title:
Reaction dynamics in Pb+Pb at the CERN/SPS: from partonic degrees of
  freedom to freeze-out

abstract:
  We analyze the reaction dynamics of central Pb+Pb collisions at 160
GeV/nucleon. First we estimate the energy density pile-up at mid-rapidity and
calculate its excitation function: 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 E > 30 GeV/nucleon. The energy density reaches
up to 4 GeV/fm^3, 95% of which are contained in partonic degrees of freedom. It
is shown that cells of hadronic matter, after the early reaction phase, can be
viewed as nearly chemically equilibrated. This matter never exceeds energy
densities of 0.4 GeV/fm^3, i.e. a density above which the notion of separated
hadrons loses its meaning. The final reaction stage is analyzed in terms of
hadron ratios, freeze-out distributions and a source analysis for final state
pions.


title:
Photon-Photon and Photon-Hadron Interactions at Relativistic Heavy Ion
  Colliders

abstract:
  In central collisions at relativistic heavy ion colliders like the
Relativistic Heavy Ion Collider RHIC/Brookhaven and the Large Hadron Collider
LHC (in its heavy ion mode) at CERN/Geneva, one aims at detecting a new form of
hadronic matter --- the Quark Gluon Plasma. We discuss here a complementary
aspect of these collisions, the very peripheral ones. Due to coherence, there
are strong electromagnetic fields of short duration in such collisions. They
give rise to photon-photon and photon-nucleus collisions with high flux up to
an invariant mass region hitherto unexplored experimentally. After a general
survey photon-photon luminosities in relativistic heavy ion collisions are
discussed. Then photon-photon physics at various gamma-gamma-invariant mass
scales is discussed. The region of several GeV, relevant for RHIC is dominated
by QCD phenomena (meson and vector meson pair production). Invariant masses of
up to about 100 GeV can be reached at LHC, and the potential for new physics is
discussed. Lepton-pair production, especially electron-positron pair production
is copious. Due to the strong fields there will be new phenomena, especially
multiple e+e- pair production.


title: Front-form calculation of the deuteron EM form factors

abstract:
  The deuteron form factors are calculated in the framework of the relativistic
nucleon-meson dynamics. The relativistic effects change considerably the S- and
D-waves of the deuteron, result in the dominating extra component in the
deuteron wave function and generate the contact interaction between the
nucleon, mesons and photon. The prediction for the polarization observable
$t_{20}$ is in good agreement with the recent data of TJNAF/CEBAF.


title: Phenomenology of Large N_c QCD

abstract:
  These lectures are designed to introduce the methods and results of large N_c
QCD in a presentation intended for nuclear and particle physicists alike.
Beginning with definitions and motivations of the approach, we demonstrate that
all quark and gluon Feynman diagrams are organized into classes based on powers
of 1/N_c. We then show that this result can be translated into definite
statements about mesons and baryons containing arbitrary numbers of
constituents. In the mesons, numerous well-known phenomenological properties
follow as immediate consequences of simply counting powers of N_c, while for
the baryons, quantitative large N_c analyses of masses and other properties are
seen to agree with experiment, even when ``large'' N_c is set equal to its
observed value of 3. Large N_c reasoning is also used to explain some simple
features of nuclear interactions.


title:
Equilibration And Out-Of-Equilibrium Effect In Relativistic Heavy Ion
  Collisions

abstract:
  The approach of a parton plasma at future heavy ion colliders towards kinetic
and chemical equilibrium is considered. A plasma with a self-consistent
evolving parton-parton interaction strength is shown to equilibrate better and
faster than the usual but inconsistent one with a fixed strength. We explain
why as a consequence of this, a parton plasma is a unique kind of many-body
system. Because our time evolution scheme does not require the plasma to be in
either kind of equilibrium from the outset, out-of-equilibrium effect on
particle productions can be revealed. We show this on photon production and
discuss the implications on photon as a signal to detect the quark-gluon
plasma.


title: Stochastic number projection method in the pairing-force problem

abstract:
  A new stochastic number projection method is proposed. The component of the
BCS wave function corresponding to the right number of particles is obtained by
means of a Metropolis algorithm in which the weight functions are constructed
from the single-particle occupation probability. Either standard BCS or
Lipkin-Nogami probability distributions can be used, thus the method is
applicable for any pairing strength. The accuracy of the method is tested in
the computation of pairing energies of model and real systems.


title:
On the equivalence of the Impulse Approximation and the
  Gersch-Rodriguez-Smith theory for structure functions

abstract:
  We derive for a non-relativistic system an approximation for Final State
Interactions in a form, resembling a DWIA which corrects the structure function
computed in the PWIA. We then compare the Gersch-Rodriguez-Smith and the IA
series for structure functions and prove that to order ${\cal O}(1/q^2)$ the
above DWIA representation is contained in the GRS series to the same order.
There is an additional term in the GRS series that is missing in the DWIA due
to the eikonal approximations in the latter. This strongly suggests that the
two approaches, when treated exactly, produce identical structure function to
arbitrary order in $1/q$.


title: Protoninduced Pion-, Eta- and Kaon-Production at Threshold

abstract:
  We present some details of our recent theoretical investigations on the total
cross section of the reactions $pp\to pp \pi^0$, $pp\to pp \eta$ and $pp\to
p\Lambda K^+$ at threshold. Applying standard nonrelativistic perturbation
theory within the framework of meson exchange models (MEC) to all of the
investigated processes we observe that theory is still far--off from a
quantitative understanding of the existing data, although the qualitative
behaviour of the threshold cross sections can be reproduced. The often quoted
$\eta^2$--dependence of the $pp\to pp \pi^0$ cross section at threshold is due
to a calculational mistake of Koltun and Reitan (1966) and not based on
theoretical grounds, where threebody phasespace behaviour would yield $\eta^4$,
which can be affected by final state and short range effects. To respect the
high momentum transfers for $pp\to pp \eta$ and $pp\to p\Lambda K^+$
relativistic models were developed. Hereby the $\eta$--production still is
based on MEC, while the $K^+$ production was investigated in the
quark-gluon-picture based on the Bethe--Salpeter formalism.


title: Strangelets in Terrestrial Atmosphere

abstract:
  A new dynamical model for the propagation of strangelets through the
terrestrial atmosphere is proposed.


title: The Axial Current in Electromagnetic Interaction

abstract:
  We discussed the possibility that the charged axial currents of matter fields
could be non-conserved in electromagnetic interaction at $O(e) $ order. It
means that chiral symmetry is broken explicitly by electromagnetic interaction.
This explicit symmetry breaking of chiral symmetry is shown to lead the mass
differences between the charged and neutral particles of matter fields.


title:
Remnants of Initial Anisotropic High Energy Density Domains in
  Nucleus-Nucleus Collisions

abstract:
  Anisotropic high energy density domains may be formed at early stages of
ultrarelativistic heavy ion collisions, e.g. due to phase transition dynamics
or non-equilibrium phenomena like (mini-)jets. Here we investigate hadronic
observables resulting from an initially created anisotropic high energy density
domain. Based on our studies using a transport model we find that the initial
anisotropies are reflected in the freeze-out multiplicity distribution of both
pions and kaons due to secondary hadronic rescattering. The anisotropy appears
to be stronger for particles at high transverse momenta. The overall kaon
multiplicity increases with large fluctuations of local energy densities, while
no change has been found in the pion multiplicity.


title: Electron-deuteron scattering in a relativistic theory of hadrons

abstract:
  We review a three-dimensional formalism that provides a systematic way to
include relativistic effects including relativistic kinematics, the effects of
negative-energy states, and the boosts of the two-body system in calculations
of two-body bound-states. We then explain how to construct a conserved current
within this relativistic three-dimensional approach. This general theoretical
framework is specifically applied to electron-deuteron scattering both in
impulse approximation and when the $\rho \pi \gamma$ meson-exchange current is
included. The experimentally-measured quantities $A$, $B$, and $T_{20}$ are
calculated over the kinematic range that is probed in Jefferson Lab
experiments. The role of both negative-energy states and meson retardation
appears to be small in the region of interest.


title:
On the behaviour of the nuclear spectral function at high momentum and
  removal energy

abstract:
  The extrapolation of the nuclear spectral function at large nucleon
three-momentum and removal energy is suggested.


title: Induced Pseudoscalar Coupling Constant

abstract:
  The recent TRIUMF experiment for $\mu^- p \to n \nu_{\mu} \gamma$ gave a
surprising result that the induced pseudoscalar coupling constant $g_P$ was
larger than the value obtained from $\mu^- p \to n \nu_{\mu}$ experiment as
much as 44 %. Reexamining contribution of the axial vector current, we found an
additional term to the matrix element of Beder and Fearing which was used to
extract the $g_P$ value from the measured photon energy spectrum. This
additional term plays a key role to restore the reliability of $g_P (- 0.88
m_{\mu}^2) = 6.77 g_A (0)$.


title: Dispersion relations in Kbar N - pi Y coupled channel analyses

abstract:
  Rapidly convergent, unsubtracted dispersion relations have been used to test
coupled channel analyses of low-energy S = -1 meson-baryon pi Y --> pi Y'
channels.
  We conclude that the low-energy S = -1 meson-baryon sector is less well known
than currently believed, and that it deserves more accurate experiments and
analyses.


title:
Thermal analysis of hadron multiplicities from relativistic quantum
  molecular dynamics

abstract:
  Some questions arising in the application of the thermal model to hadron
production in heavy ion collisions are studied. We do so by applying the
thermal model of hadron production to particle yields calculated by the
microscopic transport model RQMD(v2.3). We study the bias of incomplete
information about the final hadronic state on the extraction of thermal
parameters.It is found that the subset of particles measured typically in the
experiments looks more thermal than the complete set of stable particles. The
hadrons which show the largest deviations from thermal behaviour in RQMD(v2.3)
are the multistrange baryons and antibaryons. We also looked at the influence
of rapidity cuts on the extraction of thermal parameters and found that they
lead to different thermal parameters and larger disagreement between the RQMD
yields and the thermal model.


title:
Solar neutrino processes in the relativistic field theory model of the
  deuteron

abstract:
  The generalized version of the relativistic field theory model of the
deuteron (RFMD) is applied to the description of processes of astrophysical
interest and low-energy elastic NN scattering. The value of the astrophysical
factor S_{pp}(0) = 5.52x10^{-25} MeV b is found to be enhanced by a factor of
1.42 with respect to the classical value S^*_{pp}(0) = 3.89x10{-25} MeV b
obtained by Kamionkowski and Bahcall in the potential model approach (PMA). The
astrophysical aspects of this enhancement are discussed. The cross sections for
the disintegration of the deuteron by (anti-) neutrinos nu_e + D -> e^- + p +
p, anti-nu_e + D -> e^+ + n + n and nu_e(anti-nu_e) + D -> nu_e(anti-nu_e) + n
+ p are calculated for the energies of (anti-) neutrinos ranging from
thresholds up to 10 MeV. The results are discussed in comparison with the PMA
data. The cross sections for anti-nu_e + D -> e^+ + n + n and anti-nu_e + D ->
anti-nu_e + n + p averaged over the reactor anti-neutrino energy spectrum agree
well with experimental data. The astrophysical factor S_{pep}(0) for the
process p + e^- + p -> nu_e + D (or pep-process) is calculated relative to
S_{pp}(0) in complete agreement with the result obtained by Bahcall and May.
The reaction rate for the neutron-proton radiative capture is calculated in
agreement with the PMA result obtained for pure M1 transition. It is shown that
in the RFMD one can describe low--energy elastic NN scattering in complete
agreement with low-energy nuclear phenomenology.


title: Electromagnetic form factors of baryons

abstract:
  Nucleon elastic and transition form factors are analyzed in the framework of
a collective model of baryons. Effects of meson cloud couplings and
relativistic corrections are considered.


title:
The interacting boson model with SU(3) charge symmetry and its
  application to even--even N $\approx$ Z nuclei

abstract:
  The isospin-invariant interacting boson model IBM-3 is analyzed in situations
where $SU_T(3)$ charge symmetry [or, equivalently, $U_L(6)$ $sd$ symmetry] is
conserved. Analytic expressions for energies, electromagnetic transitions,
two-nucleon transfer probabilities, and boson-number expectation values are
obtained for the three possible dynamical symmetry limits, U(5), SU(3), and
O(6). Results found in IBM-3 are related to corresponding ones in IBM-1 and
IBM-2. Numerical calculations are presented for $f_{7/2}$-shell nuclei and some
features that distinguish IBM-3 from its predecessors IBM-1 and IBM-2 are
pointed out.


title:
Modelling the many-body dynamics of heavy ion collisions: Present status
  and future perspective

abstract:
  Basic problems of the semiclassical microscopic modelling of strongly
interactingsystems are discussed within the framework of Quantum Molecular
Dynamics (QMD). This model allows to study the influence of several types of
nucleonic interactions on a large variety of observables and phenomena
occurring in heavy ion collisions at relativistic energies.It is shown that the
same predictions can be obtained with several -- numerically completely
different and independently written -- programs as far as the same model
parameters are employed and the same basic approximations are made. Many
observables are robust against variations of the details of the model
assumptions used. Some of the physical results, however, depend also on rather
technical parameters like the preparation of the initial configuration in phase
space. This crucial problem is connected with the description of the ground
state of single nuclei,which differs among the various approaches. An outlook
to an improved molecular dynamics scheme for heavy ion collisions is given.


title: Breakup Reactions of 11Li within a Three-Body Model

abstract:
  We use a three-body model to investigate breakup reactions of 11Li (n+n+9Li)
on a light target. The interaction parameters are constrained by known
properties of the two-body subsystems, the 11Li binding energy and
fragmentation data. The remaining degrees of freedom are discussed. The
projectile-target interactions are described by phenomenological optical
potentials. The model predicts dependence on beam energy and target,
differences between longitudinal and transverse momentum distributions and
provides absolute values for all computed differential cross sections. We give
an almost complete series of observables and compare with corresponding
measurements. Remarkably good agreement is obtained. The relative neutron-9Li
p-wave content is about 40%. A p-resonance, consistent with measurements at
about 0.5 MeV of width about 0.4 MeV, seems to be necessary. The widths of the
momentum distributions are insensitive to target and beam energy with a
tendency to increase towards lower energies. The transverse momentum
distributions are broader than the longitudinal due to the diffraction process.
The absolute values of the cross sections follow the neutron-target cross
sections and increase strongly for beam energies decreasing below 100 MeV/u.


title: Effective Field Theory of Neutron Star Superfluidity

abstract:
  We apply effective field theory and renormalization group techniques to the
problem of Cooper pair formation in neutron stars. Simple analytical
expressions for the $^1 S_0$ condensate are derived which are free of nuclear
potential model dependencies. The condensate is evaluated using phase shift
data from neutron-neutron scattering.


title:
Simulated Annealing Clusterization Algorithm for Studying the
  Multifragmentation

abstract:
  We present the details of the numerical realization of the recently advanced
algorithm developed to identify the fragmentation in heavy ion reactions. This
new algorithm is based on the Simulated Annealing method and is dubbed as
Simulated Annealing Clusterization Algorithm [SACA]. We discuss the different
parameters used in the Simulated Annealing method and present an economical set
of the parameters which is based on the extensive analysis carried out for the
central and peripheral collisions of Au-Au, Nb-Nb and Pb-Pb. These parameters
are crucial for the success of the algorithm. Our set of optimized parameters
gives the same results as the most conservative choice, but is very fast. We
also discuss the nucleon and fragment exchange processes which are very
important for the energy minimization and finally present the analysis of the
reaction dynamics using the new algorithm. This algorithm is can be applied
whenever one wants to identify which of a given number of constituents form
bound objects.


title:
${\omega}N$ final state interactions and $\omega$-meson production from
  heavy-ion collisions

abstract:
  We calculate the elastic and inelastic $\omega N\to \omega N, \to \pi N, \to
\rho N, \to \rho \pi N, \to \pi \pi N, \to \sigma N$ reactions within a boson
exchange approximation where the $\omega\rho\pi$ coupling constant and form
factor are fixed by the reaction $\pi N \to \omega N$ in comparison to the
experimental data. We find rather large $\omega N$ cross sections at low
relative momenta of the $\omega$-meson which leads to a substantial broadening
of the $\omega$-meson width in nuclear matter. The implications of the
${\omega}N$ final state interactions are studied for $\omega$ production in
$^{12}C{+}^{12}C, ^{40}Ca{+}^{40}Ca$ and $^{58}Ni{+}^{58}Ni$ reactions at about
2 A GeV within the HSD transport approach; the drastic changes of the
transverse mass spectra relative to a general m_T-scaling (for $\pi^0$ and
$\eta$ mesons) might be controlled experimentally by the TAPS Collaboration.


title:
Coherent QED, Giant Resonances and $(e^{+}e^{-})$ Pairs in High Energy
  Nucleus-Nucleus Collisions

abstract:
  We show that the coherent oscillations of the e.m. field induced by the
collective quantum fluctuations of the nuclear matter field associated with the
giant resonances, with frequencies $\omega_{A}\simeq 78A^{-{1/3}}$ MeV, give
rise to a significant $(e^+e^-)$ pair production in high energy Heavy Ion
collisions. The approximate parameterless calculation of such yield is in good
agreement with recent experimental observations.


title: Effective kaon energy from a novel chiral SU(3) model

abstract:
  A new chiral SU(3) Lagrangian is proposed to describe the properties of kaons
and anti-kaons in the nuclear medium. The saturation properties of nuclear
matter are reproduced as well as the results of the Dirac-Br\"{u}ckner theory.
After introducing the coupling between the omega meson and the kaon, our
results for effective kaon and anti-kaon energy are quite similar as calculated
in the one-boson-exchange model.


title: Light-front versus Bethe-Salpeter forms of two nucleon amplitudes

abstract:
  We discuss the relation between the two nucleon Bethe-Salpeter amplitude and
the light front wave functions. Both approaches provide a covariant description
for the deuteron bound state and the two nucleon scattering state. A comparison
is done for the spin-orbit functions as well explicit integrals are given on
the basis of the Nakanishi integral representation method.


title: Mean--Field and Nonlinear Dynamics in Many--Body Quantum Systems

abstract:
  In this paper we discuss in detail the nonlinear equations of the mean--field
approximation and their connection to the exact many--body Schr\"odinger
equation. Then we analyze the mean--field approach and the nonlinear dynamics
of a trapped condensate of weakly--interacting bosons.


title: Gauge-invariant meson photoproduction with extended nucleons

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. Numerical results show that this
gauge-invariance procedure, when compared to Ohta's, leads to a much improved
description of experimental data. Predictions for the new Bonn SAPHIR data for
$p(\gamma,K^+)\Lambda$ are given.


title:
Radiative Muon Capture and Induced Pseudoscalar Coupling Constant in
  Nuclear Matter

abstract:
  The recent TRIUMF experiment for $\mu^- p \to n \nu_{\mu} \gamma$ gave a
surprising result that the induced pseudoscalar coupling constant $g_P$ was
larger than the value obtained from $\mu^- p \to n \nu_{\mu}$ experiment as
much as 44 %. Reexamining contribution of the axial vector current in
electromagnetic interaction, we found an additional term to the matrix element
which was used to extract the $g_P$ value from the measured photon energy
spectrum. This additional term, which plays a key role to restore the
reliability of $g_P (- 0.88 m_{\mu}^2) = 6.77 g_A (0)$, is shown to affect the
$g_P$ quenching problems in nucleus.


title: Final-State Interactions in (e,e'p) Reactions with Polarized Nuclei

abstract:
  The cross section for coincidence, quasielastic proton knock-out by electrons
from a polarized K39 nucleus is computed in DWIA using an optical potential in
describing the wave function of the ejected nucleon. The dependence of the FSI
on the initial polarization angles of the nucleus is analyzed and explained in
a new, semi-classical picture of the reaction in which the nuclear transparency
decreases as a function of the amount of nuclear matter that the proton has to
cross, thus providing a method for obtaining detailed information on its mean
free path in finite nuclei. We propose a procedure to find the best initial
kinematical conditions for minimizing the FSI which will be useful as a guide
for future experiments with polarized nuclei.


title:
Comment on 'Induced Pseudoscalar Coupling Constant' by Il-Tong Cheon and
  Myung Ki Cheoun (nucl-th/9811009)

abstract:
  In a recent preprint Cheon and Cheoun have derived from a chiral model an
additional term, not usually appearing in the standard matrix element for
radiative muon capture. Using that term they generate a large correction to the
RMC spectrum which tends to resolve the problem caused by the too large value
of $g_P$ found in the TRIUMF RMC experiment. In this comment we observe first
that their extra term leads to an amplitude which is not gauge invariant and
second that such a term should be present, in a gauge invariant way, in an
earlier full chiral perturbation theory calculation, which however found
negligible differences from the standard approach.


title: Fermionic and Bosonic Bubbles and Foam

abstract:
  The positioning of one or more bubbles inside a many fermion or boson system,
does not affect the volume, surface or curvature terms in the liquid drop
expansion of the total energy. If Coulomb effects are irrelevant, the only
contribution to the ground state energy of a system with one or more voids
arises from quantum effects, which is similar to the Casimir effect in vacuum
or in critical phenomena. We discuss the characteristics of such systems, the
interplay among various effects, such as shell corrections and chaotic
behavior, and briefly mention the role of the temperature and pairing.


title: n + p -> d + gamma in Effective Field Theory

abstract:
  The radiative capture process n+p-> d+gamma provides clear evidence for meson
exchange currents in nuclear physics. We compute this process at low energies
using a recently developed power counting for the effective field theory that
describes nucleon-nucleon interactions. The leading order contribution to this
process comes from the photon coupling to the nucleon magnetic moments. At
subleading order there are other contributions. Among these are graphs where
the photon couples directly to pions, i.e. meson exchange currents. These
diagrams are divergent and require the presence of a local four-nucleon-one
photon counterterm. The coefficient of this operator is determined by the
measured cross section, 334.2 +- 0.5 mb, for incident neutrons with speed
|v|=2200 m/s.


title: Anharmonic collective excitation in a solvable model

abstract:
  We apply the time-dependent variational principle, the nuclear field theory,
and the boson expansion method to the Lipkin model to discuss anharmonicities
of collective vibrational excitations. It is shown that all of these approaches
lead to the same anharmonicity to leading order in the number of particles.
Comparison with the exact solution of the Lipkin model shows that these
theories reproduce it quite well.


title: Spectral change of sigma and omega mesons in a dense nuclear medium

abstract:
  The spectra of the scalar ($\sigma$) and vector ($\omega$) mesons in nuclear
matter are studied in detail using the quark-meson coupling (QMC) model. It is
shown that above normal nuclear matter density the effects of $\sigma$-$\omega$
mixing and the decay of the $\sigma$ into $2\pi$ change the spectra of $\sigma$
and $\omega$ mesons considerably. As in Quantum Hadrodynamics we find a
remarkable spectral change in the $\sigma$ meson and the longitudinal mode of
the $\omega$ meson, namely a two-peak structure.


title:
Consistent effective description of nucleonic resonances in an unitary
  relativistic field-theoretic way

abstract:
  High energy strong interaction physics is successfully described by the local
renormalizable gauge theory called Quantum-Chromo-Dynamics (QCD) with quarks
and gluons as ``elementary'' degrees of freedom, while intermediate energy
strong interaction physics shows up to be determined by a non-local,
non--renormalizable effective field theory (EFT) of ``effective'' degrees of
freedom like mesons, ground state baryons and resonances. Within the picture of
an effective field theory of strong interaction at intermediate energies I
present a ``toy-model'' in which fermionic and bosonic resonances are
considered to be ``particles'', i.e. they consistently are described by
(anti-)commuting effective field-operators (containing dynamics of infinitely
many quark-gluon or meson-nucleon diagrams) which are comfortably treated by
Wick's Theorem in a covariant framework and obey unitarity. Non-trivial
implications to couplings of non-local interactions are shown.


title: Roles of Quarks in Strong and Weak YN Interactions

abstract:
  The short range parts of the strong and weak hyperon-nucleon interactions are
studied with quark substructure of the baryons taken into account. A summary of
the quark cluster model calculations of the baryon-baryon interactions is
presented. It is pointed out that the spin-flavor symmetry structure determines
the qualitative behaviors of the short-range YN interactions. We also show that
the spin-orbit YN forces give characteristic behaviors, which are distinct from
the meson exchange forces. Weak decays of $\Lambda$ in hypernuclei are
described by the direct quark mechanism. We find that the neutron induced
nonmesonic decay is enhanced due to the direct quark transition. Importance of
the $\Delta I=3/2$ decay amplitudes is emphasized both for the nonmesonic weak
decays and the $\pi^+$ emission in the $\Lambda$ decay.


title: Study of Delta-Delta excitations in the reaction n+p -> d+pi+pi

abstract:
  The deuteron spectrum in n+p -> d+pi+pi at k_n = 1.88 GeV/c and theta_d = 0
deg is explained by considering a Delta-Delta excitation as the reaction
mechanism for the 2pi production. We study the influence of intermediate
Delta-Delta and Delta-Nucleon interactions on the spectrum. The angular
distribution of the pions is predicted.


title: Form factors and exclusive processes -- Introduction and Overview

abstract:
  Form factors, polarizabilities and excitation spectra are different aspects
of many-body structures. These aspects are constrained by sum rules based on
general principles like relativity, gauge invariance, causality and unitarity.
Several such structure effects of baryons and mesons will be reviewed, with
particular emphasis on the neutron charge form factor, the strangeness content
of the nucleon, polarizabilities, and the Gerasimov-Drell-Hearn and related sum
rules.


title: The Delta-Nucleon Interaction in Hadronic Reactions on a Deuteron Target

abstract:
  The pi+ d scattering and the d(p,n) charge exchange reaction are used to
study the Delta-Nucleon interaction in the Delta resonance energy region.
Various observables, such as inclusive and exclusive cross sections, angular
distributions, and analyzing powers, are calculated in a coupled channel
approach and shown to be influenced by the Delta-Nucleon potential.


title: Resonant continuum in the Hartree-Fock+BCS approximation

abstract:
  A method for incorporating the effect of the resonant continuum into
  Hartree-Fock+BCS equations is proposed. The method is applied for the case of
a neutron-rich nucleus calculated with a Skyrme-type force plus a zero-range
pairing interaction and the results are compared with
  Hartree-Fock-Bogoliubov calculations. It is shown that the widths of resonant
states have an important effect on the pairing properties of nuclei close to
the drip line.


title: Exact Results for Nuclear Ground State Properties From QCD Inequalities

abstract: We thank Tom Schafer for pointing out difficulties in this paper.


title: Radiative proton-antiproton annihilation and isospin mixing in protonium

abstract:
  A detailed analysis of the radiative $p\bar p$ annihilation is made in the
framework of a two-step formalism, the $p\bar p$ annihilates into meson
channels containing a vector meson with a subsequent conversion into a photon
via the vector dominance model (VDM). Both steps are derived from the
underlying quark model. First, branching ratios for radiative protonium
annihilation are calculated and compared with data. Then, details of the
isospin interference are studied for different models of the initial protonium
state and also for different kinematical form factors. The isospin interference
is shown to be uniquely connected to the $p\bar p - n\bar n $ mixing in the
protonium state. Values of the interference terms directly deduced from data
are consistent with theoretical expectations, indicating a dominant $p\bar p$
component for the $^1S_0$ and a sizable $n\bar n$ component for the $^3S_1$
protonium state. The analysis is extended to the $p\bar p \to \gamma \Phi$
transition, where the large observed branching ratio remains unexplained in the
VDM approach.


title: Masses of hadrons in nuclei

abstract:
  We emphasize the central role played by the spectral function in the
description of hadrons in matter and discuss the applicability of the
quasiparticle concept to the propagation of hadrons in dense nuclear matter.
Theoretical and experimental results relevant for the in medium properties of
vector mesons and kaons are briefly reviewed. We also present novel results for
the $\rho$ and $\omega$ spectral functions in nuclear matter, deduced from a
coupled channel analysis of pion-nucleon scattering data.


title: Phase Transition and Hybrid Star in a Nonlinear $\sigma - \omega$ model

abstract:
  The phase transition between the nuclear matter and the quark matter is
examined. The relativistic mean field theory(RMF) is consider with interacting
nucleons and mesons using TM1 parameter set for the nuclear matter equations of
state. It is found that the trasition point depends on coupling constant
$\alpha_s$ and bag pressure. From the study of the structure of a hybrid
neutron star, it is observed that the star contains quark matter in the
interior and neutron matter on the outer perifery.


title: Pion and photon couplings of N* resonances from scattering on the proton

abstract:
  Results of a relativistic model for pion- and photon-induced reactions on the
proton are presented. The model is crossing symmetric and gauge invariant. The
nucleon resonances P_11 (1440), P_11 (1710), D_13 (1520), S_11 (1535), S_11
(1650), P_33 (1232), P_33 (1600), S_31 (1620), and D_33 (1700) have been
included explicitly in the calculation. Unitarity within the channel space \pi
N + \gamma N below the two-pion production threshold has been achieved by using
the K-matrix approach. Strong and electromagnetic coupling parameters of the N*
resonances have been determined from a fit to the pion-nucleon phase shifts,
pion-photoproduction multipoles and Compton-scattering cross sections. The
model is shown to describe simultaneously most of the available data. Results
for the electric and magnetic polarizabilities of the nucleon are presented.


title: Superdeformation: Perspectives and prospects

abstract:
  We present a review of the mean-field approaches describing superdeformed
states, which are currently used and/or being developed. As an example, we
discuss in more details the properties of superdeformed A~60 nuclei, and
present results of calculations for the rotational band in the doubly magic
superdeformed nucleus 32S.


title: Helium-4 Nuclear Ground State and QCD


title: Alternative evaluations of halos in nuclei

abstract:
  Data for the scattering of 6He, 8He, 9Li, and 11Li from hydrogen are analyzed
within a fully microscopic folding model of proton-nucleus scattering. Current
data suggest that of these only 11Li has a noticeable halo. For 6He, we have
also analysed the complementary reaction 6Li(gamma,pi)6He(gs). The available
data for that reaction support the hypothesis that 6He may not be a halo
nucleus. However, those data are scarce and there is clearly a need for more to
elicit the microscopic structure of 6He.


title: The Three-Boson System with Short-Range Interactions

abstract:
  We discuss renormalization of the non-relativistic three-body problem with
short-range forces. The problem is non-perturbative at momenta of the order of
the inverse of the two-body scattering length. An infinite number of graphs
must be summed, which 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 one local three-body force counterterm and compute the running of
the three-body force with the cutoff. This allows a calculation of the
scattering of a particle and the two-particle bound state if the corresponding
scattering length is used as input. We also obtain a model-independent relation
between binding energy of a shallow three-body bound state and this scattering
length. We comment on the power counting that organizes higher-order
corrections and on relevance of this result for the effective field theory
program in nuclear and molecular physics.


title: Effective Theory for the non-relativistic three-body System

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.


title: Imaging of Sources in Heavy-Ion Reactions

abstract:
  We discuss imaging sources from low relative-velocity correlations in
heavy-ion reactions. When the correlation is dominated by interference, we can
obtain the images by Fourier transforming the correlation function. In the
general case, we may use the method of optimized discretization. This method
stabilizes the inversion by adapting the resolution of the source to the
experimental error and to the measured velocities. The imaged sources contain
information on freeze-out density, phase-space density, and resonance decays,
among other things.


title: Second Backbend in the Mass A ~ 180 Region

abstract:
  Within the framework of selfconsistent cranked Hartree-Fock- Bogoliubov
theory(one-dimensional) we predict second backbend in the yrast line of Os-182
at $I \approx 40 $, which is even sharper than the first one observed
experimentally at $I \approx 14 $.
  Around such a high spin the structure becomes multi-quasiparticle type, but
the main source of this strong discontinuity is a sudden large alignment of
i_13/2 proton orbitals along the rotation axis followed soon by the alignment
of j_15/2 neutron orbitals. This leads to drastic structural changes at such
high spins. When experimentally confirmed, this will be observed for the first
time in this mass region, and will be at the highest spin so far.


title: Light Front Theory Of Nuclear Matter

abstract:
  A relativistic light front formulation of nuclear dynamics is applied to
infinite nuclear matter. A hadronic meson-baryon Lagrangian, consistent with
chiral symmetry, leads to a nuclear eigenvalue problem which is solved,
including nucleon-nucleon (NN) correlations, in the one-boson-exchange
approximation for the NN potential. The nuclear matter saturation properties
are reasonably well reproduced, with a compression modulus of 180 MeV. We find
that there are about 0.05 excess pions per nucleon.


title: Proton Elastic Scattering and Neutron Distribution of Unstable Nuclei

abstract:
  We study theoretically how we can determine the neutron density distributions
of unstable nuclei from proton elastic scattering. We apply the relativistic
impulse model to study the sensitivities of the observables to the density
distributionswhich are expressed in Woods-Saxon form. We find that the both
radius and diffuseness of densities can be determined from restricted elastic
scattering data in principle. We think this result is helpful to design future
experiments.


title: Carbon Isotopes Near Drip Lines in the Relativistic Mean-Field Theory

abstract:
  We have investigated the ground-state properties of carbon isotopes in the
framework of the relativistic mean-field (RMF) theory. RMF calculations have
been performed with the non-linear scalar self-coupling of the $\sigma$ meson
using an axially symmetric deformed configuration. We have also introduced the
vector self-coupling of the $\omega$ meson for the deformed mean-field
calculations. The results show that the RMF predictions on radii and
deformations are in good agreement with the available experimental data. It is
shown that several carbon isotopes possess a highly deformed shape akin to a
superdeformation. The single-particle structure of nuclei away from the
stability line has been discussed with a view to understand the properties near
the neutron drip line. Predictions of properties of carbon isotopes away from
the stability line are made.


title: Photo Reactions on the Deuteron in the Delta-Resonance

abstract:
  Photo disintegration of the deuteron and photo pionproduction on the deuteron
are described in the region of the $\Delta$-resonance. The two reactions are
unitarily coupled. A novel definition of electromagnetic exchange currents in
the presence of pionproduction is given. Numerical predictions are done for
spin-independent and spin-dependent observables of both reactions. The
sensitivity of the results with respect to the nucleon-$\Delta$ transition
current and with respect to the irreducible nucleon-$\Delta$ potential is
studied.


title: Kaon condensation at finite temperature

abstract:
  A new formulation is presented to treat thermal fluctuations around the kaon
condensate, based on chiral symmetry. Separating the zero mode from the
beginning we perform the imaginary-time path integral to the one loop to get
the thermodynamic potential at finite temperature. The role of the Goldstone
mode in the kaon condensed phase is elucidated in relation to the equation of
state.


title: Parity violating target asymmetry in electron - proton scattering

abstract:
  We analyze the parity-violating (PV) components of the analyzing power in
elastic electron-proton scattering and discuss their sensitivity to the strange
quark contributions to the proton weak form factors. We point out that the
component of the analyzing power along the momentum transfer is independent of
the electric weak form factor and thus compares favorably with the PV beam
asymmetry for a determination of the strangeness magnetic moment. We also show
that the transverse component could be used for constraining the strangeness
radius. Finally, we argue that a measurement of both components could give
experimental information on the strangeness axial charge.


title:
Pole versus Breit-Wigner resonance description of the orbitally excited
  baryons

abstract:
  We consider the masses used in recent studies involving the nonstrange sector
of the l=1 baryons. The use of T-matrix and K-matrix poles versus the
conventional Breit-Wigner masses is discussed within the context of a large-Nc
fitting scheme.


title: Spin 1 inversion: a Majorana tensor force for deuteron alpha scattering

abstract:
  We demonstrate, for the first time, successful S-matrix to potential
inversion for spin one projectiles with non-diagonal $S^j_{ll'}$ yielding a
$T_{\rm R}$ interaction. The method is a generalization of the
iterative-perturbative, IP, method. We present a test case indicating the
degree of uniqueness of the potential. The method is adapted, using established
procedures, into direct observable to potential inversion, fitting $\sigma$,
${\rm i}T_{11}$, $T_{20}$, $T_{21}$ and $T_{22}$ for d + alpha scattering over
a range of energies near 10 MeV. The $T_{\rm R}$ interaction which we find is
very different from that proposed elsewhere, both real and imaginary parts
being very different for odd and even parity channels.


title: The role of the Roper resonance in n p --> d (pi pi)

abstract:
  In this work, a model for the n p --> d (pi pi) reaction is developed. It is
shown that the structure of the deuteron momentum spectra for a neutron beam
momentum of 1.46 GeV can be explained as a consequence of the interplay of two
mechanisms involving the excitation of the N^*(1440) resonance and its
subsequent decay into N (pi pi)^{T=0}_{S-wave} and Delta pi respectively. The
relevance of the present analysis for the study of the Roper excitation and
decay properties, as well as for the interpretation of other two-pion
production experiments is discussed.


title: P- and T-violation Tests with Polarized Resonance Neutrons

abstract:
  The enhancements of CP-violating effects in resonance neutron
transmissionthrough polarized targets are studied for 2 possible versions of
experiment. The importance is stressed of error analysis and of pseudomagnetic
effects' compensation.


title: Competition of isoscalar and isovector proton-neutron pairing in nuclei

abstract:
  We use shell model techniques in the complete pf shell to study pair
correlations in nuclei. Particular attention is paid to the competition of
isoscalar and isovector proton-neutron pairing modes which is investigated in
the odd-odd N=Z nucleus 46V and in the chain of even Fe-isotopes. We confirm
the dominance of isovector pairing in the ground states. An inspection of the
level density and pair correlation strength in 46V, however, shows the
increasing relative importance of isoscalar correlations with increasing
excitation energy. In the Fe-isotopes we find the expected strong dependence of
the isovector pairing strength on the neutron excess, while the dominant J=1
isoscalar pair correlations scale much more gently with neutron number. We
demonstrate that the isoscalar pair correlations depend strongly on the
spin-orbit splitting.


title:
Accessing the Space-Time Development of Heavy-Ion Collisions With Theory
  And Experiment

abstract:
  This thesis describes two lines of work. The first line is a study of the
application of transport theory to massless particles, such as the partons in
an ultrarelativistic collision at RHIC. The second line of work is an
application of imaging techniques to extract the relative distribution of
emission points from two-particle correlation functions measured in heavy-ion
reactions. This thesis contains an introduction to transport theory and
intensity interferometry as well as updates to several papers. These papers are
D.A. Brown and P. Danielewicz, "Partons in Phase-Space," Phys. Rev. D 58 (1998)
article no. 094003 (eprint nucl-th/9802015), D.A. Brown and P. Danielewicz,
"Imaging of Sources in Heavy-Ion Reactions," Phys. Lett. B 398 (1997) pp.
252-258 (eprint nucl-th/9701010), and D.A. Brown and P. Danielewicz, "Optimized
Discretization of Sources Imaged in Heavy-Ion Reactions," Phys. Rev. C 57
(1998) pp. 2474-2483 (eprint nucl-th/9712066).


title: The pion photoproduction in the \Delta(1232) region

abstract:
  We investigate the pion photoproduction in the \Delta(1232) region in the
framework of an effective Lagrangian including pions, nulceon and \Delta(1232).
We work to third order in a small scale expansion with both $m_{\pi}$ and
$M_{\Delta}-M_N$ treated as light scales. We note that in the $\Delta$ region,
straightward power counting breaks as the amplitudes become very large, to deal
with this problem, we suggest that the appropriate way to compare theoretical
calculations with experimental data is via weighted integrals of the amplitudes
through the $\Delta$ region.


title: Eta, Omega and Charmed Mesic Nuclei

abstract:
  Using the quark-meson coupling (QMC) model, we investigate theoretically
whether $\eta$ and $\omega$ mesons form meson-nucleus bound states. We study
several nuclei from $^{6}$He to $^{208}$Pb, including those which are the final
nuclei in the proposed experiment at GSI. Results for the $\omega$ are compared
with those of the Walecka model. Our results suggest that one should expect to
find $\eta$- and $\omega$-nucleus bound states in all these nuclei.
Furthermore, we investigate the possibility of charmed mesic nuclei. It is
shown that the $D^-$ meson will inevitably form narrow bound states with
$^{208}$Pb.


title: Matter effects on $\eta$ and $\eta'$ mesons

abstract:
  We show how the nuclear medium affects the masses of the $\eta$ and $\eta'$
mesons. The change should be easily detectable for dense matter and/or strong
$\eta(\eta')N\bar N$ coupling. We also find that the $\eta-\eta'$ mixing angle
is less in magnitude in the nuclear matter than in vacuum.


title: Hadrons in the Nuclear Medium -- Introduction and Overwiew

abstract:
  In this talk I first discuss predictions based on QCD sum rules and on
hadronic models for the properties of vector mesons in the nuclear medium. I
then describe possible experimental signatures and show detailed predictions
for dilepton invariant mass spectra with a special emphasis on nuclear
reactions involving elementary incoming beams and nuclear targets. I will in
particular illustrate that the sensitivity of pion and photon induced reactions
to in-medium effects is comparable to that of heavy-ion reactions.


title: Realistic Effective Intaractions and Nuclear Structure Calculations

abstract:
  We address the two main questions relevant to microscopic nuclear structure
calculations starting from a free NN potential. These concern the accuracy of
these kinds of calculations and the extent to which they depend on the
potential used as input. Regarding the first question, we present some results
obtained for nuclei around doubly magic 132Sn and 208Pb by making use of an
effective interaction derived from the Bonn A potential. Comparison shows that
our results are in very good agreement with the experimental data. As for the
second question, we present the results obtained for the nucleus 134Te by
making use of four different NN potentials. They indicate that nuclear
structure calculations may help in understanding the off-shell nature of the NN
potential.


title: Thermal and Quantum Fluctuations in the Kaon Condensed Phase

abstract:
  A new formulation is presented to treat thermal and quantum fluctuations
around the kaon condensate on the basis of chiral symmetry; separating the
zero-mode from the beginning and using the path-integral method, we can
formulate the inclusion of fluctuations in a transparent way. Nucleons as well
as kaons are treated in a self-consistent way to the one-loop order. The
effects of the Goldstone mode, stemming from the breakdown of V- spin symmetry
in the condensed phase, are figured out. A procedure is discussed to
renormalize the divergent integrals properly up to the one-loop order.
Consequently the thermodynamic potential is derived. It is pointed out that the
zero-point fluctuation by nucleons gives a sizable effect, different from the
kaonic one.


title:
Chiral Lagrangians and the transition amplitude for radiative muon
  capture

abstract:
  The transition operator for the radiative capture of mesons mu minus by
protons is constructed starting from a chiral Lagrangian of the
N-pi-rho-a_1-omega system obtained within the approach of hidden local
symmetries. The transition operator is gauge invariant and satisfies exactly
the CVC and PCAC equations.


title:
Probing the deuteron structure at small NN distances by
  antiproton-deuteron annihilation

abstract:
  The production of pions by antiproton-deuteron annihilation at rest is
analyzed. Assuming the possible existence of two delta-isobars in a deuteron
some enhancement in the distribution over the invariant mass of two negative
charged pions is predicted.


title: J/psi and eta_c in the nuclear medium: QCD sum rule approach

abstract:
  We investigate the masses of the lowest c\bar{c} states, the J/psi and eta_c,
in nuclear matter using QCD sum rules. Up to dimension four, the differences
between the operator product expansions in vacuum and in medium arise from the
density-dependent change in the gluon condensate and from a new contribution
proportional to the nucleon expectation value of the twist-2 gluon operator.
Both terms together give an attractive shift of about 5-10 MeV to the J/psi and
eta_c masses in nuclear matter.


title:
Polarization degrees-of-freedom in electronuclear hadron production from
  finite nuclei

abstract:
  The polarization degrees-of-freedom in electronuclear two-nucleon knockout
reactions are discussed. Model calculations for the unpolarized
$^{16}$O(e,e$'$pp) cross sections at ($\mid \vec{q} \mid$,$\omega$)=(210
MeV,300 MeV/c) are compared to recently obtained data. Predictions for the
polarization observables in electronuclear two-nucleon knockout are presented.
It is stressed that detailed studies of two-nucleon emission processes permit
to constrain the contribution from two-nucleon mechanisms (like meson-exchange
and isobar effects) to the single-nucleon knockout channel (e,e$'$p).


title:
Spin-orbit final state interaction in the framework of Glauber theory
  for (e,e'p) reactions

abstract:
  We investigate the reactions D(e,e'p)n and D(\vec e,e'p)n at GeV energies and
discuss the opportunities to distinguish between different models for the
nuclear ground state by measuring the response functions. In calculating the
final-state interaction (FSI) we employ Glauber theory, and we also include
relativistic effects in the electromagnetic current. We include not only the
central FSI, but also the spin-orbit FSI which is usually neglected in (e,e'p)
calculations within the Glauber framework and we show that this contribution
plays a crucial role for the fifth response function. All of the methods
developed here can be applied to any target nucleus.


title:
Self-consistent solution of Galitskii-Feynman equations at finite
  temperature

abstract:
  We solve the in-medium T-matrix equation at finite temperature including the
off-shell propagation of nucleons. In this way a self-consistent spectral
function for the nucleons is obtained. The results are compared to a
calculation using the quasiparticle approximation in the T-matrix equation.
Also the effective in-medium cross sections for the two cases are compared.


title: Spurious states in the Faddeev formalism for few-body systems

abstract:
  We discuss the appearance of spurious solutions of few-body equations for
Faddeev amplitudes. The identification of spurious states, i.e., states that
lack the symmetry required for solutions of the Schroedinger equation, as well
as the symmetrization of the Faddeev equations is investigated. As an example,
systems of three and four electrons, bound in a harmonic-oscillator potential
and interacting by the Coulomb potential, are presented.


title: Effect of the source charge on charged-beam interferometry

abstract:
  We investigate quantal perturbations of the interferometric correlations of
charged bosons by the Coulomb field of an instantaneous, charged source. The
source charge increases the apparent source size by weakening the correlation
at non-zero relative momenta. The effect is strongest for pairs with a small
total momentum and is stronger for kaons than for pions of the same momenta.
The experimental data currently available are well described by this effect
without invoking Pratt's exploding source model. A simple expression is
proposed to account for the effect.


title: Proton-Proton Scattering Lengths from Effective Field Theory

abstract:
  Using a recently developed effective field theory for the interactions of
nucleons at non-relativistic energies, we calculate the Coulomb corrections to
proton-proton scattering. Including the dimension-eight derivative interaction
in PDS regularization scheme, we obtain a modified Jackson-Blatt relation for
the scattering lengths which is found to be phenomenologically satisfactory.
The effective range is not modified by Coulomb effects to this order in the
calculation.


title: Pairing in low-density Fermi gases

abstract:
  We consider pairing in a dilute system of Fermions with a short-range
interaction. While the theory is ill-defined for a contact interaction, the BCS
equations can be solved in the leading order of low-energy effective field
theory. The integrals are evaluated with the dimensional regularization
technique, giving analytic formulas relating the pairing gap, the density, and
the energy density to the two-particle scattering length.


title: On local and global equilibrium in heavy ion collisions

abstract:
  The thermal model is commonly used in two different ways for the description
of hadron production in ultra-relativistic heavy ion collision. One is the
application of the thermal model to 4pi integrated data and the other is the
thermal description of central dN/dy ratios. While the first method implicitly
assumes global equilibrium the other scenario assumes Bjorken scaling within
the investigated rapidity range. Both assumptions are only approximations for
real physical collision systems. We study the impact of both approximations for
the extraction of thermal parameters on the exemplary case of S+S collisions at
SPS energies. The particle distributions are modeled by a hydrodynamical
description of the relevant collision system.


title: Nuclear astrophysics and neutrinos

abstract:
  In this report, centered on the activities within the MURST-PRIN project
"Fisica teorica del nucleo e dei sistemi a pi\`u corpi" we discuss recent
advances on the following items: i)neutrinos as probes of the solar interior
and of other astrophysical objects; ii)neutrinos as probes of physics beyond
the Standard Model of electroweak interactions; iii)the role of nuclear physics
in i) and ii); iv) who is doing what within the italian network; v)future
projects.


title:
Comments on the last development in constructing the amplitude for the
  radiative muon capture

abstract:
  It has recently been claimed by Cheon and Cheoun that the discrepancy between
the experimental value of the induced pseudoscalar g_P, obtained at TRIUMF from
a measurement of the radiative muon capture by proton, and its value predicted
by using PCAC and pion pole dominance can be explained by a contact term
generated from a simple pion-nucleon Lagrangian. We show in our comment that
this claim is ill founded.


title:
Thermal distributions in stellar plasmas, nuclear reactions and solar
  neutrinos

abstract:
  The physics of nuclear reactions in stellar plasma is reviewed with special
emphasis on the importance of the velocity distribution of ions. Then the
properties (density and temperature) of the weak-coupled solar plasma are
analysed, showing that the ion velocities should deviate from the Maxwellian
distribution and could be better described by a weakly-nonexstensive
(|q-1|<0.02) Tsallis' distribution. We discuss concrete physical frameworks for
calculating this deviation: the introduction of higher-order corrections to the
diffusion and friction coefficients in the Fokker-Plank equation, the influence
of the electric-microfield stochastic distribution on the particle dynamics, a
velocity correlation function with long-time memory arising from the coupling
of the collective and individual degrees of freedom. Finally, we study the
effects of such deviations on stellar nuclear rates, on the solar neutrino
fluxes, and on the pp neutrino energy spectrum, and analyse the consequences
for the solar neutrino problem.


title:
Excitation of the GDR and the Compressional Isoscalar Dipole State by
  alpha scattering

abstract:
  The excitation of the isovector giant dipole resonance (GDR) by alpha
scattering is investigated as a method of probing the neutron excess in exotic
nuclei. DWBA calculations are presented for 28O and 70Ca and the interplay of
Coulomb and nuclear excitation is discussed. Since the magnitude of the Coulomb
excitation amplitude is strongly influenced by the Q-value, the neutron excess
plays an important role, as it tends to lower the energy of the GDR. The
excitation of the compressional isoscalar dipole state in 70Ca by alpha
scattering is also investigated. It is shown that the population of this latter
state may be an even more sensitive probe of the neutron skin than the
isovector GDR.


title:
Boson expansion methods applied to a two-level model in the study of
  multiple giant resonances

abstract:
  We apply boson expansion methods to an extended Lipkin-Meshkov-Glick model
including anharmonicities in analogy with previous microscopic calculations. We
study the effects of different approximations present in these calculations,
among which the truncation of the hamiltonian and of the space, in connection
with the study of the properties of two-phonon and three-phonon states. By
comparing the approximate results on the spectrum with the exact ones we
conclude that the approximations made in the microscopic calculations on
two-phonon states are well justified. We find also that a good agreement with
the exact results for the three-phonon state is obtained by using a bosonic
hamiltonian truncated at the fourth order. This result makes us confident that
such approximation can be used in realistic calculations, thus allowing a
theoretical study of triple excitations of giant resonances.


title: Spectral Properties of Faddeev Equations in Differential Form

abstract:
  Three-body Faddeev equations are considered as a spectral problem for
nonsymmetrical matrix operator. Invariant subspaces related to physical and
spurious solutions to Faddeev equations and its adjoint are described.
Respective eigenvectors corresponding to invariant subspaces are constructed
for Faddeev operator and its adjoint. Extensions of the formalism on CCA
equations are discussed.


title:
Survival Probabilities of Disoriented Chiral Domains in Relativistic
  Heavy Ion Collisions

abstract:
  By using a dynamical transport code we show that chirally disoriented domains
might survive the hadronization phase in a central relativistic heavy ion
collision. A successful measurement of such domains after freeze-out will
depend on the domain size and the manifestation of the disorientation in the
low part of the charged pion momentum spectrum. We investigated the measurement
of the transverse momentum and the pseudo-rapidity spectrum of pions below 200
MeV/c. In all cases the successful determination of a realistic domain requires
first and second moment analyses of the phase space.


title: The $K^\ast K\pi$ and $\rho\pi\pi$ couplings in QCD

abstract:
  The light cone QCD sum rules are derived for the $K^\ast K\pi$ coupling
$g_{K^\ast K\pi} $ and the $\rho\pi\pi$ coupling $g_{\rho\pi\pi}$. The
contribution from the excited states and the continuum is subtracted cleanly
through the double Borel transform with respect to the two external momenta,
$p_1^2$, $p_2^2=(p-q)^2$. Our result $g_{K^\ast K\pi}=(8.7\pm 0.5)$ and
$g_{\rho\pi\pi}=(11.5\pm 0.8)$ is in good agreement with the experimental
value.


title: Pionic Matrix Elements in Neutrinoless Double-Beta Decay

abstract:
  Physics beyond the standard model of electroweak interactions that violates
lepton number will, in general, induce operators involving the quark and lepton
fields that violate lepton number. I point out that some matrix elements of
particular operators are known. In the limit of exact SU(3) flavor symmetry the
operator overline{u} gamma_mu (1-gamma_5)d overline{u} gamma_mu (1-gamma_5)d is
part of the ${\bf 27}$ representation responsible for Delta I=3/2 strangeness
changing decays in the standard model. At leading order in the chiral expansion
there is only one coupling constant that describes the weak interactions of the
pseudo-Goldstone bosons induced by the 27 representation. The observed
branching fraction for K+ to pi+ pi0 determines this coupling constant.
Contributions of the form m_s log m_s are used to estimate SU(3) breaking
corrections to the relation between K+ to pi+ pi0 and the pi- to pi+ e- e-
interaction.


title: The quark-meson coupling model

abstract:
  We review the quark-meson coupling model, in which the quark degrees of
freedom are explicitly involved to describe the properties of not only nuclear
matter but also finite nuclei. Then, we present the electric and magnetic form
factors for the proton bound in specific orbits for several closed-shell
nuclei.


title: Duration and non-locality of a nucleon-nucleon collision

abstract:
  For a set of realistic nucleon-nucleon potentials we evaluate microscopic
parameters of binary collisions: a time duration of the scattering state, a
mean distance and a rotation of nucleons during a collision. These parameters
enter the kinetic equation as non-instantaneous and non-local corrections of
the scattering integral, i.e., they can be experimentally tested. Being
proportional to off-shell derivatives of the scattering T-matrix,
non-instantaneous and non-local corrections make it possible to compare the
off-shell behavior of different potentials in a vicinity of the energy shell.
The Bonn one-Boson-exchange (A-C) and Paris potentials are found to yield very
close results, while the separable Paris potential differs.


title: Lambda collective flow in heavy ion reactions

abstract:
  Collective flow of Lambda hyperons in heavy ion reactions at SIS energies is
investigated. It is found that a $\Lambda$ mean field constructed on the basis
of the quark model leads to a good description of the experimental data of the
in-plane transverse flow of $\Lambda$'s. The attractive mean field can also
give rise to an additional "virtual" $\Lambda$ radial flow directed inwards,
which is reflected by a "concave" structure of the transverse mass spectrum of
the $\Lambda$ hyperons emitted at midrapidity. The $\Lambda$ radial flow is
found to exhibit a strong mass dependence: The flow is visible in the Ni+Ni
system, but is strongly reduced in the system of Au on Au.


title: Nonlocal Kinetic Equation and Simulations of Heavy Ion Reactions

abstract:
  A kinetic equation which combines the quasiparticle drift of Landau's
equation with a dissipation governed by a nonlocal and noninstantaneous
scattering integral in the spirit of Enskog corrections is discussed. Numerical
values of the off-shell contribution to the Wigner distribution, of the
collision duration and of the collision nonlocality are presented for different
realistic potentials. On preliminary results we show that simulations of
quantum molecular dynamics extended by the nonlocal treatment of collisions
leads to a broader proton distribution bringing the theoretical spectra closer
towards the experimental values than the local approach.


title:
$J/\psi$-Nucleon Scattering Length and In-medium Mass Shift of $J/\psi$
  in QCD Sum Rule Analysis

abstract:
  We calculate the spin-averaged $J/\psi$-nucleon scattering length
$a_{J/\psi}$ by directly applying QCD sum rule to $J/\psi$-$N$ forward
scattering amplitude. Our result $a_{J/\psi} = - 0.10 \pm 0.02$ fm, predicts
the possibility of bound states with nuclei, though the force is weaker than
that of the light vector mesons ($\rho,\omega,\phi$)-$N$ cases. Up to
dimension-4 gluonic operators, we evaluate the scattering length with twist-2
contribution, which increases the absolute value of the scattering length about
30%. If we apply $a_{J/\psi}$ to the effective mass of $J/\psi$ in nuclear
matter on the basis of the linear density approximation, it shows very slight
decrease ($4 \sim 7$ MeV) at normal matter density.


title: Quadrupole Deformation of Barium Isotopes

abstract:
  The B(E2:0_1^+ -> 2_1^+) values of the Ba isotopes (Z=56) exhibit a sharp
increase in deformation as the neutron numbers approach the mid-shell value of
N=66. This behavior is anomalous because the 2_1^+ level energies are very
similar to those of the neighboring isotopes. By means of the axially-symmetric
deformed Woods-Saxon (WS) hamiltonian plus the BCS method, we investigated the
systematics of B(E2) of the Ba isotopes. We showed that 15% of the B(E2) values
at N=66 was due to the level crossing, occurring at the deformation with beta
being nearly 0.3, between the proton orbits originating from the orbits
Omega=1/2^-(h11/2) and 9/2^+(g9/2) at zero deformation. The latter of these two
was an intruder orbit originating from below the energy gap at Z=50, rising
higher in energy with the deformation and intruding the Z=50-82 shell. These
two orbits have the largest magnitude of the quadrupole moment with a different
sign among the orbits near and below the Fermi surface. Occupancy and
non-occupancy of these orbits by protons thus affect B(E2:0_1^+ -> 2_1^+)
significantly.


title: The reaction NN \to NN \phi near threshold

abstract:
  The sensitivity of polarization observables in the reaction $NN \to NN \phi$
slightly above the threshold is studied with respect to the details of the
one-boson exchange model and a possible admixture of hidden strangeness in the
nucleon. It is shown that the finite-energy predictions differ strongly from
the threshold predictions. A measurement of the beam - target asymmetry and the
$\phi$ decay anisotropy can help to disentangle the role of various reaction
mechanisms.


title:
Competition of electron capture and beta-decay rates in supernova
  collapse

abstract:
  We calculate supernova electron capture and beta decay rates for various
pf-shell nuclei using large-scale shell model techniques. We show that the
centroid of the Gamow-Teller strength distribution has been systematically
misplaced in previous rate estimates. Our total electron capture rates are
significantly smaller than currently adopted in core collapse calculations,
while the total beta decay rates change less. Our calculation shows that for
electron-to-baryon ratios Ye=0.42-0.46 beta decay rates are larger than the
competing electron capture rates.


title: Two-point correlation function with pion in QCD sum rules

abstract:
  Within the framework of the conventional QCD sum rules, we study the pion
two-point correlation function, $i\int d^4x e^{iq\cdot x} < 0| T J_N(x) {\bar
J}_N(0)|\pi(p)>$, beyond the soft-pion limit. We construct sum rules from the
three distinct Dirac structures, $i \gamma_5 \notp, i \gamma_5, \gamma_5
\sigma_{\mu \nu} {q^\mu p^\nu}$ and study the reliability of each sum rule. The
sum rule from the third structure is found to be insensitive to the continuum
threshold, $S_\pi$, and contains relatively small contribution from the
undetermined single pole which we denote as $b$. The sum rule from the $i
\gamma_5$ structure is very different even though it contains similar
contributions from $S_\pi$ and $b$ as the ones coming from the $\gamma_5
\sigma_{\mu \nu} {q^\mu p^\nu}$ structure. On the other hand, the sum rule from
the $i \gamma_5 \notp$ structure has strong dependence on both $S_\pi$ and $b$,
which is clearly in constrast with the sum rule for $\gamma_5 \sigma_{\mu \nu}
{q^\mu p^\nu}$. We identify the source of the sensitivity for each of the sum
rules by making specific models for higher resonance contributions and discuss
the implication.


title: Equation of state for finite nuclei and liquid-gas phase transition

abstract:
  We construct the equation of state (EOS) of finite nuclei including surface
and Coulomb effects in a Thomas-Fermi framework using a finite range, momentum
and density dependent two-body interaction. We identify critical temperatures
for nuclei below which the EOS so constructed shows clear signals for
liquid-gas phase transition in these finite systems. Comparison with the EOS of
infinite nuclear matter shows that the critical density and temperature of the
phase transition in nuclei are influenced by the mentioned finite size effects.


title: Isotope thermometery in nuclear multifragmentation

abstract:
  A systematic study of the effect of fragment$-$fragment interaction, quantum
statistics, $\gamma$-feeding and collective flow is made in the extraction of
the nuclear temperature from the double ratio of the isotopic yields in the
statistical model of one-step (Prompt) multifragmentation. Temperature is also
extracted from the isotope yield ratios generated in the sequential
binary-decay model. Comparison of the thermodynamic temperature with the
extracted temperatures for different isotope ratios show some anomaly in both
models which is discussed in the context of experimentally measured caloric
curves.


title: Transport Dynamics of Broad Resonances

abstract:
  The propagation of short life time particles with consequently broad mass
width are discussed in the context of transport descriptions. In the first part
some known properties of finite life time particles such as resonances are
reviewed and discussed at the example of the $\rho$-meson. Grave deficiencies
in some of the transport treatment of broad resonances are disclosed and
quantified. The second part addresses the derivation of transport equations
which permit to account for the damping width of the particles. Baym's
$\Phi$-derivable method is used to derive a self-consistent and conserving
scheme, which fulfils detailed balance relations even in the case of particles
with broad mass distributions. For this scheme a conserved energy-momentum
tensor can be constructed. Furthermore, a kinetic entropy can be derived which
besides the standard quasi-particle part also includes contributions from
fluctuations.


title:
Remark to ''On the Description of Fermion Systems in Boson
  Representations''

abstract:
  The formulae of boson powers commutation relation used by B. Sorensen [Nucl.
Phys. A, v. 119, No 1, (1968), 65] in his calculations is erroneous. We provide
the correct formulae.


title: Effective interactions for the nuclear shell model

abstract:
  Various perturbative and non-perturbative many-body techniques are discussed
in this work. Especially, we will focus on the summation of so-called Parquet
diagrams with emphasis on applications to finite nuclei. Here, the subset of
two-body Parquet equations will be discussed. A practical implementation of the
corresponding equations for studies of effective interactions for finite nuclei
is outlined.


title:
Missing momentum distributions and nuclear transparency in
  semi-inclusive A(e,e'p)X processes

abstract:
  A linked cluster expansion for the distorted one-body mixed density matrix is
obtained within the Glauber multiple scattering theory with correlated wave
functions. The nuclear transparency for 16O is calculated using realistic
central and non-central correlations. The convergence of the expansion is
investigated in the case of 4He for which the transparency and the distorted
momentum distributions are calculated to all order in the correlations using a
variational wave function obtained from realistic NN interactions. The
important role played by non central correlations is illustrated.


title: Coulomb Final State Interactions for Gaussian Wave Packets

abstract:
  Two-particle like-sign and unlike-sign correlations including Coulomb final
state interactions are calculated for Gaussian wave packets emitted from a
Gaussian source. We show that the width of the wave packets can be fully
absorbed into the spatial and momentum space widths of an effective emission
function for plane wave states, and that Coulomb final state interaction
effects are sensitive only to the latter, but not to the wave packet width
itself. Results from analytical and numerical calculations are compared with
recently published work by other authors.


title: A first order transition and parity violation in a color superconductor

abstract:
  In cold, dense quark matter, quarks of different flavor can form Cooper pairs
which are anti-triplets under color and have total spin J=0. The transition to
a phase where strange quarks condense with either up or down quarks is driven
first order by the Coleman-Weinberg mechanism. At densities sufficiently high
to (effectively) restore the axial U(1) symmetry, then relative to the ordinary
vacuum, the condensation of up with down quarks (effectively) breaks parity
spontaneously.


title: Chiral symmetry and properties of hadron correlators in matter

abstract:
  The constraints imposed by chiral symmetry on hadron correlation functions in
nuclear medium are discussed. It is shown that these constraints implies the
certain structure of the in-medium hadron correlators and lead to the
cancellation of the order $\rho m_\pi$ term in the in-medium nucleon
correlator. We also consider the effect of mixing of the chiral partners
correlaton functions arising from the interaction of nuclear pions with
corresponding interpolating currents. It reflects the phenomena of partial
restoration of chiral symmetry. The different scenarios of such restoration are
briefly discussed.


title: Chiral kaon dynamics in heavy ion collisions

abstract:
  The influence of the chiral mean field on the collective motion of kaons in
relativistic heavy ion reactions at SIS energies is investigated. We consider
three types of collective motion, i.e. the transverse flow, the out-of-plane
flow (squeeze-out) and the radial flow. The kaon dynamics is thereby described
with a relativistic mean field as it originates form chiral lagrangiens. For
the $K$ mesons inside the nuclear medium we adopt a covariant quasi-particle
picture including scalar and vector fields and compare this to a treatment with
a static potential like force. The comparison to the available data ($K^+$)
measured by FOPI and KaoS strongly favor the existence of an in-medium
potential. However, using full covariant dynamics makes it more difficult to
describe the data which might indicate that the mean field level is not
sufficient for a reliable description of the kaon dynamics.


title: Dirac Structure of the Nucleus-Nucleus Potential in Heavy Ion Collisions

abstract:
  We investigate nuclear matter properties in the relativistic Brueckner
approach. The in-medium on-shell T-matrix is represented covariantly by five
Lorentz invariant amplitudes from which we deduce directly the nucleon
self-energy. To enforce correct Hartree-Fock results we develop a subtraction
scheme which treats the bare nucleon-nucleon potential exactly in accordance to
the different types of meson exchanges. For the higher order correlations we
employ two different covariant representations in order to study the
uncertainty inherent in the approach. The nuclear matter bulk properties are
only slightly sensitive on the explicit representation used. However, we obtain
new Coester lines for the various Bonn potentials which are shifted towards the
empirical region of saturation.


title: Pions in isospin asymmetric matter and nuclear Drell-Yan scattering

abstract:
  Using a self-consistent delta-hole model the pion propagation in isospin
asymmetric nuclear matter is studied. In neutron-rich matter, corresponding to
heavy nuclei, a significant difference in positive and negative pion light-cone
distributions is obtained leading to a nuclear enhancement of up antiquark
distribution compared to the down antiquark one. This means that the sea-quark
asymmetry in the free nucleon cannot be extracted model independently from an
experiment on a neutron-rich nucleus.


title: Structure in two_pion production in the d d -> alpha X reaction

abstract:
  A model for the d d -> alpha pi pi reaction, based on two parallel N N -> d
pi reactions, is extended to incorporate a complete set of input amplitudes.
While low-energy cross sections are underestimated, the rich structure observed
in the alpha-particle momentum distributions for 0.8 < T_d < 1.9 GeV (the ABC
effect) is extraordinarily well reproduced. In addition, a recent measurement
of deuteron analyzing powers agrees quite well with our predictions, both in
frequency and magnitude of the oscillations.


title: Modeling Nonperturbative QCD for Mesons and Couplings

abstract:
  We discuss aspects of a covariant QCD modeling of meson physics by
illustrating applications to several coupling constants and form factors. In
particular, we cover the $\rho\pi\pi$ and $\pi^0 \gamma \gamma$ interactions,
the $\rho$ contribution to the pion charge radius, and $\pi NN$ coupling.


title: Photons from Pb + Pb and S + Au Collisions at CERN SPS Energies

abstract:
  The effects of the variation of vector meson masses and decay widths on
photon production from hot strongly interacting matter formed after Pb + Pb and
S + Au collisions at CERN SPS energies are considered. It has been shown that
the present photon spectra measured by WA80 and WA98 Collaborations can not
distinguish between the formation of quark matter and hadronic matter in the
initial state.


title: On The pp->pp\eta (eta') Reactions Near Threshold

abstract:
  The production rate for \eta' in pp ->pp \eta' at rest is calculated in a
covariant one boson exchange model, previously applied to study pi^0 and \eta
production in NN collisions. The transition amplitudes for the elementary BN ->
eta' N processes with B being the meson exchanged (B = pi, sigma, eta, rho,
omega and delta) are taken to be the sum of s and u channels with a nucleon in
the intermediate states, and a delta meson pole in a t-channel. The couplings
of the eta' to hadrons are a factor 0.437 weaker than the respective eta-hadron
couplings, as suggested by a quark model and a singlet-octetmixing angle theta
= -23 degree. The model reproduces near threshold cross sections for the
quasielastic processes pi- p ->n eta (eta') and pp -> pp eta (eta') reactions.


title: Isospin structure of one- and two-phonon GDR excitations

abstract:
  Isospin is included in the description of Coulomb excitation of multiple
giant isovector dipole resonances. In the excitation of even-even nuclei, a
relevant portion of the excitation strength is shown to be associated with 1+
two-phonon states, which tends to be hindered or completely supressed in
calculations in which the isospin degree of freedom is not considered. We find
that the excitation cross sections is strongly dependent on the ground state
isospin.


title: Is The Heavy Fermion Formalism Applicable to Meson Production Process?

abstract:
  We consider tree diagram contributions to neutral pion production in pp ->pp
pi0 using chiral perturbation theory in the relativistic and extremely
non-relativistic limits. In marked difference with the results from heavy
fermion formalism, the impulse and s-wave rescattering terms in the
relativistic limit have equal signs and therefore add constructively, giving
rise to a substantial contribution to the cross section. We argue that the
power series expansion of the nucleon propagator is on the border of its
convergence circle. Consequently, a finite order heavy fermion formalism does
not predict nucleon pole terms correctly and therefore can not be applied to
meson production.


title: Gauge invariance in quantum hadrodynamics

abstract:
  This paper describes the derivation of a new representation of an $SU(2)_L
\times SU(2)_R$ locally-invariant model of the strong interactions called
quantum hadrodynamics 3 (QHD-III). QHD-III is a gauge-invariant theory based on
the linear $\sigma$ model, the gauge bosons being the $\rho$ and the $a_1$. The
new representation considerably simplifies the lagrangian. To derive the new
representation, the gauge invariance of the model is exploited. The role of the
gauge boson masses in gauge-invariant models of the strong interactions based
on the $\sigma$ model is also discussed, and it is shown that these masses are
necessary if the pion is to survive as a physical field.


title: Pauli exclusion operator and binding energy of nuclear matter

abstract:
  Brueckner-Hartree-Fock calculations are performed for nuclear matter with an
exact treatment of the Pauli exclusion operator in the Bethe-Goldstone
equation. The differences in the calculated binding energy, compared to the
angle-average approximation, which is commonly used, are non-negligible. These
difference exhibits a specific density dependence, which shifts the calculated
saturation point towards smaller densities. This effect is observed for various
versions of modern models for the NN interaction.


title: Chiral Symmetry In Nuclear Physics

abstract:
  How chiral symmetry -- which is a basic ingredient of quantum chromodynamics
(QCD) for light-quark hadrons -- enters and plays an eminent role in nuclear
physics is discussed. This is done in two steps. In the first step, I introduce
the notion of the Cheshire Cat Principle which describes how a
strong-interaction phenomenon can be described in various different languages.
In the second step, I treat two cases of widely different density regimes. The
first case deals with formulating nuclear physics of {\it dilute} nuclear
systems with a focus on both bound and scattering processes in two-nucleon
systems in terms of effective field theories (EFT), e.g., in the framework of
chiral perturbation theory. The second case requires formulating effective
field theories for {\it dense} hadronic matter such as heavy nuclei and nuclear
matter under normal as well as extreme conditions expected to be encountered in
compact stars and in heavy-ion collisions at relativistic energy. The first
case is rigorously formulated but the second relies on several assumptions that
appear to be reasonable but need ultimately to be justified. The Cheshire Cat
Principle is proposed to play an essential role in lending support to the
latter development.


title: Hydrogen-like Atoms from Ultrarelativistic Nuclear Collisions

abstract:
  The number of hydrogen-like atoms produced when heavy nuclei collide is
estimated for central collisions at the Relativistic Heavy Ion Collider using
the sudden approximation of Baym et al. As first suggested by Schwartz, a
simultaneous measurement of the hydrogen and hadron spectra will allow an
inference of the electron or muon spectra at low momentum where a direct
experimental measurement is not feasible.


title: An Effective Model for Hot Gluodynamics

abstract:
  We consider an effective Lagrangian containing contributions from glueball
and gluon degrees of freedom with a scale-invariant coupling between the two.
The thermodynamic potential is calculated taking into account thermal
fluctuations of both fields. The glueball mean field dominates at low
temperature, while the high temperature phase is governed by low-mass
gluon-like excitations. The model shows some similarities to the lattice
results in the pure glue sector of QCD. In particular, it exhibits a strong
first order phase transition at a critical temperature of approximately 265 MeV
when reasonable parameters are taken.


title: Caloric curve in fragmentation

abstract:
  We study phase transitions of small two dimensional Lennard Jones drops via
microcanonical molecular dynamics in a broad energy range. We found that the
caloric curve can be extended to high energies to comprehend high evaporation
rates and highly non-equilibrium phenomena such as multifragmentation.
Multifragmentation appears as a constant temperature region in the caloric
curve like the solid-liquid phase transition.


title: Temperature and energy partition in fragmentation

abstract:
  We study fragmentation of small atomistic clusters via molecular dynamics. We
calculate the time scales related to fragment formation and emission. We also
show that some degree of thermalization is achieved during the expansion
process, which allows the determination of a local temperature. In this way we
can calculate the break-up temperature as a function of excitation energy, i.e.
the fragmentation caloric curve. Fragmentation appears as a rather constant
temperature region of the caloric curve. Furthermore, we show that different
definitions of temperature, related to different degrees of freedom, yield very
similar values.


title: What Chiral Symmetry Can Tell Us About Hadron Correlators in Matter

abstract:
  The constraints imposed by chiral symmetry on hadron correlation functions in
nuclear medium are discussed. It is shown that these constraints imply some
structure of the in-medium hadron correlators, lead to the cancellation of the
order $\rho m_\pi$ term in the in-medium nucleon correlator and result in the
effect of mixing of the chiral partners correlators, reflecting the phenomena
of partial restoration of chiral symmetry. The different scenarios of such
restorations are briefly discussed.


title: Surface behaviour of the pairing gap in semi-infinite nuclear matter

abstract:
  The $^1S_0$-pairing gap in semi-infinite nuclear matter is evaluated
microscopically using the effective pairing interaction recently found
explicitly in the coordinate representation starting from the separable form of
the Paris NN-potential. Instead of direct iterative solution of the gap
equation, a new method proposed by V.A.Khodel, V.V.Khodel and J.W.Clark was
used which simplifies the procedure significantly. The gap $\Delta$ obtained in
our calculations exibits a strong variation in the surface region with a
pronounced maximum near the surface.


title: Cascade in Muonic and Pionic Atoms with Z=1

abstract:
  Recent theoretical and experimental studies of the exotic atoms with Z=1 are
reviewed. An interplay between the atomic internal and external degrees of
freedom is essential for a good description of the atomic cascade. The
perspective of ab initio cascade calculations is outlined.


title:
Comment on piNN Coupling from High Precision np Charge Exchange at 162
  MeV

abstract:
  In this updated and expanded version of our delayed Comment we show that the
np backward cross section, as presented by the Uppsala group, is seriously
flawed (more than 25 sd.). The main reason is the incorrect normalization of
the data. We show also that their extrapolation method, used to determine the
charged piNN coupling constant, is a factor of about 10 less accurate than
claimed by Ericson et al. The large extrapolation error makes the determination
of the coupling constant by the Uppsala group totally uninteresting.


title:
Systematic Study of High p_T Hadron Spectra in pp, pA and AA Collisions
  from SPS to RHIC Energies

abstract:
  High-$p_T$ particle spectra in $p+p$ ($\bar p + p$), $p+A$ and $A+B$
collisions are calculated within a QCD parton model in which intrinsic
transverse momentum, its broadening due to initial multiple parton scattering,
and jet quenching due to parton energy loss inside a dense medium are included
phenomenologically. The intrinsic $k_T$ and its broadening in $p+A$ and $A+B$
collisions due to initial multiple parton scattering are found to be very
important at low energies ($\sqrt{s}<50$ GeV). Comparisons with $S+S$, $S+Au$
and $Pb+Pb$ data with different centrality cuts show that the differential
cross sections of large transverse momentum pion production ($p_T>1$ GeV/$c$)
in $A+B$ collisions scale very well with the number of binary nucleon-nucleon
collisions (modulo effects of multiple initial scattering). This indicates that
semi-hard parton scattering is the dominant particle production mechanism
underlying the hadron spectra at moderate $p_T \stackrel{>}{\sim} 1$ GeV/$c$.
However, there is no evidence of jet quenching or parton energy loss. Within
the parton model, one can exclude an effective parton energy loss
$dE_q/dx>0.01$ GeV/fm and a mean free path $\lambda_q< 7$ fm from the
experimental data of $A+B$ collisions at the SPS energies. Predictions for high
$p_T$ particle spectra in $p+A$ and $A+A$ collisions with and without jet
quenching at the RHIC energy are also given. Uncertainties due to initial
multiple scattering and nuclear shadowing of parton distributions are also
discussed.


title:
On momentum dependence of the reaction $\pi^- p \to \omega n$ near
  threshold

abstract:
  We discuss the near-threshold behavior of the $\omega$ production amplitude
in the reaction $\pi^-p \to \omega n$. In contrast to the results of earlier
analyses we find that the averaged squared matrix element of the production
amplitude must be a decreasing function of energy in order to describe the
existing experimental data.


title: Hard Thermal Loops from Transport Processes

abstract:
  This paper discusses attempts to numerically compute the effects of hard
thermal loops in non-abelian gauge theories at finite temperature by means of
solutions of Heinz' transport equation for an ensemble of classical colored
particles interacting with a real-time lattice gauge field. Results for the
real-time response functions and the Chern-Simons number diffusion rate in the
unbroken SU(2) guage theory are presented.


title: Revisting Lepton Pairs at the SPS

abstract:
  We confirm the importance of standard medium effects (hadronic rescattering)
in heavy-ion collisions by using a pQCD-based model to investigate the dilepton
spectra from Pb+Au collisions at 158 GeV/nucleon.


title:
Implications of Pseudospin Symmetry on Relativistic Magnetic Properties
  and Gamow - Teller Transitions in Nuclei

abstract:
  Recently it has been shown that pseudospin symmetry has its origins in a
relativistic symmetry of the Dirac Hamiltonian. Using this symmetry we relate
single - nucleon relativistic magnetic moments of states in a pseudospin
doublet to the relativistic magnetic dipole transitions between the states in
the doublet, and we relate single - nucleon relativistic Gamow - Teller
transitions within states in the doublet. We apply these relationships to the
Gamow - Teller transitions from $^{39}Ca$ to its mirror nucleus $^{39}K$.


title: Non-instant collisions and two concepts of quasiparticle

abstract:
  The kinetic theory recently implemented in heavy ion reactions combines a
non-local and non-instant picture of binary collisions with quasiparticle
features. We show that the non-instant description is compatible with the
spectral concept of quasiparticles while the commonly used variational concept
is consistent only with instant collisions. The rearrangement energy, by which
the variational concept surpasses the spectral one, is shown to be covered by a
medium effect on non-instant collisions.


title: Two-particle properties in nuclear matter at finite temperatures

abstract:
  Correlation effects in nuclear matter at finite temperatures are studied for
subnuclear densities ($\rho<\rho_0$) and medium excitation energy, where a
nonrelativistic potential approach is possible. A quantum statistical approach
is given, where clusters are treated under the influence of a clustered medium
treated within a mean field approximation. Spectral functions, in-medium cross
sections, and reaction rates are considered as well as the formation of a
quantum condensate. In particluar, exploratory calculations are shown with
respect to the pseudo gap in the nucleon level density close to the superfluid
phase transition. Estimates of isospin singlet pairing and quartetting in
nuclear binding energies are given.


title:
e+e- yields in Pb+Au collisions at 158 AGeV/c: Assessment of baryonic
  contributions

abstract:
  Using a hydrodynamic approach to describe Pb+Au collisions at 158 AGeV/c, we
analyze e+e- yields from matter containing baryons in addition to mesons. We
employ e+e- production rates from two independent calculations, which differ
both in their input physics and in their absolute magnitudes, especially in the
mass range where significant enhancements over expected backgrounds exist in
the CERES data. Although the presence of baryons leads to significant
enhancement of e+e- emission relative to that from mesons-only matter, the
calculated results fall below the data in the range 400 < M_ee/MeV < 600, by a
factor of 2-3. Since the calculated e+e- spectra are relatively insensitive to
the equation of state for initial conditions that fit the observed hadronic
spectra, either in-medium modifications of the e+e- sources more significant
than so far considered, or the presence of hitherto unidentified additional
sources of e+e- is indicated.


title: Test of final state approximations using threshold $pp \to pp\pi^0$

abstract:
  The Watson-Migdal approximation scheme to take into account final state
interactions is shown to give the actual threshold momentum dependence of the
reaction $pp \to pp\pi^0$. However, by an explicit plane wave replacement of
the final state wave function it is stressed that not too much physical
significance should be given to the proportionality coefficient extracted using
this procedure. The plane wave approximation is not physically reliable even
after introducing the Watson-Migdal or a more sophisticated final state
interaction factor, since direct production (impulse term) is missed. Also with
short range interactions there can be discrepancies of a factor two.


title:
A Poincar\'e Covariant Current Operator for Deep Inelastic Structure
  Functions and Deuteron Electromagnetic Properties

abstract:
  In front-form dynamics the current operator can be constructed from auxiliary
operators, defined in a Breit frame where initial and final three-momenta of
the system are directed along the $z$ axis. Poincar\'e covariance constraints
reduce for auxiliary operators to the ones imposed only by kinematical
rotations around the $z$ axis.
  Elastic and transition form factors can be extracted without any ambiguity
and in the elastic case the continuity equation is automatically satisfied,
once Poincar\'e, ${\cal P}$ and ${\cal T}$ covariance, together with
hermiticity, are imposed. Applications to deep inelastic structure functions in
an exactly solvable model and to the calculation of the deuteron
electromagnetic form factors are presented.


title: Monte Carlo methods and applications for the nuclear shell model

abstract:
  The shell-model Monte Carlo (SMMC) technique transforms the traditional
nuclear shell-model problem into a path-integral over auxiliary fields. We
describe below the method and its applications to four physics issues:
calculations of sdpf- shell nuclei, a discussion of electron-capture rates in
pf-shell nuclei, exploration of pairing correlations in unstable nuclei, and
level densities in rare earth systems.


title: DCC dynamics with the SU(3) linear sigma model

abstract:
  The SU(3) extension of the linear sigma model is employed to elucidate the
effect of including strangeness on the formation of disoriented chiral
condensates. By means of a Hartree factorization, approximate dispersion
relations for the 18 scalar and pseudoscalar meson species are derived and
their self-consistent solution makes it possible to trace out the thermal path
of the two order parameters as well as delineate the region of instability
within which spontaneous pair creation becomes possible. The results depend
significantly on the employed sigma mass, with the highest values yielding the
largest regions of instability. An approximate solution of the equations of
motion for the order parameter in scenarios emulating uniform scaling
expansions show that even with a rapid quench only the pionic modes grow
unstable. Nevertheless, the rapid and oscillatory relaxation of the order
parameters leads to enhanced production of both pions and (to a lesser degree)
kaons.


title: Nonextensive statistical effects in nuclear physics problems

abstract:
  Recent progresses in statistical mechanics indicate the Tsallis nonextensive
thermostatistics as the natural generalization of the standard classical and
quantum statistics, when memory effects and long-range forces are not
negligible. In this framework, weakly nonextensive statistical deviations can
strongly reduce the puzzling discrepancies between experimental data and
theoretical previsions for solar neutrinos and for pion transverse-momentum
correlations in Pb-Pb high-energy nuclear collisions.