185 research outputs found
Multifragmentation and nuclear phase transitions (liquid-fog and liquid-gas)
Thermal multifragmentation of hot nuclei is interpreted as the nuclear
liquid-fog phase transition. The charge distributions of the intermediate mass
fragments produced in p(3.6 GeV) + Au and p(8.1 GeV) + Au collisions are
analyzed within the statistical multifragmentation model with the critical
temperature for the nuclear liquid-gas phase transition Tc as a free parameter.
The analysis presented here provides strong support for a value of Tc > 15 MeV.Comment: 4 pages, 2 figures, Submittet to Proc. of NN2003 to be published in
Nucl. Phys.
Recoil Studies in the Reaction of 12-C Ions with the Enriched Isotope 118-Sn
The recoil properties of the product nuclei from the interaction of 2.2
GeV/nucleon 12-C ions from Nuclotron of the Laboratory of High Energies (LHE),
Joint Institute for Nuclear Research (JINR) at Dubna with a 118-Sn target have
been studied using catcher foils. The experimental data were analyzed using the
mathematical formalism of the standard two-step vector model. The results for
12-C ions are compared with those for deuterons and protons. Three different
Los Alamos versions of the Quark-Gluon String Model (LAQGSM) were used for
comparison with our experimental data.Comment: 10 pages, 6 figures, submitted to Nucl. Phys.
Measurement of the complete nuclide production and kinetic energies of the system 136Xe + hydrogen at 1 GeV per nucleon
We present an extensive overview of production cross sections and kinetic
energies for the complete set of nuclides formed in the spallation of 136Xe by
protons at the incident energy of 1 GeV per nucleon. The measurement was
performed in inverse kinematics at the FRagment Separator (GSI, Darmstadt).
Slightly below the Businaro-Gallone point, 136Xe is the stable nuclide with the
largest neutron excess. The kinematic data and cross sections collected in this
work for the full nuclide production are a general benchmark for modelling the
spallation process in a neutron-rich nuclear system, where fission is
characterised by predominantly mass-asymmetric splits.Comment: 18 pages, 14 figure
Critical Temperature for the Nuclear Liquid-Gas Phase Transition
The charge distribution of the intermediate mass fragments produced in p (8.1
GeV) + Au collisions is analyzed in the framework of the statistical
multifragmentation model with the critical temperature for the nuclear
liquid-gas phase transition as a free parameter. It is found that
MeV (90% CL).Comment: 4 pages, 3 figures, published in Phys. Rev.
High-resolution velocity measurements on fully identified light nuclides produced in 56Fe + hydrogen and 56Fe + titanium systems
New experimental results on the kinematics and the residue production are
obtained for the interactions of 56Fe projectiles with protons and (nat)Ti
target nuclei, respectively, at theincident energy of 1 A GeV. The
titanium-induced reaction serves as a reference case for multifragmentation.
Already in the proton-induced reaction, the characteristics of the isotopic
cross sections and the shapes of the velocity spectra of light residues
indicate that high thermal energy is deposited in the system during the
collision. In the 56Fe+p system the high excitation seems to favour the onset
of fast break-up decays dominated by very asymmetric partitions of the
disassembling system. This configuration leads to the simultaneous formation of
one or more light fragments together with one heavy residue.Comment: 24 pages, 21 figures, 1 table, this work forms part of the PhD thesis
of P.Napolitani, background information on http://www-w2k.gsi.de/kschmidt
Exact thermodynamics of an Extended Hubbard Model of single and paired carriers in competition
By exploiting the technique of Sutherland's species, introduced in
\cite{DOMO-RC}, we derive the exact spectrum and partition function of a 1D
extended Hubbard model. The model describes a competition between dynamics of
single carriers and short-radius pairs, as a function of on-site Coulomb
repulsion () and filling (). We provide the temperature dependence of
chemical potential, compressibility, local magnetic moment, and specific heat.
In particular the latter turns out to exhibit two peaks, both related to
`charge' degrees of freedom. Their origin and behavior are analyzed in terms of
kinetic and potential energy, both across the metal-insulator transition point
and in the strong coupling regime.Comment: 14 pages, 15 eps figure
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