29,261 research outputs found
Testing the Mutually Enhanced Magicity Effect in Nuclear Incompressibility via the Giant Monopole Resonance in the Pb Isotopes
Using inelastic -scattering at extremely forward angles, including
, the strength distributions of the isoscalar giant monopole resonance
(ISGMR) have been measured in the Pb isotopes in order to
examine the proposed mutually enhanced magicity (MEM) effect on the nuclear
incompressibility. The MEM effect had been suggested as a likely explanation of
the "softness" of nuclear incompressibility observed in the ISGMR measurements
in the Sn and Cd isotopes. Our experimental results rule out any manifestation
of the MEM effect in nuclear incompressibility and leave the question of the
softness of the open-shell nuclei unresolved still.Comment: Accepted for publication in Physics Letters B. Very minor changes in
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Dynamical nucleus-nucleus potential and incompressibility of nuclear matter
The dynamical nucleus-nucleus potentials for some fusion reactions are
investigated by using the improved quantum molecular dynamics (ImQMD) model
with different sets of parameters in which the corresponding incompressibility
coefficient of nuclear matter is different. Two new sets of parameters SKP* and
IQ3 for the ImQMD model are proposed with the incompressibility coefficient of
195 and 225 MeV, respectively. The measured fusion excitation function for
16O+208Pb and the charge distribution of fragments for Ca+Ca and Au+Au in
multi-fragmentation process can be reasonably well reproduced. Simultaneously,
the influence of the nuclear matter incompressibility and the range of
nucleon-nucleon interaction on the nucleus-nucleus dynamic potential is
investigated.Comment: 7 figures, 3 tables, to appear in Phys. Rev.
Effect of pairing correlations on incompressibility and symmetry energy in nuclear matter and finite nuclei
The role of superfluidity in the incompressibility and in the symmetry energy
is studied in nuclear matter and finite nuclei. Several pairing interactions
are used: surface, mixed and isovector dependent. Pairing has a small effect on
the nuclear matter incompressibility at saturation density, but the effects are
significant at lower densities. The pairing effect on the centroid energy of
the isoscalar Giant Monopole Resonance (GMR) is also evaluated for Pb and Sn
isotopes by using a microscopic constrained-HFB approach, and found to change
at most by 10% the nucleus incompressibility . It is shown by using the
Local Density Approximation (LDA) that most of the pairing effect on the GMR
centroid come from the low-density nuclear surface.Comment: 9 pages, 6 figure
Incompressibility of strange matter
Strange stars calculated from a realistic equation of state (EOS), that
incorporate chiral symmetry restoration as well as deconfinement at high
density show compact objects in the mass radius curve. We compare our
calculations of incompressibility for this EOS with that of nuclear matter. One
of the nuclear matter EOS has a continuous transition to ud-matter at about
five times normal density. Another nuclear matter EOS incorporates density
dependent coupling constants. From a look at the consequent velocity of sound,
it is found that the transition to ud-matter seems necessary.Comment: Accepted for publication in Phys Lett
Large Alphabets and Incompressibility
We briefly survey some concepts related to empirical entropy -- normal
numbers, de Bruijn sequences and Markov processes -- and investigate how well
it approximates Kolmogorov complexity. Our results suggest th-order
empirical entropy stops being a reasonable complexity metric for almost all
strings of length over alphabets of size about when surpasses
Incompressibility of orthogonal grassmannians
We prove the following conjecture due to Bryant Mathews (2008). Let Q be the
orthogonal grassmannian of totally isotropic i-planes of a non-degenerate
quadratic form q over an arbitrary field (where i is an integer in the interval
[1, (\dim q)/2]). If the degree of each closed point on Q is divisible by 2^i
and the Witt index of q over the function field of Q is equal to i, then the
variety Q is 2-incompressible.Comment: 5 page
The Compression-Mode Giant Resonances and Nuclear Incompressibility
The compression-mode giant resonances, namely the isoscalar giant monopole
and isoscalar giant dipole modes, are examples of collective nuclear motion.
Their main interest stems from the fact that one hopes to extrapolate from
their properties the incompressibility of uniform nuclear matter, which is a
key parameter of the nuclear Equation of State (EoS). Our understanding of
these issues has undergone two major jumps, one in the late 1970s when the
Isoscalar Giant Monopole Resonance (ISGMR) was experimentally identified, and
another around the turn of the millennium since when theory has been able to
start giving reliable error bars to the incompressibility. However, mainly
magic nuclei have been involved in the deduction of the incompressibility from
the vibrations of finite nuclei. The present review deals with the developments
beyond all this. Experimental techniques have been improved, and new
open-shell, and deformed, nuclei have been investigated. The associated changes
in our understanding of the problem of the nuclear incompressibility are
discussed. New theoretical models, decay measurements, and the search for the
evolution of compressional modes in exotic nuclei are also discussed.Comment: Review paper to appear in "Progress in Particle and Nuclear Physics
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