistic mean field model we study the properties of kaons and antikaons in dense nuclear matter. The kaon effective mass tends to saturate at high densities. Kaons do not undergo condensation. Antikaon condensation may occur in chiral models, only for relatively high values of the nucleon effective mass, m N ∗ /m N > 0.75 , and does not occur in models based on one boson exchange underlying K N interactions.

Antibaryon\(\left( {\bar p,\bar \Lambda } \right)\) production in relativistic nuclear collisions

AbstractThe relativistic meson field theory is used to study the effects of the in-medium interaction on the predicted antibaryon abundancy in hot hadronic matter. It is demonstrated that subtreshold production of antiprotons in high energy heavy ion collisions at Elab =1–2 GeV/nucleon is enhanced by 2–3 orders of magnitude as compared to a standard fireball model estimate. Furthermore, we show that after the inclusion of interactions the anti-hyperon yields, e.g.

PHYSICS OF STRANGE MATTER FOR RELATIVISTIC HEAVY-ION COLLISIONS

\bar \Lambda

Multistrangeness production in heavy ion collisions

/π− are enhanced by about a factor ten. Predicted yields are in excess of the data measured by the NA35 and WA85 collaborations at CERN. The annihilation of antibaryons in surrounding matter at the final stage of the reaction may essentially reduce their abundancy.

Physics in the baryon-rich regime☆

We investigate a phenomenological equation of state for the gluon plasma, which differs from the ideal gluon gas equation of state in three aspects: (a) it is assumed that gluons withlow momentum are subject to confining interactions anddo not contribute to the energy spectrum of free gluons; (b)only gluons withhigh momentum are considered as an ideal gas with perturbative corrections of orderO(αs); (c) a non-perturbative vacuum pressure is included. We show that feature (a) allows for a reasonable perturbative treatment of the interaction between gluons with high momentum. The equation of state reproduces lattice data for the thermodynamical functions of theSU(3) pure gauge theory above the deconfinement transition temperatureTc. This result suggests that a possible way to describe the gluon plasma is in terms of perturbatively interacting gluons and non-perturbative “glueball” states.

Proton halos in100Sn using a relativistic shell model

Relativistic heavy-ion collisions offer the possibility to produce exotic metastable or even absolutely stable states of nuclear matter containing (roughly) equal number of strangeness compared to the baryon number: Strangelets, small pieces of strange quark matter, were proposed as a signal of quark-gluon plasma formation. As their hadronic counterpart, also small pieces of strange hadronic matter may also show up with rather similar properties. The reasoning of both their stability and existence, the possible separation of strangeness necessary for their formation, and the chances for their detection, are reviewed.

Strange quark matter droplets in ultrarelativistic heavy ion collisions

Abstract We calculate the properties of the hadronic counterparts of the strangelet, metastable exotic multihypernuclear objects (MEMOs), in a relativistic meson field theory. We find out that they behave quite similar to the strangelets and could therefore be indistinguishable from them in heavy ion collisions.

Strange matter — a new domain of nuclear physics

Abstract The creation of multistrange objects (strangelets and multi hypernuclei) in heavy ion collisions is contrasted with the occurrence of strangelets in astrophysics.