Study of new reaction mechanisms for the synthesis of heavy and superheavy nuclei

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Exotic nuclei are usually produced by projectile fragmentation or projectile fission at relativistic energies or in complete fusion reactions at Coulomb barrier energies. These production methods and the available beam intensities determine the present boarders of the chart of nuclides. A possible way to expand into unknown territory might be multi-nucleon transfer (MNT) reactions. They allow, in principle, to produce neutron-rich as well as neutron-deficient isotopes with proton numbers reaching far beyond uranium. This option has become a topical subject in various laboratories around the world. Appropriate separation and detection techniques are being developed as well as the theoretical framework.In our recent work, we have succeeded in producing and identifying several new neutron-deficient transuranium isotopes produced in MNT reactions of 48Ca + 248Cm using the velocity filter SHIP at GSI. This experimental method turned out to be very sensitive for the detection of heavy target-like transfer products which are emitted in forward direction and allowed us to reach limit cross-sections two orders of magnitude lower than in previous experiments.Our investigations represent pioneering work which is still at the beginning and needs further experimental and theoretical elaboration. Ongoing and future investigations include the continuation of data analysis of the existing data and new experiments at different beam energies. Special focus will be put on the search for further new isotopes in existing and future data, the population of reaction products above the target and on the possible population of neutron-rich isotopes below Pb, along the N = 126 shell. The study also includes the investigation of acceptance and transport properties of the existing velocity filters for MNT products in order to optimize the separator settings in future experiments and for the design of a possible next-generation velocity filter.