title:
Dynamic study on fusion reactions for $^{40,48}$Ca+$^{90,96}$Zr around
  Coulomb barrier

abstract:
  By using the updated improved Quantum Molecular Dynamics model in which a
surface-symmetry potential term has been introduced for the first time, the
excitation functions for fusion reactions of $^{40,48}$Ca+$^{90,96}$Zr at
energies around the Coulomb barrier have been studied. The experimental data of
the fusion cross sections for $^{40}$Ca+$^{90,96}$Zr have been reproduced
remarkably well without introducing any new parameters. The fusion cross
sections for the neutron-rich fusion reactions of $^{48}$Ca+$^{90,96}$Zr around
the Coulomb barrier are predicted to be enhanced compared with a
non-neutron-rich fusion reaction. In order to clarify the mechanism of the
enhancement of the fusion cross sections for neutron-rich nuclear fusions, we
pay a great attention to study the dynamic lowering of the Coulomb barrier
during a neck formation. The isospin effect on the barrier lowering is
investigated. It is interesting that the effect of the projectile and target
nuclear structure on fusion dynamics can be revealed to a certain extent in our
approach. The time evolution of the N/Z ratio at the neck region has been
firstly illustrated. A large enhancement of the N/Z ratio at neck region for
neutron-rich nuclear fusion reactions is found.


title:
$^3P_2$-$^3F_2$ Pairing in Dense Neutron Matter: The Spectrum of
  Solutions

abstract:
  The $^3P_2$-$^3F_2$ pairing model is generally considered to provide an
adequate description of the superfluid states of neutron matter at densities
some 2-3 times that of saturated symmetrical nuclear matter. The problem of
solving the system of BCS gap equations expressing the $^3P_2$-$^3F_2$ model is
attacked with the aid of the separation approach. This method, developed
originally for quantitative study of S-wave pairing in the presence of strong
short-range repulsions, serves effectively to reduce the coupled, singular,
nonlinear BCS integral equations to a set of coupled algebraic equations. For
the first time, sufficient precision becomes accessible to resolve small energy
splittings between the different pairing states. Adopting a perturbative
strategy, we are able to identify and characterize the full repertoire of real
solutions of the $^3P_2$-$^3F_2$ pairing model, in the limiting regime of small
tensor-coupling strength. The P-F channel coupling is seen to lift the striking
parametric degeneracies revealed by a earlier separation treatment of the pure,
uncoupled $^3P_2$ pairing problem. Remarkably, incisive and robust results are
obtained solely on the basis of analytic arguments. Unlike the traditional
Ginzburg-Landau approach, the analysis is not restricted to the immediate
vicinity of the critical temperature, but is equally reliable at zero
temperature. Interesting connections and contrasts are drawn between triplet
pairing in dense neutron matter and triplet pairing in liquid $^3$He.


title: Intruder bands and configuration mixing in the lead isotopes

abstract:
  A three-configuration mixing calculation is performed in the context of the
interacting boson model with the aim to describe recently observed collective
bands built on low-lying $0^+$ states in neutron-deficient lead isotopes. The
configurations that are included correspond to the regular, spherical states as
well as two-particle two-hole and four-particle four-hole excitations across
the Z=82 shell gap.


title: Reaction Mechanisms with Exotic Nuclei

abstract:
  This talk examines a number of reaction mechanisms for scattering initiated
by an exotic projectile. Comparisons are made with recent experimental data, in
order to extract information on the peculiarity of the nuclear structure under
extreme conditions and to test the accuracy of the available theoretical
methods. Predictions for future experiments are also made.


title:
Theoretical developments for low energy experiments with radioactive
  beams

abstract:
  In this talk I discuss two types of experiments with exotic nuclei which
could be performed at the forthcoming Italian INFN facilities with radioactive
beams. First I will discuss nuclear and Coulomb breakup experiments which
involve heavy exotic beams and intermediate incident energies, thus being
suited for the LNL-SPES proposed facility. Then I will discuss transfer to the
continuum reactions aiming at performing spectroscopy in the continuum of light
unbound nuclei like $^{10}$Li. Such reactions are best matched if the incident
beam energy is very low, as it will be at the LNS-EXCYT facility.


title: Microscopic calculations in asymmetric nuclear matter

abstract:
  A microscopic calculation of the equation of state for asymmetric nuclear
matter is presented. We employ realistic nucleon-nucleon forces and operate
within the Dirac-Brueckner-Hartree-Fock approach to nuclear matter. The focal
point of this paper is a (momentum-space) G-matrix which properly accounts for
the asymmetry between protons and neutrons. This will merge naturally into the
development of an effective interaction suitable for applications to asymmetric
nuclei, which will be the object of extensive study in the future.


title: Dynamics of Phase Transitions in Asymmetric Nuclear Matter

abstract:
  We present several possibilities offered by the reaction dynamics of
dissipative heavy ion collisions to study in detail the symmetry term of the
nuclear equation of state, $EOS$. In particular we discuss isospin effects on
the nuclear liquid-gas phase transition, {\it Isospin Distillation}, and on
collective flows. We stress the importance of a microscopic relativistic
structure of the effective interaction in the isovector channel. The
possibility of an {\it early} transition to deconfined matter in high isospin
density regions is also suggested. We finally select {\it Eleven} observables,
in different beam energy regions, that appear rather sensitive to the isovector
part of the nuclear $EOS$, in particular in more exclusive experiments.


title:
Induced pseudoscalar form factor of the nucleon at two-loop order in
  chiral perturbation theory

abstract:
  We calculate the imaginary part of the induced pseudoscalar form factor of
the nucleon $G_P(t)$ in the framework of two-loop heavy baryon chiral
perturbation theory. The effect of the calculated three-pion continuum on the
pseudoscalar constant $g_P = (m_\mu/2M) G_P(t=-0.877m_\mu^2)$ measurable in
ordinary muon capture $\mu^-p\to \nu_\mu n$ turns out to be negligibly small.
Possible contributions from counterterms at two-loop order are numerically
smaller than the uncertainty of the dominant pion-pole term proportional to the
pion-nucleon coupling constant $g_{\pi N}= 13.2\pm 0.2$. We conclude that a
sufficiently accurate representation of the induced pseudoscalar form factor of
the nucleon at low momentum transfers $t$ is given by the sum of the pion-pole
term and the Adler-Dothan-Wolfenstein term: $G_P(t) = 4g_{\pi N} M f_\pi/
(m_\pi^2 -t)- 2g_A M^2 < r_A^2 >/3$, with $<r_A^2> = (0.44 \pm 0.02)$ fm$^2$
the axial mean square radius of the nucleon.


title:
Prediction and formation mechanism of triaxial superdeformed nuclei for
  $A\sim 80$

abstract:
  The three dimensional Total Routhian Surface (TRS) calculations are carried
out for 64 nuclei between $70\leq A\leq 90$ to find triaxial superdeformed
nuclei. Total of 12 nuclei were predicted to have triaxial superdeformation in
which the neutron rotational energy plays a key role and the neutron shell
energy plays additional role in the formation of triaxial superdeformed nuclei.


title: Eta Production in the pp Scattering

abstract:
  Total cross section for pp->pp eta process has been calculated in meson
exchange model. Eta production T-matrices are from our PWA. Initial and final
state interactions are disregarded for the moment, due to large uncertainties.
Preliminary results do not show rho meson exchange dominance.


title: The Pion Form Factor Within the Hidden Local Symmetry Model

abstract:
  We analyze a pion form factor formulation which fulfills the Analyticity
requirement within the Hidden Local Symmetry (HLS) Model. We show that it
implies an $s$--dependent dressing of the $\rho-\gamma$ VMD coupling and an
account of several coupled channels. The corresponding function $F_\pi(s)$
provides nice fits of the pion form factor data from $s=-0.25$ to $s=1$
GeV$^2$. It is shown that the coupling to $K \bar{K}$ has little effects, while
$\omg \pi^0$ improves significantly the fit quality below the $\phi$ mass. All
parameters, except for the subtraction polynomial coefficients are fixed from
the rest of the HLS phenomenology. The fits show consistency with the expected
behaviour of $F_\pi(s)$ at $s=0$ up to ${\cal O} (s^2)$ and with the phase
shift data on $\delta_1^1(s)$ from threshold to somewhat above the $\phi$ mass.
The $\omg$ sector is also examined in relation with recent data from CMD--2.


title:
Short-Range Correlations in Nuclear Matter at Finite Temperatures and
  High Densities

abstract:
  The density and temperature dependence of nucleonic single particle spectral
function in symmetric nuclear matter at finite temperatures and densities
beyond normal nuclear matter density is investigated in a model emphasizing
short-range correlations and phase space aspects. A simple but self-consistent
approach based on quantum transport theory is used. In particular we consider
the density and temperature regime occuring e.g. during the core collapse in a
supernova explosion and the subsequent formation of a neutron star. Mean-field
effects are incorporated by a Skyrme type potential.


title:
Probing the high-density behavior of nuclear symmetry energy with
  high-energy radioactive beams

abstract:
  Central collisions induced by high energy radioactive beams can be used as a
novel means to obtain crucial information about the high density ({\rm HD})
behaviour of nuclear symmetry energy. This information is critical for
understanding several key issues in astrophysics. Within an isospin-dependent
hadronic transport model using phenomenological equations of state ({\rm EOS})
for dense neutron-rich matter, we investigate several experimental probes of
the HD behavior of nuclear symmetry energy, such as, the $\pi^-$ to $\pi^+$
ratio, neutron-proton differential flow and its excitation function.
Measurements of these observables will provide the first terrestrial data to
constrain stringently the HD behaviour of nuclear symmetry energy and thus also
the {\rm EOS} of dense neutron-rich matter.


title: Covariant QCD Modeling of Light Meson Physics

abstract:
  We summarize recent progress in soft QCD modeling based on the set of
Dyson--Schwinger equations truncated to ladder-rainbow level. This covariant
approach to hadron physics accommodates quark confinement and implements the
QCD one-loop renormalization group behavior. We compare the dressed quark
propagator, pseudoscalar and vector meson masses as a function of quark mass,
and the rho -> pi pi coupling to recent lattice-QCD data. The error in the
Gell-Mann--Oakes--Renner relation with increasing quark mass is quantified by
comparison to the exact pseudoscalar mass relation as evaluated within the
ladder-rainbow Dyson-Schwinger model.


title:
Relativity, chiral symmetry, and the nucleon electromagnetic form
  factors

abstract:
  A relativistic interpretation for why the proton's $G_E/G_M$ falls and
$QF_2/F_1$ is approximately constant is presented. Reproducing the observed
$G_E^n$ mandates the inclusion of the effects of the pion cloud. The full
relativistic model with a pion cloud provides a good reproduction of all of the
nucleon electromagnetic form factors.


title:
Back-to-back correlations of high p_T hadrons in relativistic heavy ion
  collisions

abstract:
  We investigate the suppression factor and the azimuthal correlation function
for high $p_T$ hadrons in central Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV
by using a dynamical model in which hydrodynamics is combined with explicitly
traveling jets. We study the effects of parton energy loss in a hot medium,
intrinsic $k_T$ of partons in a nucleus, and $p_{\perp}$ broadening of jets on
the back-to-back correlations of high $p_T$ hadrons. Parton energy loss is
found to be a dominant effect on the reduction of the away-side peaks in the
correlation function.


title:
The $A_y$-Problem in Refined Resonating Group Model calculations for
  ($p-^3{\rm He}$) Scattering

abstract:
  We report on a microscopic Refined Resonating Group Model (RRGM) calculation
of scattering of $p$ off ${}^3{\rm He}$ employing the Argonne-$v_{14}$ and the
Bonn nucleon-nucleon potentials without three-nucleon forces at low energies up
to 30 MeV. The calculated phase-shifts verify the well-known proton analyzing
power $A_y$-problem. We demonstrate that with corrected ${}^3P_2$ phase-shifts
experimental differential cross-section and analyzing power data can be
explained.


title: Homogeneity and Size Effects on the Liquid-Gas Coexistence Curve

abstract:
  The effects of (in)homogeneity and size on the phase diagram of Lennard-Jones
fluids are investigated. It is shown that standard multifragmentation scenarios
(finite equilibrated systems with conserved center of mass position and
momentum) are implying a strong radial inhomogeneity of the system strongly
affecting the phase diagram. The homogeneity constraint is therefore necessary
for finite systems in order to align to the ``meaning'' of infinite systems
phase diagrams. In this respect, a method which deduces the equation of state
of homogeneous finite systems from the one corresponding to bulk matter is
designed. The resultant phase diagrams show a strong dependence on the system's
size.


title: Neutrino Opacities in Neutron Stars with Kaon Condensates

abstract:
  The neutrino mean free paths in hot neutron-star matter are obtained in the
presence of kaon condensates. The kaon-induced neutrino absorption process,
which is allowed only in the presence of kaon condensates, is considered for
both nondegenerate and degenerate neutrinos. The neutrino mean free path due to
this process is compared with that for the neutrino-nucleon scattering. While
the mean free path for the kaon-induced neutrino absorption process is shown to
be shorter than the ordinary two-nucleon absorption process by several orders
of magnitude when temperature is not very high, the neutrino-nucleon scattering
process has still a dominant contribution to the neutrino opacity. Thus, the
kaon-induced neutrino absorption process has a minor effect on the thermal and
dynamical evolution of protoneutron stars.


title: Deformation effects in low-momentum distributions of heavy nuclei

abstract:
  Momentum distributions (MD) of deep hole proton states in $^{238}$U are
studied paying particular attention to the influence of deformation. Two
essentially different mean-field models, Woods-Saxon (WS) and
Skyrme-Hartree-Fock with the SkM$^*$ force, are used. Noticeable deviations
between the WS and SkM$^*$ results are found. They are mainly due to the
difference in effective nucleon mass. In particular, SkM$^*$ gives much weaker
deformation effects at low momenta than WS. It is shown that, in spite of the
deformation mixing, MD at low momenta can serve for identification of
$K^{\pi}=1/2^+$ hole states originating from $s_{1/2}$ spherical sub-shells.
Moreover, following the WS calculations, the deformation results in additional
$K^{\pi}=1/2^+$ states with strong $l=0$ contributions. A possibility to probe
such states in knock-out experiments is discussed.


title:
Reply on the "Comment on "Investigating the phase diagram of finite
  extensive and nonextensive systems" by Al. H. Raduta and Ad. R. Raduta" by A.
  S. Botvina and I. N. Mishustin

abstract:
  This is a reply to the the nucl-th/0203059 manuscript by Botvina and
Mishustin. We show that their pressure versus volume curves (converging to
finite values when the system's density approaches the normal nuclear density)
are not realistic. Some other comments are also included.


title: Kugo-Ojima confinement and QCD Green's functions in covariant gauges

abstract:
  In Landau gauge QCD the Kugo-Ojima confinement criterion and its relation to
the infrared behaviour of the gluon and ghost propagators are reviewed. It is
demonstrated that the realization of this confinement criterion (which is
closely related to the Gribov-Zwanziger horizon condition) results from quite
general properties of the ghost Dyson-Schwinger equation. The numerical
solutions for the gluon and ghost propagators obtained from a truncated set of
Dyson--Schwinger equations provide an explicit example for the anticipated
infrared behaviour. The results are in good agreement, also quantitatively,
with corresponding lattice data obtained recently. The resulting running
coupling approaches a fixed point in the infrared, $\alpha(0) = 8.915/N_c$.
Solutions for the coupled system of Dyson--Schwinger equations for the quark,
gluon and ghost propagators are presented. Dynamical generation of quark masses
and thus spontaneous breaking of chiral symmetry takes place. In the quenched
approximation the quark propagator functions agree well with those of
corresponding lattice calculations. For a small number of light flavours the
quark, gluon and ghost propagators deviate only slightly from the ones in
quenched approximation. While the positivity violation of the gluon spectral
function is manifest in the gluon propagator, there are no clear indications of
analogous positivity violations for quarks so far.


title: Dyson-Schwinger equations: a tool for hadron physics

abstract:
  Dyson-Schwinger equations furnish a Poincare' covariant framework within
which to study hadrons. A particular feature is the existence of a
nonperturbative, symmetry preserving truncation that enables the proof of exact
results. The gap equation reveals that dynamical chiral symmetry breaking is
tied to the long-range behaviour of the strong interaction, which is thereby
constrained by observables, and the pion is precisely understood, and seen to
exist simultaneously as a Goldstone mode and a bound state of strongly dressed
quarks. The systematic error associated with the simplest truncation has been
quantified, and it underpins a one-parameter model efficacious in describing an
extensive body of mesonic phenomena. Incipient applications to baryons have
brought successes and encountered challenges familiar from early studies of
mesons, and promise a covariant field theory upon which to base an
understanding of contemporary large momentum transfer data.


title: Surface Symmetry Energy

abstract:
  Binding energy of symmetric nuclear matter can be accessed straightforwardly
with the textbook mass-formula and a sample of nuclear masses. We show that,
with a minimally modified formula (along the lines of the droplet model), the
symmetry energy of nuclear matter can be accessed nearly as easily. Elementary
considerations for a macroscopic nucleus show that the surface tension needs to
depend on asymmetry. That dependence modifies the surface energy and implies
the emergence of asymmetry skin. In the mass formula, the volume and surface
and (a)symmetry energies combine as energies of two connected capacitors, with
the volume and surface capacitances proportional to the volume and area,
respectively. The net asymmetry partitions itself into volume and surface
contributions in proportion to the capacitances. A combination of data on skin
sizes and masses constrains the volume symmetry parameter to 27 MeV < alpha <
31 MeV and the volume-to-surface symmetry-parameter ratio to 2.0 < alpha/beta <
2.8. In Thomas-Fermi theory, the surface asymmetry-capacitance stems from a
drop of the symmetry energy per nucleon S with density. We establish limits on
the drop at half of normal density, to 0.57 < S(rho_0/2)/S(rho_0) < 0.83. In
considering the feeding of surface by an asymmetry flux from interior, we
obtain a universal condition for the collective asymmetry oscillations, in
terms of the asymmetry-capacitance ratio.


title: Three-Nucleon Photodisintegration of 3He

abstract:
  The three-nucleon photodisintegration of 3He has been calculated in the whole
phase space using consistent Faddeev equations for the three-nucleon bound and
scattering states. Modern nucleon-nucleon and 3N forces have been applied as
well as different approaches to nuclear currents. Phase space regions are
localized where 3N force effects are especially large. In addition
semi-exclusive cross sections for 3He(gamma,N) have been predicted which carry
interesting peak structures. Finally some data for the exclusive 3N breakup
process of 3He and its total breakup cross section have been compared to
theory.


title: An alternative model of jet suppression at RHIC energies

abstract:
  We propose a simple Glauber-type mechanism for suppression of jet production
up to transverse momenta of about 10 GeV/c at RHIC. For processes in this
kinematic region, the formation time is smaller than the interval between two
successive hard partonic collisions and the subsequent collision influences the
jet production. Number of jets then roughly scales with the number of
participants. Proportionality to the number of binary collisions is recovered
for very high transverse momenta. The model predicts suppression of jet
production in d+Au collisions at RHIC.


title: Time-dependent wave-packet approach for fusion reactions of halo nuclei

abstract:
  The fusion reaction of a halo nucleus 11Be on 208Pb is described by a
three-body direct reaction model. A time-dependent wave packet approach is
applied to a three-body reaction problem. The wave packet approach enables us
to obtain scattering solutions without considering the three-body scattering
boundary conditions. The time evolution of the wave packet also helps us to
obtain intuitive understanding of the reaction dynamics. The calculations
indicate a decrease of the fusion probability by the presence of the halo
neutron.


title:
The $(\pi^-,\gamma\gamma)$ reaction in nuclei and the $\sigma$ meson in
  the medium

abstract:
  A theoretical analysis of the $(\pi^-,\gamma\gamma)$ reaction in nuclei is
made in order to find the viability of this reaction to test modifications of
the $\sigma$ meson mass in nuclear matter. The $\pi\pi$ correlation in the
scalar-isoscalar channel in nuclear matter could, in principle, manifest itself
in this reaction since it plays an important role in the
$\pi\pi\to\gamma\gamma$ mechanism. But we conclude that this effect is hardly
visible in this reaction due to the strong background of the
pion-Bremsstrahlung terms. Only with some special cuts and for some
polarization states are the effect visible at the cost of a strong reduction in
the cross section.


title:
Testing a hadronic rescattering model for RHIC collisions using the
  subdivision method

abstract:
  Recently it has been shown that calculations based on a hadronic rescattering
model agree rather well with experimental results from the first RHIC run.
Because of the large particle densities intrinsically present at the early time
steps of Monte Carlo calculations attempting to model RHIC collisions
undesirable artifacts resulting in non-causality may be present. These effects
may compromise the results of such calculations. The subdivision method, which
can remove such artifacts, has been used to test the present rescattering model
calculations. It is shown that no appreciable changes are seen in the present
calculations in using the subdivision method, thus strengthing the confidence
in the results of this rescattering model for RHIC.


title: Order generated by random many-body dynamics

abstract:
  New features related to collective properties generated in the systems driven
by random dynamics are observed and their implications for further
understanding of interplay between coherence and chaos are discussed.


title: The role of E1-E2 interplay in multiphonon Coulomb excitation

abstract:
  In this work we study the problem of a charged particle, bound in a
harmonic-oscillator potential, being excited by the Coulomb field from a fast
charged projectile. Based on a classical solution to the problem and using the
squeezed-state formalism we are able to treat exactly both dipole and
quadrupole Coulomb field components. Addressing various transition amplitudes
and processes of multiphonon excitation we study different aspects resulting
from the interplay between E1 and E2 fields, ranging from classical dynamic
polarization effects to questions of quantum interference. We compare exact
calculations with approximate methods. Results of this work and the formalism
we present can be useful in studies of nuclear reaction physics and in atomic
stopping theory.


title: Effective Field Theory for Nuclear Physics

abstract:
  I review the current status of the application of effective field theory to
nuclear physics, and its present implications for nuclear astrophysics.


title:
Cluster Structures of the Ground and Excited States of 12Be Studied with
  Antisymmetrized Molecular Dynamics

abstract:
  The structures of the ground and excited states of 12Be were studied with
antisymmetrized molecular dynamics. The ground state was found to be a state
with a developed 2-alpha core with two neutrons occupying the intruder orbits.
The energy levels of the newly measured spin-assigned states were described
well, except for the $1^-_1$ state. The calculations indicated that many exotic
cluster structures appear in the low-energy region. The widths concerning alpha
and 6He decays were discussed by using reduced width amplitudes.


title: Isospin and F-spin structure in low-lying levels of 48,50Cr isotopes

abstract:
  The low-energy level structure and electromagnetic transitions of
$^{48,50}$Cr nuclei have been studied by using interacting boson model with
isospin (IBM-3). A sequence of isospin excitation bands with isospin $(T=
T_{z}$, $T_{z}+1$ and $ T_{z}+2) $ has been assigned, and compared with
available data. According to this study, the $2^{+}_{3} $ and $2^{+}_{2} $
states are the lowest mixed symmetry states in $^{48,50}$Cr respectively. In
particular, the present calculations suggest that a combination of isospin and
F-spin excitation can explain the structure in these nuclei. The transition
probabilities between the levels are analyzed in terms of isoscalar and
isovector decomposition which reveal the detailed nature of the energy levels.
The results obtained are found in good agreement with recent experimental data.


title: Geometry of random interactions

abstract:
  It is argued that spectral features of quantal systems with random
interactions can be given a geometric interpretation. This conjecture is
investigated in the context of two simple models: a system of randomly
interacting d bosons and one of randomly interacting fermions in a j=7/2 shell.
In both examples the probability for a given state to become the ground state
is shown to be related to a geometric property of a polygon or polyhedron which
is entirely determined by particle number, shell size, and symmetry character
of the states. Extensions to more general situations are discussed.


title: The Equation of State for Cold and Dense Strongly Interacting Matter

abstract:
  We discuss recent results for the equation of state for cold and dense
strongly interacting matter. We consider the extreme cases of very high
densities, where weak-coupling approaches may in principle give reasonable
results, and very low densities, where we use the framework of heavy-baryon
chiral perturbation theory. We also speculate on the nature of the chiral
transition and present possible astrophysical implications.


title:
Role of the Coulomb and the vector-isovector $\rho$ potentials in the
  isospin asymmetry of nuclear pseudospin

abstract:
  We investigate the role of the Coulomb and the vector-isovector $\rho$
potentials in the asymmetry of the neutron and proton pseudospin splittings in
nuclei. To this end, we solve the Dirac equation for the nucleons using central
vector and scalar potentials with Woods-Saxon shape and $Z$ and $N-Z$ dependent
Coulomb and $\rho$ potentials added to the vector potential. We study the
effect of these potentials on the energy splittings of proton and neutron
pseudospin partners along a Sn isotopic chain. We use an energy decomposition
proposed in a previous work to assess the effect of a pseudospin-orbit
potential on those splittings. We conclude that the effect of the Coulomb
potential is quite small and the $\rho$ potential gives the main contribution
to the observed isospin asymmetry of the pseudospin splittings. This isospin
asymmetry results from a cancellation of the various energy terms and cannot be
attributed only to the pseudospin-orbit term, confirming the dynamical
character of this symmetry pointed out in previous works.


title:
Nuclear structure calculations with a separable approximation for Skyrme
  interactions

abstract:
  A finite rank separable approximation for the quasiparticle RPA calculations
with Skyrme interactions that was proposed in our previous work is extended to
take into account the coupling between one- and two-phonon terms in the wave
functions of excited states. It is shown that characteristics calculated within
the suggested approach are in a good agreement with available experimental
data.


title: Aspects of Dynamical Chiral Symmetry Breaking

abstract:
  Dynamical chiral symmetry breaking is a nonperturbative phenomenon that may
be studied using QCD's gap equation. Model-independent results can be obtained
with a nonperturbative and symmetry preserving truncation. The gap equation
yields the massive dressed-quark propagator, which has a spectral
representation when considered as a function of the current-quark mass. This
enables an explication of the connection between the infrared limit of the QCD
Dirac operator's spectrum and the quark condensate appearing in the operator
product expansion.


title: Geometrical analysis of the algebraic cluster model

abstract:
  Three-body clusters are studied in the algebraic cluster model. Particular
attention is paid to the case of three identical particles. It is shown in a
geometrical analysis that the harmonic oscillator, the deformed oscillator and
the oblate symmetric top are contained as special solutions. An application of
the oblate top limit to the nucleus 12C suggests that the low-lying spectrum
can be described as a configuration of three identical alpha particles at the
vertices of an equilateral triangle.


title:
Exploring isospin, strangeness charm distillation in heavy ion
  collisions

abstract:
  The isospin and strangeness dimensions of the Equation of State are explored.
RIA and the SIS200 accelerator at GSI will allow to explore these regions in
compressed baryonic matter. $^{132}$Sn+$^{132}$Sn and $^{100}$Sn+$^{100}$Sn
collisions as well as the excitation functions of $K/\pi$, $\Lambda/\pi$ and
the centrality dependence of charmonium suppression from the UrQMD and HSD
transport models are presented and compared to data. Unambiguous proof for the
creation of a 'novel phase of matter' from strangeness and charm yields is not
in sight.


title: Multipole Analysis of Recent Pion Electroproduction Data

abstract:
  We have performed a series of global and single-Q2 fits to the growing
database for pion electroproduction. We compare to some other recent fits which
have used different formalisms, more selective datasets, and truncated
multipole expansions. We present results for the E2/M1 and S2/M1 ratios, as a
function of Q2.


title:
Interactions, symmetry breaking, and effective fields from quarks to
  nuclei. (A primer in nuclear theory)

abstract:
  An introduction to nuclear theory is given starting from the quantum
chromodynamics foundations for quark and gluon fields, then discussing
properties of pions and nucleons, interactions between nucleons, structure of
the deuteron and light nuclei, and finishing at the description of heavy
nuclei. It is shown how concepts of different energy and size scales and ideas
related to effective fields and symmetry breaking, enter our description of
nuclear systems.


title: Continuum effects in reactions involving weakly bound nuclei

abstract:
  The relevance of the continuum effects in transfer reactions is discussed in
conection with the determination of observables of astrophysical interest. In
particular, we examine the validity of the Distorted Wave Born Approximation
(DWBA) as a tool to extract the astrophysical \emph{(S_{17}(0))} factor. For
this purpose, we present calculations for the reaction (^{14})N((^{7}
)Be,(^{8})B)(^{13})C comparing the DWBA method with the more sophysticated
CDCC-Born approximation


title:
Disentangling the transfer and breakup contributions from the inclusive
  8Li+ 208Pb reaction

abstract:
  An analysis of the elastic and one-neutron removal channel for the reaction
8Li+208Pb reaction at energies around the Coulomb barrier is presented. For the
elastic scattering, an optical model analysis of the experimental data is
performed. The observed 7Li is interpreted as the superposition of the
one-neutron transfer reaction, 208Pb(8Li,7Li)209Pb, and the breakup reaction.
The separate contribution of each one of these processes has been calculated
within the DWBA formalism. The sum of both contributions explains adequately
the experimental angular distribution of 7Li.


title: Mapping exchange in relativistic Hartree-Fock

abstract:
  We show that formally for the standard ansatz relativistic point-coupling
mean-field (RMF-PC) model a lagrangian density L is not equivalent in Hartree
and Hartree-Fock approximations. The equivalency can be achieved only if we use
a ``complete'' ansatz at the cost of introducing new parameters in the model.
An approximate treatment of the exchange terms from standard RMF-PC indicates
that these effects cannot be easily, if at all, absorbed by a Dirac-Hartree
approximation.


title: Giant-dipole Resonance and the Deformation of Hot, Rotating Nuclei

abstract:
  The development of nuclear shapes under the extreme conditions of high spin
and/or temperature is examined. Scaling properties are used to demonstrate
universal properties of both thermal expectation values of nuclear shapes as
well as the minima of the free energy, which can be used to understand the
Jacobi transition. A universal correlation between the width of the giant
dipole resonance and quadrupole deformation is found, providing a novel probe
to measure the nuclear deformation in hot nuclei.


title: The role of the Dirac sea in the quenching of Gamow-Teller strength

abstract:
  The issue of Gamow-Teller sum rule in atomic nuclei is reexamined in the
framework of a relativistic description of nuclei. It is shown that the total
Gamow-Teller strength in the nucleon sector is reduced by about 12% as compared
to the prediction of a non-relativistic description. This reduction is due to
the antinucleon degrees of freedom.


title:
Relativistic predictions of exclusive $^{208}Pb(\vec{p},2p) ^{207}T\ell$
  analyzing powers at an incident energy of 202 MeV

abstract:
  Within the framework of the relativistic distorted wave impulse approximation
(DWIA), we investigate the sensitivity of the analyzing power - for exclusive
proton knockout from the 3s$_{1/2}$, 2d$_{3/2}$ and 2d$_{5/2}$ states in
$^{208}$Pb, at an incident laboratory kinetic energy of 202 MeV, and for
coincident coplanar scattering angles ($28.0^{\circ}$, $-54.6^{\circ}$) - to
different distorting optical potentials, finite-range (FR) versus zero-range
(ZR) approximations to the DWIA, as well as medium-modified coupling constants
and meson masses. Results are also compared to the nonrelativistic DWIA
predictions based on the Schr\"{o}dinger equation. Whereas the nonrelativistic
model fails severely, both ZR and FR relativistic DWIA models provide an
excellent description of the data. For the FR predictions, it is necessary to
invoke a 20% reduction of sigma-nucleon and omega-nucleon coupling constants as
well as for $\sigma$-, $\rho$- and $\omega$-meson masses, by the nuclear
medium. On the other hand, the ZR predictions suggest that the strong
interaction in the nuclear medium is adequately represented by the free
nucleon-nucleon interaction associated with the impulse approximation. We also
demonstrate that, although the analyzing power is relatively insensitive to the
use different relativistic global optical potential parameter sets, the
prominent oscillatory behavior of this observable is largely attributed to
distortion of the scattering wave functions relative to their plane wave
values.


title:
Effective field theory approach to electroweak transitions of nuclei far
  from stability

abstract:
  In a previous paper, the convergence of the effective field theory approach
of Furnstahl, Serot and Tang to the nuclear many-body problem was studied by
applying it to selected doubly-magic, and neighboring single-particle and
single-hole, nuclei far from stability. The success of that approach,
interpreted through density functional theory, would imply reliable densities.
In this paper, the single-particle (Kohn-Sham) wave functions are probed using
weak transitions near the Fermi surface. The weak currents are the Noether
currents derived from the effective Lagrangian. The general single-particle
transition matrix elements, from which any semi-leptonic weak rate can be
calculated, are obtained in terms of upper and lower components of the Dirac
wave functions. Here beta-decays in nuclei neighboring 132-Sn are studied and
compared with available experimental data. Calibration of the theoretical
results for such decays may also have useful application in element formation.


title: On energy densities reached in heavy-ion collisions at the CERN SPS

abstract:
  We present a few estimates of energy densities reached in heavy-ion
collisions at the CERN SPS. The estimates are based on data and models of
proton-nucleus and nucleus-nucleus interactions. In all of these estimates the
maximum energy density in central Pb+Pb interactions is larger than the
critical energy density of about 0.7 GeV/fm^3 following from lattice gauge
theory computations. In estimates which we consider as realistic the maximum
energy density is about twice the critical value. In this way our analysis
gives some support to claims that deconfined matter has been produced at the
CERN SPS. Any definite statement requires a deeper understanding of formation
times of partons and hadrons in nuclear collisions. We also compare our results
with implicit energy estimates contained in earlier models of anomalous J/psi
suppression in nuclear collisions.


title: Bound Nucleon Form Factors, Quark-Hadron Duality, and Nuclear EMC Effect

abstract:
  We discuss the electromagnetic form factors, axial form factors, and
structure functions of a bound nucleon in the quark-meson coupling (QMC) model.
Free space nucleon form factors are calculated using the improved cloudy bag
model (ICBM). After describing finite nuclei and nuclear matter in the
quark-based QMC model, we compute the in-medium modification of the bound
nucleon form factors in the same framework. Finally, limits on the medium
modification of the bound nucleon $F_2$ structure function are obtained using
the calculated in-medium electromagnetic form factors and local quark-hadron
duality.


title: Recent results in chiral nuclear dynamics

abstract:
  Some recent developments in the description of nuclear forces and few-nucleon
dynamics derived from chiral effective field theory are reviewed.


title:
Renormalization of the 1S0 One-Pion-Exchange NN Interaction in Presence
  of Derivative Contact Interactions

abstract:
  We use standard distorted wave theory techniques and dimensional
regularization to find out solutions of the nucleon-nucleon Lippman--Schwinger
equation with a kernel determined by the Weinberg's next-to-leading potential,
which consists of one--pion exchange and additional contact terms with
derivatives. Though for simplicity, we restrict the discussion to the $^1S_0$
channel and to contact terms containing up to two derivatives, the
generalization to higher waves and/or number of derivatives is straightforward.
The undetermined low energy constants emerging out of the renormalization
procedure are fitted to data.


title: The Hypercentral Constituent Quark Model

abstract:
  The hypercentral constituent quark model contains a spin independent
three-quark interaction inspired by lattice QCD calculations which reproduces
the average energy of SU(6) multiplets. The splittings are obtained with a
residual generalized SU(6)-breaking interaction including an isospin dependent
term. The long standing problem of the Roper is absent and all the 3- and
4-star states are well reproduced. The model has been used in a systematic way
for transverse and longitudinal electromagnetic transition form factor of the
3- and 4- star and also for the missing resonances. The prediction of the
electromagnetic helicity amplitudes agrees quite well with the data except for
low $Q^2$, showing that it can supply a realistic set of quark wave functions.
In particular we report the calculated helicity amplitude $A_{1/2}$ for the
$S11(1535)$, which is in agreement with the TJNAF data.


title: Charmonium photoproduction

abstract:
  The available data on $J/\Psi$ photoproduction are analyzed in terms of
pomeron exchange, two gluon exchange and photon-gluon fusion models. Allowing
the pomeron-quark interaction to be flavour dependent and introducing the soft
and hard pomerons it is possible to reproduce the data at $\sqrt{s}{>}$10 GeV
and small $|t|$. The two gluon exchange calculations indicate strong
sensitivity to the gluon distribution function. The results obtained with the
most modern MRST2001 and DL PDF reproduce the forward $J/\Psi$ photoproduction
cross section at $\sqrt{s}{>}$10 GeV. The calculations with the photon-gluon
fusion model and with MRST2001 and DL PDF are also in reasonable agreement with
the data on the total $J/\Psi$ photoproduction cross section. We allocate the
$J/\Psi$ photoproduction at low energies and large $|t|$ to the mechanism
different from pomeron or two gluon exchanges. We consider that this might be
axial vector trajectory exchange that couples to the axial form factor of the
nucleon.


title: Open charm and charmonium production at relativistic energies

abstract:
  We calculate open charm and charmonium production in $Au+Au$ reactions at
$\sqrt{s}$ = 200 GeV within the hadron-string dynamics (HSD) transport approach
employing open charm cross sections from $pN$ and $\pi N$ reactions that are
fitted to results from PYTHIA and scaled in magnitude to the available
experimental data. Charmonium dissociation with nucleons and formed mesons to
open charm ($D+\bar{D}$ pairs) is included dynamically. The 'comover'
dissociation cross sections are described by a simple phase-space model
including a single free parameter, i.e. an interaction strength $M_0^2$, that
is fitted to the $J/\Psi$ suppression data for $Pb+Pb$ collisions at SPS
energies. As a novel feature we implement the backward channels for charmonium
reproduction by $D \bar{D}$ channels employing detailed balance. From our
dynamical calculations we find that the charmonium recreation is comparable to
the dissociation by 'comoving' mesons. This leads to the final result that the
total $J/\Psi$ suppression at $\sqrt{s}$ = 200 GeV as a function of centrality
is slightly less than the suppression seen at SPS energies by the NA50
Collaboration, where the 'comover' dissociation is substantial and the backward
channels play no role. Furthermore, even in case that all directly produced
$J/\Psi$ mesons dissociate immediately (or are not formed as a mesonic state),
a sizeable amount of charmonia is found asymptotically due to the $D+\bar{D}
\to J/\Psi$ + meson channels in central collisions of $Au+Au$ at $\sqrt{s}$ =
200 GeV which, however, is lower than the $J/\Psi$ yield expected from binary
scaling of $pp$ collisions.


title: Inclusive electron scattering in a relativistic Green function approach

abstract:
  A relativistic Green function approach to the inclusive quasielastic (e,e')
scattering is presented. The single particle Green function is expanded in
terms of the eigenfunctions of the nonhermitian optical potential. This allows
one to treat final state interactions consistently in the inclusive and in the
exclusive reactions. Numerical results for the response functions and the cross
sections for different target nuclei and in a wide range of kinematics are
presented and discussed in comparison with experimental data.


title:
Chiral symmetry restoration in linear sigma models with different
  numbers of quark flavors

abstract:
  Chiral symmetry restoration at nonzero temperature is studied in the
framework of the O(4) linear sigma model and the U(N_f)_r x U(N_f)_l linear
sigma model with N_f=2,3, and 4 quark flavors. We investigate the temperature
dependence of the masses of the scalar and pseudoscalar mesons, and the
non-strange, strange, and charm condensates within the Hartree approximation as
derived from the Cornwall-Jackiw-Tomboulis formalism. We find that the masses
of the non-strange and strange mesons at nonzero temperature depend sensitively
on the particular symmetry of the model and the number of light quark flavors
N_f. On the other hand, due to the large charm quark mass, neither do charmed
mesons significantly affect the properties of the other mesons, nor do their
masses change appreciably in the temperature range around the chiral symmetry
restoration temperature. In the chiral limit, the transition temperatures for
chiral symmetry restoration are surprisingly close to those found in lattice
QCD.


title: Velocity of sound in relativistic heavy-ion collisions

abstract:
  We have studied the rapidity distribution of secondary hadrons produced in
nucleus-nucleus collisions at ultra-relativistic energies within the ambit of
the Landau's hydrodynamical model. A reasonable description of the data can
also be obtained by using the Bjorken's hydrodynamical model if the boost
invariance is restricted to a finite rapidity range. The sensitivity of the
hadronic spectra on the equation of state vis- a -vis the velocity of sound has
been discussed. The correlation between the velocity of sound and the
freeze-out temperature has been indicated. The effects of the non-zero widths
of various mesonic and baryonic degrees of freedom up to the mass value ~ 2.5
GeV is seen to be small.


title:
Hadronization in heavy ion collisions: Recombination and fragmentation
  of partons

abstract:
  We argue that the emission of hadrons with transverse momentum up to about 5
GeV/c in central relativistic heavy ion collisions is dominated by
recombination, rather than fragmentation of partons. This mechanism provides a
natural explanation for the observed constant baryon-to-meson ratio of about
one and the apparent lack of a nuclear suppression of the baryon yield in this
momentum range. Fragmentation becomes dominant at higher transverse momentum,
but the transition point is delayed by the energy loss of fast partons in dense
matter.


title: On the Boson Number Operator in the Deformed Boson Scheme

abstract:
  Concerning the energy of harmonic oscillator, a prescription is proposed for
making the original form unchanged even after q-deformation. Applicability of
the prescription is limited, but, it can be applied to various cases which are
well known.


title: The $g_{V\sigma\gamma}$-coupling constants in hadron electrodynamic

abstract:
  Recent measurements of the branching ratios for the decays
$\omega\to\pi^0\pi^0\gamma$ and $\rho^0\to\pi^0\pi^0\gamma$ lead to coupling
constants of the $V\sigma\gamma$-interaction ($V$ is a vector meson) one order
of magnitude smaller than previously assumed to describe the threshold cross
section of $\gamma+p\to p+\rho^0$ and the HERMES effect. The new
$g^2_{V\sigma\gamma}$ couplings are in contradiction with the predictions of
the QCD sum rules, but are in good agreement with VDM-estimation of the
$\sigma\to \gamma\gamma$-width.


title: Electromagnetic Meissner effect in spin-one color superconductors

abstract:
  It is shown that color-superconducting quark matter, where quarks of the same
flavor form Cooper pairs with spin one, exhibits an electromagnetic Meissner
effect. This is in contrast to spin-zero color superconductors where Cooper
pairs consist of quarks with different flavors.

categories: nucl-th astro-ph cond-mat.supr-con hep-ph


title: Deuteron distribution in nuclei and the Levinger's factor

abstract:
  We compute the distribution of quasideuterons in doubly closed shell nuclei.
The ground states of $^{16}$O and $^{40}$Ca are described in $ls$ coupling
using a realistic hamiltonian including the Argonne $v_{8}^\prime$ and the
Urbana IX models of two-- and three--nucleon potentials, respectively. The
nuclear wave function contains central and tensor correlations, and correlated
basis functions theory is used to evaluate the distribution of neutron-proton
pairs, having the deuteron quantum numbers, as a function of their total
momentum. By computing the number of deuteron--like pairs we are able to
extract the Levinger's factor and compare to both the available experimental
data and the predictions of the local density approximation, based on nuclear
matter estimates. The agreement with the experiments is excellent, whereas the
local density approximation is shown to sizably overestimate the Levinger's
factor in the region of the medium nuclei.


title: Relativistic mean-field study of neutron-rich nuclei

abstract:
  A relativistic mean-field model is used to study the ground-state properties
of neutron-rich nuclei. Nonlinear isoscalar-isovector terms, unconstrained by
present day phenomenology, are added to the model Lagrangian in order to modify
the poorly known density dependence of the symmetry energy. These new terms
soften the symmetry energy and reshape the theoretical neutron drip line
without compromising the agreement with existing ground-state information. A
strong correlation between the neutron radius of 208Pb and the binding energy
of valence orbitals is found: the smaller the neutron radius of 208Pb, the
weaker the binding energy of the last occupied neutron orbital. Thus, models
with the softest symmetry energy are the first ones to drip neutrons. Further,
in anticipation of the upcoming one-percent measurement of the neutron radius
of 208Pb at the Thomas Jefferson Laboratory, a close relationship between the
neutron radius of 208Pb and neutron radii of elements of relevance to atomic
parity-violating experiments is established.


title: Parton coalescence and antiproton/pion anomaly at RHIC

abstract:
  Coalescence of minijet partons with the partons from the quark-gluon plasma
formed in relativistic heavy ion collisions is suggested as the mechanism for
production of hadrons with intermediate transverse momentum. The resulting
enhanced antiproton and pion yields at intermediate transverse momentum gives a
plausible explanation for the observed large antiproton to pion ratio. With
further increasing momentum, the ratio is predicted to decrease and approach
the small value given by independent fragmentations of minijet partons after
their energy loss in the quark-gluon plasma.


title: Dynamics of open quantum systems

abstract:
  The coupling between the states of a system and the continuum into which it
is embedded, induces correlations that are especially large in the short time
scale. These correlations cannot be calculated by using a statistical or
perturbational approach. They are, however, involved in an approach describing
structure and reaction aspects in a unified manner. Such a model is the SMEC
(shell model embedded in the continuum). Some characteristic results obtained
from SMEC as well as some aspects of the correlations induced by the coupling
to the continuum are discussed.


title: The Contribution of the Quark Condensate to the pi N Sigma Term

abstract: This paper has been withdrawn at the request of one of the authors.


title: Constraints on background contributions from K+ Lambda electroproduction

abstract:
  Results for response functions for kaon electroproduction on the proton are
presented. A tree-level hadrodynamical model is adopted and it is shown that
some of the electroproduction response functions are particularly powerful with
the eye on gaining control over the parameterization of the background
diagrams. The existing data set for the p(e,e'K+)Lambda reaction appears to
rule out the use of a g_{K+ Lambda p} coupling constant beyond the boundaries
of softly broken SU(3) flavor symmetry. Also the use of soft hadronic form
factors, which has been proposed as a valid alternative for a hadrodynamical
description of the p(gamma,K+)Lambda data in the resonance region, seems to be
disfavored by the magnitude of the measured p(e,e'K+)Lambda cross sections.


title:
Parity inversion, breakdown of shell closure and particle-vibration
  coupling in Be-isotopes

abstract:
  The coupling of single-particle motion and of vibrations in $^{11}_4$Be
produces dressed neutrons which spend only a fraction of the time in pure
single-particle states, and which weighting differently from the bare neutrons,
lead to parity inversion. The interaction of the two least bound neutrons in
the ground state of $^{12}_4$Be mediated by the $v_{14}$ Argonne
nucleon-nucleon potential and by the exchange of the phonon cloud, give rise to
a strongly correlated state, where the neutrons spend more than half of the
time in (s$^2$+d$^2$)-configurations, resulting in a breaking of the N=8 shell
closure.


title: Nuclear Wave Functions for Spin and Pseudospin Partners

abstract:
  Using relations between wave functions obtained in the framework of the
relativistic mean field theory, we investigate the effects of pseudospin and
spin symmetry breaking on the single nucleon wave functions in spherical
nuclei. In our analysis, we apply both relativistic and non-relativistic
self-consistent models as well as the harmonic oscillator model.


title: The Effect of Shear Viscosity on Spectra, Elliptic Flow, and HBT Radii

abstract:
  I calculate the first correction to the thermal distribution function of an
expanding gas due to shear viscosity. With this modified distribution function
I estimate viscous corrections to spectra, elliptic flow, and HBT radii in
hydrodynamic simulations of heavy ion collisions using the blast wave model.
For reasonable values of the shear viscosity, viscous corrections become of
order one when the transverse momentum of the particle is larger than 1.7 GeV.
This places a bound on the $p_{T}$ range accessible to hydrodynamics for this
observable. Shear corrections to elliptic flow cause $v_{2}(p_{T})$ to veer
below the ideal results for $p_{T} \approx 0.9$ GeV. Shear corrections to the
longitudinal HBT radius $R^{2}_{L}$ are large and negative. The reduction of
$R_{L}^2$ can be traced to the reduction of the longitudinal pressure. Viscous
corrections cause the longitudinal radius to deviate from the
$\frac{1}{\sqrt{m_T}}$ scaling which is observed in the data and which is
predicted by ideal hydrodynamics. The correction to the sideward radius
$R^{2}_{S}$ is small. The correction to the outward radius $R^{2}_{O}$ is also
negative and tends to make $R_{O}/R_{S} \approx 1$.


title:
Annihilation range and final-state interaction in the antiproton-proton
  annihilation into pi-pi+

abstract:
  The large set of accurate data on differential cross section and analyzing
power from the CERN LEAR experiment on $\bar pp \to \pi^+\pi^-$ in the range
from 360 to 1550 MeV/c is well reproduced within a distorted wave approximation
approach. The initial $\bar pp$ scattering wave functions originate from a
recent $\bar N N$ model. The transition operator is obtained from a combination
of the $^3P_0$ and $^3S_1$ quark-antiquark annihilation mechanisms. A good fit
to the data, in particular the reproduction of the double dip structure
observed in the analyzing powers, requires quark wave functions for proton,
antiproton, and pions with radii slightly larger than the respective measured
charge radii. This corresponds to an increase in range of the annihilation
mechanisms and consequently the amplitudes for total angular momentum J=2 and
higher are much larger than in previous approaches. The final state $\pi\pi$
wave functions, parameterized in terms of $\pi\pi$ phase shifts and
inelasticities, are also a very important ingredient for the fine tuning of the
fit to the observables.


title:
Competition of ferromagnetic and antiferromagnetic spin ordering in
  nuclear matter

abstract:
  In the framework of a Fermi liquid theory it is considered the possibility of
ferromagnetic and antiferromagnetic phase transitions in symmetric nuclear
matter with Skyrme effective interaction. The zero temperature dependence of
ferromagnetic and antiferromagnetic spin polarization parameters as functions
of density is found for SkM$^*$, SGII effective forces. It is shown that in the
density domain, where both type of solutions of self--consistent equations
exist, ferromagnetic spin state is more preferable than antiferromagnetic one.


title: Light-front time picture of the Bethe-Salpeter equation

abstract:
  We show the light-front representation of the field theoretical
Bethe-Salpeter equation (BSE) in the ladder approximation using the quasi
potential reduction. We discuss the equivalence of the covariant ladder
Bethe-Salpeter equation with an infinite set of coupled equations for the
Green's functions of the different light-front Fock-states.


title: A model for A=3 antinuclei production in proton-nucleus collisions

abstract:
  A simple coalescence model based on the same diagrammatic approach of
antimatter production in hadronic collisions as used previously for
antideuterons is used here for the hadroproduction of mass 3 antinuclei. It is
shown that the model is able to reproduce the existing experimental data on
Tbar and 3hebar production without any additional parameter.


title: Proton vs. neutron halo breakup

abstract:
  In this paper we show how effective parameters such as effective binding
energies can be defined for a proton in the combined nuclear-Coulomb potential,
including also the target potential, in the case in which the proton is bound
in a nucleus which is partner of a nuclear reaction. Using such effective
parameters the proton behaves similarly to a neutron. In this way some
unexpected results obtained from dynamical calculations for reactions initiated
by very weakly bound proton halo nuclei can be interpreted. Namely the fact
that stripping dominates the nuclear breakup cross section which in turn
dominates over the Coulomb breakup even when the target is heavy at medium to
high incident energies. Our interpretation helps also clarifying why the
existence and characteristics of a proton halo extracted from different types
of data have sometimes appeared contradictory.


title: Initial State Parton Broadening and Energy Loss Probed in d+Au at RHIC

abstract:
  The impact parameter and rapidity dependence of the Cronin effect for
massless pions in $d+Au$ reactions at $\sqrt{s}_{NN}=200$ GeV at RHIC is
computed in the framework of pQCD multiple elastic scattering on a nuclear
target. We introduce a formalism to incorporate initial state energy loss in
perturbative calculations and take into account the elastic energy loss in
addition to the transverse momentum broadening of partons.We argue that the
centrality dependence of the Cronin effect can distinguish between different
hadron production scenarios at RHIC. Its magnitude and rapidity dependence are
shown to carry important experimental information about the properties of cold
nuclear matter up to the moderate- and large-$x$ antishadowing/EMC regions.


title:
Analyses of $dN_{ch}/d\eta$ and $dN_{ch}/dy$ distributions of BRAHMS
  Collaboration by means of the Ornstein-Uhlenbeck process

abstract:
  Interesting data on $dN_{\rm ch}/d\eta$ in Au-Au collisions ($\eta=-\ln \tan
(\theta/2)$) with the centrality cuts have been reported by BRAHMS
Collaboration. Using the total multiplicity $N_{\rm ch} = \int (dN_{\rm
ch}/d\eta)d\eta$, we find that there are scaling phenomena among $(N_{\rm
ch})^{-1}dN_{\rm ch}/d\eta = dn/d\eta$ with different centrality cuts at
$\sqrt{s_{NN}} =$ 130 GeV and 200 GeV, respectively. To explain these scaling
behaviors of $dn/d\eta$, we consider the stochastic approach named the
Ornstein-Uhlenbeck process with two sources. The following Fokker-Planck
equation is adopted for the present analyses, $$ \frac{\partial
P(x,t)}{\partial t} = \gamma [\frac{\partial}{\partial x}x + \frac
12\frac{\sigma^2}{\gamma}\frac{\partial^2}{\partial x^2}] P(x, t) $$ where $x$
means the rapidity (y) or pseudo-rapidity ($\eta$). $t$, $\gamma$ and
$\sigma^2$ are the evolution parameter, the frictional coefficient and the
variance, respectively. Introducing a variable of $z_r = \eta/\eta_{\rm rms}$
($\eta_{\rm rms}=\sqrt{< \eta^2 >}$) we explain the $dn/d z_r$ distributions in
the present approach. Moreover, to explain the rapidity (y) distributions from
$\eta$ distributions at 200 GeV, we have derived the formula as $$
\frac{dn}{dy}=J^{-1}\frac{dn}{d \eta}, $$ where $J^{-1}=\sqrt{M(1+\sinh^2
y)}/\sqrt{1+M\sinh^2 y}$ with $M = 1 + (m/p_{\rm t})^2$. Their data of pion and
all hadrons are fairly well explained by the O-U process. To compare our
approach with another one, a phenomenological formula by Eskola et al. is also
used in calculations of $dn/d\eta$.


title:
Semi-relativistic meson exchange currents in (e,e') and (e,e'p)
  reactions

abstract:
  Electron-induced one-nucleon knock-out observables are computed for moderate
to high momentum transfer making use of semi-relativistic expressions for the
one-body and two-body meson-exchange current matrix elements. Emphasis is
placed on the semi-relativistic form of the $\Delta$-isobar exchange current
and several prescriptions for the dynamical-equivalent form of the
$\Delta$-propagator are analyzed. To this end, the inclusive transverse
response function, evaluated within the context of the semi-relativistic
approach and using different prescriptions for the $\Delta$-propagator, is
compared with the fully relativistic calculation performed within the scheme of
the relativistic Fermi gas model. It is found that the best approximation
corresponds to using the traditional static $\Delta$-propagator. These
semi-relativistic approaches, which contain important aspects of relativity,
are implemented in a distorted wave analysis of quasielastic $(e,e'p)$
reactions. Final state interactions are incorporated through a phenomenological
optical potential model and relativistic kinematics is assumed when calculating
the energy of the ejected nucleon. The results indicate that meson exchange
currents may modify substantially the $TL$ asymmetry for high missing momentum.


title:
The Density Matrix Renormalization Group in Nuclear Physics: A Status
  Report

abstract:
  We report on the current status of recent efforts to develop the Density
Matrix Renormalization Group method for use in large-scale nuclear shell-model
calculations.


title:
Scaling Distributions of Quarks, Mesons and Proton for all $p_T$, Energy
  and Centrality

abstract:
  We present the evidences for the existence of a universal scaling behavior of
the production of $\pi^0$ at all transverse momenta in heavy-ion collisions at
all centralities and all collision energies. The corresponding scaling behavior
of the quarks is then derived just before the quarks recombine with antiquarks
to form the pions. The degradation effect of the dense medium on the quark
$p_T$ is derived from the scaling distribution. In the recombination model it
is then possible to calculate the $p_T$ distributions of the produced proton
and kaon, which are scaling also. Experimentally verifiable predictions are
made. Implications of the existence of the scaling behavior are discussed.


title:
Appendix to: Energy Density Functional Approach to Superfluid Nuclei,
  nucl-th/0210047

abstract:
  This report is not meant to be submitted for publication at the present time
and it is simply a supplement to our work nucl-th/0210047. We have collected
together all our results for one--nucleon and two--nucleon separation energies
for several isotope and isotone chains and compare them to the values extracted
from the 1995 Audi and Wapstra table of recommended masses. Where it was
possible we have compared our results to the results of Fayans et al. and
Goriely et al. We also present results for the charge radii and compare them to
experiment and results of Goriely et al.


title: Quadrupole collectivity of neutron-rich Neon isotopes

abstract:
  The angular momentum projected Generator Coordinate Method, with the
quadrupole moment as collective coordinate and the Gogny force (D1S) as the
effective interaction, is used to describe the properties of the ground state
and low-lying excited states of the even-even Neon isotopes $^{20-34}$Ne, that
is, from the stability valley up to the drip-line. It is found that the ground
state of the N=20 nucleus $^{30}$Ne is deformed but to a lesser extent than the
N=20 isotope of the Magnesium. In the calculations, the isotope $^{32}$Ne is at
the drip-line in good agreement with other theoretical predictions. On the
other hand, rather good agreement with experimental data for many observables
is obtained.


title: Pseudoscalar Mesons in Nuclear Medium

abstract:
  The behavior of pseudoscalar mesons in nuclear medium is reviewed with an
emphasis on the possibility of their Bose-Einstein condensation in dense
matter. In particular pion condensation is reexamined in detail, stimulated by
recent theoretical and observational developments.


title:
Pair Fluctuations in Ultra-small Fermi Systems within Self-Consistent
  RPA at Finite Temperature

abstract:
  A self-consistent version of the Thermal Random Phase Approximation (TSCRPA)
is developed within the Matsubara Green's Function (GF) formalism. The TSCRPA
is applied to the many level pairing model. The normal phase of the system is
considered. The TSCRPA results are compared with the exact ones calculated for
the Grand Canonical Ensemble. Advantages of the TSCRPA over the Thermal Mean
Field Approximation (TMFA) and the standard Thermal Random Phase Approximation
(TRPA) are demonstrated. Results for correlation functions, excitation
energies, single particle level densities, etc., as a function of temperature
are presented.


title: A schematic model for QCD I: Low energy meson states

abstract:
  A simple model for QCD is presented, which is able to reproduce the meson
spectrum at low energy. The model is a Lipkin type model for quarks coupled to
gluons. The basic building blocks are pairs of quark-antiquarks coupled to a
definite flavor and spin. These pairs are coupled to pairs of gluons with spin
zero. The multiplicity problem, which dictates that a given experimental state
can be described in various manners, is removed when a particle-mixing
interaction is turned on. In this first paper of a series we concentrates on
the discussion of meson states at low energy, the so-called zero temperature
limit of the theory. The treatment of baryonic states is indicated, also.


title: A schematic model for QCD II: finite temperature regime

abstract:
  A schematic model for QCD, developed in a previous paper, is applied to
calculate meson properties in the high temperature (up to 0.5 GeV) regime. It
is a Lipkin model for quark-antiquark pairs coupled to gluon pairs of spin
zero. The partition function is constructed with the obtained meson spectrum
and several thermodynamical observables are calculated, like: the energy
density, heat capacity, as well as relative production rates of mesons and
absolute production rates for pions and kaons. The model predictions show a
qualitative agreement with data. Based on these results we advocate the use of
the model as a toy model for QCD.


title: Hydrodynamics Near a Chiral Critical Point

abstract:
  We introduce a model for the real-time evolution of a relativistic fluid of
quarks coupled to non-equilibrium dynamics of the long wavelength (classical)
modes of the chiral condensate. We solve the equations of motion numerically in
3+1 space-time dimensions. Starting the evolution at high temperature in the
symmetric phase, we study dynamical trajectories that either cross the line of
first-order phase transitions or evolve through its critical endpoint. For
those cases, we predict the behavior of the azimuthal momentum asymmetry for
high-energy heavy-ion collisions at nonzero impact parameter.


title: Elliptic flow at large transverse momenta from quark coalescence

abstract:
  We show that hadronization via quark coalescence enhances hadron elliptic
flow at large pT relative to that of partons at the same transverse momentum.
Therefore, compared to earlier results based on covariant parton transport
theory, more moderate initial parton densities dN/d\eta(b=0) ~ 1500-3000 can
explain the differential elliptic flow v_2(pT) data for Au+Au reactions at
s^1/2=130 and 200 AGeV from RHIC. In addition, v2(pT) could saturate at about
50% higher values for baryons than for mesons. If strange quarks have weaker
flow than light quarks, hadron v_2 at high pT decreases with relative
strangeness content.


title:
Spinodal decomposition of expanding nuclear matter and
  multifragmentation

abstract:
  Density fluctuations of expanding nuclear matter are studied within a
mean-field model in which fluctuations are generated by an external stochastic
field. Fluctuations develop about a mean one-body phase-space density
corresponding to a hydrodinamic motion that describes a slow expansion of the
system. A fluctuation-dissipation relation suitable for a uniformly expanding
medium is obtained and used to constrain the strength of the stochastic field.
The distribution of the liquid domains in the spinodal decomposition is
derived. Comparison of the related distribution of the fragment size with
experimental data on the nuclear multifragmentation is quite satisfactory.


title: Dynamics of many-particle fragmentation in a Cellular Automaton model

abstract:
  A 3D Cellular Automaton model developed by the authors to deal with the
dynamics of N-body interactions has been adapted to investigate the head-on
collision of two identical bound clusters of particles, and the ensuing process
of fragmentation. The range of impact energies is chosen low enough, to secure
that a compound bound cluster can be formed. The model is devised to simulate
the laboratory set-up of fragmentation experiments as monitored by 4pi
detectors. The particles interact via a Lennard-Jones potential. At low impact
energies the numerical experiments following the dynamics of the individual
particles indicate a phase of energy sharing among all the particles of the
compound cluster. Fragments of all sizes are then found to evaporate from the
latter cluster. The cluster sizes, measured in our set-up by simulated 4pi
detectors, conform to a power law of exponent around 2.6.


title:
Analysis of previous microscopic calculations for second $0^+$ state in
  $^{12}$C in terms of 3-alpha particle Bose-condensed state

abstract:
  The wave function of the second $0^+$ state of $^{12}$C which was obtained
long time ago by solving the microscopic 3$\alpha$ problem is shown to be
almost completely equivalent to the wave function of the 3$\alpha$ condensed
state which has been proposed recently by the present authors. This equivalence
of the wave functions is shown to hold in two cases where different effective
two-nucleon forces are adopted. This finding gives strong support for
interpreting the second $0^+$ state of $^{12}$C which is the key state for the
synthesis of $^{12}$C in stars ('Hoyle' state), and which is one of the typical
mysterious $0^+$ states in light nuclei, as a gas-like structure of three
$\alpha$ particles, Bose-condensed into an identical s-wave function.


title: On the stability of three-body bound states on the light front

abstract:
  We investigate the stability of the relativistic three-boson system with a
zero range force in the light front form. In particular we study the dependence
of the system on an invariant cut-off. We discuss the conditions for the
relativistic Thomas collapse. Finally, we fix the parameters of the model
introducing a scale.


title: Extra S11 and P13 in the Hypercentral Constituent Quark Model

abstract:
  We report on the recent results of the hypercentral Constituent Quark Model
(hCQM). The model contains a spin independent three-quark interaction which is
inspired by Lattice QCD calculations and reproduces the average energy values
of the SU(6) multiplets. The splittings within each multiplet are obtained with
a SU(6)-breaking interaction, which can include also an isospin dependent term.
All the 3- and 4-stars resonances are well reproduced. Moreover, as all the
Constituent Quark models, the hCQM predicts ``missing'' resonances ({\em e.g.}
extra $S11$ and $P13$ states) which can be of some help for the experimental
identification of new resonances. The model provides also a good description of
the medium $Q^2$-behavior of the electromagnetic transition form factors. In
particular the calculated helicity amplitude $A_{{1/2}}$ for the $S_{11}(1535)$
resonance agrees very well with the recent CLAS data. More recently, the
elastic nucleon form factors have been calculated using a relativistic version
of the hCQM and a relativistic quark current.


title: Modified two-potential approach to tunneling problems

abstract:
  One-body quantum tunneling to continuum is treated via the two-potential
approach, dividing the tunneling potential into external and internal parts. We
show that corrections to this approach can be minimized by taking the
separation radius inside the interval determined by simple expressions. The
resulting two-potential approach reproduces the resonance energy and its width,
both for narrow and wide resonances. We also demonstrate that, without losing
its accuracy, the two-potential approach can be modified to a form resembling
the R-matrix theory, yet without any uncertainties of the latter related to the
choice of the matching radius.


title: Screened alpha decay in dense astrophysical plasmas and magnetars

abstract:
  This paper shows that ultrastrong magnetic fields (such as those of
magnetars) and dense astrophysical plasmas can reduce the half life of alpha
decaying nuclei by many orders of magnitude. In such environments the
conventional Geiger-Nuttall law is modifed so that all half lives are shifted
to dramatically lower values. Those effects, which have never been investigated
before, may have significant implications on the universal abundances of heavy
radioactive elements and the cosmochronological methods that rely on them.


title:
Mean first passage time for nuclear fission and the emission of light
  particles

abstract:
  The concept of a mean first passage time is used to study the time lapse over
which a fissioning system may emit light particles. The influence of the
"transient" and "saddle to scission times" on this emission are critically
examined. It is argued that within the limits of Kramers' picture of fission no
enhancement over that given by his rate formula need to be considered.


title:
Relativistic Quantum Mechanics - Particle Production and Cluster
  Properties

abstract:
  This paper constructs relativistic quantum mechanical models of particles
satisfying cluster properties and the spectral condition which do not conserve
particle number. The treatment of particle production is limited to systems
with a bounded number of bare-particle degrees of freedom. The focus of this
paper is about the realization of cluster properties in these theories.


title: Charm production from photo-nucleon reaction in a hadronic model

abstract:
  We study the total cross section for photo production of open charm hadrons
near threshold using a hadronic Lagrangian. Both two-body final states
involving $\Lambda_c$ and a charmed meson as well as three-body final states
involving nucleon and a charm-anticharm meson pair are included. With
appropriate cut-off parameters in the form factors at interaction vertices, the
model gives a total cross section that is consistent with the measured data at
center-of-mass energy of 6 GeV. The result is compared with the prediction from
the leading-order perturbative QCD.


title: Fusion cross sections at deep subbarrier energies

abstract:
  A recent publication reports that heavy-ion fusion cross sections at extreme
subbarrier energies show a continuous change of their logarithmic slope with
decreasing energy, resulting in a much steeper excitation function compared
with theoretical predictions. We show that the energy dependence of this slope
is partly due to the asymmetric shape of the Coulomb barrier, that is its
deviation from a harmonic shape. We also point out that the large low-energy
slope is consistent with the surprisingly large surface diffusenesses required
to fit recent high-precision fusion data.


title: Recent Advances in Dyson-Schwinger Studies

abstract:
  There have been many demonstrations of the utility of the Dyson-Schwinger
equations of QCD as a systematic, phenomenological framework for describing the
perturbative and non-perturbative dynamics of hadrons in terms of Euclidean
Green functions of quarks and gluons. Still, there remain some unanswered
questions regarding the theoretical underpinnings of the approach. I review
several studies that are shedding light on how these questions might be
resolved and review predictions for some exotic meson states.


title: Baryon-baryon interactions in free space and baryonic medium

abstract:
  We study the interactions of the octet baryons in a relativistic meson
exchange approach connecting free-space and in-medium interactions with those
in finite (hyper)nuclei. A short sketch of the model including the relativistic
T- and G-matrix and the mapping of the G-matrix onto density dependent vertex
functionals in the density dependent relativistic hadron field theory (DDRH) is
given. From new spectroscopic data on medium mass hypernuclei we extract the
single particle spectrum including spin-orbit splitting. An extraction of the
$\Lambda\omega$ vector- and tensor vertex as well as the $\Lambda\sigma$-vertex
shows a strong breaking of SU(3) symmetry.


title: Anapole moment of an exotic nucleus

abstract:
  We demonstrate that there is no appreciable enhancement of the anapole moment
of $^{11}$Be. The effect of small energy intervals is compensated for by a
small overlap of the halo neutron wave function with core.


title:
Evolution of Baryon-Free Matter Produced in Relativistic Heavy-Ion
  Collisions

abstract:
  A 3-fluid hydrodynamic model is introduced for simulating heavy-ion
collisions at incident energies between few and about 200 AGeV. In addition to
the two baryon-rich fluids of 2-fluid models, the new model incorporates a
third, baryon-free (i.e. with zero net baryonic charge) fluid which is created
in the mid-rapidity region. Its evolution is delayed due to a formation time
$\tau$, during which the baryon-free fluid neither thermalizes nor interacts
with the baryon-rich fluids. After formation it thermalizes and starts to
interact with the baryon-rich fluids. It is found that for $\tau$=0 the
interaction strongly affects the baryon-free fluid. However, at reasonable
finite formation time, $\tau$=1 fm/c, the effect of this interaction turns out
to be substantially reduced although still noticeable. Baryonic observables are
only slightly affected by the interaction with the baryon-free fluid.


title: The Glauber model and the heavy ion reaction cross section

abstract:
  We reexamine the Glauber model and calculate the total reaction cross section
as a function of energy in the low and intermediate energy range, where many of
the corrections in the model, are effective.
  The most significant effect in this energy range is by the modification of
the trajectory due to the Coulomb field. The modification in the trajectory due
to nuclear field is also taken into account in a self consistent way.
  The energy ranges in which particular corrections are effective, are
quantified and it is found that when the center of mass energy of the system
becomes 30 times the Coulomb barrier, none of the trajectory modification to
the Glauber model is really required.
  The reaction cross sections for light and heavy systems, right from near
coulomb barrier to intermediate energies have been calculated. The exact
nuclear densities and free nucleon-nucleon (NN) cross sections have been used
in the calculations. The center of mass correction which is important for light
systems, has also been taken into account.
  There is an excellent agreement between the calculations with the modified
Glauber model and the experimental data. This suggests that the heavy ion
reactions in this energy range can be explained by the Glauber model in terms
of free NN cross sections without incorporating any medium modification.


title:
Final state interaction in spin asymmetry and GDH sum rule for
  incoherent pion production on the deuteron

abstract:
  The contribution of incoherent single pion photoproduction to the spin
response of the deuteron, i.e., the asymmetry of the total photoabsorption
cross section with respect to parallel and antiparallel spins of photon and
deuteron, is calculated over the region of the $\Delta$-resonance with
inclusion of final state $NN$- and $\pi N$-rescattering. Sizeable effects,
mainly from $NN$-rescattering, are found leading to an appreciable reduction of
the spin asymmetry. Furthermore, the contribution to the Gerasimov-Drell-Hearn
integral is explicitly evaluated by integration up to a photon energy of 550
MeV. Final state interaction reduces the value of the integral to about half of
the value obtained for the pure impulse approximation.


title:
Study of Proton Magic Even-Even Isotopes and Giant Halos of Ca Isotopes
  with Relativistic Continuum Hartree-Bogoliubov Theory

abstract:
  We study the proton magic O, Ca, Ni, Zr, Sn, and Pb isotope chains from the
proton drip line to the neutron drip line with the relativistic continuum
Hartree-Bogoliubov (RCHB) theory. Particulary, we study in detail the
properties of even-even Ca isotopes due to the appearance of giant halos in
neutron rich Ca nuclei near the neutron drip line. The RCHB theory is able to
reproduce the experimental binding energies $E_b$ and two neutron separation
energies $S_{2n}$ very well. The predicted neutron drip line nuclei are
$^{28}$O, $^{72}$Ca, $^{98}$Ni, $^{136}$Zr, $^{176}$Sn, and $^{266}$Pb,
respectively. Halo and giant halo properties predicted in Ca isotopes with
$A>60$ are investigated in detail from the analysis of two neutron separation
energies, nucleon density distributions, single particle energy levels, the
occupation probabilities of energy levels including continuum states. The
spin-orbit splitting and the diffuseness of nuclear potential in these Ca
isotopes are studied also. Furthermore, we study the neighboring lighter
isotopes in the drip line Ca region and find some possibility of giant halo
nuclei in the Ne-Na-Mg drip line nuclei.


title:
The reaction antirproton-proton into pi+pi-: relativistic aspects and
  final-state interaction in the pion wave functions

abstract:
  We use a distorted wave approximation approach which includes $^3P_0$ and
$^3S_1$ quark-antiquark annihilation mechanisms to reproduce the data set from
LEAR on $\bar p p\to \pi^+\pi^-$ in the range from 360 to 1550 MeV/c.
Improvements of the model are sought by implementing final-state interactions
of the pions and by observing that the annihilation is too short-ranged in
earlier attempts to describe the data. While the former improvement is due to
to the final-state $\pi\pi$ wave functions solely, the latter one originates
from quark wave functions for proton, antiproton, and pions with radii slightly
larger than the respective measured charge radii. This increase in hadron
radius, as compared with typically much smaller radii used before in the quark
model, increases the annihilation range and thereby the amplitudes for $J\ge2$
are much higher. Finally, given the very high kinetic energy of the final
pions, we investigate the role of relativistic corrections in the pion wave
functions when boosted into the center-of-mass frame.


title:
New treatment of breakup continuum in the method of continuum
  discretized coupled channels

abstract:
  A new method of pseudo-state discretization is proposed for the method of
continuum discretized coupled channels (CDCC) to deal with three-body breakup
processes. We propose real- and complex-range Gaussian bases for the
pseudo-state wave functions, and show that they form in good approximation a
complete set in the configuration space which is important for breakup
processes.
  Continuous S-matrix elements are derived with the approximate completeness
from discrete ones calculated by CDCC.
  Accuracy of the method is tested quantitatively for two realistic examples,
d+$^{58}$Ni scattering at 80 MeV and $^{6}$Li+$^{40}$Ca scattering at 156 MeV
with the satisfactory results. Possibility of application of the method to
four-body breakup processes is also discussed.


title: Surface behaviour of the pairing gap in a slab of nuclear matter

abstract:
  The surface behaviour of the pairing gap previously studied for semi-infinite
nuclear matter is analyzed in the slab geometry. The gap-shape function is
calculated in two cases: (a) pairing with the Gogny force in a hard-wall
potential and (b) pairing with the separable Paris interaction in a Saxon-Woods
mean-field potential. It is shown that the surface features are preserved in
the case of slab geometry, being almost independent of the width of the slab.
It is also demonstrated that the surface enhancement is strengthened as the
absolute value of chemical potential $|\mu|$ decreases which simulates the
approach to the nucleon drip line.


title:
Spin effects and relative momentum spectrum of two protons in deuteron
  charge-exchange breakup

abstract:
  The relation between the differential cross section of the charge-exchange
breakup of a fast deuteron d+p -> (pp)+n and the differential cross section of
the charge transfer process n+p -> p+n is discussed taking into account the
effects of the proton identity and of the Coulomb and strong interactions of
protons in the final state. The distribution of the relative momenta of the
protons is found in the framework of the impulse approach. It is shown that the
use of polarized initial deuterons and protons allows one to separate two
spin-dependent terms in the amplitude of the charge transfer reaction n+p ->
p+n at zero angle and to determine their phase difference. The influence of the
deuteron d-wave state is investigated.


title: Effect of gluon-exchange pair-currents on the ratio G(E(P))/G(M(P))

abstract:
  The effect of one-gluon-exchange (OGE) pair-currents on the ratio $\mu_p
G_E^p/G_M^p$ for the proton is investigated within a nonrelativistic
constituent quark model (CQM) starting from $SU(6) \times O(3)$ nucleon wave
functions, but with relativistic corrections. We found that the OGE
pair-currents are important to reproduce well the ratio $\mu_p G_E^p/G_M^p$.
With the assumption that the OGE pair-currents are the driving mechanism for
the violation of the scaling law we give a prediction for the ratio $\mu_n
G_E^n/G_M^n$ of the neutron.


title: Renormalization of the isovector $\pi N$ amplitude in pionic atoms

abstract:
  The extraction of the isovector s-wave pi N amplitude from pionic atoms is
studied with special emphasis on uncertainties and their dependence on the
assumptions made regarding the neutron density distributions in nuclei and on
the size of the data base used . Only `global' analyses of pionic-atom data
reveal a discrepancy between the extracted isovector s-wave pi N amplitude
b_1=-0.108\pm0.007 m_\pi^{-1} and its free pi N counterpart
b_1^{free}=-0.0885^{+0.0010}_{-0.0021} m_\pi ^{-1}, where the uncertainty in
the neutron densities is included in the error analysis. The role of `deeply
bound' pionic atom states is discussed and the reason for failure of these
states to provide new information is explained.


title: Baryons from the lattice: past, present and future

abstract:
  I review recent lattice results on the spectrum and structure of baryons.
Limitations due to the quenched approximation and un-physically heavy up and
down quarks are discussed, and interfaces between first principles studies of
QCD (or approximations to it) and ``model building'' are highlighted.


title:
Off-shell pairing correlations from meson-exchange theory of nuclear
  forces

abstract:
  We develop a model of off-mass-shell pairing correlations in nuclear systems,
which is based on the meson-exchange picture of nuclear interactions. The
temporal retardations in the model are generated by the Fock-exchange diagrams.
The kernel of the complex gap equation for baryons is related to the in-medium
spectral function of mesons, which is evaluated nonperturbatively in the random
phase approximation. The model is applied to the low-density neutron matter in
neutron star crusts by separating the interaction into a long-range
one-pion-exchange component and a short-range component parametrized in terms
of Landau Fermi liquid parameters. The resulting Eliashberg-type coupled
nonlinear integral equations are solved by an iterative procedure.We find that
the self-energies extend to off-shell energies of the order of several tens of
MeV. At low energies the damping of the neutron pair correlations due to the
coupling to the pionic modes is small, but becomes increasingly important as
the energy is increased. We discuss an improved quasiclassical approximation
under which the numerical solutions are obtained.


title: Quantum Monte Carlo Calculations of Neutron Matter

abstract:
  Uniform neutron matter is approximated by a cubic box containing a finite
number of neutrons, with periodic boundary conditions. We report variational
and Green's function Monte Carlo calculations of the ground state of fourteen
neutrons in a periodic box using the Argonne $\vep $ two-nucleon interaction at
densities up to one and half times the nuclear matter density. The effects of
the finite box size are estimated using variational wave functions together
with cluster expansion and chain summation techniques. They are small at
subnuclear densities. We discuss the expansion of the energy of low-density
neutron gas in powers of its Fermi momentum. This expansion is strongly
modified by the large nn scattering length, and does not begin with the
Fermi-gas kinetic energy as assumed in both Skyrme and relativistic mean field
theories. The leading term of neutron gas energy is ~ half the Fermi-gas
kinetic energy. The quantum Monte Carlo results are also used to calibrate the
accuracy of variational calculations employing Fermi hypernetted and single
operator chain summation methods to study nucleon matter over a larger density
range, with more realistic Hamiltonians including three-nucleon interactions.


title:
Electromagnetic interaction in chiral quantum hadrodynamics and decay of
  vector and axial-vector mesons

abstract:
  The chiral invariant QHD-III model of Serot and Walecka is applied in the
calculation of some meson properties. The electromagnetic interaction is
included by extending the symmetry of the model to the local U(1) \times
SU(2)_{R} \times SU(2)_{L} group. The minimal and nonminimal contributions to
the electromagnetic Lagrangian are obtained in a new representation of QHD-III.
Strong decays of the axial-vector meson, a_{1} \to \pi \rho, a_{1} \to \pi
\sigma, and the electromagnetic decays \rho \to \pi \pi \gamma, a_{1} \to \pi
\gamma and \rho \to \pi \gamma are calculated. The low-energy parameters for
the \pi-\pi scattering are calculated in the tree-level approximation. The
effect of the auxiliary Higgs bosons, introduced in QHD-III in order to
generate masses of the vector and axial-vector mesons via the Higgs mechanism,
is studied as well. This is done on the tree level for \pi-\pi scattering and
on the level of one-loop diagrams for the a_{1} \to \pi \gamma decay. It is
demonstrated that the model successfully describes some features of meson
phenomenology in the non-strange sector.


title:
Short versus long range interactions and the size of two-body weakly
  bound objects

abstract:
  Very weakly bound systems may manifest intriguing "universal" properties,
independent of the specific interaction which keeps the system bound. An
interesting example is given by relations between the size of the system and
the separation energy, or scaling laws. So far, scaling laws have been
investigated for short-range and long-range (repulsive) potentials. We report
here on scaling laws for weakly bound two-body systems valid for a larger class
of potentials, i.e. short-range potentials having a repulsive core and
long-range attractive potentials. We emphasize analogies and differences
between the short- and the long-range case. In particular, we show that the
emergence of halos is a threshold phenomenon which can arise when the system is
bound not only by short-range interactions but also by long-range ones, and
this for any value of the orbital angular momentum $\ell$. These results
enlarge the image of halo systems we are accustomed to.


title: Nuclear absorption of Charmoniums in pA and AA collisions

abstract:
  We have analysed the latest NA50 data on $J/\psi$ production in pA and AA
collisions. The $J/\psi$ production is assumed to be a two step process, (i)
formation of $c\bar{c}$ pairs, perturbatively calculable, and (ii) formation of
$J/\psi$ from the pair, a non-perturbative process, which is conviniently
parametrized. In a nuclear medium, as the $c\bar{c}$ pair passes through the
nuclear medium, it gain relative square momentum and some of the pairs can gain
enough square momentum to cross the threshold for open charm meson, leading to
suppression in nuclear medium. Few parameters of the model were fixed from the
latest high statistics NA50 pA and NA38 SU total $J/\psi$ cross sectional data.
The model then reproduces the centrality dependence of $J/\psi$ over Drell-Yan
ration in 200 GeV/c S+U and 158 GeV/c Pb+Pb collisions. We also discuss the
centrality dependence of $J/\psi$ suppression at RHIC energy.


title:
The Importance of Parity-Dependence of the Nuclear Level Density in the
  Prediction of Astrophysical Reaction Rates

abstract:
  A simple description for obtaining the parity distribution of nuclear levels
in the pf + g9/2 shell as a function of excitation energy was recently derived.
We implement this in a global nuclear level density model. In the framework of
the statistical model, cross sections and astrophysical reaction rates are
calculated in the Fe region and compared to rates obtained with the common
assumption of an equal distribution of parities. We find considerable
differences, especially for reactions involving particles in the exit channel.


title:
Reaction Rates and Nuclear Properties Relevant for Nucleosynthesis in
  Massive Stars and Far From Stability

abstract:
  Explosive nuclear burning in astrophysical environments produces unstable
nuclei which again can be targets for subsequent reactions. In addition, it
involves a large number of stable nuclides which are not fully explored by
experiments, yet. Thus, it is necessary to be able to predict reaction cross
sections and thermonuclear rates with the aid of theoretical models. Such
predictions are also of interest for investigations at radioactive ion beam
facilities. An extended library of theoretical cross sections and reaction
rates is presented. The problem of alpha+nucleus potentials is addressed and
new parametrizations presented. The problem of properly predicting cross
sections at low level densities is illustrated by the 62Ni(n,gamma) reaction.


title: Extraction of N* information from the limited p(gamma,K+)Lambda data set

abstract:
  Nucleon resonance information is often obtained from fitting hadrodynamical
model calculations to data, where model parameters such as resonance coupling
constants are the free parameters in the fitting procedure. For reactions with
a limited data set, such as p(gamma, K+)Lambda, complications in the extraction
of reliable N* information occur not only through theoretical uncertainties,
but also due to technical difficulties in the fitting procedure. In this
article we outline a fitting strategy based on a genetic algorithm and
illustrate the kind of ambiguities which can arise.


title: Can Modern Nuclear Hamiltonians Tolerate a Bound Tetraneutron?

abstract:
  I show that it does not seem possible to change modern nuclear Hamiltonians
to bind a tetraneutron without destroying many other successful predictions of
those Hamiltonians. This means that, should a recent experimental claim of a
bound tetraneutron be confirmed, our understanding of nuclear forces will have
to be significantly changed. I also point out some errors in previous
theoretical studies of this problem.


title: Parity-Violating Electron Scattering: How Strange a Future

abstract:
  I discuss several physics issues that can be addressed through the present
and future program of parity-violating electron scattering measurements. In
particular, I focus on strange quark form factors, hadronic effects in
electroweak radiative corrections, and physics beyond the Standard Model.


title:
Low-energy scattering and photoproduction of $\eta$-mesons on three-body
  nuclei

abstract:
  The optical potential approach for low-energy scattering of $\eta$-mesons on
three-body nuclei is compared to an exact treatment of the $\eta 3N$ system
using four-body scattering theory with separable interactions in s-waves only.
The higher-order terms including the interaction of the struck nucleon with the
surrounding nuclear medium and virtual target excitations in between successive
$\eta$-scatterings are found to cause important corrections. Effects of final
state interaction in $\eta$-photoproduction on $^3$H and $^3$He are also
studied and sizable contributions beyond the optical model approach are found.


title: Nuclear Moments and Electron Density Functionals in Atoms

abstract:
  An electron density functional approach for the calculation of the nuclear
multipole moments is presented. The electronic matrix elements entering the
experimentally observed hyperfine electron-nucleus interaction constants in
atoms are expressed in terms of the electron density functionals of the charge
or spin distributions. In principle, the construction of the charge or spin
distribution density functionals can be obtained by means of every relativistic
or non-relativistic quantum-mechanical or DFT method. The electronic matrix
elements for all the electronic operators of the existing Hamiltonians of
hyperfine electron-nuclear interactions are considered.