7,432 research outputs found
Impact of the symmetry energy on the outer crust of non-accreting neutron stars
The composition and equation of state of the outer crust of non-accreting
neutron stars is computed using accurate nuclear mass tables. The main goal of
the present study is to understand the impact of the symmetry energy on the
structure of the outer crust. First, a simple "toy model" is developed to
illustrate the competition between the electronic density and the symmetry
energy. Then, realistic mass tables are used to show that models with a stiff
symmetry energy - those that generate large neutron skins for heavy nuclei -
predict a sequence of nuclei that are more neutron-rich than their softer
counterparts. This result may be phrased in the form of a correlation: the
larger the neutron skin of 208Pb, the more exotic the composition of the outer
crust.Comment: 21 pages, 8 figures, submitted to Physical Review
Zero-curvature condition in two dimensions. Relativistic particle models and finite \W-transformations
A relation between an gauge particle model and the zero-curvature
condition in a two-dimensional gauge theory is presented. For the case
we construct finite \W-transformations.Comment: 14 pages, UTTG-04-9
Particle Mechanics Models with W-symmetries
We introduce a particle mechanics model with Sp() gauge invariance.
Different partial gauge-fixings by means of sl(2) embeddings on the gauge
algebra lead to reduced models which are invariant under diffeomorphisms and
classical non-linear \W-transformations as the residual gauge symmetries thus
providing a set of models of gauge and matter fields coupled in a \W-invariant
way. The equations of motion for the matter variables give Lax operators in a
matrix form. We examine several examples in detail and discuss the issue of
integration of infinitesimal \W-transformations.Comment: 34 pages, LaTeX, no figures. Several changes (including Title) and
new material added. Version to appear in Ann. Phy
On the nature of the K*2(1430), K*3(1780), K*4(2045), K*5(2380) and K*6 as K*--multi-rho states
We show that the , , ,
and a not yet discovered resonance are basically molecules made of an
increasing number of and one mesons. The idea relies on
the fact that the vector-vector interaction in s-wave with spins aligned is
very strong both for and . We extend a recent work, where
several resonances showed up as multi- molecules, to the strange
sector including the into the system. The resonant structures show
up in the multi-body scattering amplitudes, which are evaluated in terms of the
unitary two-body vector-vector scattering amplitudes by using the fixed center
approximation to the Faddeev equations
Chiral Dynamics of scalar mesons: radiative decay and in the medium through nuclear photoproduction
In order to assess the relevance of chiral dynamics in the scalar sector we
address two recent problems: radiative decay of the , for which there are
quite recent data from Frascati, and the modification of the
properties in the nuclear medium seen through the photoproduction
in nuclei.Comment: Talk given at the High Energy Physics Workshop "Scalar Mesons: an
Interesting Puzzle for QCD", Utica, New York, May 200
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