title: Quark contribution to the nucleon polarizabilities and three-body forces

abstract:
  We study the response of the nucleon, as a system of three bound
(constituent) non relativistic quarks, to external (quasi static) electric and
magnetic fields. The approach, based on a sum rule technique, is applied to a
large class of two and three-body interquark potentials. Lower and upper bounds
to the electric polarizability and para-magnetic susceptibility are explicitly
calculated within a large variety of constituent models and their values
related to the features of the interquark interaction picture. The r\^ole of
three-body forces is investigated in details as well as the effects of SU(6)
breaking terms in the potential model. Our results can be used to extract the
mesonic contributions to the static polarizabilty and susceptibility. The quark
degrees of freedom give a quite sizeable contributions to both and the meson
cloud accounts roughly for 30% and 60% of the electric proton and neutron
polarizability respectively. The quark contribution to the paramagnetic
susceptibility is even higher and the mesonic effects are rather uncertain.


title: Infrared Behaviour of Propagators and Vertices

abstract:
  We elucidate constraints imposed by confinement and dynamical chiral symmetry
breaking on the infrared behaviour of the dressed-quark and -gluon propagators,
and dressed-quark-gluon vertex. In covariant gauges the dressing of the gluon
propagator is completely specified by P(k^2):= 1/[1+Pi(k^2)], where Pi(k^2) is
the vacuum polarisation. In the absence of particle-like singularities in the
dressed-quark-gluon vertex, extant proposals for the dressed-gluon propagator
that manifest P(k^2=0)=0 and Max[P(k^2)]~10 neither confine quarks nor break
chiral symmetry dynamically. This class includes all existing estimates of
P(k^2) via numerical simulations.


title: A Possible Solution to the Tritium Endpoint Problem

abstract:
  Scalar or right-chiral interaction currents may be expected to produce a
neutrino coupled to the electron which is different from, and perhaps even
orthogonal to, that coupled to the electron by the standard model weak
interaction. We show that, using reasonable parameter values for such
additional interactions, it is possible to generate a spectrum which, if
analyzed in the manner commonly employed by experimental groups, produces a
negative neutrino mass-squared.


title:
Proton Particle-Neutron Hole States in 132Sb with a Realistic
  Interaction

abstract:
  The structure of the particle-hole nucleus 132Sb provides a direct source of
information on the effective neutron-proton interaction in the 132Sn region. We
have performed a shell-model calculation for this nucleus using a realistic
effective interaction derived from the Bonn A nucleon-nucleon potential. The
results are in very good agreement with the experimental data evidencing the
reliability of our effective interaction matrix elements both with isospin T=1
and T=0.


title: Neutron-3H and Proton-3He Zero Energy Scattering

abstract:
  The Kohn variational principle and the (correlated) Hyperspherical Harmonics
technique are applied to study the n-3H and p-3He scattering at zero energy.
Predictions for the singlet and triplet scattering lengths are obtained for
non-relativistic nuclear Hamiltonians including two- and three-body potentials.
The calculated n-3H total cross section agrees well with the measured value,
while some small discrepancy is found for the coherent scattering length. For
the p-3He channel, the calculated scattering lengths are in reasonable
agreement with the values extrapolated from the measurements made above 1 MeV.


title: Transport Simulations with Pi and Delta In-Medium Properties

abstract:
  Transport simulations including in-medium properties derived in a microscopic
pi + nucleon-hole + delta-hole model in infinite nuclear matter are presented.
In-medium pion dispersion relations, partial delta decay widths, pion
absorption cross sections and delta cross sections are incorporated into the
transport description by means of a local-density approximation. Strong
modifications of pi and delta production and absorption rates are found, but
only small effects on pion observables.


title: Benchmark calculations for polarization observables in 3N scattering

abstract:
  High precision benchmark calculations for phase-shifts and mixing parameters
as well as observables in elastic neutron-deuteron scattering below the
deuteron breakup threshold are presented using a realistic nucleon-nucleon
potential. Two totally different methods, one using a variational principle in
configuration space and the other solving the Faddeev equations in momentum
space are used and compared to each other. The agreement achieved in
phase-shifts and mixing parameters as well as in the polarization observables
is excellent. The extreme sensitivity of the vector analyzing power Ay to small
changes of the phase shifts and mixing parameters is pointed out.


title:
Size of Fireballs Created in High Energy Lead-Lead Collisions as
  Inferred from Coulomb Distortions of Pion Spectra

abstract:
  We compute the Coulomb effects produced by an expanding, highly charged
fireball on the momentum distribution of pions. We compare our results to data
on Au+Au at 11.6 A GeV from E866 at the BNL AGS and to data on Pb+Pb at 158 A
GeV from NA44 at the CERN SPS. We conclude that the distortion of the spectra
at low transverse momentum and mid-rapidity can be explained in both
experiments by the effect of the large amount of participating charge in the
central rapidity region. By adjusting the fireball expansion velocity to match
the average transverse momentum of protons, we find a best fit when the
fireball radius is about 10 fm, as determined by the moment when the pions
undergo their last scattering. This value is common to both the AGS and CERN
experiments.


title:
Realistic Shell-Model Calculations for Nuclei in the Region of Shell
  Closures off Stability

abstract:
  We have performed realistic shell-model calculations for nuclei around doubly
magic 100Sn and 132Sn using an effective interaction derived from the Bonn A
nucleon-nucleon potential. The results are in remarkably good agreement with
the experimental data showing the ability of our effective interaction to
provide an accurate description of nuclear structure properties.


title: Thermodynamics - a valuable approach to multifragmentation?

abstract:
  Since years it has been vividly debated whether multifragmentation is a
thermal or a dynamical process. Recently it has been claimed \cite{toek1,po}
that new data allow to decide this question. The conclusion, drawn in these
papers, are, however, opposite. Whereas \cite{toek1} states that the behavior
of different observables as a function of the fragment multiplicity excludes a
thermal origin of the fragments in \cite{po} it has been argued that data show
a first order phase transition between a liquid and a gaseous phase. It is the
aim of this paper to show that both conclusions are premature. They are based
on the salient assumption, that the system is sufficiently large to be
susceptible to a canonical description. We will show that this is not the case.
A micro canonical approach describes the data as good as dynamical
calculations. Hence the quest for the physical origin of multifragmentation
continues.


title:
Dynamical Effects on the Parallel Momentum Distributions of Neutrons
  from Halo Breakup

abstract:
  In this paper we study the energy spectra and related parallel momentum
distributions of the neutrons from the breakup of 11Be. Earlier papers on
transfer to the continuum reactions have shown that the breakup amplitude
reduces to a simple eikonal approximation in the limit of weakly bound
projectiles. The aim is to establish a reliable method to obtain information on
the structure of the halo from the experimental results which depend on the
reaction mechanism.
  Theoretical results for the widths of the parallel momentum distributions and
for the total breakup cross section are compared to recent experimental data.


title:
Comment on "Statistical nature of multifragmentation" (A.S.Botvina and
  D.H.E.Gross, Phys.Rev. C56, R23 (1998)

abstract:
  It is shown that conclusions regarding the statistical nature of
multifragmentation, drawn by Botvina and Gross from experimental data, are
unfounded. Imperfections of the experimental apparatus cannot restore
information, once destroyed by statistical fluctuations. Attention is also
called to the special treatment of neutron phase space in the Berlin MMMC,
affecting the predicted relation between excitation energy and transversal
kinetic energy of associated particles.


title:
Full-folding optical potential for preequilibrium nucleon scattering at
  low energies

abstract:
  The real part of the optical potential for the nucleon-nucleus scattering at
lower energies (E_i<100MeV) has been calculated including nucleonic and mesonic
form factors by a double folding approach. Realistic density- and
energy-dependent effective NN-interactions DDM3Y, BDM3Y and HLM3Y based on the
Reid and Paris potentials are used in this respect. The effects of the nucleon
density distribution and the average relative momentum on the folded potential
have been analysed. A good agreement with the phenomenological potential of
Lagrange-Lejeune, as well as with the parametrization of
Jeukenne-Lejeune-Mahaux for both neutron and proton double-folded potentials is
obtained. The results indicate that the strongly simplified model interactions
used in preequilibrium reaction theory neglect important dynamical details of
such processes.


title: Particle production from off-shell nucleons

abstract:
  Particle production in equilibrium and nonequilibrium quantum systems is
calculated. The effects of the off-shell propagation of nucleons in medium on
the particle production are discussed. Comparision to the semiclassical
production rate is given.


title: Hot Nuclear Matter in the Quark Meson Coupling Model with Dilatons

abstract:
  We study hot nuclear matter in an explicit quark model based on a mean field
description of nonoverlapping nucleon bags bound by the self-consistent
exchange of scalar and vector mesons as well as the glueball field. The
glueball exchange as well as a realization of the broken scale invariance of
quantum chromodynamics is achieved through the introduction of a dilaton field.
The calculations also take into account the medium-dependence of the bag
constant. The effective potential with dilatons is applied to nuclear matter.
The nucleon properties at finite temperature as calculated here are found to be
appreciably different from cold nuclear matter. The introduction of the dilaton
potential improves the shape of the saturation curve at T=0 and is found to
affect hot nuclear matter significantly.


title: Isovector Vibrations in Nuclear Matter at Finite Temperature

abstract:
  We consider the propagation and damping of isovector excitations in heated
nuclear matter within the Landau Fermi-liquid theory. Results obtained for
nuclear matter are applied to calculate the Giant Dipole Resonance (GDR) at
finite temperature in heavy spherical nuclei within Steinwedel and Jensen
model.
  The centroid energy of the GDR slightly decreases with increasing temperature
and the width increases as $T^2$ for temperatures $T < 5$ MeV in agreement with
recent experimental data for GDR in $^{208}$Pb and $^{120}$Sn.
  The validity of the method for other Fermi fluids is finally suggested.


title: Low-Energy Theorems for Gluodynamics at Finite Temperature

abstract:
  We generalize the low-energy theorems of gluodynamics to finite temperature.
Examples of the theorems in the low and high temperature limits are given.


title:
Mass Shift and Width Broadening of Rho-Mesons Produced in Heavy Ion
  Collisions

abstract:
  The mass shift and width broadening of rho-mesons produced in heavy ion
collisions is estimated using general formulae which relate the in-medium mass
shift of a particle to the real part of the forward scattering amplitude of
this particle on constituents of the medium and the width broadening to the
corresponding cross section. It is found that the mass increases by some tens
of MeV but, more importantly, the width becomes large, increasing by several
hundred MeV at beam energies of a few GeV per nucleon and by twice that amount
at beam energies of about a hundred GeV per nucleon.


title: eta-^4He Bound States in the Skyrme Model

abstract:
  The rational map ansatz for light nuclei in the Skyrme model is shown to
imply the existence of an \eta-^4He bound state, with a binding energy of ~ 30
KeV.


title: Electromagnetic form factors of the bound nucleon

abstract:
  We calculate electromagnetic form factors of the proton bound in specified
orbits for several closed shell nuclei. The quark structure of the nucleon and
the shell structure of the finite nuclei are given by the QMC model. We find
that orbital electromagnetic form factors of the bound nucleon deviate
significantly from those of the free nucleon.


title: Relativistic and Polarization Phenomena in NN -> D\pi processes

abstract:
  A detailed analysis of the processes of the type NN -> D\pi is presented
taking into account the exchange graphs of a nucleon and a pion. A large
sensitivity of polarization observables to the off-mass shell effects of
nucleons inside the deuteron is shown. The influence of the inclusion of the
P-wave in the Deuteron Wave Function (DWF) is studied. We have analysed the
sensitivity of all the observables to the form of \pi NN - current taking into
account the off-shellnis of the nucleon and the choice of the DWF relativistic
form. One can see the very large sensitivity of all the observables, especialy
of the polarization characteristics to the choice of the DWF form. The
inclusion of the P-wave contribution to the DWF within framework of Gross's
approach results in a better description of the experimental data on the
differential cross section and the polarization observables.


title:
Sensitivity of electromagnetic spectra to equation of state and initial
  energy density in the Pb+Pb collisions at SPS

abstract:
  We study Pb+Pb collisions at 158 A GeV/c using a hydrodynamical approach. We
test different equations of state (EoSs) and different initial conditions and
show that there are more than one initial state for each EoS which reproduce
the observed hadronic spectra. We also find that different equations of state
favour different freeze-out temperature. Simultaneously we calculate the
thermal dilepton and photon spectra for each EoS and initial state. We compare
the dilepton mass spectrum to data measured by the CERES collaboration and find
that the differences in spectra obtained using different EoSs and initial
states are not resolvable within the current experimental resolution. However,
at invariant masses over 2 GeV the difference in the yield due to various
initial states is close to an order of magnitude. We also study the rapidity
distribution of lepton pairs and find that for masses around 800 MeV the shape
of the distribution depends strongly on the EoS.


title: Consistent off-shell $\pi N N$ vertex and nucleon self-energy

abstract:
  We present a consistent calculation of half-off-shell form factors in the
pion-nucleon vertex and the nucleon self-energy. Numerical results are
presented. Near the on-shell point the pion-nucleon vertex is dominated by the
pseudovector coupling, while at large nucleon invariant masses we find a
sizable pseudoscalar admixture.


title:
Collective coordinates, shape transitions and shape coexistence: a
  microscopic approach

abstract:
  We investigate a description of shape-mixing and shape-transitions using
collective coordinates. To that end we apply a theory of adiabatic
large-amplitude motion to a simplified nuclear shell-model, where the
approximate results can be contrasted with exact diagonalisations. We find
excellent agreement for different regimes, and contrast the results with those
from a more standard calculation using a quadrupole constraint. We show that
the method employed in this work selects diabatic (crossing) potential energy
curves where these are appropriate, and discuss the implications for a
microscopic study of shape coexistence.


title: Bonn Potential and Shell-Model Calculations for 206,205,204Pb

abstract:
  The structure of the nuclei 206,205,204Pb is studied interms of shell model
employing a realistic effective interaction derived from the Bonn A
nucleon-nucleon potential. The energy spectra, binding energies and
electromagnetic properties are calculated and compared with experiment. A very
good overall agreement is obtained. This evidences the reliability of our
realistic effective interaction and encourages use of modern realistic
potentials in shell-model calculations for heavy-mass nuclei.


title: Charge-Dependence of the Nucleon-Nucleon Interaction

abstract:
  Based upon the Bonn meson-exchange-model for the nucleon-nucleon ($NN$)
interaction, we calculate the charge-independence breaking (CIB) of the $NN$
interaction due to pion-mass splitting. Besides the one-pion-exchange (OPE), we
take into account the $2\pi$-exchange model and contributions from three and
four irreducible pion exchanges. We calculate the CIB differences in the
$^1S_0$ effective range parameters as well as phase shift differences for
partial waves up to total angular momentum J=4 and laboratory energies below
300 MeV. We find that the CIB effect from OPE dominates in all partial waves.
However, the CIB effects from the $2\pi$ model are noticable up to D-waves and
amount to about 40% of the OPE CIB-contribution in some partial waves, at 300
MeV. The effects from 3$\pi$ and 4$\pi$ contributions are negligible except in
$^1S_0$ and $^3P_2$.


title:
An Effective Field Theory Calculation of the Parity Violating Asymmetry
  in n+p -> d+gamma

abstract:
  Weak interactions are expected to induce a parity violating pion-nucleon
coupling, h_{\pi NN}^{(1)}. This coupling should be measurable in a proposed
experiment to study the parity violating asymmetry A_\gamma in the process \vec
n + p \to d+\gamma. We compute the leading dependence of A_\gamma on the
coupling h_{\pi NN}^{(1)} using recently developed effective field theory
techniques and find an asymmetry of A_\gamma = +0.17 h_{\pi NN}^{(1)} at
leading order. This asymmetry has the opposite sign to that given by
Desplanques, Donoghue and Holstein.


title: Soft-core hyperon-nucleon potentials

abstract:
  A new Nijmegen soft-core OBE potential model is presented for the low-energy
YN interactions. Besides the results for the fit to the scattering data, which
largely defines the model, we also present some applications to hypernuclear
systems using the G-matrix method. An important innovation with respect to the
original soft-core potential is the assignment of the cut-off masses for the
baryon-baryon-meson (BBM) vertices in accordance with broken SU(3)$_F$, which
serves to connect the NN and the YN channels. As a novel feature, we allow for
medium strong breaking of the coupling constants, using the $^3P_0$ model with
a Gell-Mann--Okubo hypercharge breaking for the BBM coupling. We present six
hyperon-nucleon potentials which describe the available YN cross section data
equally well, but which exhibit some differences on a more detailed level. The
differences are constructed such that the models encompass a range of
scattering lengths in the $\Sigma N$ and $\Lambda N$ channels. For the
scalar-meson mixing angle we obtained values $\theta_S=37$ to 40 degrees, which
points to almost ideal mixing angles for the scalar $q\bar{q}$ states. The
G-matrix results indicate that the remarkably different spin-spin terms of the
six potentials appear specifically in the energy spectra of $\Lambda$
hypernuclei.


title:
Anharmonic double-$\gamma$ vibrations in nuclei and their description in
  the interacting boson model

abstract:
  Double-$\gamma$ vibrations in deformed nuclei are studied in the context of
the interacting boson model with special reference to their anharmonic
character. It is shown that large anharmonicities can be obtained with
interactions that are (at least) of three-body nature between the bosons. As an
example the $\gamma$ vibrations of the nucleus
$^{166}_{\phantom{0}68}$Er$^{\phantom{00}}_{98}$ are studied in detail.


title:
Translationally invariant treatment of pair correlations in nuclei: II.
  Tensor correlations

abstract:
  We study the extension of our translationally invariant treatment of few-body
nuclear systems to include tensor forces and correlations. It is shown that a
direct application of our method is not as successful for realistic V6
interactions as our previous results for V4 potentials suggested. We
investigate the cause in detail for the case of $^4$He, and show that a
combination of our method with that of Jastrow-correlated wave functions seems
to be a lot more powerful, thereby suggesting that for mildly to strongly
repulsive forces such a hybrid procedure may be an appropriate description.


title: Meson exchange and nucleon polarizabilities in the quark model

abstract:
  Modifications to the nucleon electric polarizability induced by pion and
sigma exchange in the q-q potentials are studied by means of sum rule
techniques within a non-relativistic quark model. Contributions from meson
exchange interactions are found to be small and in general reduce the quark
core polarizability for a number of hybrid and one-boson-exchange q-q models.
These results can be explained by the constraints that the baryonic spectrum
impose on the short range behavior of the mesonic interactions.


title: Collective modes and current-algebraic sum rules in nuclear medium

abstract:
  In-medium sum rules following from the chiral charge algebra of QCD are
reviewed, and new sum rules are derived. The new sum rules relate the
I^G(J^{PC})=1^-(0^{++}) excitations (quantum numbers of a_0(980)) to the scalar
and isovector densities, and are nontrivial for the isospin-asymmetric medium.
We present an extensive illustration of the sum rules with help of quark matter
in the Nambu-Jona--Lasinio model. Collective excitations different from the
usual meson branches (spin-isospin sound modes) are shown to contribute
significantly to the sum rules and to play a crucial role in the limit of
vanishing current quark masses.


title: Elastic scattering analyses and dispersion relation constraints

abstract:
  We present the results of energy-dependent and single-energy partial-wave
analyses of pi-N elastic scattering data with laboratory kinetic energies below
2.1 GeV. We have considered the effect of adding dispersion-relation
constraints required for a more reliable extraction of the pi-N sigma term. The
results of these new fits are compared with those generated previously, using a
reduced set of constraints, and with a fit which has only utilized forward
constraints associated with the S-wave scattering lengths. We compare the
results in terms of their resonance spectra and preferred values for the pi-N-N
coupling and pi-N sigma term.


title: Probing the softest region of nuclear equation of state

abstract:
  An attractive, energy-dependent mean-field potential for baryons is
introduced in order to generate a soft region in the nuclear equation-of-state,
as suggested by recent lattice QCD calculations of baryon free matter at finite
temperature. Based on a hadronic transport model, we find that although this
equation-of-state has negligible effects on the inclusive hadronic spectra, it
leads to a minimum in the energy dependence of the transverse collective flow
and a delayed expansion of the compressed matter. In particular, the transverse
flow changes its direction as the colliding system passes through the softest
region in the equation-of-state.


title: Nuclear Deformation Effects in the Cluster Radioactivity

abstract:
  We investigate the influence of the nuclear deformation on the decay rates of
some cluster emission processes. The interaction between the daughter and the
cluster is given by a double folding potential including quadrupole and
hexadecupole deformed densities of both fragments. The nuclear part of the
nucleus-nucleus interaction is density dependent and at small distances a
repulsive core in the potential will occur. In the frame of the
WKB-approximation the assault frequency of the cluster will depend on the
geometric properties of the potential pocket whereas the penetrability will be
sensitive to changes in the barrier location. The results obtained in this
paper point out that various combinations of cluster and daughter deformations
may account for the measured values of the decay rate.T he decay rather are
however more sensitive to the changes in the daughter deformation due to the
large mass asymmetry of the process.


title: Proton Decay from Excited States in Spherical Nuclei

abstract:
  Based on a single particle model which describes the time evolution of the
wave function during tunneling across a one dimensional potential barrier we
study the proton decay of $^{208}$Pb from excited states with non-vanishing
angular momentum $\ell$. Several quantities of interest in this process like
the decay rate $\lambda$, the period of oscillation $T_{osc}$, the transient
time $t_{tr}$, the tunneling time $t_{tun}$ and the average value of the proton
packet position $ r_{av} $ are computed and compared with the WKB results.


title: Long Range Alpha the Ternary Cold Fission of $^{252}$Cf

abstract:
  We compute the final kinetic energies of the fragments emitted in the light
charged particle accompanied cold fission of $^{252}$Cf taking into account the
ground state quadrupole deformation and the finite-size effects of the
fragments and integrating the equations of motion for a three-body system
subjected only to Coulomb forces. The initial conditions for the trajectory
calculations were derived in the frame of a deformed cluster model which
includes also the effect due to the absorbative nuclear part. Although the
distributions of initial kinetic energies is rather broad we show that in cold
fission the initial conditions can be better determined than in the usual
spontaneous fission.


title:
Reply on Toke's and Schroeder's comment on our paper "Statistical nature
  of multifragmentation"

abstract:
  We point out some basic misunderstandings and wrong statements about our
microcanonical Metropolis Monte Carlo (MMMC) model of nuclear fragmentation.


title: Radiative decays of decuplet hyperons

abstract:
  We calculate the radiative decay widths of decuplet hyperons in a chiral
constituent quark model including electromagnetic exchange currents between
quarks. Exchange currents contribute significantly to the E2 transition
amplitude, while they largely cancel for the M1 transition amplitude.
Strangeness suppression of the radiative hyperon decays is found to be weakened
by exchange currents. Differences and similarities between our results and
other recent model predictions are discussed.


title:
Systematic Power Counting in Cutoff Effective Field Theories for
  Nucleon-Nucleon Interactions and the Equivalence With PDS

abstract:
  An analytic expression for the ${}^1S_0$ phase shifts in nucleon-nucleon
scattering is derived in the context of the Schr\"odinger equation in
configuration space with a short distance cutoff and with a consistent power
counting scheme including pionic effects. The scheme treats the pion mass and
the inverse scattering length over the intrinsic short distance scale as small
parameters. Working at next-to-leading order in this scheme, we show that the
expression obtained is identical to one obtained using the recently introduced
PDS approach which is based on dimensional regularization with a novel
subtraction scheme. This strongly supports the conjecture that the schemes are
equivalent provided one works to the same order in the power counting.


title: Effective Field Theory for Short-Range Forces

abstract:
  The method of effective field theories (EFTs) is developed for the scattering
of two particles at wavelengths which are large compared to the range of their
interaction. It is shown that the renormalized EFT is equivalent to the
effective range expansion, to a Schroedinger equation with a pseudo-potential,
and to an energy expansion of a generic boundary condition at the origin. The
roles of regulators and potentials are also discussed. These ideas are
exemplified in a toy model.


title: Classical Quark Models: An Introduction

abstract:
  We present an elementary introduction to some of the quark models used to
understand the properties of light mesons and baryons. These lectures are
intended for both theoretical and experimental graduate students beginning
their study of the strong interaction.


title: Faddeev-type calculation of eta-d threshold scattering

abstract:
  The scattering length for the eta-meson collision with deuteron is calculated
on the basis of rigorous few-body equations (AGS) for various eta-N input. The
results obtained strongly support the existence of a resonance or quasi-bound
state close to the eta-d threshold.


title: Weak capture of protons by protons

abstract:
  The cross section for the proton weak capture reaction $^1H(p,e^+\nu_e)^2H$
is calculated with wave functions obtained from a number of modern, realistic
high-precision interactions. To minimize the uncertainty in the axial two-body
current operator, its matrix element has been adjusted to reproduce the
measured Gamow-Teller matrix element of tritium $\beta$ decay in model
calculations using trinucleon wave functions from these interactions. A
thorough analysis of the ambiguities that this procedure introduces in
evaluating the two-body current contribution to the pp capture is given. Its
inherent model dependence is in fact found to be very weak. The overlap
integral $\Lambda^2(E=0)$ for the pp capture is predicted to be in the range
7.05--7.06, including the axial two-body current contribution, for all
interactions considered.


title: Lattice Gauge Description of Colliding Nuclei

abstract:
  We propose a novel formalism for simultaneously describing both, the hard and
soft parton dynamics in ultrarelativistic collisions of nuclei. The emission of
gluons from the initially coherent parton configurations of the colliding
nuclei and low-$p_t$ color coherence effects are treated in the framework of a
Yang-Mills transport equation on a coupled lattice-particle system. A collision
term is added to the transport equation to account for the remaining
intermediate and high-$p_t$ interactions in an infrared finite manner.


title:
The analysis of particle multiplicities in Pb+Pb collisions at 158A
  GeV/c within hadron gas models

abstract:
  The preliminary data on hadron multiplicities measured in central Pb+Pb
collisions at 158A GeV/c are analyzed. The ideal hadron gas model fails to give
a reasonable explanation to the Pb+Pb data sets. We study the possible effects
of pion enhancement due to different hard-core repulsion for pions and other
hadrons and strangeness suppression because of incomplete chemical equilibrium.
Each of these two modifications improves the results. The combined effect of
these two mechanisms leads to an extremely good agreement with the data. An
interpretation of the obtained results in terms of the possible quark-gluon
plasma formation at the early stage of the collision is also discussed.


title: Hadronic Transport Model with a Phase Transition

abstract:
  We specify a tractable transport model with thermodynamic properties close to
those expected for the strongly interacting matter. In particular, at high
temperatures, the matter undergoes a phase transition, such as to the
quark-gluon plasma, with a drop in masses of elementary excitations and a rapid
increase in the number of degrees of freedom. We show that a softening of the
equation of state such as associated with the transition to quark-gluon plasma
should be observable in the elliptic-flow excitation function from heavy-ion
reactions.


title: Vector Meson Dominance and Rho-Omega Mixing

abstract:
  The scale of a phenomenologically successful charge-symmetry-violating
nucleon-nucleon interaction, that attributed to meson exchange with a $\Delta I
=1$ rho-omega transition, is set by the Coleman-Glashow SU(2) breaking tadpole
mechanism. A single tadpole scale has been obtained from symmetry arguments,
electromagnetic meson and baryon measured mass splittings, and the observed
isospin violating ($\Delta I=1$) decay $\omega \to \pi^+\pi^-$. The hadronic
realization of this tadpole mechanism lies in the $I = 1$ $a_0$ scalar meson.
We show that measured hadronic and two-photon widths of the $a_0$ meson, with
the aid of the Vector Meson Dominance model, recover the universal
Coleman-Glashow tadpole scale.


title: Relativistic corrections to the electric polarizability of the neutron

abstract:
  We demonstrate in a solvable model the connection between the intrinsic
electric polarizability $\bar{\alpha}$ and the value $\alpha_{Sch}$ obtained
from neutron-atom scattering.


title:
Hadronic properties of the S_{11}(1535) studied by electroproduction off
  the deuteron

abstract:
  Properties of excited baryonic states are investigated in the context of
electroproduction of baryon resonances off the deuteron. In particular, the
hadronic radii and the compositeness of baryon resonances are studied for
kinematic situations in which their hadronic reinteraction is the dominant
contribution. Specifically, we study the reaction $d(e,e'S_{11})N$ at $Q^2\ge 1
GeV^2$ for kinematics in which the produced hadronic state reinteracts
predominantly with the spectator nucleon. A comparison of constituent quark
model and effective chiral Lagrangian calculations of the $S_{11}$ shows
substantial sensitivity to the structure of the produced resonance.


title:
Isocalar Roper excitation in the pp --> pp pi0 reaction close to
  threshold

abstract:
  A new mechanism for the pp --> pp pi0 reaction close to threshold is
suggested coming from the isoscalar excitation of the Roper and its decay into
N(pi pi)S-wave, with one of the pi0 emitted and the other one reabsorbed on the
second nucleon. The mechanism can lead to important interference with other
mechanisms and, together with experiment, serves to exclude large ranges of the
2pi N* decay parameters allowed by the N* partial decay widths.


title:
Various Models for Pion Probability Distributions from Heavy-Ion
  Collisions

abstract:
  Various models for pion multiplicity distributions produced in relativistic
heavy ion collisions are discussed. The models include a relativistic
hydrodynamic model, a thermodynamic description, an emitting source pion laser
model, and a description which generates a negative binomial description. The
approach developed can be used to discuss other cases which will be mentioned.
The pion probability distributions for these various cases are compared.
Comparison of the pion laser model and Bose-Einstein condensation in a laser
trap and with the thermal model are made. The thermal model and hydrodynamic
model are also used to illustrate why the number of pions never diverges and
why the Bose-Einstein correction effects are relatively small. The pion
emission strength $\eta$ of a Poisson emitter and a critical density $\eta_c$
are connected in a thermal model by $\eta/n_c = e^{-m/T} < 1$, and this fact
reduces any Bose-Einstein correction effects in the number and number
fluctuation of pions. Fluctuations can be much larger than Poisson in the pion
laser model and for a negative binomial description. The clan representation of
the negative binomial distribution due to Van Hove and Giovannini is discussed
using the present description. Applications to CERN/NA44 and CERN/NA49 data are
discussed in terms of the relativistic hydrodynamic model.


title: D' Production in Heavy Ion Collisions

abstract:
  The production of d' dibaryons in heavy ion collisions due to the elementary
process NN -> d' + pion is considered. The cross section NN -> d' + pion is
estimated using the vacuum d' width = 0.5 MeV extracted from data on the double
charge exchange reactions on nuclei. The d' production rate per single
collision of heavy ions is estimated at an incident beam energy of 1 A GeV
within the framework of the Quantum Molecular Dynamics transport model. We
suggest to analyse the invariant mass spectrum of the NN + pion system in order
to search for an abundance of events with the invariant mass of the d'
dibaryon. The d' peak is found to exceed the statistical fluctuations of the
background at a level of 6 standard deviations for 2 10^5 A central collisions
of heavy ions with the atomic number A.


title:
Role of the $\Delta$ isobar in the reaction $NN \to NN\pi$ near
  threshold

abstract:
  A model calculation for pion production in nucleon-nucleon collisions is
presented. Direct production, pion rescattering and contributions from pair
diagrams are taken into account. The amplitudes for the elementary processes
are based on well established microscopic models of nucleon-nucleon and
pion-nucleon scattering. The $\Delta (1232)$ is included explicitly and is
found to play an important role even at energies close to production threshold.
A good overall agreement with existing data from the pion production threshold
up to the Delta resonance region is achieved.


title:
Excitation Function of Energy Density and Partonic Degrees of Freedom in
  Relativistic Heavy Ion Collisions

abstract:
  We estimate the energy density pile-up at mid-rapidity in central Pb+Pb
collisions from 2 - 200 GeV/nucleon. The energy density is decomposed into
hadronic and partonic contributions. A detailed analysis of the collision
dynamics in the framework of a microscopic transport model shows the importance
of partonic degrees of freedom and rescattering of leading (di)quarks in the
early phase of the reaction for lab-energies > 30 GeV/nucleon. In Pb+Pb
collisions at 160 GeV/nucleon the energy density reaches up to 4 GeV/fm^3, 95%
of which are contained in partonic degrees of freedom.


title: Removing Pions from Two-Nucleon Effective Field Theory

abstract:
  Two-nucleon effective field theory (EFT) beyond momenta of order the pion
mass is studied for both cutoff regularization and dimensional regularization
with power divergence subtraction (PDS). Models with two mass scales illustrate
how effects of long-distance pion physics must be removed from the coefficients
that encode short-distance physics. The modified effective range expansion
shows that treating pions perturbatively, as in the PDS power counting, limits
the radius of convergence of the EFT. Predictions from both regularization
schemes with one-pion contributions are compared to data. The breakdown of the
effective field theory occurs for momenta of order 300 MeV, even using the
modified effective range expansion. This behavior is shown to be consistent
with that expected from two-pion contributions.


title: Introduction to light cone field theory and high energy scattering

abstract:
  In this set of four lectures, we provide an elementary introduction to light
cone field theory and some of its applications in high energy scattering.


title: Non-ideal Particle Distributions from Kinetic Freeze Out Models

abstract:
  In fluid dynamical models the freeze out of particles across a three
dimensional space-time hypersurface is discussed. The calculation of final
momentum distribution of emitted particles is described for freeze out
surfaces, with both space-like and time-like normals, taking into account
conservation laws across the freeze out discontinuity.


title: J/Psi Suppression in Heavy Ion Collisions at the CERN SPS

abstract:
  We reexamine the production of J/Psi and other charmonium states for a
variety of target-projectile choices at the SPS. For this study we use a newly
constructed cascade code LUCIFER II, which yields acceptable descriptions of
both hard and soft processes, specifically Drell-Yan and hidden charm
production, and soft energy loss and meson production, at the SPS. Glauber
calculations of other authors are redone, and compared directly to the cascade
results. The modeling of the charmonium states differs from that of earlier
workers in its unified treatment of the hidden charm meson spectrum, which is
introduced from the outset as a set of coupled states. The result is a
description of the NA38 and NA50 data in terms of a conventional hadronic
picture. The apparently anomalous suppression found in the most massive Pb+Pb
system arises from three sources: destruction in the initial nucleon-nucleon
cascade, use of coupled channels to exploit the larger breakup in the less
bound Chi and Psi' states, and comover interaction in the final low energy
phase.


title:
The pseudo-spin symmetry in Zr and Sn isotopes from the proton drip line
  to the neutron drip line

abstract:
  Based on the Relativistic continuum Hartree-Bogoliubov (RCHB) theory, the
pseudo-spin approximation in exotic nuclei is investigated in Zr and Sn
isotopes from the proton drip line to the neutron drip line. The quality of the
pseudo-spin approximation is shown to be connected with the competition between
the centrifugal barrier (CB) and the pseudo-spin orbital potential (PSOP). The
PSOP depends on the derivative of the difference between the scalar and vector
potentials $dV/dr$. If $dV/dr = 0$, the pseudo-spin symmetry is exact. The
pseudo-spin symmetry is found to be a good approximation for normal nuclei and
to become much better for exotic nuclei with highly diffuse potential, which
have $dV/dr \sim 0$. The energy splitting of the pseudo-spin partners is
smaller for orbitals near the Fermi surface (even in the continuum) than the
deeply bound orbitals. The lower components of the Dirac wave functions for the
pseudo-spin partners are very similar and almost equal in magnitude.


title:
Combined effects of nuclear Coulomb field, radial flow, and opaqueness
  on two-pion correlations

abstract:
  Correlations of two like charged pions emitted from a hot and charged
spherically expanding nuclear system are investigated. The motion of the pions
is described quantum mechanically using the Klein-Gordon equation which
includes Coulomb field and pion absorption. Flow modifies the radial
distribution of the source function and rescales the pion wave functions. The
radii extracted from the correlation functions are calculated in sideward and
outward direction as a function of the pair momentum. Comparison with recent
measurements at SIS and AGS energies is made.


title: Photopion reactions on deltas preexisting in nuclei

abstract:
  Reactions A(\gamma, pi^+p) are considered to proceed through the formation of
pion-proton pairs on delta constituents in nuclei. We develop the
nonrelativistic operator for \Delta^{++}(\gamma, pi^+)p process in an arbitrary
frame. The calculated cross section for C12(\gamma, \pi^+p) reaction is
compared to the existing experimental data.


title: Inside Mesons: Coupling Constants and Form Factors

abstract:
  We illustrate the progress of covariant QCD phenomenology for the description
of meson coupling constants and form factors. As examples, we discuss the
$\rho\pi\pi$ and $\gamma \pi\rho$ interactions, the $\rho$ contribution to the
pion charge radius, and the $\rho NN$ and $\omega NN$ vector and tensor
coupling constants and form factors.


title:
Unified Description of Freeze-Out Parameters in Relativistic Heavy Ion
  Collisions

abstract:
  It is shown that the chemical freeze-out parameters obtained at CERN/SPS,
BNL/AGS and GSI/SIS energies all correspond to a unique value of 1 GeV per
hadron in the local rest frame of the system, independent of the beam energy
and of the target and beam particles.


title:
Gluon Field Dynamics in Ultra-Relativistic Heavy-Ion Collisions: Time
  evolution on a Gauge Lattice in 3+1 Dimensions

abstract:
  We describe the dynamics of gluons and quarks in a relativistic nuclear
collision, within the framework of classical mean-field transport theory, by
the coupled equations for the classical Yang-Mills field and a collection of
colored point particles. The particles represent the valence quarks in the
colliding nuclei. We explore the time evolution of the gauge field in a
numerical simulation of the collision of two Lorentz-boosted ``nuclei'' on a
long three-dimensional gauge lattice. We report first results on soft gluon
scattering and coherent gluon radiation.


title: Charmonium production from the hadronic phase

abstract:
  Charmonium production from the hadron gas formed in ultra-relativistic
heavy-ion collisions is studied. Using the $J/\psi$-hadron absorption cross
section determined from the nonperturbative quark-exchange model, which has a
peak value similar to that used in the comover model for $J/\psi$ suppression
and a thermally averaged value consistent from that extracted from $J/\psi$
data in heavy-ion collisions, we find that $J/\psi$ production from the hadron
gas is negligible in heavy-ion collisions at RHIC energies but is important at
LHC energies as a result of the large number of charm mesons produced at higher
energy collisions. The number of $J/\psi$ produced from these secondary
collisions at LHC may be comparable to that of primary $J/\psi$'s, which are
expected to be dissociated in the quark-gluon plasma created in the collisions,
leading thus to a possible absence of $J/\psi$ suppression. Similar results are
obtained for $\psi^\prime$ production in ultra-relativistic heavy-ion
collisions.


title:
Enhancement of Intermediate Mass Dileptons From Charm Decays At SPS
  Energies

abstract:
  We study the dimuon yield from open charm decays in the intermediate mass
region(IMR) in heavy-ion collisions at the CERN-SPS energy. We find that final
state rescatterings which broaden the $m_T$ spectrum of charmed mesons can
enrich the part of the phase space covered by the NA50 experiment, thus leading
to an apparent enhancement of IMR dileptons within the acceptance of the
experiment. Such an enhancement increases with the dimuon invariant mass and
the single muon energy cut-off.


title: Jost function for coupled channels

abstract:
  Recently, we proposed an exact method for direct calculation of the Jost
function for central potentials (which may have Coulombic tails) and the Jost
matrix for non-central short range potentials. This method works for all real
or complex momenta of physical interest, including the spectral points
corresponding to bound and Siegert states. In this work we extend it for
potentials which couple channels with different thresholds. The proposed method
is based on simple differential equations of the first order, which can be
easily solved numerically. Thus, the spectrum generated by any given potential
can be thoroughly investigated. At the same time the physical wave function can
be obtained having the correct asymptotic behaviour.


title:
Calculation of Higher Order Effects in Electron-Positron Pair Production
  in Relativistic Heavy Ion Collisions

abstract:
  We present a calculation of higher order effects for the impact parameter
dependent probability for single and multiple electron-positron pairs in
(peripheral) relativistic heavy ion collisions. Also total cross sections are
given for SPS and RHIC energies. We make use of the expression derived recently
by several groups where the summation of all higher orders can be done
analytically in the high energy limit. An astonishing result is that the cross
section, that is, integrating over all impact parameters, is found to be
identical to the lowest-order Born result for symmetric collisions. For the
probability itself on the other hand we find rather large effects at small
impact parameters compared to the lowest order results, which translate to
large effects for the cross section for multiple pair production.


title: Cranked shell model and isospin symmetry near N=Z

abstract:
  A cranked shell model approach for the description of rotational bands in
$N\approx Z$ nuclei is formulated. The isovector neutron-proton pairing is
taken into account explicitly. The concept of spontaneous breaking and
subsequent restoration of the isospin symmetry turns out to be crucial. The
general rules to construct the near yrast-spectra for rotating nuclei are
presented. For the model case of particles in a j-shell, it is shown that
excitation spectra and the alignment processes are well described as compared
to the exact shell model calculation. Realistic cranked shell model
calculations are able to describe the experimental spectra of $^{72,73}$Kr and
$^{74}$Rb isotopes. \


title: Angular Correlations in Breakup of Three-Body Halo Nuclei

abstract:
  We use the three-body model and the sudden approximation to compute angular
correlations in high-energy fragmentation reactions of two-neutron halos on
light targets. The contribution from one-neutron absorption by far dominates
over that of neutron scattering. We use 6He (n+n+alpha) and 11Li (n+n+9Li) as
examples and study the dependence of the predictions of this model on different
physical assumptions and parameters.
  PACS number(s): 25.60.-t, 25.60.Gc, 21.45.+v}


title: Low Energy Theorems For Nucleon-Nucleon Scattering

abstract:
  Low energy theorems are derived for the coefficients of the effective range
expansion in s-wave nucleon-nucleon scattering valid to leading order in an
expansion in which both $m_\pi$ and $1/a$ (where $a$ is the scattering length)
are treated as small mass scales. Comparisons with phase shift data, however,
reveal a pattern of gross violations of the theorems for all coefficients in
both the $^1S_0$ and $^3S_1$ channels. Analogous theorems are developed for the
energy dependence $\epsilon$ parameter which describes $^3S_1 - ^3D_1$ mixing.
These theorems are also violated. These failures strongly suggest that the
physical value of $m_\pi$ is too large for the chiral expansion to be valid in
this context. Comparisons of $m_\pi$ with phenomenological scales known to
arise in the two-nucleon problem support this conjecture.


title: Multiphonon and ``hot''-phonon Isovector Electric-Dipole Excitations

abstract:
  We argue that a substantial increase in the cross section for Coulomb
excitation in the region of the Double Giant Dipole Resonance should be
expected from Coulomb excitation of excited states involved in the spreading of
the one-phonon resonance, in a manifestation of the Brink-Axel phenomenon. This
generates an additional fluctuating amplitude and a corresponding new term to
be added incoherently to the usual cross-section. The appropriate extension of
an applicable reaction calculation is considered in order to estimate this
effect.


title: Decay theory of double giant resonances

abstract:
  The decay theory of double giant resonances incorporating fluctuation
contributions of the Brink-Axel type is developed. The gamma and neutron
emission decay of Double Giant Dipole Resonances (DGDR) in 208Pb is discussed
in connection with a recent measurement.


title: The stability of the spectator, Dirac, and Salpeter equations for mesons

abstract:
  Mesons are made of quark-antiquark pairs held together by the strong force.
The one channel spectator, Dirac, and Salpeter equations can each be used to
model this pairing. We look at cases where the relativistic kernel of these
equations corresponds to a time-like vector exchange, a scalar exchange, or a
linear combination of the two. Since the model used in this paper describes
mesons which cannot decay physically, the equations must describe stable
states. We find that this requirement is not always satisfied, and give a
complete discussion of the conditions under which the various equations give
unphysical, unstable solutions.


title:
Scaling of particle production with number of participants in
  high-energy A+A collisions in the parton-cascade model

abstract:
  In view of the recent WA98 data of pi0 spectra from central Pb+Pb collisions
at the CERN SPS, we analyze the production of neutral pions for A+$ collisions
across the periodic table at sqrt(s)=17 AGeV and 200 AGeV within the framework
of the parton-cascade model for relativistic heavy ion collisions. The
multiplicity of the pions (having pT > 0.5 GeV/c) in the central rapidity
region, is seen to scale as \sim (N_part)^alpha, where N_part$ is the number of
participating nucleons, which we have approximated as 2A for central collisions
of identical nuclei. We argue that the deviation of \alpha (\simeq 1.2) from
unity may have its origin in the multiple scattering suffered by the partons.
We also find that the constant of proportionality in the above scaling relation
increases substantially in going from SPS to RHIC energies. This would imply
that the (semi)hard partonic activity becomes a much cleaner signal above the
soft particle production at the higher energy of RHIC, and thus much less
dependent on the (lack of) understanding of the underlying soft physics
background.


title:
Bose-Einstein Final State Symmetrization for Event Generators of Heavy
  Ion Collisions

abstract:
  We discuss algorithms which allow to calculate identical two-particle
correlations from numerical simulations of relativistic heavy ion collisions. A
toy model is used to illustrate their properties.


title: Multiquark picture for Sigma(1620)

abstract:
  In this work we report on a new QCD sum rule analysis to predict masses of
the excited baryon states (e.g. Sigma(1620) and Lambda(1405)) by using
multiquark interpolating fields ($(q\bar{q})(qqq)$). For the Sigma(1620) we
consider the $\bar{K}N$, $\pi\Sigma$, and $\pi\Lambda$ (I=1) multiquark
interpolating fields. The calculated mass from those multiquark states is about
1.592 GeV. For the Lambda(1405) we first show the result using the
  $\pi^+\Sigma^- + \pi^0\Sigma^0 + \pi^-\Sigma^+$ (I=0) multiquark
interpolating field, and compare the calculated mass to that of our previous
result using the $\pi^0\Sigma^0$ multiquark state. We then show that the mass
1.405 GeV is well reproduced when using the $\bar{K}N$ (I=0) multiquark state.
The uncertainties in our sum rules are also discussed.


title:
Semiclassical description of multiple giant dipole resonance excitation
  and decay

abstract:
  A semiclassical description of multiple giant resonance excitation and decay
that incorporates incoherent fluctuation contributions of the Brink-Axel type
is developed. Numerical calculations show that the incoherent contributions are
important at low to intermediate bombarding energies.


title:
Ground State Wave Functions in the Hyperspherical Formalism for Nuclei
  with A > 4

abstract:
  The general formulation of a technically advantageous method to find the
ground state solution of the Schrodinger equation in configuration space for
systems with a number of particles A greater than 4 is presented. The wave
function is expanded in pair correlated hyperspherical harmonics beyond the
lowest order approximation and then calculated in the Faddeev approach. A
recent efficient recursive method to construct antisymmetric A-particle
hyperspherical harmonics is used. The accuracy is tested for the bound state
energies of nuclei with A = 6,8,12. The high quality of the obtained results
becomes evident from a comparison with other approaches.


title: Magnetic Radius of the Deuteron

abstract:
  The root-mean square radius of the deuteron magnetic moment distribution, $
r_{Md}$, is calculated for several realistic models of the $NN$--interaction.
For the Paris potential the result is $r_{Md} = 2.312 \pm 0.010 $ fm. The
dependence of $r_{Md} $ on the choice of $NN$ model, relativistic effects and
meson exchange currents is investigated. The experimental value of $r_{Md}$ is
also considered. The necessity of new precise measurements of the deuteron
magnetic form factor at low values of $Q^2$ is stressed.


title: Radiative capture of protons by deuterons

abstract:
  The differential cross section for radiative capture of protons by deuterons
is calculated using different realistic NN interactions. We compare our results
with the available experimental data below $E_x = 20 MeV$. Excellent agreement
is found when taking into account meson exchange currents, dipole and
quadrupole contributions, and the full initial state interaction. There is only
a small difference between the magnitudes of the cross sections for the
different potentials considered. The angular distributions, however, are
practically potential independent.


title: Soft Electromagnetic Radiations From Equilibrating Quark-Gluon Plasma

abstract:
  We evaluate the bremsstrahlung production of low mass dileptons and soft
photons from equilibrating and transversely expanding quark gluon plasma which
may be created in the wake of relativistic heavy ion collisions. We use initial
conditions obtained from the self screened parton cascade model. We consider a
boost invariant longitudinal and cylindrically symmetric transverse expansion
of the parton plasma and find that for low mass dileptons ($M \leq 0.3$ GeV)
and soft photons ($p_{T} \leq 0.5$ GeV), the bremsstrahlung contribution is
rather large compared to annihilation process at both RHIC and LHC energies. We
also find an increase by a factor of 15-20 in the low mass dileptons and soft
photons yield as one goes from RHIC to LHC energies.


title:
Omega- and Phi-meson production in pn -> dV reactions and OZI-rule
  violation

abstract:
  We investigate the reactions p n -> d omega and p n -> d phi close to
threshold and at higher energies. Near threshold we calculate the S-wave
amplitudes within the framework of the two-step model which is described by a
triangle graph with pi-mesons in the intermediate state and find a ratio of the
S-wave amplitudes squared of R =|A(phi)|^2/|A(omega)|^2 = (4-8) x 10^{-3}. Any
significant enhancement of the experimental value of R(phi/omega) over this
prediction can be interpreted as a possible contribution of the intrinsic s -
anti s component in the nucleon-wave function. We present arguments that there
is a strong resonance effect in the omega N channel close to threshold. At
higher energies we calculate the differential cross sections of the reactions p
n -> d omega, p n -> d phi and the ratio of the phi/omega yields within the
framework of the quark-gluon string model. An irregular behavior of the
phi/omega-ratio is found at s <= 12 GeV^2 due to the interference of the t- and
u-channel contributions.


title: Canonical Ensemble of Initial States Leading to Chiral Fluctuations

abstract:
  In energetic heavy ion collisions, if quark-gluon plasma is formed, its
hadronization may lead to observable critical fluctuations, i.e., DCC
formation. The strength and observability of these fluctuations depend on the
initial state. Here we study the canonical ensemble of initial states of chiral
fluctuations in heavy ion collisions and the probability to obtain observable
domains of chiral condensates.


title: Dirac Sea Effects on Superfluidity in Nuclear Matter

abstract:
  We study two kinds of Dirac sea effects on the $^1S_0$ pairing gap in nuclear
matter based on the relativistic Hartree approximation to quantum hadrodynamics
and the Gor'kov formalism. We show that the vacuum fluctuation effect on the
nucleon effective mass is more important than the direct coupling between the
Fermi sea and the Dirac sea due to the pairing interaction. The effects of the
high-momentum cutoff are also discussed.


title: Coefficients of Fractional Parentage for Nuclear Shell Model

abstract:
  A new procedure for the calculation of shell model coefficients of fractional
parentage has been developed. This procedure is free of numerical
diagonalization, orthogonalization, and even of grop theoretical classification
of antisymmetric states.


title: Intrinsic Density Matrices of the Nuclear Shell Model

abstract:
  A new method for calculation of shell model intrinsic density matrices,
defined as two-particle density matrices integrated over the centre-of-mass
position vector of two last particles and complemented with isospin variables,
has been developed. The intrinsic density matrices obtained are completely
antisymmetric, translation-invariant, and do not employ a group-theoretical
classification of antisymmetric states. They are used for exact realistic
density matrix expansion within the framework of the reduced Hamiltonian
method. The procedures based on precise arithmetic for calculation of the
intrinsic density matrices that involve no numerical diagonalization or
orthogonalization have been developed and implemented in the computer code.


title: Elimination of Spurious States of Oscillator Shell Model

abstract:
  A new method for elimination of the 'spurious' states comprising reguirement
of translational invariance and simplicity of the enumeration scheme of
antisymmetric A-particle states has been developed. The method presented
enables one to project off the space of purely spurious antisymmetric
A-particle oscillator functions with singled out dependence on intrinsic
coordinates of two last particles onto the subspace of the nonspurious motion.
The method is based on constructing the matrix elements of the centre-ofmass
Hamiltonian and spectral decomposition of the corresponding real symmetric
matrix. The obtained coefficients of the expansion of the antisymmetric
A-particle oscillator functions in terms of the ones with singled out
dependence on intrinsic coordinates of two last particles and with eliminated
spurious states are required for calculation of two-particle oscillator
intrinsic density matrices. Software tools based on root rational fraction
expression of numbers for the theoretical formulation presented have been
developed.


title:
Effects of hyperons on the dynamical deconfinement transition in cold
  neutron star matter

abstract:
  The influence of the presence of hyperons in dense hadronic matter on the
quantum nucleation of quark matter is examined at low temperatures relevant to
neutron star cores. We calculate the equation of state and the composition of
matter before and after deconfinement by using a relativistic mean-field theory
and an MIT bag model, respectively; the case in which hyperons are present in
the hadronic system is considered, together with the case of the system without
hyperons. We find that strangeness contained in hyperons acts to reduce a
density jump at deconfinement as well as a lepton fraction in the hadronic
phase. As a result of these reductions, a quark matter droplet being in a
virtual or real state has its effective mass lightened and its electric charge
diminished into nearly zero. The Coulomb screening of leptons on the droplet
charge, which has significance to the droplet growth after nucleation in the
absence of hyperons, is thus shown to be of little consequence. If the
effective droplet mass is small enough to become comparable to the height of
the potential barrier, the effect of relativity brings about an exponential
increase in the rate of droplet formation via quantum tunneling, whereas the
role played by energy dissipation in decelerating the droplet formation,
dominant for matter without hyperons, becomes of less importance. For matter
with and without hyperons, we estimate the overpressure needed to form the
first droplet in the star during the compression due to stellar spin-down or
mass accretion from a companion star. The temperature at which a crossover from
the quantum nucleation to the Arrhenius-type thermal nucleation takes place is
shown to be large compared with the temperature of matter in the core.


title: Microscopic structure of a vortex line in superfluid neutron star matter

abstract:
  The microscopic structure of an isolated vortex line in superfluid neutron
star matter is studied by solving the Bogoliubov-de Gennes equations. Our
calculation, which is the starting point for a microscopic calculation of
pinning forces in neutron stars, shows that the size of the vortex core varies
differently with density, and is in general smaller than assumed in some
earlier calculations of vortex pinning in neutron star crusts. The implications
of this result are discussed


title:
Non-perturbative renormalization group equations and approximate
  discrete gamma_5-symmetry in quantum hadrodynamics

abstract:
  The quantum hadrodynamics are studied by using non-perturbative
renormalization group equations. Approximate discrete gamma_5-symmetry is
studied. It is shown that the contributions of one-loop diagrams are important
for effective potential. A relation between the local-potential approximation
and the usual Hartree approximation is discussed. The local-potential
approximation includes contribution of the Fock term to nucleon self-energy,
contribution in the usual random phase approximation to meson self-energy and
vertex corrections in part as well as the Hartree contribution to the effective
potential. Approximate discrete gamma_5-symmetry is studied phenomenologically
in the Hartree approximation. This approximate symmetry may exist in nuclear
matter.


title:
The nucleus as a fluid of skyrmions: Energy levels and nucleon
  properties in the medium

abstract:
  A model of a fluid of skyrmions coupled to a scalar and to the $\o $ meson
mean fields is developed. The central and spin-orbit potentials of a skyrmion
generated by the fields predict correct energy levels in selected closed shell
nuclei. The effect of the meson fields on the properties of skyrmions in nuclei
is investigated.


title: Two-pion exchange and strong form-factors in covariant field theories

abstract:
  In this work improvements to the application of the Gross equation to nuclear
systems are tested. In particular we evaluate the two pion exchange diagrams,
including the crossed-box diagram, using models developed within the
spectator-on-mass-shell covariant formalism. We found that the form factors
used in these models induce spurious contributions that violate the unitary cut
requirement. We tested then some alternative form-factors in order to preserve
the unitarity condition. With this new choice, the difference between the exact
and the spectator-on-mass-shell amplitudes is of the order of the one boson
scalar exchange, supporting the idea that this difference may be parameterized
by this type of terms.


title:
Longitudinal and Transverse Spin Responses in Relativistic Many Body
  Theory

abstract:
  Spin longitudinal and transverse response function are studied by means of
the relativistic many-body theory. The spin response functions in the
relativistic theory are largely reduced from those in the non-relativistic
theory. The local density approximation with the eikonal approximation is
applied to the the nuclear absorption in the $(\vec{p},\vec{n})$ reactions on C
and Ca. We compare the calculated results with the recent experimental data.


title: Search for excited states in H-3 and He-3

abstract:
  The d+N systems are studied in a three-body model, using phenomenological N-N
interactions. The scattering matrices are calculated by using the Kohn-Hulthen
variational method. Then, they are analytically continued to complex energies
and their singularities are localized. We find a virtual state at E=-1.66 MeV
in H-3 and a pair of states at E=(-0.42+-i0.52) MeV in He-3 relative to the d+N
thresholds, respectively. In addition, we discuss some general aspects and
problems of virtual states which may be useful also in the study of other
systems, like Li-10.


title: Hadronic modes in the quark plasma with an internal symmetry

abstract:
  We show that requiring the quark partition function to be color singlet of
SU(3) color gauge group leads to reordering the thermodynamic potential in
terms of the colorless multi-quark modes ($q{\bar q}, qqq, {\bar q}{\bar
q}{\bar q}, ...$) at any given temperature. In accord with the "preconfinement"
property of QCD, under a suitable confining mechanism, these could evolve into
color singlet hadrons/baryons at low temperatures. At fairly high temperatures
these multi-quark color singlet structures propagate in the plasma like
hadronic modes, just as in the more familiar low temperature phase. This
suggests that there exists a strong correlation in the plasma at all
temperatures which is in conformity with lattice results.


title: Strangeness Modes in Nuclei Tested by Anti-Neutrinos

abstract:
  Production of negative strangeness in reactions of inelastic anti-neutrino
scattering on a nucleus provides information on the modification of strange
degrees of freedom in nuclear matter. We calculate cross-sections of the
reaction channels $\bar{\nu}_{e(\mu)}\to e^+(\mu^+) + K^{-}$ and
$\bar{\nu}_{e(\mu)} + p \to \Lb + e^+(\mu^+)$ and investigate their sensitivity
to the medium effects. In particular, we consider effects induced by the
presence of a low-energy excitation mode in the $K^-$ spectrum, associated with
the correlated $\Lambda$-particle and proton-hole states, and the
renormalization of the weak interaction in medium. In order to avoid double
counting, various contributions to anti-neutrino scattering are classified with
the help of the optical theorem, formulated within the non-equilibrium Green's
function technique.


title:
Fragment Multiplicity Distributions, a Signal of True Nuclear
  Multifragmentation

abstract:
  Multiplicity fluctuations of intermediate-mass fragments are studied with the
percolation model. It is shown that super-Poissonian fluctuations occur near
the percolation transition and that this behavior is associated with the
fragmentative nature of the percolation model. The consequences of various
choices in defining and binning fragments are also evaluated. Several
suggestions for experiments in nuclear fragmentation are presented.


title:
B-Spline Finite Elements and their Efficiency in Solving Relativistic
  Mean Field Equations

abstract:
  A finite element method using B-splines is presented and compared with a
conventional finite element method of Lagrangian type. The efficiency of both
methods has been investigated at the example of a coupled non-linear system of
Dirac eigenvalue equations and inhomogeneous Klein-Gordon equations which
describe a nuclear system in the framework of relativistic mean field theory.
Although, FEM has been applied with great success in nuclear RMF recently, a
well known problem is the appearance of spurious solutions in the spectra of
the Dirac equation. The question, whether B-splines lead to a reduction of
spurious solutions is analyzed. Numerical expenses, precision and behavior of
convergence are compared for both methods in view of their use in large scale
computation on FEM grids with more dimensions. A B-spline version of the object
oriented C++ code for spherical nuclei has been used for this investigation.


title:
Saturation Properties of Nuclear Matter with a Nonlocal Confining
  Solitons

abstract:
  We examine saturation properties of a quark-based picture of nuclear matter.
Soliton matter consisting of nonlocal confining solitons is used to model
nuclear matter. Each composite nucleon is described by a non-topological
soliton as given by the Global Color Model. We apply techniques and concepts
from the discription of crystal lattices. In particular, the Wigner-Seitz
approximation is used to calculate the properties of the soliton lattice at the
mean-field level. We focus on infinite nuclear matter at around standard
nuclear matter density with the simplest one-parameter assumption for the gluon
propagator. the saturation density and incompressibility are calculated as
functions of the single parameter of the model


title:
Size Matters: Origin of Binomial Scaling in Nuclear Fragmentation
  Experiments

abstract:
  The relationship between measured transverse energy, total charge recovered
in the detector, and size of the emitting system is investigated. Using only
very simple assumptions, we are able to reproduce the observed binomial
emission probabilities and their dependences on the transverse energy.


title: Coulomb and nuclear breakup of $^8$B

abstract:
  The cross sections for the ($^8$B,$^7$Be-$p$) breakup reaction on $^{58}$Ni
and $^{208}$Pb targets at the beam energies of 25.8 MeV and 415 MeV have been
calculated within a one-step prior-form distorted-wave Born approximation. The
relative contributions of Coulomb and nuclear breakup of dipole and quadrupole
multipolarities as well as their interference have been determined. The nuclear
breakup contributions are found to be substantial in the angular distributions
of the $^7$Be fragment for angles in the range of 30$^\circ$ - 80$^\circ$ at
25.8 MeV beam energy. The Coulomb-nuclear interference terms make the dipole
cross section larger than that of quadrupole even at this low beam energy.
However, at the incident energy of 415 MeV, these effects are almost negligible
in the angular distributions of the ($^7$Be-p) coincidence cross sections at
angles below 4$^\circ$.


title: On Mesoatoms of the Deuterium and Possible Existence of Exotic Dibaryons

abstract:
  As a desirable supplement to the reaction $pp \to pp2\gamma$, proposed
earlier (nucl-th/9712064 and references therein) to probe for the NN--decoupled
dibaryon resonances we suggest to use for the same goal the radiative capture
processes in mesoatoms of the deuterium which we consider to be especially
feasible for further test and invesigation of possible low-lying exotic
resonance states.


title: Meson-nucleon scattering and vector mesons in nuclear matter

abstract:
  The properties of vector mesons in nuclear matter are discussed. I examine
the constraints imposed by elementary processes on the widths of $\rho$ and
$\omega$ mesons in nuclear matter. Furthermore, results for the $\rho$- and
$\omega$-nucleon scattering amplitudes obtained by fitting meson-nucleon
scattering data in a coupled-channel approach are presented.


title: Describing Hot and Dense Nuclear Matter with Gauged Linear sigma-Model

abstract:
  To describe nuclear matter at high temperature and high baryon density
appropriate for RHIC and LHC, an effective theory is proposed. Three
developments underlie the effective theory: (1) relativistic mean field theory
description of nuclear matter with mesons mediating interactions; (2)
topological soliton description of the nucleon with hidden local symmetry; (3)
phenomenological knowledge of nucleon-nucleon interaction and nucleon structure
obtained from elastic NN scattering at c.m. energies of hundreds of GeV. When
these developments are combined together, a gauged linear sigma-model with
anomalous action and condensed quark-antiquark ground state emerges as the
effective theory.


title:
Nonlinear Enhancement of the Multiphonon Coulomb Excitation in
  Relativistic Heavy Ion Collisions

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. Enhancement of the Double Giant Resonance excitation
probabilities in relativistic ion collisions scales as $(2 k +1)(2k)^{-1}$ for
the degree of nonlinearity $(2k)^{-1}$ and is able to reach values $1.5-2$
compatible with experimental data. The enhancement factor is found to decrease
with increasing bombarding energy. [KEYWORDS: Relativistic Heavy Ion
Collisions,Double Giant Resonance]


title:
Chemical equilibration in viscous quark-gluon plasma and electromagnetic
  signals

abstract:
  We investigate the chemical equilibration of the parton distributions in
collisions of two heavy nuclei, assuming the partonic fluid to be ideal as well
as viscous. The initial conditions are taken from HIJING calculations for Au+Au
collisions at RHIC and LHC energies. It was seen that when the viscous drag is
taken into account in the fluid flow, the life time of the plasma is increased
by nearly a factor of 2. The temperature as well as fugacities evolve slowly
than their ideal counterpart. The photon and lepton pair production was also
investigated. There is a two fold increase in the photon and lepton pair
numbers with viscosity on. The increase in the large $p_T$ photons and the
large invariant mass lepton pairs are due to slower rate of temperature
evolution.


title: Asymptotic expansion in the fission process

abstract:
  Asymptotic expansion of the Fokker-Planck equation in terms of the strength
of the fluctuation has been carried out. The mean and the variance of the total
kinetic energies of the fission fragments have been calculated and compared
with the experimental values.


title: Mean field exponents and small quark masses

abstract:
  We demonstrate that the restoration of chiral symmetry at finite-T in a class
of confining Dyson-Schwinger equation (DSE) models of QCD is a mean field
transition, and that an accurate determination of the critical exponents using
the chiral and thermal susceptibilities requires very small values of the
current-quark mass: log_{10}(m/m_u) < -5. Other classes of DSE models
characterised by qualitatively different interactions also exhibit a mean field
transition. Incipient in this observation is the suggestion that mean field
exponents are a result of the gap equation's fermion substructure and not of
the interaction.


title:
Hadron Probing of the Deuteron Structure at Short Distances in Deuteron
  Breakup Reactions

abstract:
  We discuss deuteron $A(d,p)X$ breakup and cumulative pion production
$A(d,\pi)X$ in the framework of constituent quark model of the deuteron. We
demonstrate that consideration of the Pauli principle at the quark level, as
well as multiple scattering, affect drastically cross section and polarization
observables of these reactions and provide good description of the experimental
data.


title:
Bose-Einstein Correlations and the Equation of State of Nuclear Matter
  in Relativistic Heavy-Ion Collisions

abstract:
  Experimental spectra of the CERN/SPS experiments NA44 and NA49 are fitted
while using four different equations of state of nuclear matter within a
relativistic hydrodynamic framework. For the freeze-out temperatures, $T_f =
139$ MeV and $T_f = 116$ MeV, respectively, the corresponding freeze-out
hypersurfaces and Bose-Einstein correlation functions for identical pion pairs
are discussed. It is concluded, that the Bose-Einstein interferometry measures
the relationship between the temperature and the energy density in the equation
of state of nuclear matter at the late hadronic stage of the fireball
expansion. It is necessary, to use the detailed detector acceptances in the
calculations for the Bose-Einstein correlations.


title: Bremsstrahlung in $\alpha$ Decay

abstract:
  A quantum mechanical analysis of the bremsstrahlung in $\alpha$ decay of
$^{210}$Po is performed in close reference to a semiclassical theory. We
clarify the contribution from the tunneling, mixed, outside barrier regions and
from the wall of the inner potential well to the final spectral distribution,
and discuss their interplay. We also comment on the validity of semiclassical
calculations, and the possibility to eliminate the ambiguity in the nuclear
potential between the alpha particle and daughter nucleus using the
bremsstrahlung spectrum.


title: Few nucleon dynamics in a nuclear medium

abstract:
  Few body methods are used in many particle physics to describe correlations,
bound states, and reactions in strongly correlated quantum systems. Although
this has already been recognized earlier, rigorous attempts to treat three-body
collisions have only been done recently. In this talk I shall give examples and
areas where few-body methods have been and might be of use in the future.


title: Nonlinear dynamics of giant resonances in atomic nuclei

abstract:
  The dynamics of monopole giant resonances in nuclei is analyzed in the
time-dependent relativistic mean-field model. The phase spaces of isoscalar and
isovector collective oscillations are reconstructed from the time-series of
dynamical variables that characterize the proton and neutron density
distributions. The analysis of the resulting recurrence plots and correlation
dimensions indicate regular motion for the isoscalar mode, and chaotic dynamics
for the isovector oscillations. Information-theoretic functionals identify and
quantify the nonlinear dynamics of giant resonances in quantum systems that
have spatial as well as temporal structure.


title: QCD sum rule calculation of the $\pi NN$ coupling-revisited

abstract:
  In the conventional QCD sum rule calculation for the $\pi NN$ coupling beyond
the soft-pion limit, there are three distinct Dirac structures, each of which
can be used to construct separate sum rule. We point out subtleties in the
previous sum rule results, based on one of the Dirac structure, associated with
using either the PV or the PS coupling schemes in modeling the phenomenological
side. We propose a sum rule coming from a different Dirac structure, which is
independent of the coupling schemes used and has less uncertainty in the OPE.
The obtained value is $g_{\pi N}=9.76 \pm 2.04$ where the uncertainty mainly
comes from the quark-gluon mixed condensate.


title:
Semiclassical Origin of Superdeformed Shell Structure in the Spheroidal
  Cavity Model

abstract:
  Classical periodic orbits responsible for emergence of the superdeformed
shell structures for single-particle motions in spheroidal cavities are
identified and their relative contributions to the shell structures are
evaluated. Both prolate and oblate superdeformations (axis ratio about 2:1) as
well as prolate hyperdeformation (axis ratio about 3:1) are investigated.
Fourier transforms of quantum spectra clearly show that three-dimensional
periodic orbits born out of bifurcations of planar orbits in the equatorial
plane become predominant at large prolate deformations, while butterfly-shaped
planar orbits bifurcated from linear orbits along the minor axis are important
at large oblate deformations.


title:
Time-dependent properties of proton decay from crossing single-particle
  metastable states in deformed nuclei

abstract:
  A dynamical study of the decay of a metastable state by quantum tunneling
through an anisotropic, non separable, two-dimensional potential barrier is
performed by the numerical solution of the time-dependent Schrodinger equation.
Initial quasi- stationary proton states are chosen in the framework of a
deformed Woods-Saxon single-particle model. The decay of two sets of states
corresponding to true and quasi levels-crossing is studied and the evolution of
their decay properties as a function of nuclear deformation is calculated
around the crossing point. The results show that the investigation of the
proton decay from metastable states in deformed nuclei can unambiguously
distinguish between the two types of crossing and determine the structure of
the nuclear states involved.


title: Axial and Vector Correlator Mixing in Hot and Dense Hadronic Matter

abstract:
  We study the manifestations of chiral symmetry restoration which have a
significance for the parity mixing. Restricting to pions and nucleons we
establish a formalism for the expression of the vector correlator, which
displays the mixing of the axial correlator into the vector one and unifies the
cases of the heat bath and the dense medium. We give examples of mixing
cross-sections. We also establish a link between the energy integrated mixing
cross-sections and the pion scalar density which governs the quenching factors
of coupling constants, such as the pion decay one, as well as the quark
condensate evolution.


title: Neutron Transfer to the Continuum Reactions

abstract:
  In this contribution we show that the theory of neutron transfer to the
continuum reactions is an useful tool to study different characteristics of the
single particle structure of nuclei. In one example we discuss properties of
the single particle resonances in $^{208}Pb$. Another interesting application
deals with the neutron breakup from weakly bound nuclei. Here one can use the
theoretical calculations to help establishing the angular momentum of the
decaying state which is experimentally not known.


title: Isospin breaking in the reaction np --> dpi^0 at threshold

abstract:
  The model for charge symmetry breaking in the reaction np --> dpi^0 applied
earlier around the Delta region is used to calculate the integrated
forward-backward asymmetry of the cross section close to threshold. The mixing
of the pi and eta mesons appears as strongly dominant at these energies. This
contrasts elastic np scattering experiments, where the np mass difference in
OPE dominates, or np --> d\pi^0 closer to the Delta region.


title: Relaxation of fast collective motion in heated nuclei

abstract:
  The damping of the collective vibrations in hot nuclei is studied within the
semiclassical Vlasov-Landau kinetic theory. The extention of the method of
independent sources of dissipation is used to allow for irreversible energy
transfer by chaos weighted wall formula. The expressions for the intrinsic
width of the giant multipole resonances are obtained. The interplay between the
one-body and the two-body channels which contribute to the formation of the
intrinsic width in nuclei is discussed.


title: Simple analytic solution of fireball hydrodynamics

abstract:
  A new family of simple analytic solutions of hydrodynamics is found for
non-relativistic, rotationally symmetric fireballs assuming an ideal gas
equation of state. The solution features linear flow profile and a non-trivial
transverse temperature profile. The radial temperature gradient vanishes only
in the collisionless gas limit. The Zimanyi-Bondorf-Garpman solution and the
Buda-Lund parameterization of expanding hydrodynamical sources are recovered as
special cases. The results are applied to predict new features of proton-proton
correlations and spectra data at 1.93 AGeV Ni + Ni reactions.


title:
An investigation of interplay between dissipation mechanisms in heated
  Fermi systems by means of radiative strength functions

abstract:
  A simple analytical expression for the gamma-decay strength function is
derived with microcanonical ensemble for initial excited states. The approach
leads to both a non-zero limit of the strength function for vanishing gamma-ray
energy and a partial breakdown of Brink hypothesis. It is shown that the low
energy behaviour of the gamma-decay strength functions is governed by the
energy behavior of the damping width. It may provides a new tool for study of
the interplay between different relaxation mechanisms of the collective
excitations.


title: Signatures of QCD Matter at RHIC

abstract:
  We discuss possible experimental signatures of forming a Quark-Gluon plasma
in high energy nuclear collisions. In first order phase transitions such as the
chiral symmetry restoration supercooling may lead to density fluctuations such
as droplet formation and hot spots. These will lead to rapidity fluctuations
event-by-event and triggering on such fluctuations will have distinct effects
for HBT radii.


title:
Specific Interactions at Cosmic Ray Energies for Extensive Air Showers
  Experiments

abstract:
  The HIJING and VENUS models of relativistic hadron-nucleus and
nucleus-nucleus collisions are used to study interactions of hadron-hadron,
hadron-nitrogen and nucleus-nitrogen collisions, specific for the extensive air
shower developments initiated by cosmic rays in the atmosphere. The transverse
energy, transverse momenta and spectra of secondary particles as well as their
energy and mass dependence have been investigated in detail. Results are
presented with particular emphasis on the contributions of minijets in HIJING
model and validity of superposition models in this energy range.


title: Exchange currents in octet hyperon charge radii

abstract:
  Octet hyperon charge radii are calculated in a chiral constituent quark model
including electromagnetic exchange currents between quarks. In impulse
approximation one observes a decrease of the hyperon charge radii with
increasing strangeness. This effect is reduced by exchange currents. Due to
exchange currents, the charge radius of the negatively charged hyperons are
close to the proton charge radius.


title:
Isospin symmetry breaking nucleon-nucleon potentials and nuclear
  structure

abstract:
  Modern nucleon-nucleon (NN) potentials, which accurately fit the
nucleon-nucleon scattering phase shifts, contain terms which break isospin
symmetry. The effects of these symmetry violating terms on the bulk properties
of nuclear matter are investigated. The predictions of the charge symmetry
breaking (CSB) terms are compared with the Nolen-Schiffer (NS) anomaly
regarding the energies of neighboring mirror nuclei. We find that, for a
quantitative explanation of the NS anomaly, it is crucial to include CSB in
partial waves with $L>0$ (besides $^1S_0$) as derived from a microscopic model
for CSB of the NN interaction.


title: Nuclear Transport at Small Excitations: Thermal and Quantal Aspects

abstract:
  The application of the locally harmonic approximation to large scale
collective motion is briefly reviewed. Particular emphasis is paid to issues
which might be useful in the more general context, or which are specific to our
treatment, like there are: Self-consistency between collective and intrinsic
motion, a $T$ dependent coupling constant, the inclusion of quantum effects for
the dynamics of fluctuations. Finally, open problems are addressed, like the
use of thermodynamic concepts at smaller excitations, the ergodicity question,
the variation of transport coefficients with the nuclear shape due to shell
structure, the limits of the LHA at smaller $T$.


title: Effect of friction on disoriented chiral condensate formation

abstract:
  We have investigated the effect of friction on the DCC domain formation. We
solve the Newton equation of motion for the O(4) fields, with quenched initial
condition. The initial fields are randomly distributed in a Gaussian form. In
one dimensional expansion, on the average, large DCC domains can not be formed.
However, in some particular orbits, large instabilities may occur. This
possibility also greatly diminishes with the introduction of friction. But, if
the friction is large, the system may be overdamped and then, there is a
possibility of large DCC domain formation in some events.


title: Band Structures of $^{182}$ Os Studied by GCM based on 3D-CHFB

abstract:
  Band structure properties of $^{182}$Os are investigated through a particle
number and angular momentum constrained generator coordinate(GCM) calculation
based on self-consistent three-dimensional cranking solutions. From the
analysis of the wave function of the lowest GCM solution, we confirm that this
nucleus shows a tilted rotational motion in its yrast states, at least with the
present set of force parameters of the pairing-plus-quadrupole interaction
Hamiltonian. A close examination of behavior of other GCM solutions reveals a
sign of a possible occurrence of multi-band crossing in the nucleus.
Furthermore, in the course of calculations, we have also found a new potential
curve along the prime meridian on the globe of the $J=18\hbar$ sphere. Along
this new solution the characters of proton and neutron gap parameters get
interchanged. Namely, $\Delta_p$ almost vanishes while $\Delta_n$ grows to a
finite value close to the one corresponding to the principal axis
rotation(PAR). A state in the new solution curve at the PAR point turns out to
have almost the same characteristic features of an yrare $s$-band state which
gets located just above the $g$-band in our calculation. This fact suggests a
new type of seesaw vibrational mode of the proton and the neutron pairing,
occurring through a wobbling motion. The mode is considered to bridge the
$g$-band states and the $s$-band states in the backbending region.


title:
$J/\psi$ normal and anomalous suppressions in a hadron and string
  cascade model

abstract:
  A mechanism for the effective dissociation of a $c\bar{c}$ pair in the colour
electric field of strings is introduced into a hadron and string cascade model,
i.e. JPCIAE, which is based on the LUND model, simulating ultra-relativistic
nucleus - nucleus collisions. This new mechanism together with the known
mechanism of nuclear absorption (both baryons and mesons) could reproduce
fairly the data of the normal and anomalous $J/\psi$ suppressions in minimum
bias pA, AB (with light projectile), and Pb + Pb collisions at 200 A GeV/c.
However the impact parameter (E_T) dependence of the $J/\psi$ suppression
factor, both, in S + U and Pb + Pb reactions at 200 A GeV/c and 158 A GeV/c,
respectively, is not well reproduced. We also tested the additional mechanism
of the energy degradation of leading particles, with which both, the normal and
anomalous $J/\psi$ suppressions in minimum bias pA, AB, and Pb + Pb collisions
and the E_T dependence of the $J/\psi$ suppression factor are better
reproduced.


title: Weak Chiral Lagrangian and $pi^+$ Emission in ${}^4_{Lambda}$He

abstract:
  A new mechanism of $pi^+$ meson emission from the ${}^4_{Lambda}$He
hypernucleus is suggested.


title: Antikaon Production and Medium Effects in Heavy Ion Collisions at AGS

abstract:
  Antikaon production from heavy ion collisions at energies available from the
Alternating Gradient Synchrotron (AGS) at the Brookhaven National Laboratory is
studied in a relativistic transport (ART) model. We include contributions from
the baryon-baryon, meson-baryon, and meson-meson interactions. The final-state
interaction of antikaons via both absorption and elastic scattering by nucleons
and pions are also considered. To compare with presently available or future
experimental data, we have calculated the antikaon rapidity and transverse
momentum distributions as well as its collective flow. Medium effects on these
observables due to mean field potentials have also been investigated. It is
found that the ratio of antikaon transverse momentum spectrum to that of kaon
and their transverse flow are most sensitive to the in-medium properties of
kaons and antikaons.


title: Gamma-Deuteron Compton Scattering in Effective Field Theory

abstract:
  The differential cross section for gamma-deuteron Compton scattering is
computed to next-to-leading order (NLO) in an effective field theory that
describes nucleon-nucleon interactions below the pion production threshold.
Contributions at NLO include the nucleon isoscalar electric polarizability from
its 1/m_pi behavior in the chiral limit. The parameter free prediction of the
gamma-deuteron differential cross section at NLO is in good agreement with
data.


title: Effects of Isospin Asymmetry and In-Medium Corrections on Balance Energy

abstract:
  The effects of an isospin asymmetry and in-medium corrections to the nucleon
collision cross section on the balance energy are explored. The BUU model for
intermediate energy heavy-ion collisions is used with isospin-dependent mean
fields to calculate the balance energies of 58Fe + 58Fe and 58Ni + 58Ni for a
range of impact parameters. We find that we are able to reproduce the impact
parameter dependence of the balance energy, and the sign (but not the
magnitude) of the shift in balance balance energy as a function of isospin
asymmetry.


title: Renormalization of the Three-Body System with Short-Range Interactions

abstract:
  We discuss renormalization of the non-relativistic three-body problem with
short-range forces. The problem becomes non-perturbative at momenta of the
order of the inverse of the two-body scattering length, and an infinite number
of graphs must be summed. This summation leads to a cutoff dependence that does
not appear in any order in perturbation theory. We argue that this cutoff
dependence can be absorbed in a single three-body counterterm and compute the
running of the three-body force with the cutoff. We comment on relevance of
this result for the effective field theory program in nuclear and molecular
physics.


title: Kaon photoproduction with form factors in a gauge-invariant approach

abstract:
  The general gauge-invariant photoproduction formalism given by Haberzettl is
applied to kaon photoproduction off the nucleon at the tree level, with form
factors describing composite nucleons. We demonstrate that, in contrast to
Ohta's gauge-invariance prescription, this formalism allows electric current
contributions to be multiplied by a form factor, i.e., they do not need to be
treated like bare currents. Numerical results show that Haberzettl's gauge
procedure, when compared to Ohta's, leads to much improved $\chi^2$ values.
Moreover, predictions for the new Bonn SAPHIR data for $p(\gamma,K^+)\Lambda$
are given.


title:
Influence of Impact Parameter on Thermal Description of Relativistic
  Heavy Ion Collisions at GSI/SIS

abstract:
  Attention is drawn to the role played by the size of the system in the
thermodynamic analysis of particle yields in relativistic heavy ion collisions
at SIS energies. This manifests itself in the non-linear dependence of K+ and
K- yields in $AA$ collisions at 1 -- 2 A.GeV on the number of participants. It
is shown that this dependence can be quantitatively well described in terms of
a thermal model with a canonical strangeness conservation. The measured
particle multiplicity ratios (pi+/p, pi-/pi+, d/p, K+/pi+ and K+/K- but not
eta/pi0) in central Au-Au and Ni-Ni collisions at 0.8 -- 2.0 A.GeV are also
explained in the context of a thermal model with a common freeze-out
temperature and chemical potential. Including the concept of collective flow a
consistent picture of particle energy distributions is derived with the flow
velocity being strongly impact-parameter dependent.


title: Polarization observables in electronuclear two-nucleon knockout

abstract:
  Differential (e,e'pp) measurements are presently recognized as a way of
studying short-range correlations in finite nuclei. The ($\vec{e},e'\vec{p}p$)
and ($\vec{e},e'\vec{p}n$) differential cross section and polarization
observables are studied in a microscopic model that accounts for the
short-range correlations, outgoing-nucleon distortions, meson-exchange and
$\Delta$-isobar currents. It is pointed out that polarization observables
represent an attractive alternative for absolute electronuclear two-nucleon
knockout measurements. In the polarization transfer $P'_t$ for
($\vec{e},e'\vec{p}p$), the effect of central short-range correlations is
predicted to be large while at the same time the final-state interaction
effects are small.