23,732 research outputs found
Double neutron/proton ratio of nucleon emissions in isotopic reaction systems as a robust probe of nuclear symmetry energy
The double neutron/proton ratio of nucleon emissions taken from two reaction
systems using four isotopes of the same element, namely, the neutron/proton
ratio in the neutron-rich system over that in the more symmetric system, has
the advantage of reducing systematically the influence of the Coulomb force and
the normally poor efficiencies of detecting low energy neutrons. The double
ratio thus suffers less systematic errors. Within the IBUU04 transport model
the double neutron/proton ratio is shown to have about the same sensitivity to
the density dependence of nuclear symmetry energy as the single neutron/proton
ratio in the neutron-rich system involved. The double neutron/proton ratio is
therefore more useful for further constraining the symmetry energy of
neutron-rich matter
On the Common Envelope Efficiency
In this work, we try to use the apparent luminosity versus displacement
(i.e., vs. ) correlation of high mass X-ray binaries (HMXBs) to
constrain the common envelope (CE) efficiency , which is a key
parameter affecting the evolution of the binary orbit during the CE phase. The
major updates that crucial for the CE evolution include a variable
parameter and a new CE criterion for Hertzsprung gap donor stars, both of which
are recently developed. We find that, within the framework of the standard
energy formula for CE and core definition at mass \%, a high value of
, i.e., around 0.8-1.0, is more preferable, while likely can not reconstruct the observed vs.
distribution. However due to an ambiguous definition for the core boundary in
the literature, the used here still carries almost two order of
magnitude uncertainty, which may translate directly to the expected value of
. We present the detailed components of current HMXBs and
their spatial offsets from star clusters, which may be further testified by
future observations of HMXB populations in nearby star-forming galaxies.Comment: 14 pages, 10 figures, 7 tables, accepted for publication in MNRA
Deformation and orientation effects in the driving potential of the dinuclear model
A double-folding method is used to calculate the nuclear and Coulomb
interaction between two deformed nuclei with arbitrary orientations. A
simplified Skryme-type interaction is adopted. The contributions of nuclear
interaction and Coulomb interaction due to the deformation and orientation of
the nuclei are evaluated for the driving potential used in the description of
heavy-ion fusion reaction. So far there is no satisfactory theory to describe
the evolution of the dynamical nuclear deformation and orientations during the
heavy-ion fusion process. Our results estimated the magnitude of above effects.Comment: 15 pages, 6 figures, Accepted by Eur. Phys. Jour.
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