Title: Extension of the Periodic System: Superneutronic, Superheavy, Superstrange Elements Speaker: Professor Walter Greiner, Frankfurt Institute for Advanced Studies (FIAS), Frankfurt am Main, Germany Time: Tuesday 24 November 2009 at 3.15 p.m. (Coffee from 3 p.m.) Place: Physics Auditorium Abstract: The extension of the periodic system into various new areas is investigated. Experiments for the synthesis of superheavy elements and the predictions of magic numbers are reviewed. Different ways of nuclear decay are discussed like cluster radioactivity, cold fission and cold multifragmentation. Up to now superheavy nuclei were only produced close to the proton drip line. The recent Dubna experiments utilizing a 48Ca beam have been confirmed at an essential intermediate decay at GSI. Thus we can state that superheavy nuclei up to Z=118 have been found. In order to make superheavies closer to the stable valley by increasing the neutron number we investigate the bombardment of e.g. U+Cm and its decay down to the superheavy island around Z=114 and 120. In this connection also the time delay during the formation of the giant nuclear system U+Cm up to 10-19 sec is found. This is most important for studying the decay of the supercritical electron-positron vacuum. A trigger for such giant nuclear systems with long delay times (~ 10-19s) is e.g. large mass transfer such as U+Cm to Pb+rest. In this connection I remind the basics of the decay of the vacuum in supercritical Coulomb fields. A very important, novel idea came up a number of years ago in work with K. Gridnev and collaborators. We suggested that extremely neutron rich nuclei might exist, i.e. nuclei like 42O, 42Mg, 42Al, 260Pb, etc. About two years ago the Michigan group of Toennessen, Gade et al. found 42Mg and 42Al. This opens the door to an extremely wide and new field of research, which is very important in nuclear astrophysics. A perspective for future research is given. This includes also a theoretical study of superheavy element (SHE) formation by supernova explosions and thus the possible occurrence of SHE in nature. Furthermore, investigations on hypernuclei and the possible production of antimatter-clusters in heavy-ion collisions are reported. Various versions of the meson field theory serve as effective field theories. They are the basis of modern nuclear structure and suggest structure in the vacuum which is important for the production of hyper- and antimatter. Thus, the table of nuclei can be extended into the sectors of strangeness and antimatter. This is interesting in itself but also contributes to the creation of ordinary elements during nucleo-synthesis. I also discuss the possibility of producing a new kind of nuclear systems by putting a few antibaryons inside ordinary nuclei. Surprising results emerge: In particular cold compression of nuclear matter- in contrast to hot compression via nuclear shock waves becomes possible. General Physics Colloquium Location Physics Auditorium Start time tirsdag 24. of november 2009, 15:00 End time tirsdag 24. of november 2009, 16:00 ************** Ulrik Uggerhøj Department of Physics and Astronomy Aarhus University Denmark Phone: +45 8942 3738 e-mail: ulrik@phys.au.dk