Year of publication
- 1998 (4) (remove)
- Article (4) (remove)
- Potential energy surfaces of superheavy nuclei (1998)
- We investigate the structure of the potential energy surfaces of the superheavy nuclei 158258Fm100, 156264Hs108, 166278112, 184298114, and 172292120 within the framework of self-consistent nuclear models, i.e., the Skyrme-Hartree-Fock approach and the relativistic mean-field model. We compare results obtained with one representative parametrization of each model which is successful in describing superheavy nuclei. We find systematic changes as compared to the potential energy surfaces of heavy nuclei in the uranium region: there is no sufficiently stable fission isomer any more, the importance of triaxial configurations to lower the first barrier fades away, and asymmetric fission paths compete down to rather small deformation. Comparing the two models, it turns out that the relativistic mean-field model gives generally smaller fission barriers.
- Role of the higher static deformations of fragments in the cold binary fission of 252Cf (1998)
- We study the binary cold fission of 252Cf in the frame of a cluster model where the fragments are born to their respective ground states and interact via a double-folded potential with deformation effects taken into account up to multipolarity lambda=4. The preformation factors were neglected. In the case when the fragments are assumed to be spherical or with ground-state quadrupole deformation, the Q-value principle dictates the occurrence of a narrow region around the double magic 132Sn, like in the case of cluster radioactivity. When the hexadecupole deformation is turned on, an entire mass region of cold fission in the range 138–156 for the heavy fragment arise, in agreement with the experimental observations. This fact suggests that in the above-mentioned mass region, contrary to the usual cluster radioactivity where the daughter nucleus is always a neutron/proton (or both) closed shell or nearly closed shell spherical nucleus, the clusterization mechanism seems to be strongly influenced by the hexadecupole deformations rather than the Q value.
- Intermediate mass dileptons from secondary Drell-Yan processes (1998)
- Recent reports on enhancements of intermediate and hight mass muon pairs producedin heavy ion collisions have attracted much attention.
- Fluctuations and inhomogenities of energy density and isospin in Pb + Pb at the SPS (1998)
- The main goal of heavy ion physics in the last fifteen years has been the search for the quark-gluon-plasma(QGP). Until now, unambigous experimental evidence for the QGP is missing.