13,646 research outputs found
Supersymmetric Reciprocal Transformation and Its Applications
The supersymmetric analog of the reciprocal transformation is introduced.
This is used to establish a transformation between one of the supersymmetric
Harry Dym equations and the supersymmetric modified Korteweg-de Vries equation.
The reciprocal transformation, as a B\"{a}cklund-type transformation between
these two equations, is adopted to construct a recursion operator of the
supersymmetric Harry Dym equation. By proper factorization of the recursion
operator, a bi-Hamiltonian structure is found for the supersymmetric Harry Dym
equation. Furthermore, a supersymmetric Kawamoto equation is proposed and is
associated to the supersymmetric Sawada-Kotera equation. The recursion operator
and odd bi-Hamiltonian structure of the supersymmetric Kawamoto equation are
also constructed.Comment: 31 pages, expande
Isospin effect in the statistical sequential decay
Isospin effect of the statistical emission fragments from the equilibrated
source is investigated in the frame of statistical binary decay implemented
into GEMINI code, isoscaling behavior is observed and the dependences of
isoscaling parameters and on emission fragment size, source
size, source isospin asymmetry and excitation energies are studied. Results
show that and neither depends on light fragment size nor on
source size. A good linear dependence of and on the inverse of
temperature is manifested and the relationship of
and
from different
isospin asymmetry sources are satisfied. The symmetry energy coefficient
extracted from simulation results is 23 MeV which includes
both the volume and surface term contributions, of which the surface effect
seems to play a significant role in the symmetry energy.Comment: 8 pages, 8 figures; A new substantially modified version which has
been accepted by the Physical Review
The roles of deformation and orientation in heavy-ion collisions induced by light deformed nuclei at intermediate energy
The reaction dynamics of axisymmetric deformed Mg + Mg
collisions have been investigated systematically by an isospin-dependent
quantum molecular dynamics (IDQMD) model. It is found that different
deformations and orientations result in apparently different properties of
reaction dynamics. We revealed that some observables such as nuclear stopping
power (), multiplicity of fragments, and elliptic flow are very sensitive to
the initial deformations and orientations. There exists an eccentricity scaling
of elliptic flow in central body-body collisions with different deformations.
In addition, the tip-tip and body-body configurations turn out to be two
extreme cases in central reaction dynamical process.Comment: 5 pages, 7 figures, to appear in Physical Review C (Rapid
Communication
Hard photon flow and photon-photon correlation in intermediate energy heavy-ion collisions
Hard photons emitted from energetic heavy ion collisions are very interesting
since they do not experience nuclear interaction, and therefore they are useful
to explore properties of nuclear matter. We investigated hard photon production
and its properties in intermediate energy heavy-ion collisions with the help of
the Blotzmann-Uehling-Ulenbeck model. Two components of hard photons are
discussed: direct and thermal. The positive directed flow parameter and
negative elliptic flow parameter of direct photons are demonstrated and they
are anti-correlated to the flows of free protons. The dependencies of hard
photon production and anisotropic parameters on impact parameter, beam energy,
nuclear equation of state and symmetry energy are also discussed. Furthermore,
we investigated the two-photon momentum correlation function from which the
space-time structure information of the photon source could be extracted as
well as the two-photon azimuthal correlation which could provide another good
method to determine the elliptic flow parameter of direct hard photons.Comment: 13 pages, 18 figure
Radio and X-ray images of SNR G18.8+0.3 interacting with molecular clouds
New HI images from the VLA Galactic Plane Survey (VGPS) show clear absorption
features associated with the supernova remnant (SNR) G18.8+0.3. High-resolution
CO images reveal that molecular clouds overlap the radio filaments of
G18.8+0.3. The CO emission spectrum over the full velocity range in the
direction of G18.8+0.3 shows two molecular components with high
brightness-temperatureand three molecular components with low
brightness-temperature, all with respective HI absorption. This implies that
these clouds are in front of G18.8+0.3. In the HI images, the highest velocity
absorption feature seen against the continuum image of G18.8+0.3 is at 129 km
s, which corresponds to the tangent point in this direction. This yields
a lower distance limit of 6.9 kpc for G18.8+0.3. Absence of absorption at
negative velocities gives an upper distance limit of 15 kpc. The broadened
profile at 205 km s in the CO emission spectra is a strong
indicator of a possible SNR/CO cloud interaction. Thus, G18.8+0.3 is likely to
be at the distance of about 12 kpc. The upper mass limit and mean density of
the giant CO cloud at 205 km s are \sim 6 \times 10^{5} M_{\odot}
and \sim 2 \times 10^{2} cm^{-3}. We find an atomic hydrogen column density in
front of G18.8+0.3 of \sim 2 \times 10^{22} cm^{-2}. The ROSAT PSPC
observations show a diffuse X-ray enhancement apparently associated with part
of the radio shell of G18.8+0.3. Assuming an association, the unabsorbed flux
is 2.2 \times10^{-12} erg cm^{-2} s^{-1}, suggesting an intrinsic luminosity of
3.6 \times 10^{34} erg s^{-1} for G18.8+0.3.Comment: 8 pages, 6 figures, two tables, accepted by A&
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