92 research outputs found
1S0 Proton and Neutron Superfluidity in beta-stable Neutron Star Matter
We investigate the effect of a microscopic three-body force on the proton and
neutron superfluidity in the channel in -stable neutron star
matter. It is found that the three-body force has only a small effect on the
neutron pairing gap, but it suppresses strongly the proton
superfluidity in -stable neutron star matter.Comment: 12 pages, 2 figure
Effect of Three-body Interaction on Phase Transition of Hot Asymmetric Nuclear Matter
The properties and the isospin dependence of the liquid-gas phase transition
in hot asymmetric nuclear matter have been investigated within the framework of
the finite temperature Brueckner-Hartree-Fock approach extended to include the
contribution of a microscopic three-body force. A typical Van der Waals
structure has been observed in the calculated isotherms (of pressure) for
symmetric nuclear matter implying the presence of the liquid-gas phase
transition. The critical temperature of the phase transition is calculated and
its dependence on the proton-to-neutron ratio is discussed. It is shown that
the three-body force gives a repulsive contribution to the nuclear equation of
state and reduces appreciably the critical temperature and the mechanical
instable region. At fixed temperature and density the pressure of asymmetric
nuclear matter increases monotonically as a function of isospin asymmetry. In
addition, it turns out that the domain of mechanical instability for hot
asymmetric nuclear matter gradually shrinks with increasing asymmetry and
temperature. We have compared our results with the predictions of other
theoretical models especially the Dirac Brueckner approach. A possible
explanation for the discrepancy between the values of the critical temperature
predicted by the present non-relativistic Brueckner calculations including the
three-body force and the relativistic Dirac-Brueckner method is given.Comment: 16 pages, 5 figure
Recent breakthroughs in Skyrme-Hartree-Fock-Bogoliubov mass formulas
We review our recent achievements in the construction of microscopic mass
tables based on the Hartree-Fock-Bogoliubov method with Skyrme effective
interactions. In the latest of our series of HFB-mass models, we have obtained
our best fit ever to essentially all the available mass data, by treating the
pairing more realistically than in any of our earlier models. The rms deviation
on the 2149 measured masses of nuclei with N and Z>8 has been reduced for the
first time in a mean field approach to 0.581 MeV. With the additional
constraint on the neutron-matter equation of state, this new force is thus very
well-suited for the study of neutron-rich nuclei and for the description of
astrophysical environments like supernova cores and neutron-star crusts.Comment: Proceedings of the Fifth International Conference on Exotic Nuclei
and Atomic Masses, September 7-13 2008, Ryn (Poland). To appear in the
European Physical Journal
Strong Couplings of Heavy Mesons to A Light Vector Meson in QCD
We make a detailed analysis of the and
strong couplings and
using QCD light cone sum rules(LCSR). The
existing some negligence is pointed out in the previous LCSR calculation on
) and an updated estimate is presented. Our
findings can be used to understand the behavior of the
semileptonic form factors at large momentum transitions.Comment: 15 pages, latex, 2 figures, version appearing in PRD, typos correcte
Fine structure in the α decay of 223U
Fine structure in the α decay of 223U was observed in the fusion-evaporation reaction 187Re(40Ar, p3n) by using fast digital pulse processing technique. Two α-decay branches of 223U feeding the ground state and 244 keV excited state of 219Th were identified by establishing the decay chain 223U →α1 219Th →α2 215Ra →α3 211Rn. The α-particle energy for the ground-state to ground-state transition of 223U was determined to be 8993(17) keV, 213 keV higher than the previous value, the half-life was updated to be 62−10+14 μs. Evolution of nuclear structure for N = 131 even-Z isotones from Po to U was discussed in the frameworks of nuclear mass and reduced α-decay width, a weakening octupole deformation in the ground state of 223U relative to its lighter isotones 219Ra and 221Th was suggested
Quasifree Neutron Knockout Reaction Reveals a Small s-Orbital Component in the Borromean Nucleus 17B
International audienceA kinematically complete quasifree (p,pn) experiment in inverse kinematics was performed to study the structure of the Borromean nucleus B17, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for 1s1/2 and 0d5/2 orbitals, and a surprisingly small percentage of 9(2)% was determined for 1s1/2. Our finding of such a small 1s1/2 component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in B17. The present work gives the smallest s- or p-orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of s or p orbitals is not a prerequisite for the occurrence of a neutron halo
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