641 research outputs found
Production of hypernuclei in multifragmentation of nuclear spectator matter
In peripheral collisions of relativistic heavy ions highly excited spectators
containing Lambda-hyperons can be produced. Such strange spectator matter may
undergo a break-up into many fragments (multifragmentation) as it is well
established for ordinary nuclear systems. We generalize the statistical
multifragmentation model, previously successfully used for the description of
experimental data, for the case of hypernuclear systems. We predict relative
yields of hypernuclei and the main characteristics of such a break-up. We point
at a connection of this phenomenon with a liquid-gas phase transition in
hypermatter.Comment: 4 pages including 4 figure
Formation of hot heavy nuclei in supernova explosions
We point out that during the supernova II type explosion the thermodynamical
condition of stellar matter between the protoneutron star and the shock front
corresponds to the nuclear liquid-gas phase coexistence region, which can be
investigated in nuclear multifragmentation reactions. We have demonstrated,
that neutron-rich hot heavy nuclei can be produced in this region. The
production of these nuclei may influence dynamics of the explosion and
contribute to the synthesis of heavy elements.Comment: 6 pages with 4 figure
External Coulomb and angular momentum influence on isotope composition of nuclear fragments
The Markov chain statistical multifragmentation model predicts inhomogeneous
distributions of fragments and their isospin in the freeze-out volume caused by
an angular momentum and external long-range Coulomb field. These effects can
take place in peripheral nucleus-nucleus collisions at intermediate energies
and lead to neutron-rich isotopes produced in the midrapidity kinematical
region of the reactions.Comment: 4 pages with 2 figures. A talk at the International Conference
"Bologna-2000: Structure of the Nucleus at the Dawn of the Century", May 29 -
June 3, Bologna, Ital
Isospin and symmetry energy effects on nuclear fragment production in liquid-gas type phase transition region
We have demonstrated that the isospin of nuclei influences the fragment
production during the nuclear liquid-gas phase transition. Calculations for
Au197, Sn124, La124 and Kr78 at various excitation energies were carried out on
the basis of the statistical multifragmentation model (SMM). We analyzed the
behavior of the critical exponent tau with the excitation energy and its
dependence on the critical temperature. Relative yields of fragments were
classified with respect to the mass number of the fragments in the transition
region. In this way, we have demonstrated that nuclear multifragmentation
exhibits a 'bimodality' behavior. We have also shown that the symmetry energy
has a small influence on fragment mass distribution, however, its effect is
more pronounced in the isotope distributions of produced fragments.Comment: 8 pages, 9 figures, accepted for publication in EPJ
Production of Neutron-rich Heavy Residues and the Freeze-out Temperature in the Fragmentation of Relativistic 238U Projectiles Determined by the Isospin Thermometer
Isotope yields of heavy residues produced in collisions of 238U with lead at
1AGeV show indications for a simultaneous break-up process. From the average
N-over-Z ratio of the final residues up to Z = 70, the average limiting
temperature of the break-up configuration at freeze out was determined to T
approximately 5 MeV using the isospin-thermometer method. Consequences for the
understanding of other phenomena in highly excited nuclear systems are
discussed.Comment: 22 pages, 9 figures, accepted by Nucl. Phys.
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