487 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
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
What is the Physics behind the 3He-4He Anomaly ?
We show that coalescence of nucleons emitted prior to thermalization in
highly excited nuclei can explain the anomaly of kinetic energies of helium
clusters. A new coalescence algorithm has been included into the statistical
approach to nuclear reactions formerly used to describe intermediate mass
fragment production.Comment: 5 pages, 4 figures, accepted at Eur. Phys.
Statistical evolution of isotope composition of nuclear fragments
Calculations within the statistical multifragmentation model show that the
neutron content of intermediate mass fragments can increase in the region of
liquid-gas phase transition in finite nuclei. The model predicts also
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 kinematic region.Comment: 14 pages with 4 figures. GSI preprint, Darmstadt, 200
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