title: Chemical equilibration of quarks and gluons at RHIC and LHC energies

abstract:
  We study chemical equilibration of quarks and gluons in central nuclear
collisions at RHIC and LHC energies. The initial quark and gluon densities are
taken from earlier studies as well as from recent perturbative QCD estimates
and are then evolved via rate equations coupled to longitudinally
boost-invariant fluid dynamics. We find that, for RHIC initial conditions, the
lifetime of quark-gluon matter is too short in order for the quark and gluon
number densities to chemically equilibrate prior to hadronization. In contrast,
at LHC energies chemical equilibration is complete before the system
hadronizes. Entropy production due to chemical equilibration can be as large as
30%.


title: Describing Nuclear Matter with Effective Field Theories

abstract:
  An accurate description of nuclear matter starting from free-space nuclear
forces has been an elusive goal. The complexity of the system makes
approximations inevitable, so the challenge is to find a consistent truncation
scheme with controlled errors. The virtues of an effective field theory
approach to this problem are discussed.


title:
Effects of $\beta_{6}$ deformation and low-lying vibrational bands on
  heavy-ion fusion reactions at sub-barrier energies

abstract:
  We study fusion reactions of $^{16}$O with $^{154}$Sm, $^{186}$W and
$^{238}$U at sub-barrier energies by a coupled-channels framework. We focus
especially on the effects of $\beta_{6}$ deformation and low-lying vibrational
excitations of the target nucleus. It is shown that the inclusion of
$\beta_{6}$ deformation leads to a considerable improvement of the fit to the
experimental data for all of these reactions. For the $^{154}$Sm and $^{238}$U
targets, the octupole vibration significantly affects the fusion barrier
distribution. The effect of $\beta$ band is negligible in all the three
reactions, while the $\gamma$ band causes a non-negligible effect on the
barrier distribution at energies above the main fusion barrier. We compare the
optimum values of the deformation parameters obtained by fitting the fusion
data with those obtained from inelastic scatterings and the ground state mass
calculations. We show that the channel coupling of high multipolarity beyond
the quadrupole coupling is dominated by the nuclear coupling and hence higher
order Coulomb coupling does not much influence the optimum values of $\beta_4$
and $\beta_6$ parameters. We also discuss the effect of two neutron transfer
reactions on the fusion of $^{16}$O with $^{238}$U.


title: Crossed-boson exchange contribution and Bethe-Salpeter equation

abstract:
  The contribution to the binding energy of a two-body system due to the
crossed two-boson exchange contribution is calculated, using the Bethe-Salpeter
equation. This is done for distinguishable, scalar particles interacting via
the exchange of scalar massive bosons. The sensitivity of the results to the
off-shell behavior of the operator accounting for this contribution is
discussed. Large corrections to the Bethe-Salpeter results in the ladder
approximation are found. For neutral scalar bosons, the mass obtained for the
two-body system is close to what has been calculated with various forms of the
instantaneous approximation, including the standard non-relativistic approach.
The specific character of this result is demonstrated by a calculation
involving charged bosons, which evidences a quite different pattern. Our
results explain for some part those obtained by Nieuwenhuis and Tjon on a
different basis. Some discrepancy appears with increasing coupling constants,
suggesting the existence of sizeable contributions involving more than
two-boson exchanges.


title:
Transport equations of a consistent description of the kinetics and
  hydrodynamics of dense quantum systems. I: General approach within the frame
  of nonequilibrium thermo field dynamics

abstract:
  We present basic equations of nonequilibrium thermo field dynamics of dense
quantum systems. A formulation of nonequilibrium thermo field dynamics has been
performed using the nonequilibrium statistical operator method by D.N.Zubarev.
Generalized transfer and hydrodynamic equations of a consistent description of
kinetics and hydrodynamics have been obtained in thermo field representation.
To demonstrate how obtained results do work at the description of kinetics and
hydrodynamics of a dense nuclear matter we consider quantum system with
strongly coupled states.


title:
Vanishing Gamow-Teller Transition Rate for A=14 and the Nucleon-Nucleon
  Interaction in the Medium

abstract:
  The problem of the near vanishing of the Gamow-Teller transition ($GT$) in
the A=14 system between the lowest $J=0^+~ T=1$ and $J=1^+~ T=0$ states is
revisited. The model space is extended from the valence space $(p^{-2})$ to the
valence space plus all 2$\hbar \omega$ excitations. The question is addressed
as to what features of the effective nucleon-nucleon interaction in the medium
are required to obtain the vanishing $GT$ strength in this extended space. It
turns out that a combination of a realistic strength of the tensor force
combined with a spin-orbit interaction which is enhanced as compared to the
free interaction yields a vanishing $GT$ strength. Such an interaction can be
derived from a microscopic meson exchange potential if the enhancement of the
small component of the Dirac spinors for the nucleons is taken into account.


title: Antiflow of Nucleons at the Softest Point of the EoS

abstract:
  We investigate flow in semi-peripheral nuclear collisions at AGS and SPS
energies within macroscopic as well as microscopic transport models. The hot
and dense zone assumes the shape of an ellipsoid which is tilted by an angle
Theta with respect to the beam axis. If matter is close to the softest point of
the equation of state, this ellipsoid expands predominantly orthogonal to the
direction given by Theta. This antiflow component is responsible for the
previously predicted reduction of the directed transverse momentum around the
softest point of the equation of state.


title:
Dependence of the Shell-Model Single-Particle Energies on Different
  Components of the Nucleon-Nucleon Interaction

abstract:
  The spin-orbit splittings in the spectra of nuclei with mass numbers 5, 15
and 17 are studied within the framework of shell-model configuration mixing
calculations including 2$\hbar \omega$ excitations. The contributions of the
two-body spin-orbit and tensor components of the nucleon-nucleon interaction
are studied in various model spaces. It is found that the effects of the
two-body spin-orbit interaction are dominant and quite sensitive to the size of
the model-space considered. The effects of the tensor interaction are weaker.
The correlations effects which are included in the larger (0+2) $\hbar \omega$
shell-model space reduce the spin-orbit splitting in the case of A=5 by 20%,
and enhance it for A=15 by about the same 20%. However, it is found that the
correlations have a very small effect on the $d_{3/2} - d_{5/2}$ splitting in
A=17.


title:
Role of break-up processes in fusion enhancement of drip-line nuclei at
  energies below the Coulomb barrier

abstract:
  We carry out realistic coupled-channels calculations for
  $^{11}$Be + $^{208}$Pb reaction in order to discuss the effects of break-up
of the projectile nucleus on sub-barrier fusion.
  We discretize in energy the particle continuum states, which are associated
with the break-up process, and construct the coupling form factors to these
states on a microscopic basis.
  The incoming boundary condition is employed in solving coupled-channels
equations, which enables us to define the flux for complete fusion inside the
Coulomb barrier. It is shown that complete fusion cross sections are
significantly enhanced due to the couplings to the continuum states compared
with the no coupling case at energies below the Coulomb barrier, while they are
hindered at above barrier energies.


title: Looking For Disoriented Chiral Condensates From Pion Distributions

abstract:
  We suggest two methods for the detection of the formation of disoriented
chiral condensates in heavy ion collisions. We show that the variance in the
number of charged pions (in a suitable range of momentum space) provides a
signature for the observation of a disoriented chiral condensate. The signal
should be observable even if multiple domains of D$\chi$C form provided the
average number of pions per domain is significantly larger than unity. The
variance of the number charged pions alone provides a signal which can be used
even if the number of neutral pions cannot be measured in a given detector. On
the other hand, the probability distribution in $R$, the proportion of neutral
pions to all pions emitted in heavy ion collisions in certain kinematic
regions, has been suggested as a signal of a disoriented chiral condensate.
Here we note that the signature can be greatly enhanced by making suitable cuts
in the data. In particular, we consider reducing the data set such that the $k$
pions with lowest $p_T$ are all neutral. We find that, given such cuts, $<R>$
can be substantially different from 1/3. For example, for a single D$\chi$C
domain without contamination due to incoherently emitted pions, $<R>$ is 3/5
given the pion with lowest $p_T$ is neutral, and 5/7 given the two pions with
lowest $p_T$ are both neutral, {\it etc.}. The effects of multi-domain D$\chi$C
formation and noise due to incoherent pion emission can be systematically
incorporated. Potential applications to experiments and their limitations are
briefly discussed.


title: K-Factors in Parton Cascades at RHIC and SPS

abstract:
  Different treatments for the inclusion of higher-order perturbative QCD
corrections in parton based transport models of relativistic heavy-ion
collisions are studied and their influence on experimental observables is
investigated. At RHIC, particle multiplicities may vary by more than 30%,
depending on the correction scheme. A detailed analysis of the squared relative
momentum transfers to be expected in parton (re)scatterings at RHIC casts doubt
on the applicability of pQCD based transport approaches at the SPS and rules
out the application of higher-order correction schemes based on a rescaling of
the relative squared momentum transfers in the running coupling constant at all
energies.


title: Effective Field Theory For Nuclei, Dense Matter And The Cheshire Cat

abstract:
  In this talk I discuss three related topics based on some of the recent
developments in hadron and nuclear physics: one, effective field theory
approach to two-nucleon systems; two, an explanation of the flavor singlet
axial charge in the proton (i.e., "proton spin problem") in terms of a Cheshire
Cat phenomenon; and three, the quark-hadron duality in hadronic matter at high
density and "qualitons" at high density ("superqualitons"). The principal
common theme in these discussions will be the emergence of the generic feature
of the Cheshire Cat Principle.


title: Initial State Dependence of the Breakup of Weakly Bound Carbon Isotopes

abstract:
  The one-neutron nuclear breakup from the Carbon isotopes $^{19}$C and
$^{17}$C, is calculated as an example of application of the theory of transfer
to the continuum reactions in the formulation which includes spin coupling.
  The effect of the energy sharing between the parallel and transverse neutron
momentum distributions is taken into account thus resulting in a theory which
is more general than sudden eikonal approaches. Both effects are necessary to
understand properly the breakup from not too weakly bound $l_i>1$ orbitals.
Breakup which leaves the core into an excited state below particle threshold is
also considered. The core-target interaction is treated in the smooth cut-off
approximation. By comparing to presently available experimental data we show
how to make some hypothesis on the quantum numbers and occupancy of the neutron
initial state. Possible ambiguities in the interpretation of inclusive cross
sections are discussed.


title: Unifying Nucleon and Quark Dynamics at Finite Baryon Number Density

abstract:
  We present a model of baryonic matter which contains free constituent quarks
in addition to bound constituent quarks in nucleons. In addition to the common
linear sigma-model we include the exchange of vector-mesons. The percentage of
free quarks increases with baryon density but the nucleons resist a restoration
of chiral symmetry.


title:
Continued fraction representation of the Coulomb Green's operator and
  unified description of bound, resonant and scattering states

abstract:
  If a quantum mechanical Hamiltonian has an infinite symmetric tridiagonal
(Jacobi) matrix form in some discrete Hilbert-space basis representation, then
its Green's operator can be constructed in terms of a continued fraction. As an
illustrative example we discuss the Coulomb Green's operator in
Coulomb-Sturmian basis representation. Based on this representation, a quantum
mechanical approximation method for solving Lippmann-Schwinger integral
equations can be established, which is equally applicable for bound-, resonant-
and scattering-state problems with free and Coulombic asymptotics as well. The
performance of this technique is illustrated with a detailed investigation of a
nuclear potential describing the interaction of two $\alpha$ particles.


title: Renormalization Group Flow Equation at Finite Density

abstract:
  For the linear sigma model with quarks we derive renormalization group flow
equations for finite temperature and finite baryon density using the heat
kernel cutoff. At zero temperature we evolve the effective potential to the
Fermi momentum and compare the solutions of the full evolution equation with
those in the mean field approximation. We find a first order phase transition
either from a massive constituent quark phase to a mixed phase, where both
massive and massless quarks are present, or from a metastable constituent quark
phase at low density to a stable massless quark phase at high density. In the
latter solution, the formation of droplets of massless quarks is realized even
at low density.


title: Dynamical Evolution of the Scalar Condensate in Heavy Ion Collisions

abstract:
  We derive the effective coarse-grained field equation for the scalar
condensate of the linear sigma model in a simple and straightforward manner
using linear response theory. The dissipative coefficient is calculated at tree
level on the basis of the physical processes of sigma-meson decay and of
thermal sigma-mesons and pions knocking sigma-mesons out of the condensate. The
field equation is solved for hot matter undergoing either one or three
dimensional expansion and cooling in the aftermath of a high energy nuclear
collision. The results show that the time constant for returning the scalar
condensate to thermal equilibrium is of order 2 fm/c.


title: Color Molecular-Dynamics for High Density Matter

abstract:
  We propose a microscopic simulation for quark many-body system based on
molecular dynamics. Using color confinement and one-gluon exchange potentials
together with the meson exchange potentials between quarks, we construct
nucleons and nuclear/quark matter. Statistical feature and the dynamical change
between confinement and deconfinement phases are studied with this molecular
dynamics simulation.


title:
A variational calculation of particle-antiparticle bound states in the
  scalar Yukawa model

abstract:
  We consider particle-antiparticle bound states in the scalar Yukawa
(Wick-Cutkosky) model. The variational method in the Hamiltonian formalism of
quantum field theory is employed. A reformulation of the model is studied, in
which covariant Green's functions are used to solve for the mediating field in
terms of the particle fields. A simple Fock-state variational ansatz is used to
derive a relativistic equation for the particle-antiparticle states. This
equation contains one-quantum-exchange and virtual-annihilation interactions.
  It is shown that analytic solutions of this equation can be obtained for the
simplified case where only the virtual annihilation interaction is retained.
More generally, numerical and perturbative solutions of the equation are
obtained for the massive and massless-exchange cases. We compare our results
with various Bethe-Salpeter-based calculations.


title:
A next-to-next-to-leading order pp -> pp\pi^0 transition operator in
  chiral perturbation theory

abstract:
  We discuss the results of a systematic calculation of the
next-to-next-to-leading order amplitude for the pp -> pp\pi^0 S-wave production
at the threshold in heavy-baryon chiral perturbation theory. We find six new
diagrams, two of which can be viewed as vertex corrections, of 15 - 20 %, to
the pion-exchange graph, whereas the rest are much larger, one exceeding 900 %.
We discuss the reasons for this enhancement, as well as the steps necessary to
be taken before the final comparison with experiment.


title:
Expected Production of Strange Baryons and Antibaryons in Baryon-Poor
  QGP

abstract:
  In a dynamical model of QGP at RHIC we obtain the temporal evolution of
strange phase space occupancy at conditions expected to occur in 100+100A GeV
nuclear collisions. We show that the sudden QGP break up model developed to
describe the SPS experimental results implies dominance of both baryon and
antibaryon abundances by the strange baryon and antibaryon yields.


title: Nuclear Physics on the Light Front

abstract:
  High energy scattering experiments involving nuclei are typically analyzed in
terms of light front variables. The desire to provide realistic, relativistic
wave functions expressed in terms of these variables led me to try to use light
front dynamics to compute nuclear wave functions. The progress is summarized
here.


title: Secondary Charmonium Production at LHC Energy

abstract:
  We consider the production of charmonium by $D\bar D$ annihilation during the
mixed and hadronic phase of Pb-Pb collision at LHC energy. The calculations for
secondary $J/\psi$ and $\psi^,$ production are performed within a kinetic model
taking into account the space-time evolution of a longitudinally and
transversely expanding medium. It is shown that the yield of secondary $J/\psi$
mesons depends strongly on the $J/\psi$ dissociation cross section with
co-moving hadrons. Within the most likely scenario for the dissociation cross
section it will be negligible. The secondary production of $\psi^,$ mesons,
however, due to their large cross section above the threshold, can
substantially exceed the primary yield.


title:
On the Origin of the Multiplicity Fluctuations in High Energy Heavy Ion
  Collisions

abstract:
  Multiplicity fluctuations in heavy ion collisions obtain comparable
contributions both from initial stage of the collisions, and from final stage
interaction. We calculate the former component, using the ``wounded nucleon''
model and standard assumptions about nuclei and NN cross section. Combining it
with the second one, calculated previously by Stephanov,Rajagopal and Shuryak,
ref.2, we obtain good quantitative description of experimental data (ref.3)
from NA49 collaboration at CERN on central PbPb collisions.


title: Critique of a Pion Exchange Model for Interquark Forces

abstract:
  I describe four serious defects of a widely discussed pion exchange model for
interquark forces: it doesn't solve the "spin-orbit problem" as advertised, it
fails to describe the internal structure of baryon resonances, it leads to
disastrous conclusions when extended to mesons, and it is not reasonably
connected to the physics of heavy-light systems.


title: The relativistic field theory model of the deuteron from low-energy QCD

abstract:
  The relativistic field theory model of the deuteron (RFMD) is reformulated
from the first principles of QCD. The deuteron appears as a neutron-proton
collective excitation, i.e. a Cooper np-pair, induced by a phenomenological
local four-nucleon interaction in the nuclear phase of QCD. The RFMD describes
the deuteron coupled to hadrons through one-nucleon loop exchanges providing a
minimal transfer of nucleon flavours from initial to final nuclear states and
accounting for contributions of nucleon-loop anomalies which are completely
determined by one-nucleon loop diagrams. The dominance of contributions of
nucleon-loop anomalies to effective Lagrangians of low-energy nuclear
interactions is justified in the large N expansion, where N is the number of
quark colours.


title: Statistical Mechanics of semi-classical colored Objects

abstract:
  A microscopic model of deconfined matter based on color interactions between
semi-classical quarks is studied. A hadronization mechanism is imposed to
examine the properties and the disassembly of a thermalized quark plasma and to
investigate the possible existence of a phase transition from quark matter to
hadron matter.


title: Nonequilibrium dynamics of a hadronizing quark-gluon plasma

abstract:
  We investigate the hadronic cooling of a quark droplet within a microscopic
model. The color flux tube approach is used to describe the hadronization of
the quark phase. The model reproduces experimental particle ratios equally well
compared to a static thermal hadronic source. Furthermore, the dynamics of the
decomposition of a quark-gluon plasma is investigated and time dependent
particle ratios are found.


title: Deuteron formation in nuclear matter

abstract:
  We investigate deuteron formation in nuclear matter at finite temperatures
within a systematic quantum statistical approach. We consider formation through
three-body collisions relevant already at rather moderate densities because of
the strong correlations. The three-body in-medium reaction rates driven by the
break-up cross section are calculated using exact three-body equations
(Alt-Grassberger-Sandhas type) that have been suitably modified to consistently
include the energy shift and the Pauli blocking. Important quantities are the
lifetime of deuteron fluctuations and the chemical relaxation time. We find
that the respective times differ substantially while using in-medium or
isolated cross sections. We expect implications for the description of heavy
ion collisions in particular for the formation of light charged particles at
low to intermediate energies.


title:
Implications of the unusual structure in the pp correlation from Pb+Pb
  collisions at 158 AGeV

abstract:
  The recent NA49 measurement of two-proton correlation function shows an
interesting and unexpected structure at large relative momentum. Applying
source imaging techniques to the measurement, we find an unusually steep
drop-off in the two-proton source function. We show that the steep drop-off is
due to the structure in the correlation and the drop-off cannot be explained
using conventional correlation analysis. We suggest possible physics reasons
for the unusual source function.


title: Third flow component as QGP signal

abstract:
  A review of earlier fluid dynamical calculations with QGP show a softening of
the directed flow while with hadronic matter this effect is absent. The effect
shows up in the reaction plane as enhanced emission which is orthogonal to the
directed flow. Thus, it is not shadowed by the deflected projectile and target.
As both of these flow components are in the reaction plane these form an
enhanced 'elliptic flow' pattern. Recent experimental data at 11 AGeV and above
show the same softening, hinting at QGP formation.


title: Low-energy eta-d resonance

abstract:
  Elastic eta-d scattering is considered within the Alt-Grassberger-Sandhas
(AGS) formalism for various eta-N input data. A three-body resonant state is
found close to the eta-d threshold. This resonance is sustained for different
choices of the two-body eta-N scattering length a_{\eta N}. The position of the
resonance moves towards the eta-d threshold when Re a_{\eta N} is increased,
and turns into a quasi-bound state at Re a_{\eta N}=0.733 fm.


title: Vlasov Description Of Dense Quark Matter

abstract:
  We discuss properties of quark matter at finite baryon densities and zero
temperature in a Vlasov approach. We use a screened interquark Richardson's
potential consistent with the indications of Lattice QCD calculations.
  We analyze the choices of the quark masses and the parameters entering the
potential which reproduce the binding energy (B.E.) of infinite nuclear matter.
There is a transition from nuclear to quark matter at densities 5 times above
normal nuclear matter density. The transition could be revealed from the
determination of the position of the shifted meson masses in dense baryonic
matter. A scaling form of the meson masses in dense matter is given.


title: Generalized seniority from random Hamiltonians

abstract:
  We investigate the generic pairing properties of shell-model many-body
Hamiltonians drawn from ensembles of random two-body matrix elements. Many
features of pairing that are commonly attributed to the interaction are in fact
seen in a large part of the ensemble space. Not only do the spectra show
evidence of pairing with favored J=0 ground states and an energy gap, but the
relationship between ground state wave functions of neighboring nuclei show
signatures of pairing as well. Matrix elements of pair creation/annihilation
operators between ground states tend to be strongly enhanced. Furthermore, the
same or similar pair operators connect several ground states along an isotopic
chain. This algebraic structure is reminiscent of the generalized seniority
model. Thus pairing may be encoded to a certain extent in the Fock space
connectivity of the interacting shell model even without specific features of
the interaction required.


title:
Nuclear Physics on the Light Front - a new old way to do an old new
  problem

abstract:
  A brief introduction to light front techniques is presented. This is followed
by a review of recent attempts to perform realistic, relativistic nuclear
physics with those techniques.


title:
Coherent Nuclear Difractive Production of Mini-Jets - Signature of Color
  Transparency

abstract:
  The process $\pi + A$ leading to a pair of mini-jets at high relative
transverse momentum ($k_t \gsim 2$ GeV) while leaving the nucleus in its ground
state was selected as a definitive test of the existence of color transparency
by Frankfurt, Miller and Strikman in 1993. The preliminary results of Fermilab
experiment E791, led by Ashery and Weiss-Babai, show a strong A-dependence,
consistent with the notion of color transparency.


title:
The structure of superheavy elements newly discovered in the reaction of
  $^{86}$Kr with $^{208}$Pb

abstract:
  The structure of superheavy elements newly discovered in the
$^{208}$Pb($^{86}$Kr,n) reaction at Berkeley is systematically studied in the
Relativistic Mean Field (RMF) approach. It is shown that various usually
employed RMF forces, which give fair description of normal stable nuclei, give
quite different predictions for superheavy elements. Among the effective forces
we tested, TM1 is found to be the good candidate to describe superheavy
elements. The binding energies of the $^{293}$118 nucleus and its
$\alpha-$decay daughter nuclei obtained using TM1 agree with those of FRDM
within 2 MeV. Similar conclusion that TM1 is the good interaction is also drawn
from the calculated binding energies for Pb isotopes with the Relativistic
Continuum Hartree Bogoliubov (RCHB) theory. Using the pairing gaps obtained
from RCHB, RMF calculations with pairing and deformation are carried out for
the structure of superheavy elements. The binding energy, shape, single
particle levels, and the Q values of the $\alpha-$decay $Q_{\alpha}$ are
discussed, and it is shown that both pairing correlation and deformation are
essential to properly understand the structure of superheavy elements. A good
agreement is obtained with experimental data on $Q_{\alpha}$. %Especially, the
atomic number %dependence of $Q_{\alpha}$ %seems to match with the experimental
observation


title:
Multi-Phonon $\gamma$-Vibrational Bands and the Triaxial Projected Shell
  Model

abstract:
  We present a fully quantum-mechanical, microscopic, unified treatment of
ground-state band and multi-phonon $\gamma$-vibrational bands using shell model
diagonalization with the triaxial projected shell model. The results agree very
well with data on the g- and $\gamma$-band spectra in $^{156-170}$Er, as well
as with recently measured $4^+$ 2-phonon $\gamma$-bandhead energies in
$^{166}$Er and $^{168}$Er. Multi-phonon $\gamma$-excitation energies are
predicted.


title:
The surface diffuseness and the spin-orbital splitting in relativistic
  continuum Hartree-Bogoliubov theory

abstract:
  The Relativistic Continuum Hartree Bogoliubov theory (RCHB), which is the
extension of the Relativistic Mean Field and the Bogoliubov transformation in
the coordinate representation, has been used to study tin isotopes. The pairing
correlation is taken into account by a density-dependent force of zero range.
RCHB is used to describe the even-even tin isotopes all the way from the proton
drip line to the neutron drip line. The contribution of the continuum which is
important for nuclei near the drip-line has been taken into account. The
theoretical $S_{2n}$ as well as the neutron, proton, and matter $rms$ radii are
presented and compared with the experimental values where they exist. The
change of the potential surface with the neutron number has been investigated.
The diffuseness of the potentials in tin isotopes is analyzed through the
spin-orbital splitting in order to provide new way to understand the halo
phenomena in exotic nuclei. The systematic of the isospin and energy dependence
of these results are extracted and analyzed.


title:
Dibaryons with Strangeness: their Weak Nonleptonic Decay using SU(3)
  Symmetry and how to find them in Relativistic Heavy-Ion Collisions

abstract:
  Weak SU(3) symmetry is successfully applied to the weak hadronic decay
amplitudes of octet hyperons. Weak nonmesonic and mesonic decays of various
dibaryons with strangeness, their dominant decay modes, and lifetimes are
calculated. Production estimates for BNL's Relativistic Heavy-Ion Collider are
presented employing wave function coalescence. Signals for detecting strange
dibaryon states in heavy-ion collisions and revealing information about the
unknown hyperon-hyperon interactions are outlined.


title: Dyson-Schwinger studies of meson masses and decay constants

abstract:
  The masses and decay constants of the light mesons are studied within a
ladder-rainbow truncation of the set of Dyson-Schwinger equations using a model
2-point gluon function. The one phenomenological parameter and two current
quark masses are fitted to reproduce $f_\pi$, $m_\pi$ and $m_K$. Our results
for $f_K$, and for the vector mesons $\rho$, $\phi$, and $K^\star$ are in good
agreement with the experimental values.


title: The quark-photon vertex and meson electromagnetic form factors

abstract:
  The ladder Bethe-Salpeter solution for the dressed photon-quark vertex is
used to study the low-momentum behavior of the pion electromagnetic and the
$\gamma^\star \pi^0 \gamma$ transition form factors. With model parameters
previously fixed by light meson masses and decay constants, the low-momentum
slope of both form factors is in excellent agreement with the data. In
comparison, the often-used Ball-Chiu Ansatz for the vertex is found to be
deficient; less than half of the obtained $r_\pi^2$ is generated by that Ansatz
while the remainder of the charge radius could be attributed to the tail of the
$\rho$ resonance.


title:
Imaginary deuteron optical potential due to elastic and inelastic
  breakup

abstract:
  The contributions to the reaction cross section from the elastic and
inelastic breakup processes, calculated within the post-form distorted wave
Born-approximation theory, are used as constraints to determine the
contributions to the imaginary part of the deuteron optical potentials (IPDOP)
due to the breakup channels. The Coulomb part of this potential due to the
elastic breakup process is seen to account for the long range absorption in the
optical potential. The nuclear parts of the IPDOP due to the elastic and
inelastic breakup modes peak in different regions of the nuclear surface, with
the latter being almost an order of magnitude larger than the former. This
makes the IPDOP due to the breakup channels determined by us stronger than
those calculated earlier ignoring the inelastic breakup mode.


title:
Enhancement of parity violating mixing in halo nuclei and the problem of
  neutron weak parity nonconserving potential constant

abstract:
  We consider the Parity Nonconserving (PNC) mixing in the ground state of
exotic (halo) nuclei caused by the PNC weak interaction between outer neutron
and nucleons within nuclear interior. For the nucleus $^{11}Be$ as an example
of typical nucleus with neutron halo, we use analytical model for the external
neutron wave functions to estimate the scale of the PNC mixing. The amplitude
of the PNC mixing in halo state is found to be an order of magnitude bigger
than that of typical PNC mixing between the ``normal'' nuclear states in nearby
nuclei. The enhanced PNC mixing in halo cloud is proportional to the neutron
weak PNC potential constant $g^W_n$ only.


title: Dynamical Test of Constituent Quark Models with $\pi N$ Reactions

abstract:
  A dynamical approach is developed to predict the $\pi N$ scattering
amplitudes starting with the constituent quark models. The first step is to
apply a variational method to solve the three-quark bound state problem. The
resulting wave functions are used to calculate the $N^* \to \pi N, \eta N,
\pi\Delta$ vertex functions by assuming that the $\pi$ and $\eta$ mesons couple
directly to quarks. These vertex functions and the predicted baryon bare masses
then define a Hamiltonian for $\pi N$ reactions. We apply a unitary
transformation method to derive from the constructed Hamiltonian a
multi-channel and multi-resonance reaction model for predicting the $\pi N$
scattering amplitudes up to $W = 2$ GeV. With the parameters constrained by the
$\Delta(1232$) excitation, we have examined the extent to which the $\pi N$
scattering in $S_{11}$ channel can be described by the constituent quark models
based on the one-gluon-exchange or one-meson-exchange mechanisms. It is found
that the data seem to favor the spin-spin interaction due to one-meson-exchange
and the tensor interaction due to one-gluon-exchange. A phenomenological
quark-quark potential has been constructed to reproduce the $S_{11}$ amplitude.


title:
The Predictive Power of Effective Field Theory in NN Scattering:
  ^3S_1-^3D_1 Mixing at Next-to Next-to Leading Order

abstract:
  The convergence of the Q expansion in the ^3S_1-^3D_1 mixing angle is
investigated through the renormalization condition used to fit the free
paramteter encountered at NNLO. Although the NNLO calculation describes the
data well at momenta much less than 50 MeV, a variation in the renormalization
condition results in 100% expected uncertainties at momenta as low as 100 MeV.
This uncertainty can be traced to the presence of large cancelations between
terms entering at NNLO, which are found to be several times larger than the
terms entering at NLO. This implies a fundamental lack of predictive power at
this order int he Q expansion of \epsilon_1. Given the small empirical size,
this lack of predictive power is easily understood in terms of simple power
counting arguments.


title:
Gravitational coupling to two-particle bound states and momentum
  conservation in deep inelastic scattering

abstract:
  The momentum conservation sum rule for deep inelastic scattering (DIS) from
composite particles is investigated using the general theory of relativity. For
two 1+1 dimensional examples, it shown that covariant theories automatically
satisy the DIS momentum conservation sum rule provided the bound state is
covariantilly normalized. Therefore, in these cases the two DIS sum rules for
baryon conservation and momentum conservation are equivalent.


title: Giant Resonances in Coulomb Excitations of Relativistic Ions

abstract:
  We propose a soluble model to incorporate the nonlinear effects in the
transition probabilities of the multiphonon Giant Dipole Resonances based on
the SU(1,1) algebra. Analytical expressions for the multi-phonon transition
probabilities are derived. For reasonably small magnitude of nonlinearity
$x\simeq 0.1-0.2$ enhancement factor for the Double Giant Resonance excitation
probabilities and the cross sections %in relativistic ion collisions reaches
values $1.3-2$ compatible with experimental data.


title:
Charmonium Suppression - Interplay of Hadronic and Partonic Degrees of
  Freedom

abstract:
  Last year the E866-group of the Fermilab measured the $x_F$ dependence of
$J/\Psi$ and $\Psi'$ suppression in $pA$ collisions. We discuss two of the
effects found in that experiment with regard to color coherence effects: the
different suppression of the $J/\Psi$ and the $\Psi'$ at $x_F<0$ and the
significant suppression of both at large $x_F$. The small $x_F$ regions is
dominated by fully formed charmonium states and thus enables us to discuss the
formation time and the cross section of the different charmonium states. In the
large $x_F$ region the interaction of the charmonium states with nuclear matter
has to be described by partonic degrees of freedom, because in that kinematic
domain the formation time is much larger than the nuclear radii. The
understanding of this region will be crucial for the interpretation of the data
of the future heavy ion colliders RHIC and LHC.


title: The charge radii and the decay rates of the pseudoscalar meson

abstract:
  The charge radii and the decay rates of the pion and kaons are calculated,
using the relativistic equation of motion with a linear potential. Those
physical quantities are quite well explained with the current quark masses in
the case of the pion. It is found that the Van Royen-Weisskopf paradox can be
cleared out only in the linear potential model by considering the color degree
of freedom of the quark in the meson. The physical quantities for the kaon are
not so satisfactory that it should be required to reconsider the
Cabibbo-Kobayashi-Maskawa matrix element in the kaon decay.


title: Improving the Convergence of NN Effective Field Theory

abstract:
  We study a low-energy effective field theory (EFT) describing the NN system
in which all exchanged particles are integrated out. We show that fitting the
residue of the 3S1 amplitude at the deuteron pole, rather than the 3S1
effective range, dramatically improves the convergence of deuteron observables
in this theory. Reproducing the residue ensures that the tail of the deuteron
wave function, which is directly related to NN scattering data via analytic
continuation, is correctly reproduced in the EFT at next-to-leading order. The
role of multi-nucleon-electroweak operators which produce deviations from
effective-range theory can then be explicitly separated from the physics of the
wave function tail. Such an operator contributes to the deuteron quadrupole
moment, mu_Q, at low order, indicating a sensitivity to short-distance physics.
This is consistent with the failure of impulse approximation calculations in NN
potential models to reproduce mu_Q. The convergence of NN phase shifts in the
EFT is unimpaired by the use of this new expansion.


title:
Nucleon-Nucleon Scattering and Effective Field Theory: Including Pions
  Non-perturbatively

abstract:
  Next to leading order effective field theory calculations are performed for $
{}^1S_0$ NN scattering using subtractive renormalization procedure. One pion
exchange and contact interaction potentials are iterated using
Lippman-Schwinger equation. Satisfactory fit to the Nijmegen data is obtained
for the momenta up to 300 MeV in the centre of mass frame. Phase shifts are
also compared with the results of KSW approach where pions are included
perturbatively.


title: Hartree-Fock Approximation for Inverse Many-Body Problems

abstract:
  A new method is presented to reconstruct the potential of a quantum
mechanical many-body system from observational data, combining a nonparametric
Bayesian approach with a Hartree-Fock approximation. A priori information is
implemented as a stochastic process, defined on the space of potentials. The
method is computationally feasible and provides a general framework to treat
inverse problems for quantum mechanical many-body systems.


title:
Sensitivity to the pion-nucleon coupling constant in partial-wave
  analyses of elastic pi-N and NN scattering and pion photoproduction

abstract:
  We summarize results obtained in our studies of the pion-nucleon coupling
constant. Several different techniques have been applied to pi-N and NN elastic
scattering data, and the existing database for single-pion photoproduction. The
most reliable determination comes from pi-N elastic scattering. The sensitivity
in this reaction was found to be greater, by at least a factor of 3, when
compared with analyses of NN elastic scattering or single-pion photoproduction.


title: Quartet n-d Scattering Lengths

abstract:
  Quartet n-d scattering lengths are calculated using second-generation
nucleon-nucleon potential models. These results are compared to the
corresponding quantity recently calculated using chiral perturbation theory.


title: Boundary Conditions for Three-Body Scattering in Configuration Space

abstract:
  The asymptotic behavior of three-body scattering wave functions in
configuration space is studied by considering a model equation that has the
same asymptotic form as the Faddeev equations. Boundary conditions for the wave
function are derived, and their validity is verified by numerical calculations.
It is shown that these boundary conditions for the partial differential
equation can be used to obtain accurate numerical solutions for the wave
function.


title:
High-spin yrast structure of 32S suggested by symmetry-unrestricted,
  cranked Hartree-Fock calculations

abstract:
  High-spin yrast structure of 32S is investigated by means of the cranked
Skyrme-Hartree-Fock method in the three-dimensional Cartesian-mesh
representation without imposing restrictions on spatial symmetries. The result
suggests that 1) a crossover from the superdeformed to the hyperdeformed-like
configurations takes place on the yrast line at angular momentum $I \simeq 24$,
which corresponds to the ``band termination'' point in the cranked
harmonic-oscillator model, and 2) non-axial octupole deformations of the
$Y_{31}$ type play an important role in the yrast states in the range $5\leq I
\leq 13$.


title: Meson - nucleon vertex form factors at finite temperature

abstract:
  In this paper the dependence of meson-nucleon-nucleon vertex form factors is
studied as a function of termperature. The results are obtained starting from a
zero temperature Bonn potential. The temperature dependence of the vertex form
factors and radii is studied in the thermofield dynamics, a real-time operator
formalism of finite temperature field theory. It is anticipated that these
results will have an impact on the study of relativistic heavy-ion collisions
as the critical temperature for the phase transition from hadronic to
quark-gluon system is approached.


title: Three Body Force in Peripheral $N\alpha$ Scattering

abstract:
  The exchange of a single pion does not contribute to $N\alpha$ scattering,
due to the isoscalar nature of the target. Therefore peripheral $N\alpha$
scattering may be used to probe existing models for the two-pion exchange
component of the $NN$ potential. In a recent work we have considered this
possibility using an effective $N\alpha$ interaction based on two-body forces
only. In the present communication we discuss the role played by the two-pion
exchange three-nucleon force, since its range is comparable to the two-pion
exchange potential (TPEP).


title: An Update on NA50 and LUCIFER

abstract:
  Recent analysis of both new (1998) and old (1995,1996) data obtained by the
NA50 Collaboration on J/Psi suppression in Pb+Pb are examined in light of our
already existing calculations with the relativistic heavy ion simulation
LUCIFER. In particular we comment on the unexplained change of transverse
energy scale by NA50 and the apparent disappearance from the data of
discontinuities in the suppression with transverse energy.


title: Delayed Collapse of Protoneutron Stars with Kaon Condensate

abstract:
  Equation of state with kaon condensate is derived for isentropic and
neutrino-trapped matter. Both are important ingredients to study the delayed
collapse of protoneutron stars. Solving the TOV equation, we discuss the static
properties of protoneutron stars and implications for their delayed collapse.


title: Baryons and Nuclei in the Large $N_c$ Limit

abstract:
  The relation between the Skyrme model and the constituent quark model, which
appears in the large $N_c$ limit is described. Examples of similarity in the
predicted phenomenology for baryons are shown. Finally the application to
nuclei is discussed.


title:
Charge-dependence of the $\pi NN$ coupling constant and
  charge-dependence of the NN interaction

abstract:
  The recent determination of the charged $\pi NN$ coupling constant,
$g_{\pi^\pm}$, by the Uppsala Neutron Research Group implies that there may be
considerable charge-splitting of the pion coupling constant. We investigate the
consequences of this for the charge-independence breaking (CIB) of the $^1S_0$
scattering length, $\Delta a_{CIB}$. We find that $\Delta a_{CIB}$ depends
sensitively on the difference between $g_{\pi^\pm}$ and the neutral $\pi NN$
coupling constant, $g_{\pi^0}$. Moreover, if $g^2_{\pi^\pm}$ is only about 3%
larger than $g^2_{\pi^0}$, then the established theoretical explanation of
$\Delta a_{CIB}$ (in terms of pion mass splitting) is completely wiped out.


title:
Light Front Nuclear Physics: Toy Models, Static Sources and Tilted Light
  Front Coordinates

abstract:
  The principles behind the detailed results of a light-front mean field theory
of finite nuclei are elucidated by deriving the nucleon mode equation using a
simple general argument, based on the idea that a static source in equal time
coordinates corresponds to a moving source in light front coordinates. This
idea also allows us to solve several simple toy model examples: scalar field in
a box, 1+1 dimensional bag model, three-dimensional harmonic oscillator and the
Hulth\'en potential. The latter provide simplified versions of momentum
distributions and form factors of relevance to experiments. In particular, the
relativistic correction to the mean square radius of a nucleus is shown to be
very small. Solving these simple examples suggests another more general
approach-- the use of tilted light front coordinates. The simple examples are
made even simpler.


title: Constraints on vector meson photoproduction spin observables

abstract:
  Extraction of spin observables from vector meson photoproduction on a nucleon
target is described. Starting from density matrix elements in the vector
meson's rest frame, we transform to spin observables in the photon-nucleon c.m.
frame.
  Several constraints on the transformed density matrix and on the spin
observables follow from requiring that the angular distribution and the density
matrix be positive definite. A set of constraints that are required in order to
extract meaningful spin observables from forthcoming data are enunciated.


title: Calculating the critical exponents of the chiral phase transition

abstract:
  We calculate the critical exponents of the chiral phase transition at nonzero
temperature using the thermal and chiral susceptibilities. We show that within
a class of confining Dyson-Schwinger equation (DSE) models the transition is
mean field, and that an accurate determination of the critical exponents
requires extremely small values of the current-quark mass, several order of
magnitude smaller than realistic up- and down-quark masses. In general, rainbow
truncation models of QCD exhibit mean field exponents as a result of the gap
equation's fermion substructure.


title: Extraordinary Baryon Fluctuations and the QCD Tricritical Point

abstract:
  The dynamic separation into phases of high and low baryon density in a heavy
ion collision can enhance fluctuations of the net rapidity density of baryons
compared to model expectations. We show how these fluctuations arise and how
they can survive through freezeout.


abstract:
  We present analytic expressions of the Coulomb interaction between a
spherical and a deformed nuclei which are valid for all separation distance. We
demonstrate their significant deviations from commonly used formulae in the
region inside the Coulomb radius, and show that they remove various
shortcomings of the conventional formulae.


title: Chiral model for dense, hot and strange hadronic matter

abstract:
  An extended chiral SU(3) model is applied to the description of dense, hot
and strange hadronic matter. The degrees of freedom are the baryon octet and
decuplet and the spin-0 and spin-1 meson multiplets. The parameters of the
model are fitted to the hadron masses in vacumm, infinite nuclear matter
properties and soft pion theorems. At high densities the appearance of density
isomers cannot be ruled out and extrapolation to finite temperature exhibits a
first order phase transition at $T \approx 150 MeV$. The predicted dropping
baryon masses lead to drastically changed particle ratios compared to ideal gas
calculations.


title:
A Higher-Order Calculation of $np$ Scattering in Cut-Off Effective Field
  Theory

abstract:
  We report a next-to-leading-order (NLO) chiral perturbation theory
calculation of the neutron-proton scattering cross section in the ${}^1S_0$
channel using a cut-off regularization. The inclusion of two-pion exchanges in
the irreducible diagrams -- or potential -- figuring at NLO is found to be
important in enlarging the domain of validity of the effective field theory. We
are able to reproduce the {\it empirical} scattering phase shift up to p=300
MeV -- which is comparable to the cutoff scale involved -- with an agreement
which is superior to results of other effective field theory approaches. We
also discuss the role of the cutoff as a renormalization prescription and the
importance of the explicit pion degree of freedom in scattering process.


title:
Nuclear Transparency and Effective NN Cross Section in Heavy Ion
  Collisions at 14.6 GeV/nucleon

abstract:
  The probability of a projectile nucleon to traverse a target nucleus without
interaction is calculated for central Si-Cu and Si-Pb collisions. Special
attention is given to the impact parameter range which contributes to events
with large transverse energy. A fit to the data from E814 requires an effective
NN cross section of sigma_eff=54.2+-5.0mb (compared to the free space value
sigma_in=30mb) and is interpreted as one related to wounded target nucleons.


title: SU(2,1) Dynamics of Multiple Giant Dipole Resonance Coulomb Excitation

abstract:
  We construct a three-dimensional analytically soluble model of the nonlinear
effects in Coulomb excitation of multiphonon Giant Dipole Resonances (GDR)
based on the SU(2,1) algebra. The full 3-dimensional model predicts further
enhancement of the Double GDR (DGDR) cross sections at high bombarding
energies. Enhancement factors for DGDR measured in thirteen different processes
with various projectiles and targets at different bombarding energies are well
reproduced with the same value of the nonlinearity parameter with the exception
of the anomalous case of $^{136}$Xe which requires a larger value.


title: Dropping Sigma-Meson Mass and In-Medium S-Wave pion-pion Correlations

abstract:
  The influence of a dropping sigma-meson mass on previously calculated
in-medium pion-pion correlations in the J=I=0 (sigma-meson) channel is
investigated. It is found that the invariant-mass distribution around the
vacuum threshold experiences a further strong enhancement with respect to
standard many-body effects. The relevance of this result for the explanation of
recent $A(\pi,2\pi)X$ data is pointed out.


title: eta' meson production in proton-proton collisions

abstract:
  The pp -> pp eta' reaction is investigated within a relativistic
meson-exchange model of hadronic interactions. We explore the role of nucleonic
and mesonic, as well as the N* resonance currents, in producing eta' mesons. In
order to learn more about the production mechanisms, new measurements in the
energy region far from the threshold are required.


title: Photoproduction of mesons in nuclei at GeV energies

abstract:
  In a transport model that combines initial state interactions of the photon
with final state interactions of the produced particles we present a
calculation of inclusive photoproduction of mesons in nuclei in the energy
range from 1 to 7 GeV. We give predictions for the photoproduction cross
sections of pions, etas, kaons, antikaons, and $\pi^+\pi^-$ invariant mass
spectra in ^{12}C and ^{208}Pb. The effects of nuclear shadowing and final
state interaction of the produced particles are discussed in detail.


title: Relativistic Modification of the Gamow Factor

abstract:
  In processes involving Coulomb-type initial- and final-state interactions,
the Gamow factor has been traditionally used to take into account these
additional interactions. The Gamow factor needs to be modified when the
magnitude of the effective coupling constant increases or when the velocity
increases. For the production of a pair of particles under their mutual
Coulomb-type interaction, we obtain the modification of the Gamow factor in
terms of the overlap of the Feynman amplitude with the relativistic wave
function of the two particles. As a first example, we study the modification of
the Gamow factor for the production of two bosons. The modification is
substantial when the coupling constant is large.


title:
Neutron-proton radiative capture, photo-magnetic and anti-neutrino
  disintegration of the deuteron in the relativistic field theory model of the
  deuteron

abstract:
  The cross sections for the M1-capture n + p -> D + gamma, the photo-magnetic
and anti-neutrino disintegration of the deuteron are evaluated in the
relativistic field theory model of the deuteron (RFMD). The cross section for
M1-capture is evaluated by taking into account the contributions of chiral
one-meson loop corrections and the Delta(1232) resonance. The cross sections
for the photo-magnetic and anti-neutrino disintegration of the deuteron are
evaluated by accounting for final-state interaction of the nucleon pair in the
spinsinglet S-wave state. The amplitudes of low-energy elastic np and nn
scattering contributing to these processes are obtained in terms of the S-wave
scattering lengths and the effective ranges. This relaxes substantially the
statement by Bahcall and Kamionkowski (Nucl. Phys. A625 (1997) 893) that the
RFMD is unable to describe a non-zero effective range for low-energy elastic
nucleon-nucleon scattering. The cross sections for the anti-neutrino
disintegration of the deuteron averaged over the anti-neutrino energy spectrum
agree good with experimental data.


title: Low-lying continuum structures in B8 and Li8 in a microscopic model

abstract:
  We search for low-lying resonances in the B8 and Li8 nuclei using a
microscopic cluster model and a variational scattering method, which is
analytically continued to complex energies. After fine-tuning the
nucleon-nucleon interaction to get the known 1+ state of B8 at the right
energy, we reproduce the known spectra of the studied nuclei. In addition, our
model predicts a 1+ state at 1.3 MeV in B8, relative to the Be7+p threshold,
whose corresponding pair is situated right at the Li7+n threshold in Li8.
Lacking any experimental evidence for the existence of such states, it is
presently uncertain whether these structures really exist or they are spurious
resonances in our model. We demonstrate that the predicted state in B8, if it
exists, would have important consequences for the understanding of the
astrophysically important Be7(p,gamma)B8 reaction.


title:
Role of spectroscopic factors in the potential-model description of the
  Be7(p,gamma)B8 reaction

abstract:
  In standard potential-model descriptions of the Be7(p,gamma)B8 reaction the
Be7+p spectroscopic factors S appear in the cross section. We argue that the
microscopic substructure effects which are represented by S are short-ranged
and cannot affect the asymptotic normalization of the wave function. We believe
that the standard way of describing reactions in a potential model may be
incorrect and the low-energy cross section should not depend on S in the case
of external capture reactions, like Be7(p,gamma)B8


title: Skyrme mean-field studies of nuclei far from the stability line

abstract:
  Two applications of mean-field calculations based on 3D coordinate-space
techniques are presented. The first concerns the structure of odd-N superheavy
elements that have been recently observed experimentally and shows the ability
of the method to describe, in a self-consistent way, very heavy odd-mass
nuclei. Our results are consistent with the experimental data. The second
application concerns the introduction of correlations beyond a mean-field
approach by means of projection techniques and configuration mixing. Results
for Mg isotopes demonstrate that the restoration of rotational symmetry plays a
crucial role in the description of 32Mg.


title: Charge conjugation invariance of the Spectator Equations

abstract:
  In response to recent critcism, we show how to define the spectator equations
for negative energies so that charge conjugation invariance is preserved. The
result, which emerges naturally from the application of spectator principles to
systems of particles with negative energies, is to replace all factors of the
external energies $W_i$ by $\sqrt{W^2_i}$, insuring that the amplitudes are
independent of the sign of the energies $W_i$.


title:
Comment on "Evidence for the Existence of Supersymmetry in Atomic
  Nuclei"

abstract:
  Metz et al PRL (83), 1542 (1999) have presented evidence for supersymmetry in
atomic nuclei but their model Hamiltonian fails to distinguish between
irreducible representations that occur with multiplicities greater than one.
This failure raises serious questions as to the validity of the evidence.


title: Interpretation of y-scaling of the nuclear response

abstract:
  The behavior of the nuclear matter response in the region of large momentum
transfer, in which plane wave impulse approximation predicts the onset of
y-scaling, is discussed. The theoretical analysis shows that scaling violations
produced by final state interactions are driven by the momentum dependence of
the nucleon-nucleon scattering cross section.
  Their study may provide valuable information on possible modifications of
nucleon-nucleon scattering in the nuclear medium.


title:
Reaction rates for Neutron Capture Reactions to C-, N- and O-isotopes to
  the neutron rich side of stability

abstract:
  The reaction rates of neutron capture reactions on light nuclei are important
for reliably simulating nucleosynthesis in a variety of stellar scenarios.
Neutron capture reaction rates on neutron-rich C-, N-, and O-isotopes are
calculated in the framework of a hybrid compound and direct capture model. The
results are tabulated and compared with the results of previous calculations as
well as with experimental results.


title:
Microcanonical studies concerning the recent experimental evaluations of
  the nuclear caloric curve

abstract:
  The microcanonical multifragmentation model from [Al. H. Raduta and Ad. R.
Raduta, Phys. Rev. C 55, 1344 (1997); 56, 2059 (1997); 59, 323 (1999)] is
refined and improved by taking into account the experimental discrete levels
for fragments with $A \le 6$ and by including the stage of sequential decay of
the primary excited fragments. The caloric curve is reevaluated and the heat
capacity at constant volume curve is represented as a function of excitation
energy and temperature. The sequence of equilibrated sources formed in the
reactions studied by the ALADIN group ($^{197}$Au+$^{197}$Au at 600, 800 and
1000 MeV/nucleon bombarding energy) is deduced by fitting simultaneously the
model predicted mean multiplicity of intermediate mass fragments ($M_{IMF}$)
and charge asymmetry of the two largest fragments ($a_{12}$) versus bound
charge ($Z_{bound}$) on the corresponding experimental data. Calculated HeLi
isotopic temperature curves as a function of the bound charge are compared with
the experimentally deduced ones.


title: Free volume in microcanonical multifragmentation

abstract: A modified version is in preparation.


title:
Systematic Study of the Kaon to Pion Multiplicity Ratios in Heavy-Ion
  Collisions

abstract:
  We present a systematic study of the kaon to pion multiplicity ratios (K+/pi+
and K-/pi-) in heavy-ion collisions from AGS to RHIC energy using the
Relativistic Quantum Molecular Dynamics (RQMD) model. The model satisfactorily
describes the available experimental data on K+/pi+ and K-/pi-. Within the
model, we find that the strong increase of the ratios with the number of
participants is mainly due to hadronic rescattering of produced mesons with
ingoing baryons and their resonances. The enhancement of K/pi in heavy-ion
collisions with respect to elementary p+p interactions is larger at AGS energy
than SPS energy, and decreases smoothly with bombarding energy. The total
multiplicity ratios at RHIC energy are predicted by RQMD to be K+/pi+ = 0.19
and K-/pi- = 0.15.


title: Baryon phase-space density in heavy-ion collisions

abstract:
  The baryon phase-space density at mid-rapidity from central heavy-ion
collisions is estimated from proton spectra with interferometry and deuteron
coalescence measurements. It is found that the mid-rapidity phase-space density
of baryons is significantly lower at the SPS than the AGS, while those of total
particles (pion + baryon) are comparable. Thermal and chemical equilibrium
model calculations tend to over-estimate the phase-space densities at both
energies.


title: Quantum Groups and Their Applications in Nuclear Physics

abstract:
  Quantum algebras are a mathematical tool which provides us with a class of
symmetries wider than that of Lie algebras, which are contained in the former
as a special case. After a self-contained introduction to the necessary
mathematical tools (q-numbers, q-analysis, q-oscillators, q-algebras), the
SUq(2) rotator model and its extensions, the construction of deformed exactly
soluble models (u(3)>so(3) model, Interacting Boson Model, Moszkowski model),
the 3-dimensional q-deformed harmonic oscillator and its relation to the
nuclear shell model, the use of deformed bosons in the description of pairing
correlations, and the symmetries of the anisotropic quantum harmonic oscillator
with rational ratios of frequencies, which underly the structure of
superdeformed and hyperdeformed nuclei, are discussed in some detail. A brief
description of similar applications to the structure of molecules and of atomic
clusters, as well as an outlook are also given.


title: Strange Form Factors and Sum Rules of Baryon Decuplet

abstract:
  Treating perturbatively the flavor symmetry breaking effects resided in the
wave function as well as in the SU(3) Lagrangian, we calculate the strange form
factors of decuplet baryons. The higher dimensional representation mixing
components in the baryon wave function of the deccuplet baryons are found to
yield the important contributions to the strange form factors, especially of
the $\Delta$ and $\Sigma^*$ baryons. The model independent sum rules among the
baryon decuplet magnetic moments are also derived.


title: Meson mass modification in strange hadronic matter

abstract:
  We investigate in stable strange hadronic matter (SHM) the modification of
the masses of the scalar ($\sigma$, $\sigma^*$) and the vector ($\omega$,
$\phi$) mesons. The baryon ground state is treated in the relativistic Hartree
approximation in the nonlinear $\sigma$-$\omega$ and linear $\sigma^*$-$\phi$
model. In stable SHM, the masses of all the mesons reveal considerable
reduction due to large vacuum polarization contribution from the hyperons and
small density dependent effects caused by larger binding.


title:
Quadrupole deformations of neutron-drip-line nuclei studied within the
  Skyrme Hartree-Fock-Bogolyubov approach

abstract:
  We introduce a local-scaling point transformation to allow for modifying the
asymptotic properties of the deformed three-dimensional Cartesian harmonic
oscillator wave functions. The resulting single-particle bases are very well
suited for solving the Hartree-Fock-Bogoliubov equations for deformed drip-line
nuclei. We then present results of self-consistent calculations performed for
the Mg isotopes and for light nuclei located near the two-neutron drip line.
The results suggest that for all even-even elements with $Z$=10--18 the most
weakly-bound nucleus has an oblate ground-state shape.


title: Meson-baryon couplings and the $F/D$ ratio from QCD sum rules

abstract:
  Motivated by the recent work on the calculation of the $\pi NN$ coupling
constant using QCD sum rule beyond the chiral limit, we construct the
corresponding sum rules for the couplings, $\eta NN$, $\pi \Xi\Xi$, $\eta
\Xi\Xi$, $\pi \Sigma \Sigma$ and $\eta \Sigma \Sigma$. In constructing the
$\eta$-baryon sum rules, we use the second moment of the $\eta$ wave function,
which we obtain from the pion wave function after SU(3) rotation. In the SU(3)
symmetric limit, we can identify the term responsible for the $F/D$ ratio in
the OPE, which after the sum rule analysis gives $F/D\sim 0.2$, a factor of 3
smaller than from other studies. We also present a qualitative analysis
including the
  SU(3) breaking terms.


title: Multiscale fluctuations in nuclear response

abstract:
  The nuclear collective response is investigated in the framework of a doorway
picture in which the spreading width of the collective motion is described as a
coupling to more and more complex configurations. It is shown that this
coupling induces fluctuations of the observed strength. In the case of a
hierarchy of overlapping decay channels, we observe Ericson fluctuations at
different scales. Methods for extracting these scales and the related lifetimes
are discussed. Finally, we show that the coupling of different states at one
level of complexity to some common decay channels at the next level, may
produce interference-like patterns in the nuclear response. This quantum effect
leads to a new type of fluctuations with a typical width related to the level
spacing.


title:
"Pion laser" phenomenon and other possible signatures of the DCC at RHIC
  and LHC energies

abstract:
  The decay of fireballs containing the disoriented chiral condensate (DCC) in
A+A collisions has been analyzed. We found that the high phase-space density
and probably the large final fireball volume are the favorable factors to
extract a DCC signal from the thermal background. Both of these factors are
expected to take place at RHIC and LHC energies. A coherent pion component then
can be observed in pion spectra, in Bose-Einstein correlations and in
distribution of the ratio of neutral to total pions.


title:
Effects of new non-linear couplings in relativistic effective field
  theory

abstract:
  We extend the relativistic mean field theory model of Sugahara and Toki (TM1)
by adding new couplings suggested by modern effective field theories. An
improved set of parameters (TM1*) is developed with the goal to test the
ability of the models based on effective field theory to describe the
properties of finite nuclei and, at the same time, to be consistent with the
trends of Dirac-Brueckner-Hartree-Fock calculations at densities away from the
saturation region. We compare our calculations with other relativistic nuclear
force parameters for various nuclear phenomena.


title: Effective field theory for the two-nucleon system

abstract:
  I discuss the dynamics of the two-nucleon system as obtained from a chiral
nucleon-nucleon potential. This potential is based on a modified Weinberg power
counting and contains chiral one- and two-pion exchange as well as four-nucleon
contact interactions. The description of the S-waves is very precise. Higher
partial waves are also well reproduced. We also find a good description of most
of the deuteron properties.


title: Particle removal reactions with deformed projectiles

abstract:
  Single-particle removal reactions are becoming an important tool for studying
radioactive nuclei. The nuclei far from stability may reveal new regions of
large deformation. We discuss the influence of the projectile deformation on
the stripping cross sections and longitudinal momentum distributions of the
core. The Glauber formalism for describing such reactions is developed and
compared with the simpler geometric approach and with existing experimental
data. The most significant effects are expected for nuclei with valence
spherical orbitals strongly mixed by deformation. The shape of the momentum
distribution, in turn, can be used for determining the degree of deformation of
the projectile.


title:
Color superconductivity: Continuity of quark and hadron matter, the role
  of the strange quark mass, and perturbative results

abstract:
  We summarize some recent results on the structure of QCD at very high baryon
density.


title: Two-Nucleon Spectral Function in Infinite Nuclear Matter

abstract:
  The two-nucleon spectral function in nuclear matter is studied using
Correlated Basis Function perturbation theory, including central and tensor
correlations produceded by a realistic hamiltonian. The factorization property
of the two-nucleon momentum distribution into the product of the two single
nucleon distributions shows up in an analogous property of the spectral
function. The correlated model yields a two-hole contribution quenched whith
respect to Fermi gas model, while the peaks acquire a quasiparticle width that
vanishes as the two momenta approach $k_F$. In addition, three-hole
one-particle and more complicated intermediate states give rise to a
background, spread out in energy and absent in the uncorrelated models. The
possible connections with one- and two-nucleon emission processes are briefly
discussed.


title: Thermodynamics of multi-boson phenomena

abstract:
  Using the method of locally equilibrium statistical operator we consider the
thermalized relativistic quantum fields in an oscillatory trap. We compare this
thermal picture of the confined boson gas with non-relativistic model of
independent factorized sources. We find that they are equivalent in the limit
of very large effective sizes $R$, more exactly, when the Compton wave length
$1/m$ and thermal wave length $1/\sqrt{% mT}$ are much smaller than {\}$R$ .
Under this conditions we study the influence of Bose condensation in finite
volumes on the structure of the Wigner function, momentum spectra and
correlation function.


title: Elusive Neutrons from Nuclei in Effective Field Theory

abstract:
  We review recent computations of neutral pion photoproduction and Compton
scattering on the deuteron in baryon chiral perturbation theory. Progress in
extracting the neutron electric dipole amplitude, which is relevant in neutral
pion photoproduction, and the neutron polarizabilities, which are relevant in
Compton scattering, is discussed.


title:
The reactions $pp\to p\Lambda K^+$ and $pp\to p\Sigma^0K^+$ near their
  thresholds

abstract:
  The reactions $pp\to p\Lambda K^+$ and $pp\to p\Sigma^0K^+$ are studied near
their thresholds. The strangeness production process is described by the $\pi$-
and $K$ exchange mechanisms. Effects from the final state interaction in the
hyperon-nucleon system are taken into account rigorously. It is found that the
$\Lambda$ production is dominated by $K$ exchange whereas $K$- as well as $\pi$
exchange play an important role for the $\Sigma^0$ case. It is shown that the
experimentally observed strong suppression of $\Sigma^0$ production compared to
$\Lambda$ production at the same excess energy can be explained by a
destructive interference between $\pi$ and $K$ exchange in the reaction $pp\to
p\Sigma^0K^+$. Implications of such an interference on the reaction $pp\to
n\Sigma^+K^+$ are pointed out.


title: Boson spectra and correlations for thermal locally equilibrium systems

abstract:
  The single- and multi- particle inclusive spectra for strongly inhomogeneous
thermal boson systems are studied using the method of statistical operator. The
thermal Wick's theorem is generalized and the analytical solution of the
problem for an boost-invariant expanding boson gas is found. The results
demonstrate the effects of inhomogeneity for such a system: the spectra and
correlations for particles with wave-lengths larger than the system's
homogeneity lengths change essentially as compared with the results based on
the local Bose-Einstein thermal distributions. The effects noticeable grow for
overpopulated media, where the chemical potential associated with violation of
chemical equilibrium is large enough.


title: Strange nuclear matter within Brueckner-Hartree-Fock Theory

abstract:
  We have developed a formalism for microscopic Brueckner-type calculations of
dense nuclear matter that includes all types of baryon-baryon interactions and
allows to treat any asymmetry on the fractions of the different species (n, p,
$\Lambda$, $\Sigma^0$, $\Sigma^+$, $\Sigma^-$, $\Xi^-$ and $\Xi^0$). We present
results for the different single-particle potentials focussing on situations
that can be relevant in future microscopic studies of beta-stable neutron star
matter with strangeness. We find the both the hyperon-nucleon and
hyperon-hyperon interactions play a non-negligible role in determining the
chemical potentials of the different species.


title:
Superdeformations in Relativistic and Non-Relativistic Mean Field
  Theories

abstract:
  The applications of the extensions of relativistic mean field (RMF) theory to
the rotating frame, such as cranked relativistic mean field (CRMF) theory and
cranked relativistic Hartree-Bogoliubov (CRHB) theory, for the description of
superdeformed bands in the $A\sim 60$, 140-150 and 190 mass regions are
overviewed and compared briefly with the results obtained in non-relativistic
mean field theories.


title: On Isgur's "Critique of a Pion Exchange Model for Interquark Forces"

abstract:
  The conceptual issues of low-energy baryon physics are discussed. In
particular, a comparison between the naive one gluon exchange model for the
interaction between constituent quarks in hadrons and the Goldstone boson
exchange picture is made. The "defects" of the Goldstone boson exchange model
for baryons, indicated by Isgur are examined in detail. {\it All} of the
purported ``defects'' are shown to lack a valid basis.


title:
A new resonance in K+Lambda electroproduction: the D_{13}(1895) and its
  electromagnetic form factors

abstract:
  New SAPHIR p(gamma,K+)Lambda total cross section data show a resonance
structure at a total c.m. energy around 1900 MeV. We investigate this feature
with an isobar model and find that the structure can be well explained by
including a new D_{13} resonance at 1895 MeV. Such a state has been predicted
by a relativistic quark model at 1960 MeV with significant gamma-N and K-Lambda
branching ratios. We demonstrate how the measurement of single and double
polarization observables can be used to obtain additional information on this
resonance. Using recent (e,e'K+) JLab data from Hall C we extract the
electromagnetic form factors of this state.


title:
RPA approach to rotational symmetry restoration in a three-level Lipkin
  model

abstract:
  We study an extended Lipkin-Meshkov-Glick model that permits a transition to
a deformed phase with a broken continuous symmetry. Unlike simpler models, one
sees a persistent zero-frequency Goldstone mode past the transition point into
the deformed phase. We found that the RPA formula for the correlation energy
provides a useful correction to the Hartree-Fock energy when the number of
particle N satisfies N > 3, and becomes accurate for large N. We conclude that
the RPA correlation energy formula offers a promising way to improve the
Hartree-Fock energy in a systematic theory of nuclear binding energies.


title: The antikaon potential in nuclear matter at finite momentum

abstract:
  We study the antikaon potential at finite momentum for proton and neutron
nuclear matter. Our approach is based on the momentum dependence of the real
part of the total $K^-N$ scattering amplitude, which is fixed in free space by
experimental data, using the dispersion relation approach. We decompose the
contributions to the scattering amplitude from different processes and consider
the $\Lambda$(1405) and $\Sigma$(1385) to be dissolved in nuclear matter at
density $\rho_0$. Within this approach the $K^-$ potential is found to be
attractive up to high kaon momenta. Our result is in line with the data on the
antikaon potential evaluated from the analysis of kaonic atoms (low momenta),
heavy-ion (interdmediate momenta) and proton-nucleus (high momenta) collisions.


title:
A light-front description of electromagnetic form factors for $J \leq
  {3/2}$ hadrons

abstract:
  A review of the hadron electromagnetic form factors obtained in a light-front
constituent quark model, based on the eigenfunctions of a mass operator, is
presented. The relevance of different components in the q-q interaction for the
description of hadron experimental form factors is analysed.


title: Effective density dependent pairing forces in the T=1 and T=0 channels

abstract:
  Effective density dependent pairing forces of zero range are adjusted on gap
values in T=0,1 channels calculated with the Paris force in symmetric nuclear
matter. General discussions on the pairing force are presented. In conjunction
with the effective k-mass the nuclear pairing force seems to need very little
renormalization in the T=1 channel. The situation in the T=0 channel is also
discussed.


title:
A Poincar\'e-covariant current operator for interacting systems and
  deuteron electromagnetic form factors

abstract:
  In front-form dynamics a current operator for systems of interacting
particles, which fulfills Poincar\'e, parity and time reversal covariance,
together with hermiticity, can be defined. The electromagnetic form factors can
be extracted without any ambiguity and in the elastic case the continuity
equation is automatically satisfied. Applications to the calculation of
deuteron form factors are presented, and the effects of different
nucleon-nucleon interactions, as well as of different nucleon form factors are
investigated.


title: Low energy kaon photoproduction from nuclei

abstract:
  We study $K^+$-meson production in $\gamma{A}$ interaction at energies below
the reaction threshold in free space. The Thomas-Fermi and spectral function
approaches are used for the calculations of the production process. It is found
that the measurement of the differential spectra may allow to reconstruct the
production mechanism and to investigate the dispersion relations entering the
production vertex. It is shown that the contribution from secondary pion
induced reactions to the total kaon photoproduction is negligible for
$E_\gamma{<}$1.2 GeV so that strangeness production at low energies is
sensitive to the nuclear spectral function.


title: Light-Front Bethe-Salpeter Equation

abstract:
  A three-dimensional reduction of the two-particle Bethe-Salpeter equation is
proposed. The proposed reduction is in the framework of light-front dynamics.
It yields auxiliary quantities for the transition matrix and the bound state.
The arising effective interaction can be perturbatively expanded according to
the number of particles exchanged at a given light-front time. An example
suggests that the convergence of the expansion is rapid. This result is
particular for light-front dynamics. The covariant results of the
Bethe-Salpeter equation can be recovered from the corresponding auxiliary
three-dimensional ones. The technical procedure is developed for a two-boson
case; the idea for an extension to fermions is given. The technical procedure
appears quite practicable, possibly allowing one to go beyond the ladder
approximation for the solution of the Bethe-Salpeter equation. The relation
between the three-dimensional light-front reduction of the field-theoretic
Bethe-Salpeter equation and a corresponding quantum-mechanical description is
discussed.


title: Quasi-nuclear and quark model baryonium: historical survey

abstract:
  We review ideas and speculations concerning possible bound states or
resonances coupled to the nucleon-antinucleon channel.


title: Muon-catalyzed fusion in "warm-fusion"

abstract:
  In this paper formulate the hypothesis that in a molecule $D_2 O$ (in a
cluster of heavy water $(D_2 O)_N)$ when its specific energy is of the order of
150 eV one of the molecular bonds $O - D$ is changed into $O - D_{\mu}$ i.e. a
molecule $D_2 O$ transforms into a muonic molecule. This postulate is necessary
to explain the experiment which was carried out in Brookhaven National
Laboratory (USA).


title: Medium Modification of The Pion-Pion Interaction at Finite Density

abstract:
  We discuss medium modifications of the unitarized pion-pion interaction in
the nuclear medium. We incorporate both the effects of chiral symmetry
restoration and the influence of collective nuclear pionic modes originating
from the p-wave coupling of the pion to delta-hole configurations. We show in
particular that the dropping of the sigma meson mass significantly enhances the
low energy structure created by the in-medium collective pionic modes.


title: Saturation of the width of the strength function

abstract:
  The strength function of a single state $|d>$ is studied using the deformed
Gaussian orthogonal ensemble. In particular we study the dependence of the
spreading width of $|d>$ on the degree of mixing.


title:
Implications of Weak-Interaction Space Deformation for Neutrino Mass
  Measurements

abstract:
  The negative values for the squares of both electron and muon neutrino masses
obtained in recent experiments are explained as a possible consequence of a
change in metric within the weak-interaction volume in the energy-momentum
representation. Using a model inspired by a combination of the general theory
of relativity and the theory of deformation for continuous media, it is shown
that the negative value of the square of the neutrino mass can be obtained
without violating allowed physical limits. The consequence is that the negative
value is not necessary unphysical.


title: Bremsstrahlung out of the Quark-Gluon Plasma

abstract:
  A systematic investigation of hard thermal photon spectra from central
ultra-relativistic heavy ion collisions is presented with emphasis on the
effects of bremsstrahlung processes in the quark-gluon plasma (QGP).
Bremsstrahlung photon production in the quark-gluon plasma has recently been
considered within the Braaten-Pisarski method in thermal QCD, where rates have
been found that exhibit the same order in the coupling constants as those
describing the lowest order processes, Compton scattering and
q\bar{q}-annihilation. The impact of these bremsstrahlung photon production
rates on the thermal photon spectra is studied systematically within a simple,
well understood one-fluid hydrodynamical model that describes an only
longitudinally expanding fireball (1+1 Bjorken scaling hydrodynamics). It is
found that the bremsstrahlung processes enhance the thermal photon yield from
the QGP by about one order of magnitude over the complete considered
p_{\perp}-range independent of the choice of the model parameters. Experimental
upper limits on direct photon production in fixed target 200 A GeV S + Au
collisions at the CERN SPS are also considered and used to extract upper limits
for the initial temperature of the QGP, where the QGP bremsstrahlung processes
are found to make a difference of about 15 to 20 MeV depending on the
temperature at which the phase transition is assumed. In comparison with other
theoretical studies, the importance of reaction features not described in the
simple model are estimated and interesting elements for a future extension of
this systematic investigation are identified, which will be of great interest
in prospect of the upcoming experiments at the BNL RHIC and the CERN LHC.


title:
How sensitive are various NN observables to changes in the $\pi NN$
  coupling constant?

abstract:
  The deuteron, NN analyzing powers A_y, and the singlet scattering length show
great sensitivity to the $\pi NN$ coupling constant $g_\pi$. While the pp A_y
data favor $g^2_\pi/4\pi\leq 13.6$, the np A_y data and the deuteron quadrupole
moment imply $g^2_\pi/4\pi\geq 14.0$. The two diverging values could be
reconciled by the assumption of (substantial) charge-splitting of $g_\pi$.
However, the established theoretical explanation of the charge-dependence of
the $^1S_0$ scattering length (based upon pion mass splitting) is very
sensitive to a difference between $g_{\pi^0}$ and $g_{\pi^\pm}$ and rules out
any substantial charge-splitting of $g_\pi$. Thus, there are real and large
discrepancies between the values for $g_\pi$ extracted from different NN
observables. Future work that could resolve the problems is suggested.


title:
Isoscalar Giant Quadrupole Resonance State in the Relativistic Approach
  with the Momentum-Dependent Self-Energies

abstract:
  We study the excited energy of the isoscalar giant quadrupole resonance with
the scaling method in the relativistic many-body framework. In this calculation
we introduce the momentum-dependent parts of the Dirac self-energies arising
from the one-pion exchange on the assumption of the pseudo-vector coupling with
nucleon field. It is shown that this momentum-dependence enhances the Landau
mass significantly and thus suppresses the quadrupole resonance energy even
giving the small Dirac effective mass which causes a problem in the
momentum-independent mean-field theory.


title: Hyperon-nucleon interactions in the $p p \to K^+ \Lambda p$ reaction

abstract:
  We present calculations of the invariant mass spectra of the $\Lambda$p
system for the exclusive $p p \to K^+ \Lambda p$ reaction with the aim of
studying the final state interaction between the $\Lambda$-hyperon and the
proton. The reaction is described within a meson exchange framework and the
final state $\Lambda p$ interaction is incorporated through an off-shell
t-matrix for the $\Lambda p \to \Lambda p$ scattering, constructed using the
available hyperon-nucleon (YN) potentials. The cross sections are found to be
sensitive to the type of YN potential used especially at the $\Lambda$ and
$\Sigma$ production thresholds. Hence, data on this exclusive reaction, which
can be used to constrain the YN potentials are desirable.


title: Population of isomers in decay of the giant dipole resonance

abstract:
  The value of an isomeric ratio (IR) in N=81 isotones ($^{137}$Ba, $^{139}$Ce,
$^{141}$Nd and $^{143}$Sm) is studied by means of the ($\gamma, n)$ reaction.
This quantity measures a probability to populate the isomeric state in respect
to the ground state population. In ($\gamma, n)$ reactions, the giant dipole
resonance (GDR) is excited and after its decay by a neutron emission, the
nucleus has an excitation energy of a few MeV. The forthcoming $\gamma$ decay
by direct or cascade transitions deexcites the nucleus into an isomeric or
ground state. It has been observed experimentally that the IR for $^{137}$Ba
and $ ^{139}$Ce equals about 0.13 while in two heavier isotones it is even less
than half the size. To explain this effect, the structure of the excited states
in the energy region up to 6.5 MeV has been calculated within the Quasiparticle
Phonon Model. Many states are found connected to the ground and isomeric states
by $E1$, $E2$ and $M1$ transitions. The single-particle component of the wave
function is responsible for the large values of the transitions. The calculated
value of the isomeric ratio is in very good agreement with the experimental
data for all isotones. A slightly different value of maximum energy with which
the nuclei rest after neutron decay of the GDR is responsible for the reported
effect of the A-dependence of the IR.


title:
First Order Phase Transitions in Neutron star Matter: Droplets and
  Coherent Neutrino Scattering

abstract:
  A first order phase transition at high baryon density implies that a mixed
phase can occupy a significant region of the interior of a neutron star. In
this article we investigate the effect of a droplet phase on neutrino transport
inside the core. Two specific scenarios of the phase transition are examined,
one having a kaon condensate and the other having quark matter in the high
density phase. The coherent scattering of neutrinos off the droplets greatly
increases the neutrino opacity of the mixed phase. We comment on how the
existence of such a phase will affect a supernova neutrino signal.


title: Chiral Corrections to Baryon Masses Calculated within Lattice QCD

abstract:
  Consideration of the analytic properties of pion-induced baryon self energies
leads to new functional forms for the extrapolation of light baryon masses.
These functional forms reproduce the leading non-analytic behavior of chiral
perturbation theory, the correct non-analytic behavior at the $N \pi$ threshold
and the appropriate heavy-quark limit. They involve only three unknown
parameters, which may be obtained by fitting lattice QCD data. Recent dynamical
fermion results from CP-PACS and UKQCD are extrapolated using these new
functional forms. We also use these functions to probe the limit of
applicability of chiral perturbation theory.


title: Effects of the Dirac Sea on the Giant Monopole States

abstract:
  Effects of the Dirac sea on the excitation energy of the giant monopole
states are investigated in an analytic way within the $\sigma-\omega$ model.
The excitation energy is determined by the relativistic Landau-Migdal
parameters, $F_0$ and $F_1$. Their analytic expressions are derived in the
relativistic random phase approximation(RRPA) without the Dirac sea, with the
Pauli blocking terms and with the full Dirac sea. It is shown that in the RRPA
based on the mean field approximation the Pauli blocking terms should be
included in the configuration space, according to the relativistic Landau
theory. In the renormalized RRPA, the incompressibility coefficient becomes
negative, if N$\nbar$ excitations are neglected.


title: Three-Pion Interferometry of Relativistic Nuclear Collisions

abstract:
  Three-pion interferometry is investigated for new information on the
space-time structure of the pion source created in ultra-relativistic heavy-ion
collisions. The two- and three-pion correlations are numerically computed for
incoherent source functions based on the Bjorken hydrodynamical model, over a
wide range of the kinematic variables. New information provided by three-pion
interferometry, different from that provided by two-pion interferometry, should
appear in the phases of the Fourier transform of the source function. Variables
are identified that would be sensitive to the phases and suitable for
observation. For a positive, chaotic source function, however, a variation of
the three-pion phase is found to be difficult to extract from experiments.
Effects of asymmetry of the source function are also examined.


title:
Two- and Three-Pion Interferometry for a Nonchaotic Source in
  Relativistic Nuclear Collisions

abstract:
  Two- and three-pion correlation functions are investigated for a source that
is not fully chaotic. Various models are examined to describe the source. The
chaoticity and weight factor are evaluated in each model as measures of the
strength of correlations and compared to experimental results. A new measure of
three-pion correlation is also suggested.


title:
Effects of Disoriented Chiral Condensates on Two- and Three-Pion
  Correlations of Relativistic Nuclear Collisions

abstract:
  Two- and three-pion correlations are investigated in cases when disoriented
chiral condensate (DCC) occurs. A chaoticity and weight factor are used as
measures of two- and three-pion correlations, and the various models for DCC
are investigated. Some models are found to yield the chaoticity and weight
factor in a reasonable agreement with recent experimental data.


title:
A polarization relation and the measurement of the longitudinal response
  in pseudoscalar meson electroproduction off the nucleon

abstract:
  For pseudoscalar meson electroproduction off the nucleon in parallel
kinematics a relation between three polarization observables is derived. It is
shown that, without Rosenbluth separation, a measurement of the longitudinal
strength can be achieved through three different ways. They are discussed with
preliminary MAMI data for the p(\vec e, e'\vec p)\pi^0 reaction in the energy
range of the Delta(1232) resonance.


title:
Nonequilibrium Weak Processes in Kaon Condensation II - Kinetics of
  condensation ---

abstract:
  The kinetics of negatively charged kaon condensation in the early stages of a
newly born neutron star is considered. The thermal kaon process, in which kaons
are thermally produced by nucleon-nucleon collisions, is found to be dominant
throughout the equilibration process. Temporal changes of the order parameter
of the condensate and the number densities of the chemical species are obtained
from the rate equations, which include the thermal kaon reactions as well as
the kaon-induced Urca and the modified Urca reactions. It is shown that the
dynamical evolution of the condensate is characterized by three stages: the
first, prior to establishment of a condensate, the second, during the growth
and subsequent saturation of the condensate, and the third, near chemical
equilibrium. The connection between the existence of a soft kaon mode and the
instability of the noncondensed state is discussed. Implications of the
nonequilibrium process on the possible delayed collapse of a protoneutron star
are also mentioned.


title: On the search for a narrow penta-quark Z$^+$ baryon in NN interactions

abstract:
  The possibility for an observation of a narrow penta-quark $Z^+$ baryon in
$NN$ reactions is discussed. It is shown that the $pp{\to}n\Sigma^+K^+$
reaction at excess energies around 100 MeV above threshold provides optimal
conditions for $Z^+$ baryon detection by an analysis of the $nK^+$ invariant
mass spectrum, if the $Z^+$ mass is located around 1.5 GeV involving a rather
narrow width.


title:
Shape-phase transitions in mixed parity systems and the onset of
  octupole deformation

abstract:
  Shape-phase transitions in mixed parity boson systems are studied using mean
field theory. It is shown that without parity projection, shape transitions in
mixed parity systems are very similar to those in positive parity systems, both
requiring a finite interaction strength for the onset of deformation. The
shape-phase diagram in mixed parity systems, however, changes significantly
after parity projection, with the critical point for the onset of octupole
deformation moving to zero strength. Shape transitions in the Lipkin model are
shown to exhibit the same features, indicating that this is a direct
consequence of parity projection in finite, mixed parity systems independent of
the nature of interacting particles.


title:
Analysis of the 16O(p,gamma)17F capture reaction using the shell model
  embedded in the continuum

abstract:
  We apply the realistic shell model which includes the coupling between
many-particle (quasi-)bound states and the continuum of one-particle scattering
states, called the Shell Model Embedded in the Continuum, to the spectroscopy
of mirror nuclei: 17F and 17O, as well as to the description of low energy
cross section (the astrophysical S-factor) for E1, E2 and M1 components in the
capture reaction: 16O(p,gamma)17F. With the same microscopic input we calculate
the phase shifts and differential cross-section for the elastic scattering of
protons on 16O.


title:
Nucleon-Nucleon Correlations and Two-Nucleon Currents in Exclusive
  ($e,e'NN$) Reactions

abstract:
  The contributions of short-range nucleon-nucleon (NN) correlations, various
meson exchange current (MEC) terms and the influence of $\Delta$ isobar
excitations (isobaric currents, IC) on exclusive two-nucleon knockout reactions
induced by electron scattering are investigated. The nuclear structure
functions are evaluated for nuclear matter. Realistic NN interactions derived
in the framework of One-Boson-Exchange model are employed to evaluate the
effects of correlations and MEC in a consistent way. The correlations
correlations are determined by solving the Bethe-Goldstone equation. This
yields significant contributions to the structure functions W_L and W_T of the
(e,e'pn) and (e,e'pp) reactions. These contributions compete with MEC
corrections originating from the $\pi$ and $\rho$ exchange terms of the same
interaction. Special attention is paid to the so-called 'super parallel'
kinematics at momentum transfers which can be measured e.g. at MAMI in Mainz.


title: On the nucleon instability of heavy oxygen isotopes

abstract:
  The instability of the $^{26}$O nucleus with respect to decay through the
two-neutron channel is investigated. It is shown that this isotope, unobserved
in the fragmentation experiments, can exist as a narrow resonance in the system
$^{24}$O+2n. A role of deformation in formation of the neutron-drip line in the
region $N\sim 20$ is discussed.


title: Probing the antikaon potential by K$^-$A elastic scattering

abstract:
  We extract the antikaon potential from differential data on elastic $K^-A$
scattering within Glauber theory at an antikaon momentum of 800 MeV/c. The
$K^-N$ cross section at densities up to 0.1 $fm^3$ is found to be close to the
value given in free space $K^-p$ and $K^-n$ interactions (averaged over the
number of protons and neutrons) whereas the ratio $\alpha$ of the real to
imaginary part of the forward scattering amplitude $f(0)$ differs from the
ratio $\alpha$ in free space indicating a dropping of $Re f(0)$ at finite
nuclear density. The extrapolated $K^-$ potential at a momentum of 0.8 GeV/c
amounts to $\approx $--28 MeV at density $\rho_0$ which is substantially less
than the values extracted from kaonic atoms at zero momentum or heavy-ion data
at 300 MeV/c${\leq}p_K{\leq}$600 MeV/c. We, furthermore, investigate the
perspectives of scattering experiments on $^{12}C$ at low ($\approx$300 MeV/c)
and high ($\approx$1.2 GeV/c) momenta.