8,770 research outputs found
Production of heavy isotopes in transfer reactions by collisions of U+U
The dynamics of transfer reactions in collisions of two very heavy nuclei
U+U is studied within the dinuclear system (DNS) model.
Collisions of two actinide nuclei form a super heavy composite system during a
very short time, in which a large number of charge and mass transfers may take
place. Such reactions have been investigated experimentally as an alternative
way for the production of heavy and superheavy nuclei. The role of collision
orientation in the production cross sections of heavy nuclides is analyzed
systematically. Calculations show that the cross sections decrease drastically
with increasing the charged numbers of heavy fragments. The transfer mechanism
is favorable to synthesize heavy neutron-rich isotopes, such as nuclei around
the subclosure at N=162 from No (Z=102) to Db (Z=105).Comment: 4 pages, 4 figure
Surface excitations, shape deformation and the long-time behavior in a stirred Bose-Einstein condensate
The surface excitations, shape deformation and the formation of persistent
current for a Gaussian obstacle potential rotating in an highly oblate
Bose-Einstein condensate(BEC)are investigated. Vortex dipole can be produced
and trapped in the center of the stirrer even for slow motion of the stirring
beam. When the barrier angular velocity is above some critical value, the
condensate shape can be deformed remarkably according to the rotation frequency
due to the existence of plenty of surface wave excitations. After a long enough
time, a few vortices are found to be left either trapped in the condensate or
pinned by the obstacle, a vortex dipole or several vortices can be trapped at
the beam center, which enables the possibility of vortex manipulation.Comment: 5 pages, 4 figure
Pion Production in Heavy-ion Collisions in the 1 A GeV region
Within the framework of the improved isospin dependent quantum molecular
dynamics (ImIQMD) model, the pion emission in heavy-ion collisions in the
region 1 A GeV is investigated systematically, in which the pion is considered
to be mainly produced by the decay of resonances (1232) and
N*(1440). The in-medium dependence and Coulomb effects of the pion production
are included in the calculation. Total pion multiplicity and
yields are calculated for the reaction Au+Au in central
collisions for selected Skyrme parameters SkP, SLy6, Ska, SIII and compared
them with the measured data by the FOPI collaboration.Comment: 9 pages, 5 figure
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