title: Configuration Mixing in Relativistic Quark Models

abstract:
  Starting from the standard and commonly used relativistic nucleon wave
function, we show that residual interactions based on gluon or Goldstone boson
exchanges generate additional components leading to configuration mixing. This
result suggests that realistic nucleon wave functions can be expected to be far
more complex than seemingly successful form factor fits in relativistic quark
models would have one believe.


title:
The quantum mechanics of particle-correlation measurements in
  high-energy heavy-ion collisions

abstract:
  The Hanbury Brown--Twiss (HBT) effect in two-particle correlations is a
fundamental wave phenomenon that occurs at the sensitive elements of detectors;
it is one of the few processes in elementary particle detection that depends on
the wave mechanics of the produced particles. We analyze here, within a quantum
mechanical framework for computing correlations among high-energy particles,
how particle detectors produce the HBT effect. We focus on the role played by
the wave functions of particles created in collisions and the sensitivity of
the HBT effect to the arrival times of pairs at the detectors, and show that
the two detector elements give an enhanced signal when the single-particle wave
functions of the detected particles overlap at both elements within the
characteristic atomic transition time of the elements. The measured pair
correlation function is reduced when the delay in arrival times between pairs
at the detectors is of order of or larger than the transition time.


title:
Induced Pseudoscalar Coupling in Muon Capture and Second-Order
  Corrections

abstract:
  The hyperfine effect in muon capture rate is analyzed with taking into
account of the second-order terms in 1/M in the non-relativistic Hamiltonian.
It is shown that in the situation of the dominance of the squared first-order
terms the interference of zero-order and second-order terms has no significant
influence. General expression for neutrino (recoil nucleus) angular
distribution in muon capture by nucleus with non-zero spin is proposed. High
sensitivity to $g_P$ of the term related with alignment of the initial mesic
atom is discussed in the approximation of dominating Gamow--Teller matrix
element.


title: Soliton formation in the Nambu-Jona-Lasinio model

abstract:
  The soliton formation is considered in the Nambu-Jona-Lasinio model with
local four quark interaction and various schemes to regularize the energy
contribution of the polarized vacuum. No additional constraints are admitted in
order to stabilize the soliton. While solitons are unstable in the proper-time
regularized version the three momentum cut-off regularization apparently is
more appropriate. Using a semi-classical approach multi-quark solitons obtained
from that scheme are discussed. However, no self-consistent non-trivial unit
baryon number configuration has been found. We also study a renormalizable
extension of the model. In this case no stable multi-quark solitons are
obtained within the semi-classical approach.


title: The complete version of Moscow NN potential

abstract:
  A complete version of the Moscow NN potential model is presented. The
excellent description for all essential partial waves has been found in the
energy range 0 -- 350 MeV. The one-channel version of the model includes the
orthogonality condition to most symmetric six-quark states in all lowest
partial waves and thus, from this point of view, the model generalizes the well
known Saito's orthogonality condition model (OCM) for the baryon-baryon
interaction case. The specific features of the presented model which
distinguish it from many conventional force models are discussed in details.
One of them is a specific tensor mixing between nodal and nodeless
wavefunctions which results in very reasonable values of the OPE cut-off
parameter \Lambda =0.78 GeV and the \pi NN-coupling constant value f^2=0.075 in
nice agreement with modern trends. The model, in case of its confirmation in
precise few-nucleon calculations, can lead to noticeable revisions for many
nuclear properties given by conventional force models.


title: Chiral symmetry in nuclei

abstract:
  Effective field theory is considered to provide a highly useful framework for
connecting nuclear physics with the symmetries and dynamics of the underlying
theory of strong interactions, QCD. Of many issues that are of great current
interest in this domain, I concentrate here on two: (1) A new class of ab
initio calculations of obsevables in two-nucleon systems; (2) Attempts to
extend chiral perturbation calculations to higher-order terms.


title: Solution of the Bethe-Salpeter equation for pion-nucleon scattering

abstract:
  A relativistic description of pion-nucleon scattering based on the
four-dimensional Bethe-Salpeter equation is presented. The kernel of the
equation consists of s- and u-channel nucleon and delta pole diagrams, as well
as rho and sigma exchange in the t-channel. The Bethe-Salpeter equation is
solved by means of a Wick rotation, and good fits are obtained to the s- and
p-wave phase shifts up to 360 MeV pion laboratory energy. The coupling
constants determined by the fits are consistent with the commonly accepted
values in the literature.


title: Testing the Space-Time Structure of Event Generators

abstract:
  We report on work done in collaboration with Klaus Kinder-Geiger and John
Ellis which aims at connecting the space-time structure of event generator
simulations with observable output.


title: Event-by-event fluctuations in collective quantities

abstract:
  We discuss an event-by-event fluctuation analysis of particle production in
heavy ion collisions. We compare different approaches to the evaluation of the
event-by-event dynamical fluctuations in quantities defined on groups of
particles, such quantities as mean transverse momentum, transverse momentum
spectra slope, strength of anisotropic flow, etc.. The direct computation of
the dynamical fluctuations and the sub-event method are discussed in more
detail. We also show how the fluctuation in different variables can be related
to each other.


title: Directed and Elliptic Flow

abstract:
  We compare microscopic transport model calculations to recent data on the
directed and elliptic flow of various hadrons in 2 - 10 A GeV Au+Au and Pb (158
A GeV) Pb collisions. For the Au+Au excitation function a transition from the
squeeze-out to an in-plane enhanced emission is consistently described with
mean field potentials corresponding to one incompressibility. For the Pb (158 A
GeV) Pb system the elliptic flow prefers in-plane emission both for protons and
pions, the directed flow of protons is opposite to that of the pions, which
exhibit anti-flow. Strong directed transverse flow is present for protons and
Lambdas in Au (6 A GeV) Au collisions as well. Both for the SPS and the AGS
energies the agreement between data and calculations is remarkable.


title: Low energy n+t scattering and the NN forces

abstract:
  The Faddeev-Yakubovsky equations have been solved in configuration space for
the four nucleon system. The n+t elastic cross section has been calculated
using several realistic interactions and a phenomenological three-nucleon
force. Special attention is devoted to the description of the observed resonant
structure at $T_{lab}\approx 4$ MeV. In the present state of the calculations,
the realistic NN interactions are unable to describe the energy region
considered, i.e. n+t S- and P- waves. Whereas the inclusion of a three-nucleon
force improves the zero energy region, the disagreement in the resonant peak
remains. This failure contrasts with the results of a pure phenomenological
model. The origin of this disagreement as well as the possible issues are
discussed.


title: Chemical and Thermal Freeze-Out Parameters from 1 to 200 A.GeV

abstract:
  The present knowledge about hadrons produced in relativistic heavy ion
collisions is compatible with chemical freeze-out happening when the energy
density divided by the particle density reaches the value of 1 GeV. This
observation is used to determine the energy dependence of the chemical
freeze-out parameters T_{ch} and mu_B^{ch} for beam energies varying between 1
and 200 A.GeV. The consequences of this energy dependence are studied for
various particle ratios. Predictions for particle ratios at beam energy 40
A.GeV are presented. The conditions for thermal freeze-out are also determined.
These correspond either to an energy density of 45 MeV/fm**3 or to a particle
density of 0.05/fm**3.


title:
Double Delta(1232) excitation and the ABC effect in the reaction n + p
  -> 2H (pi pi)

abstract:
  The deuteron spectrum in n+p -> 2 H(pi pi) at k_n = 1.88 GeV/c and theta_d =
0^o is explained by considering a Delta Delta excitation as the dominant
reaction mechanism for the 2 pi production. We present a new theoretical
approach based on a coupled channel formalism which allows to include the
residual interaction within the intermediate Delta Delta and Delta N systems.
The corresponding interaction potentials V_{DeltaDelta} and V_{DeltaN} are
adopted from a meson exchange model with pi, rho, omega, and sigma exchange
taken into account. The influence of the residual interaction on the deuteron
spectrum is studied. We also predict the angular distribution of the two pions.
It is shown that this distribution is closely connected to the spin structure
of the DeltaDelta excitation.


title: Short-range and tensor correlations in the $^{16}$O(e,e$'$pn) reaction

abstract:
  The cross sections for electron induced two-nucleon knockout reactions are
evaluated for the example of the $^{16}$O(e,e$'$pn)$^{14}$N reaction leading to
discrete states in the residual nucleus $^{14}$N. These calculations account
for the effects of nucleon-nucleon correlations and include the contributions
of two-body meson exchange currents as the pion seagull, pion in flight and the
isobar current contribution. The effects of short-range as well as tensor
correlations are calculated within the framework of the coupled cluster method
employing the Argonne V14 potential as a model for a realistic nucleon-nucleon
interaction. The relative importance of correlation effects as compared to the
contribution of the meson exchange currents depends on the final state of the
residual nucleus. The cross section leading to specific states, like e.g. the
ground state of $^{14}$N, is rather sensitive to the details of the correlated
wave function.


title:
Production and Thermal Equilibration of Partons in Relativistic Heavy
  Ion Collisions: $\sqrt{s}= 20 vs. 200 A GeV$

abstract:
  The production and thermalization of partons liberated in relativistic heavy
ioncollisions is investigated within the parton cascade model. The momentum
distribution of the partons near z=0 is found to become isotropic beyond about
1 fm/c after the overlap for the collision of lead nuclei at $\sqrt{s}=20 A
GeV$ indicating a thermalization. At $\sqrt{s}=200 A GeV$ this is attained by
about 0.5 fm/c after the complete overlap.


title: Constraints on vector mesons with finite momentum in nuclear matter

abstract:
  Using the QCD operator product expansion, we derive the real part of the
transverse and longitudinal vector-vector correlation function with the quantum
numbers of the rho and omega mesons to leading order in density and three
momentum (q^2) for energy $\omega^2 --> -\infty $. The operator product
expansion provides, through the Borel transformed energy dispersion relation, a
model independent constraint for the momentum dependence of the vector meson
spectral density in nuclear matter. Existing model calculations for the
dispersion effect of the rho meson, where the vector-meson nucleon scattering
amplitude is obtained by resonance saturation in the s-channel, in general
violate this constraint. We trace this to an inconsistent choice for the form
factor of the $\Delta N\rho$ vertex. With a consistent choice, where both the
form factor and the coupling constant are obtained from the Bonn potential, the
contribution of the $\Delta$ is substantially reduced and we find good
agreement with the constraint equation. We briefly comment on the implications
of our result for attempts to interpret the enhancement of low-mass dileptons
in heavy-ion collisions.


title:
Bulk properties of rotating nuclei and the validity of the liquid drop
  model at finite angular momenta

abstract:
  Out of self-consistent semi-classical calculations performed within the
so-called Extended Thomas-Fermi approach for 212 nuclei at all even angular
momentum values I ranging between 0 and 80 \hbar and using the Skyrme SkM*
effective force, the I-dependence of associated liquid drop model parameters
has been studied. The latter have been obtained trough separate fits of the
calculated values of the strong interaction as well as direct and exchange
Coulomb energies. The theoretical data basis so obtained, has allowed to make a
rough quantitative assessment of the variation with I of the usual volume and
surface energy parameters up to spin of \sim 30-40 \hbar. As a result of the
combined variation of the surface and Coulomb energies, it has been shown that
this I-dependence results in a significant enhancement of the fission stability
of very heavy nuclei, balancing thus partially the well-known instability due
to centrifugal forces.


title:
On the Impossibility to Measure the Total Neutron- and Proton Induced
  Nonmesonic Decays for Hypertriton

abstract:
  Based on realistic calculations for the nonmesonic decay rate of Hypertriton
we demonstrate, that in principle it is not possible to measure the total n-
and p- induced decay rates and as a consequence $\Gamma_n /\Gamma_p$ for that
lightest hypernucleus.For the nonmesonic decay process the calculations are
performed with modern YN forces based on various meson exchanges and taking the
final state interaction among the three nucleons fully into account. Our
findings have consequences also for the interpretation of experimental
$\Gamma_n/\Gamma_p$ ratios for heavier hypernuclei where severe discrepancies
exist to theoretical $\Gamma_n/\Gamma_p$ ratios.


title: Semiclassical transport of particles with dynamical spectral functions

abstract:
  The conventional transport of particles in the on-shell quasiparticle limit
is extended to particles of finite life time by means of a spectral function
A(X,\vec{P},M^2) for a particle moving in an area of complex self-energy
\Sigma^{ret}_X = Re \Sigma^{ret}_X -i \Gamma_X/2. Starting from the
Kadanoff-Baym equations we derive in first order gradient expansion equations
of motion for testparticles with respect to their time evolution in \vec{X},
\vec{P} and M^2. The off-shell propagation is demonstrated for a couple of
model cases that simulate hadron-nucleus collisions. In case of nucleus-nucleus
collisions the imaginary part of the hadron self-energy \Gamma_X is determined
by the local space-time dependent collision rate dynamically. A first
application is presented for A + A reactions up to 95 A MeV, where the effects
from the off-shell propagation of nucleons are discussed with respect to high
energy proton spectra, high energy photon production as well as kaon yields in
comparison to the available data from GANIL.


title:
A Momentum Transformation Connecting a NN Potential in the
  Nonrelativistic and the Relativistic Two-Nucleon Schroedinger Equation

abstract:
  An analytical relation between center of mass momenta in a nonrelativistic
and a relativistic two-nucleon Schr\"odinger equation is proposed which allows
to analytically rewrite the two Schr\"odinger equations into each other. As a
consequence a NN potential occurring in the relativistic Schr\"odinger equation
can be gained from a nonrelativistic one by an analytical procedure. The
S-matrices in the two equations are exactly identical and therefore the
two-nucleon phase shifts.


title: Particle Freeze-out in Self-Consistent Relativistic Hydrodynamics

abstract:
  The particle emission in relativistic hydrodynamic model is formulated
assuming a sharp 3-dimensional space-time freeze-out hypersurface. The boundary
conditions correspond to the energy-momentum and charge conservation between
fluid and the gas of free particles. The emission and possible feedback of
particles are included into the self-consistent hydrodynamic scheme. For the
time-like parts of the freeze-out hypersurface the obtained results are
different from the well known Cooper-Frye formula and lead to the shock-like
freeze-out. A simple-wave hydrodynamic solution is considered in detail to
illustrate some aspects of new freeze-out procedure.


title:
Baryon, Charged Hadron, Drell-Yan and J/Psi Production in High Energy
  Proton-Nucleus Collisions

abstract:
  We show that the distributions of outgoing protons and charged hadrons in
high energy proton-nucleus collisions are described rather well by a linear
extrapolation from proton-proton collisions. The only adjustable parameter
required is the shift in rapidity of a produced charged meson when it
encounters a target nucleon. Its fitted value is 0.16. Next, we apply this
linear extrapolation to precisely measured Drell-Yan cross sections for 800 GeV
protons incident on a variety of nuclear targets which exhibit a deviation from
linear scaling in the atomic number A. We show that this deviation can be
accounted for by energy degradation of the proton as it passes through the
nucleus if account is taken of the time delay of particle production due to
quantum coherence. We infer an average proper coherence time of 0.4 +/- 0.1
fm/c, corresponding to a coherence path length of 8 +/- 2 fm in the rest frame
of the nucleus. Finally, we apply the linear extrapolation to measured J/Psi
production cross sections for 200 and 450 GeV/c protons incident on a variety
of nuclear targets. Our analysis takes into account energy loss of the beam
proton, the time delay of particle production due to quantum coherence, and
absorption of the J/Psi on nucleons. The best representation is obtained for a
coherence time of 0.5 fm/c, which is consistent with Drell-Yan production, and
an absorption cross section of 3.6 mb, which is consistent with the value
deduced from photoproduction of the J/Psi on nuclear targets.


title:
A program for coupled-channels calculations with all order couplings for
  heavy-ion fusion reactions

abstract:
  A FORTRAN77 program is presented that calculates fusion cross sections and
mean angular momenta of the compound nucleus under the influence of couplings
between the relative motion and several nuclear collective motions. The
no-Coriolis approximation is employed to reduce the dimension of
coupled-channels equations. The program takes into account the effects of
non-linear couplings to all orders, which have been shown to play an important
role in heavy-ion fusion reactions at subbarrier energies.


title: Dyson-Schwinger Equations and the Quark-Gluon Plasma

abstract:
  We review applications of Dyson-Schwinger equations at nonzero temperature,
T, and chemical potential, mu, touching topics such as: deconfinement and
chiral symmetry restoration; the behaviour of bulk thermodynamic quantities;
the (T,mu)-dependence of hadron properties; and the possibility of diquark
condensation.


title: Nuclear Bag Model and Nuclear Magnetic Moments

abstract:
  In 1991, we proposed a model in which nucleus is treated as a spherical
symmetric MIT bag and nucleon satisfies the MIT bag model boundary condition.
The model was employed to calculate nuclear magnetic moments. The results are
in good agreement with experiment data. Now, we found this model is still
interesting and illuminating.


title:
Comment on ``Proton Polarization Shifts in Electronic and Muonic
  Hydrogen''

abstract:
  We demonstrate that criticisms concerning our work nucl-th/9704043, made in
the recent preprint hep-ph/9903352, are unfounded. The improvements over our
results claimed in hep-ph/9903352 are in fact spurious, being based mainly on
misunderstandings and on dubious theoretical models.


title:
The three-body Coulomb scattering problem in discrete Hilbert-space
  basis representation

abstract:
  For solving the $2\to 2,3$ three-body Coulomb scattering problem the
Faddeev-Merkuriev integral equations in discrete Hilbert-space basis
representation are considered. It is shown that as far as scattering amplitudes
are considered the error caused by truncating the basis can be made arbitrarily
small. By this truncation also the Coulomb Green's operator is confined onto
the two-body sector of the three-body configuration space and in leading order
can be constructed with the help of convolution integrals of two-body Green's
operators. For performing the convolution integral an integration contour is
proposed that is valid for all energies, including bound-state as well as
scattering energies below and above the three-body breakup threshold.


title:
Partial Wave Decomposition for Meson Exchange Currents in Few-Nucleon
  Systems

abstract:
  We develop an approach for calculating matrix elements of meson exchange
currents between 3N basis states in (jJ)-coupling and a 3N bound state. The
contribution generated by $\pi$- and $\rho$-exchange are included in the
consideration. The matrix elements are expressed in terms of multiple integrals
in the momentum space. We apply a technique of the partial wave decompositions
and carry out some angular integrations in closed form. Different
representations appropriate for numerical calculations are derived for the
matrix elements of interest. The momentum dependences of the matrix elements
are studied and benchmark results are presented. The approach developed is of
interest for the investigations of deuteron- proton radiative capture and ^3He
photo- and electrodisintegration when the interaction in the initial or final
nuclear states is taken into account by solving the Faddeev equations.


title: Infinite Nuclear Matter on the Light Front: Nucleon-Nucleon Correlations

abstract:
  A relativistic light front formulation of nuclear dynamics is developed and
applied to treating infinite nuclear matter in a method which includes the
correlations of pairs of nucleons: this is light front Brueckner theory. We
start with a hadronic meson-baryon Lagrangian that is consistent with chiral
symmetry. This is used to obtain a light front version of a one-boson-exchange
nucleon-nucleon potential (OBEP). The accuracy of our description of the
nucleon-nucleon (NN) data is good, and similar to that of other relativistic
OBEP models. We derive, within the light front formalism, the Hartree-Fock and
Brueckner Hartree-Fock equations. Applying our light front OBEP, the nuclear
matter saturation properties are reasonably well reproduced. We obtain a value
of the compressibility, 180 MeV, that is smaller than that of alternative
relativistic approaches to nuclear matter in which the compressibility usually
comes out too large. Because the derivation starts from a meson-baryon
Lagrangian, we are able to show that replacing the meson degrees of freedom by
a NN interaction is a consistent approximation, and the formalism allows one to
calculate corrections to this approximation in a well-organized manner. The
simplicity of the vacuum in our light front approach is an important feature in
allowing the derivations to proceed. The mesonic Fock space components of the
nuclear wave function are obtained also, and aspects of the meson and nucleon
plus-momentum distribution functions are computed. We find that there are about
0.05 excess pions per nucleon.


title:
Fermionic Symmetries: Extension of the two to one Relationship Between
  the Spectra of Even-Even and Neighbouring Odd mass Nuclei

abstract:
  In the single j shell there is a two to one relationship between the spectra
of certain even-even and neighbouring odd mass nuclei e.g. the calculated
energy levels of J=0^+ states in ^{44}Ti are at twice the energies of
corresponding levels in ^{43}Ti(^{43}Sc) with J=j=7/2. Here an approximate
extension of the relationship is made by adopting a truncated seniority scheme
i.e. for ^{46}Ti and ^{45}Sc we get the relationship if we do not allow the
seniority v=4 states to mix with the v=0 and v=2 states. Better than that, we
get very close to the two to one relationship if seniority v=4 states are
admixed perturbatively. In addition, it is shown that the higher isospin states
do not contain seniority 4 admixtures.


title:
Importance of the Doppler Effect to the Determination of the Deuteron
  Binding Energy

abstract:
  The deuteron binding energy extracted from the reaction
${}^1H(n,\gamma){}^2H$ is reviewed with the exact relativistic formula, where
the initial kinetic energy and the Doppler effect are taken into account. We
find that the negligible initial kinetic energy of the neutron could cause a
significant uncertainty which is beyond the errors available up to now.
Therefore, we suggest an experiment which should include the detailed
informations about the initial kinetic energy and the detection angle. It could
reduce discrepancies among the recently reported values about the deuteron
binding energy and pin down the uncertainty due to the Doppler broadening of
$\gamma$ ray.


title:
$S$-matrix poles near the $\Lambda N$ and $\Sigma N$ Thresholds in the
  Coupled \\$\Lambda N-\Sigma N$ System

abstract:
  We search $t$-matrix poles for $\Lambda N-\Sigma N$ coupling interactions
using two soft core models of the Nijmegen group which bind the hypertriton at
the correct binding energy, and hard core models which are still influential in
hypernuclear physics. To treat the hard core potentials, a useful method for
calculating the off-shell $t$-matrix is proposed. We find poles close to the
$\Sigma N$ threshold in the second or third quadrant of the complex plane of
the $\Sigma N$ relative momentum. The relation between the poles and the shape
of the $\Lambda N$ elastic total cross section is discussed based on a
so-called uniformization by which two-channel $t$-matrices become single-valued
on a complex valuable. We also find poles near the $\Lambda N$ threshold. These
are correlated to the $S$-wave $\Lambda N$ scattering lengths, the values of
which have yet to be determined.


title:
Reply to Comment on ``Determination of pion-baryon coupling constants
  from QCD sum rules''

abstract:
  In response to Kim's comment (nucl-th/9903040) on the sum rules for
pion-baryon coupling constants obtained in hep-ph/9512259 and hep-ph/9606471,
we point out that our treatment of the continuum is consistent with duality and
with the fact that the correlator in the presence of an external meson or field
should be represented by a double dispersion relation.


title:
One-Nucleon Effective Generators of the Poincare Group derived from a
  Field Theory: Mass Renormalization

abstract:
  We start from a Lagrangian describing scalar "nucleons" and mesons which
interact through a simple vertex. Okubo's method of unitary transformation is
used to describe a single nucleon dressed by its meson cloud. We find an
expression for the physical mass of the nucleon being correct up to second
order in the coupling constant. It is then verified that this result is the
same as the corresponding expression found by Feynman techniques. Finally we
also express the three boost operators in terms of the physical nucleon mass.
Doing so we find expressions for all the ten generators of Poincar\'e
transformations for the system of one single dressed nucleon.


title:
Evidence for the fourth P11 resonance predicted by the constituent quark
  model

abstract:
  It is pointed out that the third of five low-lying P11 states predicted by a
constituent quark model can be identified with the third of four states in a
solution from a three-channel analysis by the Zagreb group. This is one of the
so-called ``missing'' resonances, predicted at 1880 MeV. The fit of the Zagreb
group to the pi N -> eta N data is the crucial element in finding this fourth
resonance in the P11 partial wave.


title:
An unusual space-time evolution for heavy ion collisions at high
  energies due to the QCD phase transition

abstract:
  The space-time evolution of high energy non-central heavy ion collisions is
studied with relativistic hydrodynamics. The results are very sensitive to the
Equation of State(EoS). For an EoS with the QCD phase transition, an unusual
matter distribution develops. Before freeze-out, two shells are formed which
then physically separate and leave a maximum in the center. We make specific
predictions for the azimuthal dependence of the flow and for two-pion
interferometry, contrasting our results with a resonance gas EoS.


title: Vector mesons in dense matter

abstract:
  We will summarize the progress in understanding the changes in the vector
meson spectral density in nuclear medium using the constraint equations
obtained from the Borel transformed dispersion relation and QCD Operator
Product Expansion. We will discuss the results for the scalar mass shift and
dispersion effects (three momentum dependence) for the light quark system
($\rho, \omega$), the strange quark system ($\phi$) and the heavy quark system
($J/\psi$) in nuclear medium. For the light quark systems, a nontrivial change
in the mass and width are expected, while the dispersion effects are found to
be small. Existing model calculations for the dispersion effects are compared
to the constraint equation in detail. Very small, but accurate mass shift is
obtained for the heavy quark system.


title: Nuclear structure studies with the 7Li(e,e'p) reaction

abstract:
  Experimental momentum distributions for the transitions to the ground state
and first excited state of 6He have been measured via the reaction
7Li(e,e'p)6He, in the missing momentum range from -70 to 260 MeV/c. They are
compared to theoretical distributions calculated with mean-field wave functions
and with variational Monte Carlo (VMC) wave functions which include strong
state-dependent correlations in both 7Li and 6He. These VMC calculations
provide a parameter-free prediction of the momentum distribution that
reproduces the measured data, including its normalization. The deduced summed
spectroscopic factor for the two transitions is 0.58 +/- 0.05, in perfect
agreement with the VMC value of 0.60. This is the first successful comparison
of experiment and ab initio theory for spectroscopic factors in p-shell nuclei.


title:
Surface properties of nuclear pairing with the Gogny force in a
  simplified model

abstract:
  Surface properties of neutron-neutron (T=1) pairing in semi-infinite nuclear
matter in a hard wall potential are investigated in BCS approximation using the
Gogny force. Surface enhancement of the gap function, pairing tensor and
correlation energy density is put into evidence.


title: Photon production in relativistic heavy ion collisions

abstract:
  The production of single photons in relativistic heavy ion collisions at CERN
SPS, BNL RHIC and CERN LHC energies is re-examined in view of the recent
studies of Aurenche et al which show that the rate of photon production from
quark gluon plasma, evaluated at the order of two loops far exceeds the rates
evaluated at one-loop level which have formed the basis of all the estimates of
photons so far. We find that the production of photons from quark matter could
easily out-shine those from the hadronic matter in certain ideal conditions.


title:
Meson and Isobar Degrees of Freedom in A($\vec{e},e'\vec{p}$) reactions
  at $0.2 \leq Q^2 \leq 0.8 (GeV/c)^2$

abstract:
  The effect of meson and isobar degrees of freedom in A($\vec{e},e'\vec{p}$)
and A(e,e'n) is studied for four-momentum transfers Q^2 in the range between
0.2 and 0.8 (GeV/c)^2. The calculations are performed in a non-relativistic
framework with explicit (N,\Delta,\pi) degrees-of-freedom. For the whole range
of momentum transfers under investigation the relative effect of the
meson-exchange and isobar degrees of freedom is significant. At low missing
momenta and quasi-elastic conditions, a tendency to reduce the (e,e'p) and
(e,e'n) differential cross sections is noticed. The greatest sensitivity is
found in the interference structure functions $W_{LT}$ and $W_{TT}$. The recoil
polarization observables, on the other hand, are moderately affected by the
meson-exchange and $\Delta$-isobar currents.


title:
The Transverse Structure of the Baryon Source in Relativistic Heavy Ion
  Collisions

abstract:
  A direct method to reconstruct the transverse structure of the baryon source
formed in a relativistic heavy ion collision is presented. The procedure makes
use of experimentally measured proton and deuteron spectra and assumes that
deuterons are formed via two-nucleon coalescence. The transverse density shape
and flow profile are reconstructed for Pb+Pb collisions at the CERN-SPS. The
ambiguity with respect to the source temperature is demonstrated and possible
ways to resolve it are discussed.


title:
Excitation function of nucleon and pion elliptic flow in relativistic
  heavy-ion collisions

abstract:
  Within a relativistic transport (ART) model for heavy-ion collisions, we show
that the recently observed characteristic change from out-of-plane to in-plane
elliptic flow of protons in mid-central Au+Au collisions as the incident energy
increases is consistent with the calculated results using a stiff nuclear
equation of state (K=380 MeV). We have also studied the elliptic flow of pions
and the transverse momentum dependence of both the nucleon and pion elliptic
flow in order to gain further insight about the collision dynamics.


title: Electromagnetic form factors of baryons in an algebraic approach

abstract:
  We present a simultaneous analysis of elastic and transition form factors of
the nucleon. The calculations are performed in the framework of an algebraic
model of baryons. Effects of meson cloud couplings are considered.


title: Novel features of $J/\Psi$ dissociation in matter

abstract:
  We make a detailed study of the effect that the recently predicted
modification of the in-medium masses of charmed mesons would have on $J/\Psi$
dissociation on pion and $\rho$-meson comovers in relativistic heavy ion
collisions. We find a substantial dependence of the $J/\Psi$ absorption rates
on the density and temperature of the nuclear matter. This suggests that a
quantitative analysis of $J/\Psi$ dissociation in nucleus nucleus collisions
should include the effects of the modification of meson masses in dense matter.


title: On Studying Charm in Nuclei through Antiproton Annihilation

abstract:
  We examine the production of open charm in antiproton annihilation on finite
nuclei. The enhancement of the subthreshold production cross section, even in a
nucleus as light as carbon, should provide a clean signature of the reduction
in the masses of these mesons in-medium. We also show that a careful analysis
of the $D^+$ and $D^-$ spectra can yield important information on the cross
section for $D^{\pm}N$ scattering.


title: Baryon Masses in Chiral Perturbation Theory with Infrared Regularization

abstract:
  The baryon masses are examined in SU(3) chiral perturbation theory to third
order using the recently proposed infrared regularization scheme. Fourth order
is estimated by evaluating the dominant diagram. With this regularization the
magnitude of the loop integrals is reduced so that the convergence of the
series appears to be better than in the heavy baryon approach.


title: Kinetic Freeze-out and Radial Flow in 11.6 A GeV Au+Au Collisions

abstract:
  We study the kinetic freeze-out conditions of hadrons in Au+Au collisions at
11.6 A GeV/c using different parametrizations of an expanding thermal fireball.
We take into account the available double differential momentum spectra of a
variety of particle species, covering a large fraction of the total momentum
space. The overall fit to the data is very good and indicates a relatively low
kinetic freeze-out temperature of about 90 MeV with an average transverse
expansion velocity at midrapidity of about 0.5 c.


title:
IBM: parameter symmetry, hidden symmetries and transformations of boson
  operators

abstract:
  A symmetry of the parameter space of interacting boson models IBM-1 and IBM-2
is studied. The symmetry is associated with linear canonical transformations of
boson operators, or, equivalently, with the existence of different realizations
of the symmetry algebras of the models. The relevance of the parameter symmetry
to physical observables is discussed.


title: Nuclear Structure Functions from Constituent Quark Model

abstract:
  We have used the notion of the constituent quark model of nucleon, where a
constituent quark carries its own internal structure, and applied it to
determine nuclear structure functions ratios. It is found that the description
of experimental data require the inclusion of strong shadowing effect for
$x<0.01$. Using the idea of vector meson dominance model and other ingredients
this effect is calculated in the context of the constituent quark model. It is
rather striking that the constituent quark model, used here, gives a good
account of the data for a wide range of atomic mass number from A=4 to A=204.


title: Heavy Meson Observables

abstract:
  An accurate and unified description of the non-hadronic electroweak
interactions of light- and heavy-mesons is possible when the dressing of quark
propagators and the finite size of hadronic bound states is explicitly
accounted for.


title:
Correlation effects in single-particle overlap functions and one-nucleon
  removal reactions

abstract:
  Single-particle overlap functions and spectroscopic factors are calculated on
the basis of the one-body density matrices (ODM) obtained for the nucleus
$^{16}O$ employing different approaches to account for the effects of
correlations. The calculations use the relationship between the overlap
functions related to bound states of the (A-1)-particle system and the ODM for
the ground state of the A-particle system. The resulting bound-state overlap
functions are compared and tested in the description of the experimental data
from (p,d) reactions for which the shape of the overlap function is important.


title: Convergence Issues in Nucleon-Nucleon Effective Field Theory

abstract:
  The origin of the breakdown scale in an effective field theory treatment of
nuclear forces is investigated. Different organizational schemes used in the
nonperturbative calculation of nucleon-nucleon scattering seem to break down
for different physical reasons. It is argued that the same physics is actually
responsible, namely strong two-pion exchange as also observed in the pion
scalar form factor. The prospect of extending the applicability of the
effective field theory beyond this breakdown point is discussed.


title: Dilepton Spectra from Decays of Light Unflavored Mesons

abstract:
  The invariant mass spectrum of the $e^{+}e^{-}$ and $\mu ^{+}\mu ^{-}$ pairs
from decays of light unflavored mesons with masses below the $\phi
(1020)$-meson mass to final states containing along with a dilepton pair one
photon, one meson, and two mesons are calculated within the framework of the
effective meson theory. The results can be used for simulations of the dilepton
spectra in heavy-ion collisions and for experimental searches of dilepton meson
decays.


title: Nuclear matter, nuclear and subnuclear degrees of freedom

abstract:
  We report here theoretical investigations on the complexity of nuclear
structure, which have been carried out in the framework of different many-body
approaches, typically applied to nuclear matter and quark matter studies. The
variational, functional and perturbative scheme are illustrated in their latest
developments. The effect of various nucleon-nucleon interactions are tested,
particularly in the context of the nuclear response functions, against a large
body of experimental data. The properties and decay widths of hypernuclei are
shortly revisited, while the equation of state of isospin asymmetric nuclear
matter leads us toward nuclear systems of astrophysical interest, like the
neutron stars. Finally the transition from hadronic matter to the deconfined
phase of quark-gluon plasma endorses the application of many-body and field
theoretical techniques to a system with subnucleonic degrees of freedom.


title:
The neutron distribution in nuclei as measured with parity violating
  electron scattering

abstract:
  A short review of the present knowledge of the nucleons distribution in
nuclei is given. A proposal is made about a possible measurements of the
neutron distribution through polarized electron scattering off nuclei.


title:
Extraction of nucleon momentum distributions from inclusive electron
  scattering on nuclei

abstract:
  We address the problem of extracting single-nucleon momentum distributions
$n(p)$ from inclusice scattering data. A model for these relates nuclear and
nucleon structure functions (SF) through an intermediate SF $f^{PN}$ for a
nucleus of point-particles. In addition to the asymptotic limit (AL) which
depends on $n(p), f^{PN}$ contains, generally $q$-dependent Final State
Interactions (FSI) parts. In the inverse problem one wishes to separate
$q$-dependent FSI from the AL. In general it suffices to know the structure of
the theory, but not numerical results. It appears, that in the $q$-range of the
analyzed electron scattering data, FSI are only weakly $q$-dependent, making it
virtually impossible to obtain parameters in a free fit of the parametrized
components of $f$. Imposing a restriction, we obtain $n(p)$ for Fe and $^4$Fe.


title:
Theoretical aspects of the CEBAF 89-009 experiment on inclusive
  scattering of 4.05 GeV electrons from nuclei

abstract:
  We compare recent CEBAF data on inclusive electron scattering on nuclei with
predictions, based on a relation between structure functions (SF) of a nucleus,
a nucleon and a nucleus of point-nucleons. The latter contains nuclear
dynamics, e.g. binary collision contributions in addition to the asymptotic
limit. The agreement with the data is good, except in low-intensity regions.
Computed ternary collsion contributions appear too small for an explanation. We
perform scaling analyses in Gurvitz's scaling variable and found that for
$y_G\gtrless 0$, ratios of scaling functions for pairs of nuclei differ by less
than 15-20% from 1. Scaling functions for $<y_G>0$ are, for increasing $Q^2$,
shown to approach a plateau from above. We observe only weak $Q^2$-dependence
in FSI, which in the relevant kinematic region is ascribed to the diffractive
nature of the NN amplitudes appearing in FSI. This renders it difficult to
separate asymptotic from FSI parts and seriously hampers the extraction of
$n(p)$ from scaling analyses in a model-independnent fashion.


title: R-ratios and moments of nuclear structure functions

abstract:
  We study implications of a model, which links nuclear and nucleon structure
functions. Computed Callen-Gross functions $\kappa^A(x,Q^2)=
2xF_1^A(x,Q^2)/F_2^A(x,Q^2)$ appear for finite $Q^2$ to be close to their
asymptotic value 1. Using those $\kappa$, we compure $R$ ratios for $Q^2\ge 5
GeV^2$. We review approximate methods in use for the extraction of $R$ from
inclusive scattering and ENC data. Further we calcuate ratios of the moments of
$F_k$ and find these to describe the data, in particular their $Q^2$
dependence. The above observables, as well as inclusive cross sections, are
sensitive tests for the underlying relation between nucleonic and nuclear
structure functions. In view of the overall agreement, we speculate that the
above relation effectively circumvents a QCD calculation.


title:
Analysis of Meson Exchange and Isobar Currents in (e,e'p) Reactions from
  O-16

abstract:
  An analysis of the effects of meson exchange and isobar currents in exclusive
(e,e'p) processes from O-16 under quasi-free kinematics is presented. A model
that has probed its feasibility for inclusive quasi-elastic (e,e') processes is
considered. Sensitivity to final state interactions between the outgoing proton
and the residual nucleus is discussed by comparing the results obtained with
phenomenological optical potentials and a continuum nuclear shell-model
calculation. The contribution of the meson-exchange and isobar currents to the
response functions is evaluated and compared to previous calculations, which
differ notably from our results. These two-body contributions cannot solve the
puzzle of the simultaneous description of the different responses
experimentally separated. Copyright 1999 by The American Physical Society


title:
The N N -> NN pi+ Reaction near Threshold in a Chiral Power Counting
  Approach

abstract:
  Power-counting arguments are used to organize the interactions contributing
to the N N -> d pi, p n pi reactions near threshold. We estimate the
contributions from the three formally leading mechanisms: the Weinberg-Tomozawa
(WT) term, the impulse term, and the $\Delta$-excitation mechanism. Sub-leading
but potentially large mechanisms, including $S$-wave pion-rescattering, the
Galilean correction to the WT term, and short-ranged contributions are also
examined. The WT term is shown to be numerically the largest, and the other
contributions are found to approximately cancel. Similarly to the reaction p p
-> p p pi0, the computed cross sections are considerably smaller than the data.
We discuss possible origins of this discrepancy.


title: On the Delta I = 1/2 rule in the Lambda N ----> N N reaction

abstract:
  It is shown that the mass dependence of the $\Lambda$-lifetime in heavy
hypernuclei is sensitive to the ratio of neutron-induced to proton-induced
non-mesonic decay rates R_n/R_p. A comparison of the experimental mass
dependence of the lifetimes with the calculated ones for different values of
R_n/R_p leads to the conclusion that this ratio is larger than 2 on the
confidence level of 0.75. This suggests that the phenomenological $\Delta$I=1/2
rule might be violated for the nonmesonic decay of the $\Lambda$-hyperon.


title: Shadowing in the nuclear photoabsorption above the resonance region

abstract:
  A model based on the hadronic fluctuations of the real photon is developed to
describe the total photonucleon and photonuclear cross sections in the energy
region above the nucleon resonances. The hadronic spectral function of the
photon is derived including the finite width of vector-meson resonances and the
quark-antiquark continuum. The shadowing effect is evaluated considering the
effective interaction of the hadronic component with the bound nucleons within
a Glauber-Gribov multiple scattering theory. The low energy onset of the
shadowing effect is interpreted as a possible signature of a modification of
the hadronic spectral function in the nuclear medium. A decrease of the
$\rho$-meson mass in nuclei is suggested for a better explanation of the
experimental data.


title:
Damping of Collective Nuclear Motion and Thermodynamic Properties of
  Nuclei beyond Mean Field

abstract:
  The dynamical description of correlated nuclear motion is based on a set of
coupled equations of motion for the one-body density matrix $\rho (11';t)$ and
the two-body correlation function $c_2(12,1'2';t)$, which is obtained from the
density-matrix hierarchy beyond conventional mean-field approaches by
truncating 3-body correlations. The resulting equations nonperturbatively
describe particle-particle collisions (short-range correlations) as well as
particle-hole interactions (long-range correlations). Within a basis of
time-dependent Hartree-Fock states these equations of motion are solved for
collective vibrations of $^{40}Ca$ at several finite thermal excitation
energies corresponding to temperatures $T=0-6$ MeV. Transport coefficients for
friction and diffusion are extracted from the explicit solutions in comparison
to the solutions of the associated TDHF, VUU, Vlasov or damped quantum
oscillator equations of motion. We find that the actual magnitude of the
transport coefficients is strongly influenced by partlicle-hole correlations at
low temperature which generate large fluctuations in the nuclear shape degrees
of freedom. Thermodynamically, the specific heat and the entropy of the system
as a function of temperature does not differ much from the mean-field limit
except for a bump in the specific heat around $T\simeq 4$ MeV which we
attribute to the melting of shell effects in the correlated system.


title: Inclusive and Direct Photons in S + Au Central Collisions at 200A GeV/c

abstract:
  A hadron and string cascade model, JPCIAE, which is based on LUND string
model, PYTHIA event generator especially, is used to study both inclusive
photon production and direct photon production in 200A GeV S + Au central
collisions. The model takes into account the photon production from the
partonic QCD scattering process, the hadronic final-state interaction, and the
hadronic decay and deals with them consistently. The results of JPCIAE model
reproduce successfully both the WA93 data of low p_T inclusive photon
distribution and the WA80 data of transverse momentum dependent upper limit of
direct photon. The photon production from different decay channels is
investigated for both direct and inclusive photons. We have discussed the
effects of the partonic QCD scattering and the hadronic final-state interaction
on direct photon production as well.


title: Compressibility of Nuclear Matter from Shell Effects in Nuclei

abstract:
  The compressibility of nuclear matter has received significant attention in
the last decade and a variety of approaches have been employed to extract this
fundamental property of matter. Recently, significant differences have emerged
between the results of relativistic and non-relativistic calculations of
breathing mode giant monopole resonance (GMR). This is due to a lack of
understanding of the dynamics of GMR and of its exact relationship to the
compression modulus of the infinite nuclear matter. Here, I present an
alternative approach based upon nuclear shell effects. The shell effects are
known to manifest experimentally in terms of particle-separation energies with
an exceedingly high precision. Within the framework of the non-relativistic
density-dependent Skyrme theory, it is shown that the compressibility of
nuclear matter has a significant influence on shell effects in nuclei. It is
shown that 2-neutron separation energies and hence the empirical shell effects
can be used to constrain the compressibility of nuclear matter.


title: Scaling Analysis of Fluctuating Strength Function

abstract:
  We propose a new method to analyze fluctuations in the strength function
phenomena in highly excited nuclei. Extending the method of multifractal
analysis to the cases where the strength fluctuations do not obey power scaling
laws, we introduce a new measure of fluctuation, called the local scaling
dimension, which characterizes scaling behavior of the strength fluctuation as
a function of energy bin width subdividing the strength function. We discuss
properties of the new measure by applying it to a model system which simulates
the doorway damping mechanism of giant resonances. It is found that the local
scaling dimension characterizes well fluctuations and their energy scales of
fine structures in the strength function associated with the damped collective
motions.


title: Protoneutron stars with kaon condensate

abstract:
  A new formulation is presented to treat fluctuations around the kaon
condensate. Equation of state (EOS) is given for isothermal and isentropic
cases in the heavy-baryon-limit (HBL). The coexistent phase appears in the
latter case. The mass-radius relation is given for protoneutron stars and the
possibility of the delayed collapse is discussed.


title: Selfconsistent effective interactions and symmetry restoration

abstract:
  In this paper we propose a general framework for deriving the effective
interactions for many-body systems. We show how the selfconsistent interaction
can be constructed on the quantum level for both local and nonlocal potentials.
In particular the relation between the selfconsistent and symmetry restoring
interaction is derived. The difference between the two is related to the
coupling of the perturbing field to the kinetic energy operator.


title: $\phi$-meson production in proton-proton collisions

abstract:
  The production of $\phi$-mesons in proton-proton collisions is investigated
within a relativistic meson-exchange model of hadronic interactions. The
experimental prerequisites for extracting the $NN\phi$ coupling strength from
this reaction are discussed. In the absence of a sufficient set of data, which
would enable an accurate determination of the $NN\phi$ coupling strength, we
perform a combined analysis, based on some reasonable assumptions, of the
existing data for both $\omega$- and $\phi$-meson production. We find that the
recent data from the DISTO collaboration on the angular distribution of the
$\phi$ meson indicate that the $NN\phi$ coupling constant is small. The
analysis yields values for $g_{NN\phi}$ that are compatible with the OZI rule.


title: Constructing Hybrid Baryons with Flux Tubes

abstract:
  Hybrid baryon states are described in quark potential models as having
explicit excitation of the gluon degrees of freedom. Such states are described
in a model motivated by the strong coupling limit of Hamiltonian lattice gauge
theory, where three flux tubes meeting at a junction play the role of the glue.
The adiabatic approximation for the quark motion is used, and the flux tubes
and junction are modeled by beads which are attracted to each other and the
quarks by a linear potential, and vibrate in various string modes. Quantum
numbers and estimates of the energies of the lightest hybrid baryons are
provided.


title: (Hybrid) Baryons in the Flux-Tube Model

abstract:
  We construct baryons and hybrid baryons in the non-relativistic flux-tube
model of Isgur and Paton. The motion of the flux-tube with the three quark
positions fixed, except for centre of mass corrections, is discussed. It is
shown that the problem can to an excellent approximation be reduced to the
independent motion of a junction and strings.


title: (Hybrid) Baryons: Quantum Numbers and Adiabatic Potentials

abstract:
  We construct (hybrid) baryons in the flux-tube model of Isgur and Paton. In
the limit of adiabatic quark motion, we build proper eigenstates of orbital
angular momentum and indicate the flavour, spin, chirality and J^P of (hybrid)
baryons. The adiabatic potential is calculated as a function of the quark
positions.


title: (Hybrid) Baryons: Symmetries and Masses

abstract:
  We construct (hybrid) baryons in the flux-tube model of Isgur and Paton. In
the limit of adiabatic quark motion, we build proper eigenstates of orbital
angular momentum and construct the flavour, spin and J^P of hybrid baryons from
the symmetries of the system. The lowest mass hybrid baryon is estimated at
approximately 2 GeV.


title:
The role of pairing correlations for the description of $\beta$
  vibrations at superdeformed shapes

abstract:
  In this paper we analyze the possibility of the appearance of quadrupole
vibrational states in superdeformed nuclei from the $A\approx 150$ region. We
discuss the role of pairing correlations for a proper description of quadrupole
vibrations, especially of the $\beta$ type.


title:
Final State Interactions in Near Threshold Meson Production from pp
  Collisions

abstract:
  We analyse the experimental data on near threshold $\pi$, $\eta$, $\omega$,
$\eta'$ and $K^+$ production from $pp$ collisions and show that all information
gained so far is compatible with approximately constant production matrix
elements when including the rescattering between the baryons in the final
states. Different methods to include the final state interactions are discussed
and their range of validity is indicated. We, furthermore, show that Dalitz
plots for the proton-meson invariant mass spectra at different energies should
be suited to distinguish between final state interactions and resonant
production amplitudes.


title: Electromagnetic probes of hot and dense hadronic matter

abstract:
  The formalism of photon and dilepton productions in a thermal bath are
discussed in the frame work of finite temperature field theory. The emission
rate has been expressed in terms of the discontinuities or imaginary part of
the photon self energy in the thermal bath. The photon and dilepton emissions
have been computed by taking into account the in-medium modifications of the
particles appearing in the internal loop of the self energy diagram using a
phenomenological effective lagrangian approach. The results has been compared
with the photon spectra measured by WA 98 collaboration at CERN SPS energies.


title: Dynamical Interpretation of Chemical Freeze-Out Parameters

abstract:
  It is shown that the condition for chemical freeze-out, average energy per
hadron approximately 1 GeV, selects the softest point of the equation of state,
namely the point where the pressure divided by the energy density has a
minimum. The sensitivity to the equation of state used is discussed. The
previously proposed mixed phase model, which is consistent with lattice QCD
data naturally leads to the chemical freeze-out condition.


title: $\pi NN$ coupling determined beyond the chiral limit

abstract:
  Within the conventional QCD sum rules, we calculate the $\pi NN$ coupling
constant, $g_{\pi N}$, beyond the chiral limit using two-point correlation
function with a pion. We consider the Dirac structure, $i\gamma_5$, at
$m_\pi^2$ order, which has clear dependence on the PS and PV coupling schemes
for the pion-nucleon interactions. For a consistent treatment of the sum rule,
we include the linear terms in quark mass as they constitute the same chiral
order as $m_\pi^2$. Using the PS coupling scheme for the pion-nucleon
interaction, we obtain $g_{\pi N}=13.3\pm 1.2$, which is very close to the
empirical $\pi NN$ coupling. This demonstrates that going beyond the chiral
limit is crucial in determining the coupling and the pseudoscalar coupling
scheme is preferable from the QCD point of view.


title: Evolution of the nucleon structure in the lightest nuclei

abstract:
  The evolution of the nucleon structure as a function of atomic mass A is
considered for the first time for the lightest nuclei, D, 3H, 3He and 4He, with
an approach based on the Bethe-Salpeter formalism. We show that the pattern of
the oscillation of the structure functions ratio r^A(x) = F_2^A/F_2^N(D) varies
with A by changing the position of the cross-over point x_3 in which r^A(x) =
1, unlike the pattern for nuclei with masses A larger than 4, where only the
amplitude of the oscillation changes. In particular we find that the pattern of
F_2(x) modifications is controlled with the values (1 - x_3) = 0.32 (D/N), 0.16
(3He/D) and 0.08 (4He/D). The obtained results follow from the relativistic
consideration of the nuclear structure and allow us to define a whole class of
modifications of the partonic distributions in the nucleon bound in a nucleus.
The EMC effect is explained as a particular case of the considered class.


title: Compression modes in nuclei: microscopic models with Skyrme interactions

abstract:
  The isoscalar giant monopole resonances (ISGMR) and giant dipole resonances
(ISGDR) in medium-heavy nuclei are investigated in the framework of HF+RPA and
HF-BCS+QRPA with Skyrme effective interactions. It is found that pairing has
little effect on these modes. It is also found that the coupling of the RPA
states to 2p-2h configurations results in about (or less than) 1 MeV shifts of
the resonance energies and at the same time gives the correct total widths. For
the ISGMR, comparison with recent data leads to a value of nuclear matter
compression modulus close to 215 MeV. However, a discrepancy between calculated
and measured energies of the ISGDR in $^{208}$Pb is found and remains an open
problem.


title: Perturbative Pions and the Effective Range Expansion

abstract:
  In this talk the $Q$ counting scheme to implement effective field theory is
discussed. It is pointed out that there are two small mass scales in the
problem $m_\pi$ and $1/a$ with $1/a \ll m_\pi$. It is argued that while the
expansion based on $1/a$ being small compared to the underlying short distance
scales works well, the chiral expansion may not. The coefficients of the
effective range expansion are sensitive to the chiral physics and are very
poorly described in $Q$ counting at lowest nontrivial order. A ``shape
function'' is introduced which again is sensitive to pionic physics and
insensitive to fitting procedures. It is also poorly described in $Q$ counting.


title: On Making Predictions With Effective Field Theories In Nuclear Physics

abstract:
  Based on the effective field theory previously formulated by us to accurately
postdict all low-energy two-nucleon properties as well as predict certain
electroweak transitions in heavy nuclei, we make parameter-free predictions for
the polarized np capture process \vec{n}+\vec{p} --> d +\gamma presently being
measured at the Institut Laue-Langevin in Grenoble. Other participants of this
meeting are invited to make their own predictions using their preferred
approaches and join the bet for the best prediction to confront the forthcoming
experiment.


title: Local harmonic approaches with approximate cranking operators

abstract:
  Methods of large amplitude collective motion in the adiabatic limit are
examined with a special emphasis on conservation laws. We show that the
restriction to point transformations, which is a usual assumption of the
adiabatic time-dependent mean-field theory, needs to be lifted. In order to
facilitate the application of large amplitude collective motion techniques, we
examine the possibility of representing the RPA normal-mode coordinates by
linear combinations of a limited number of one-body operators. We study the
pairing-plus-quadrupole model of Baranger and Kumar as an example, and find
that such representations exist in terms of operators that are state-dependent
in a characteristic manner.


title:
Effect of nucleon structure variation on the longitudinal response
  function

abstract:
  Using the quark-meson coupling (QMC) model, we study the longitudinal
response function for quasielastic electron scattering from nuclear matter. In
QMC the coupling constant between the scalar ($\sigma$) meson and the nucleon
is expected to decrease with increasing nuclear density, because of the
self-consistent modification of the structure of the nucleon. The reduction of
the coupling constant then leads to a smaller contribution from relativistic
RPA than in the Walecka model. However, since the electromagnetic form factors
of the in-medium nucleon are modified at the same time, the longitudinal
response function and the Coulomb sum are reduced by a total of about 20% in
comparison with the Hartree contribution. We find that the relativistic RPA and
the nucleon structure variation both contribute about fifty-fifty to the
reduction of the longitudinal response.


title: Isospin Effects of the Critical Behavior in the Lattice Gas Model

abstract:
  Isospin effects of the critical phenomena were studied via Xe isotopes in the
frame of lattice gas model. All the critical temperatures for four Xe isotopes
are close to 5.5 MeV at the same freeze-out density of about 0.39 $\rho_0$. The
critical values of power law parameter of mass distribution, mean multiplicity
of intermediate mass fragments (IMF), information entropy and Campi's second
moment show minor dependence on the isospin at the critical point.


title: Excitation Energy as a Basic Variable to Control Nuclear Disassembly

abstract:
  Thermodynamical features of Xe system is investigated as functions of
temperature and freeze-out density in the frame of lattice gas model. The
calculation shows different temperature dependence of physical observables at
different freeze-out density. In this case, the critical temperature when the
phase transition takes place depends on the freeze-out density. However, a
unique critical excitation energy reveals regardless of freeze-out density when
the excitation energy is used as a variable insteading of temperature.
Moreover, the different behavior of other physical observables with temperature
due to different $\rho_f$ vanishes when excitation energy replaces temperature.
It indicates that the excitation energy can be seen as a more basic quantity to
control nuclear disassembly.


title:
Photodisintegration of the deuteron in the few GeV region using
  asymptotic amplitudes

abstract:
  Exclusive photodisintegration of the deuteron in the 1-4GeV range is
described in terms of a simple covariant and gauge invariant approach using an
effective counting rule as the hard part of the d-np vertex.
  At a scattering angle of theta_cm=90 degrees a prescaling behavior of the
differential cross section proportional to 1/s^(n-2) with n ~ 12 is obtained;
going away from 90 degrees the value of n decreases slowly, in qualitative
agreement with the recent data.


title:
Study of relativistic nuclear collisions at AGS energies from p+Be to
  Au+Au with hadronic cascade model

abstract:
  A hadronic cascade model based on resonances and strings is used to study
mass dependence of relativistic nuclear collisions from p+Be to Au+Au at AGS
energies ($\sim 10\AGeV$) systematically. Hadron transverse momentum and
rapidity distributions obtained with both cascade calculations and Glauber type
calculations are compared with experimental data to perform detailed discussion
about the importance of rescattering among hadrons. We find good agreement with
the experimental data without any change of model parameters with the cascade
model. It is found that rescattering is of importance both for the explanation
of high transverse momentum tail and for the multiplicity of produced
particles.


title: The c-term of the TM 3-body Force: to be or not to be

abstract:
  In Faddeev calculations of ^3Hwe study the dependence of the binding on the
three nucleon force. We adopt the 2 pi -exchange Tucson-Melbourne three-nucleon
force and investigate phenomenologically the dependence on the strength of the
individual three-body force operators (a -, b -, c - and d -terms). While the a
-term provides a tiny contribution the b - and d -terms provides a tiny
contribution the b - and d -terms are important to gain the experimental
binding energy. We find two solutions for the c -term, one around the value
used in the Tucson-Melbourne model and a new one close to zero, which supports
the recentrecommendation of chiral perturbation theory that the short-range c
-term should be dropped.


title: The Influence of High Multiplicities at RHIC on the Gamov Factor

abstract:
  The corrections for two-pion correlations due to electromagnetic final-state
interactions at high secondary multiplicities are investigated. The analysis is
performed by solving the Schr\"odinger equation with a potential which is
dictated by the multi-particle environment. Two different post-freeze-out
scenarios are examined. First, for a uniformly spread environment of secondary
particles, a screened Coulomb potential is exploited. It is shown that the
presence of a static and uniform post-freeze-out medium results in a noticeable
deviation from the standard Gamov factor. However, after going to a more
realistic model of an expanding pion system, this conclusion changes
drastically. We argue that the density of the secondary pions n_\pi(t,R), where
R is a distance from the fireball, is bounded from above by n_\pi(t,R)\le
const/R^2 for all times t. Then, a two-particle scalar potential which is found
as a solution of the Maxwell equation for non-uniform medium replaces the
screened one. Even this upper limit does not result in an essential deviation
from the Gamov correction.


title:
Effects of Neutron Spatial Distributions on Atomic Parity
  Nonconservation in Cesium

abstract:
  We have examined modifications to the nuclear weak charge due to small
differences between the spatial distributions of neutrons and protons in the Cs
nucleus. We derive approximate formulae to estimate the value and uncertainty
of this modification based only on nuclear rms neutron and proton radii.
Present uncertainties in neutron distributions in Cs are difficult to quantify,
but we conclude that they should not be neglected when using atomic parity
nonconservation experiments as a means to test the Standard Model.


title: Imaging Three-Dimensional Relative Sources from Nuclear Reactions

abstract:
  One can access the space-time development of a heavy-ion reaction directly by
imaging the source function from two particle correlation functions. In the
case of like-charged pions, this imaging can be recast as a Fourier inversion
problem. We will demonstrate how this inversion can be performed on full
three-dimensional (i.e. in long, side and out coordinates) experimentally
determined correlation functions. We will discuss the resulting three
dimensional images of the relative sources. Finally, we will discuss how to
perform the full three dimensional inversion for particles whose final state
interactions are more complicated than those of the pions.


title:
Neutron rich nuclei in density dependent relativistic Hartree-Fock
  theory with isovector mesons

abstract:
  Density dependent relativistic Hartree-Fock theory has been extended to
describe properties of exotic nuclei. The effects of Fock exchange terms and of
pi - and rho - meson contributions are discussed. These effects are found to be
more important for neutron rich nuclei than for nuclei near the valley of
stability.


title: Nuclear Physics of Double Beta Decay

abstract:
  Study of the neutrinoless $\beta\beta$ decay allows us to put a stringent
limit on the effective neutrino Majorana mass, a quantity of fundamental
importance. To test our ability to evaluate the nuclear matrix elements that
govern the decay rate, it is desirable to be able to describe the allowed
two-neutrino decay. It is argued that only low-lying virtual intermediate
states are important for that process, and thus it appears that the large-scale
shell model evaluation, free from the various difficulties of QRPA, is the
preferred method. In the $0\nu$ decay, it is shown that there is a substantial
cancellation between the paired and broken pair pieces of the nuclear wave
function. Thus, despite the popular claim to the contrary, one expects that the
$0\nu$ rate is also sensitive to the details of nuclear structure. This is
reflected in the spread of the theoretical values, leading to the uncertainty
of about factor 2-3 in the deduced $<m_{\nu}>$ limit. Finally, brief comment
about the $0\nu$ decay with the exchange of a very heavy neutrino are made.


title: Effective-Range Corrections to the Proton-Proton Fusion Rate

abstract:
  Proton-proton fusion is considered in the effective field theory of Kaplan,
Savage and Wise. Coulomb effects are included systematically in a
non-perturbative way. Including the dimension-eight derivative coupling which
determines the effective ranges of the scattering amplitudes, next-to-leading
order corrections to the fusion rate are calculated. When the renormalization
mass is well above the characteristic energies of the system, this contribution
gives a rate which is eight percent below the standard value. The difference
can be due to an unknown counterterm which comes in at this order.


title:
Is the Time-Delay Signal in Bose-Einstein Correlations a Signature for
  the Quark-Gluon Plasma at RHIC ?

abstract:
  In 1996, D.H. Rischke and M. Gyulassy proposed to use the time-delay signal
in Bose-Einstein correlations (BEC) as a signature for the possible formation
of a quark-gluon plasma (QGP) in relativistic heavy-ion collisions. In
particular, they suggested to measure the ratio of the transversal
interferometry radii, $R_{out}/R_{side}$, which can be obtained by fitting
experimental BEC data with a parametrization introduced by G. Bertsch et al. in
1988. The transverse radius parameter $R_{out}$ has compared to the transverse
radius parameter $R_{side}$ an additional temporal dependence which should be
sensitive to a prolonged lifetime of a fireball, in case a QGP was formed in a
relativistic heavy-ion collision. In my presentation, I am going to revisit the
above made considerations by addressing various possible scenarios for hadron
spectra (single and double inclusives) for Pb+Pb collisions at CERN/SPS beam
energies and for Au+Au collisions at BNL/RHIC beam energies, respectively,
within a relativistic {\it true} hydrodynamic framework (i.e., HYLANDER-C). I
claim, that the time-delay signal in Bose-Einstein correlations {\it is not} a
signature for the possible formation of a QGP, and I am going to explain why
this is the case.


title: The Prediction of the Maximum Modes of Decay of Mesons

abstract:
  In an earlier work, several properties of fundamental particles were brought
together by a simple equation based on continuity and discreteness. It is shown
here, that the maximum modes of decay of all fundamental particles can also be
predicted without any arbitrary parameters. The method used is to break up the
mean lifetimes of particles to obtain the maximum modes of decay. This is done
by using a binary expansion of $\hbar/MT$ where M is the mass of the particle
and T is the mean lifetime. The agreements between that obtained from theory
and experiment are remarkable. The ordering of the flavours plays an important
part in understanding the reasons for this agreement. It is shown that the Zeno
effect in Quantum mechanics is connected with use of the binary series.


title: On nuclear transport at small excitations

abstract:
  Numerical computations of transport coefficients at low temperatures are
presented for shapes typically encountered in nuclear fission. The influence of
quantum effects of the nucleonic degrees of freedom is examined, with pair
correlations included. Consequences for global collective motion are studied
for the case of the decay rate. The range of temperatures is specified above
which this motion may be described as a quantal diffusion process.


title:
Correlator mixing and mass reduction as signals of chiral symmetry
  restoration

abstract:
  Chiral symmetry restoration in a dense medium is to some extent a consequence
of the nuclear pion cloud. These pions induce a mixing of the axial and vector
current contributions in the axial and vector correlators. We discuss their
influence on hadron masses and investigate the signal produced by the remaining
contribution associated with chiral symmetry restoration. Using the quark-meson
coupling model we find that the latter is associated with the reduction of
hadron masses.


title: Two-Body Density Matrix for Closed s-d Shell Nuclei

abstract:
  The two-body density matrix for $^{4}He,^{16}O$ and $^{40}Ca$ within the
Low-order approximation of the Jastrow correlation method is considered. Closed
analytical expressions for the two-body density matrix, the center of mass and
relative local densities and momentum distributions are presented. The effects
of the short-range correlations on the two-body nuclear characteristics are
investigated.


title:
Pion cloud and the $Q^2-$dependence of $\gamma^* N \leftrightarrow
  \Delta$ transition form factors

abstract:
  Recent experiment indicates that the behavior exhibited by the ratios
$E_{1^+}/M_{1^+}$ and $S_{1^+}/M_{1^+}$ of the $\gamma^* N \leftrightarrow
\Delta$ transition remain small and negative for $Q^2 \le 4.0 GeV^2$. It
implies that the perturbative QCD is still not applicable at these momentum
transfers. We show that these data can be explained in a dynamical model for
electromagnetic production of pions, together with a simple scaling assumption
for the bare $\gamma^* N \Delta$ form factors. Within our model we find that
the bare $\Delta$ is almost spherical and the electric E2 and Coulomb C2
quardrupole excitations of the physical $\Delta$ are nearly saturated by pion
cloud contribution in $Q^2 \le 4.0 GeV^2$.


title: Tri-axial Octupole Deformations and Shell Structure

abstract:
  Manifestations of pronounced shell effects are discovered when adding
nonaxial octupole deformations to a harmonic oscillator model. The degeneracies
of the quantum spectra are in a good agreement with the corresponding main
periodic orbits and winding number ratios which are found by classical
analysis.

categories: nucl-th chao-dyn nlin.CD physics.atm-clus


title: Enhanced Signatures for Disoriented Chiral Condensates

abstract:
  The probability distribution in $R$, the proportion of neutral pions to all
pions emitted in heavy ion collisions in certain kinematic regions, has been
suggested as a signal of a disoriented chiral condensate (D$\chi$C). Here we
note that the signature can be greatly enhanced by making suitable cuts in the
data. In particular, we consider reducing the data set such that the $k$ pions
with lowest $p_T$ are all neutral. We find that, given such cuts, $<R >$ can be
substantially different from 1/3. For example, for a single D$\chi$C domain
without contamination due to incoherently emitted pions, $<R>$ is 3/5 given the
pion with lowest $p_T$ is neutral, and 5/7 given the two pions with lowest
$p_T$ are both neutral, etc.. The effects of multi-domain D$\chi$C formation
and noise due to incoherent pion emission can be systematically incorporated.
Potential applications to experiments and their limitations are briefly
discussed.


title: A transport model for heavy ion collisions at RHIC

abstract:
  To study heavy ion collisions at energies to be available from the
Relativistic Heavy Ion Collider (RHIC), we have developed a transport model
that includes both initial partonic and final hadronic interactions.
Specifically, the parton cascade model ZPC, which uses as input the parton
distribution from the HIJING model, is extended to include the quark-gluon to
hadronic matter transition and also final-state hadronic interactions based on
the ART model. Comparisons with SPS data and predictions for RHIC are reported.


title: Strange chiral nucleon form factors

abstract:
  We investigate the strange electric and magnetic form factors of the nucleon
in the framework of heavy baryon chiral perturbation theory to third order in
the chiral expansion. All counterterms can be fixed from data. In particular,
the two unknown singlet couplings can be deduced from the parity-violating
electron scattering experiments performed by the SAMPLE and the HAPPEX
collaborations. Within the given uncertainties, our analysis leads to a small
and positive electric strangeness radius, $<r_{E,s}^2> = (0.05 \pm 0.09) fm^2$.
We also deduce the consequences for the upcoming MAMI A4 experiment.


title:
Mass number dependence in Lambda hypernuclei by means of the Hypervirial
  Theorems

abstract:
  The Hypervirial Theorems are applied to a wide class of single particle
nuclear potentials, in order to study the mass number dependence of various
quantities in Lambda hypernuclei. A very efficient model is assumed for the
radius parameter of the potentials and the limitations of the whole method are
discussed.


title:
Two approximate formulae for the binding energies in Lambda hypernuclei
  and light nuclei

abstract:
  Two approximate formulae are given for the binding energies in
Lambda-hypernuclei and light nuclei by means of the (reduced) Poeschl-Teller
and the Gaussian central potentials. Those easily programmable formulae combine
the eigenvalues of the transformed Jacobi eigenequation and an application of
the hypervirial theorems.


title:
Meson-loop contributions to the rho-omega mass splitting & rho charge
  radius

abstract:
  Contributions of two-pseudoscalar and vector-pseudoscalar meson loops to the
rho-omega mass splitting are evaluated in a covariant model based on studies of
the Schwinger-Dyson equations of QCD. The role and importance of the different
time orderings of the meson loops is analyzed and compared with those obtained
within time-ordered perturbation theory. It is shown that each meson loop
contributes less than 10% of the bare mass, and decreases as the masses of the
intermediate mesons increase beyond approximately m_rho/2. A mass splitting of
m_omega - m_rho ~= 25 MeV is obtained from the pi pi, K K(bar), omega pi, rho
pi, omega eta, rho eta and K* K channels. The model is then used to determine
the effect of the two-pion loop on the rho-meson electromagnetic form factor.
It is shown that the inclusion of pion loops increases the rho-meson charge
radius by 10%.


title:
Deuterons and space-momentum correlations in high energy nuclear
  collisions

abstract:
  Using a microscopic transport model together with a coalescence after-burner,
we study the formation of deuterons in Au + Au central collisions at
$\sqrt{s}=200 AGeV$. It is found that the deuteron transverse momentum
distributions are strongly affected by the nucleon space-momentum correlations,
at the moment of freeze-out, which are mostly determined by the number of
rescatterings. This feature is useful for studying collision dynamics at
ultrarelativistic energies.


title: P and T Odd Electromagnetic Moments of Deuteron in Chiral Limit

abstract:
  P odd anapole moment of the deuteron is found in the chiral limit, $m_{\pi}
\to 0$. The contact current generated by the P odd pion exchange does not
contribute to the deuteron anapole. Being combined with usual radiative
corrections to the weak electron -- deuteron interaction, our calculation
results in a sufficiently accurate theoretical prediction for the corresponding
effective constant $C_{2d}$. The experimental measurement of this constant
would give valuable information on the P odd $\pi$NN constant and on the
$s$-quark content of nucleons. We calculate also in the same limit $m_{\pi} \to
0$ the deuteron P odd and T odd multipoles: electric dipole moment and magnetic
quadrupole moment.


title: Elliptic Flow Based on a Relativistic Hydrodynamic Model

abstract:
  Based on the (3+1)-dimensional hydrodynamic model, the space-time evolution
of hot and dense nuclear matter produced in non-central relativistic heavy-ion
collisions is discussed. The elliptic flow parameter v_2 is obtained by Fourier
analysis of the azimuthal distribution of pions and protons which are emitted
from the freeze-out hypersurface. As a function of rapidity, the pion and
proton elliptic flow parameters both have a peak at midrapidity.


title: Occupation numbers in Self Consistent RPA

abstract:
  A method is proposed which allows to calculate within the SCRPA theory the
occupation numbers via the single particle Green function. This scheme complies
with the Hugenholtz van Hove theorem. In an application to the Lipkin model it
is found that this prescription gives consistently better results than two
other commonly used approximations: lowest order boson expansion and the number
operator method.


title: Hot Hypernuclear Matter in the Modified Quark Meson Coupling Model

abstract:
  Hot hypernuclear matter is investigated in an explicit SU(3) quark model
based on a mean field description of nonoverlapping baryon bags bound by the
self-consistent exchange of scalar $\sigma, \zeta$ and vector $\omega, \phi$
mesons. The $\sigma, \omega$ mean fields are assumed to couple to the
u,d-quarks while the $\zeta, \phi$ mean fields are coupled to the s-quark. The
coupling constants of the mean fields with the quarks are assumed to satisfy
SU(6) symmetry. The calculations take into account the medium dependence of the
bag parameter on the scalar fields $\sigma, \zeta$. We consider only the octet
baryons $N,\Lambda,\Sigma,\Xi$ in hypernuclear matter. An ideal gas of the
strange mesons $K$ and $K^{*}$ is introduced to keep zero net strangeness
density. Our results for symmetric hypernuclear matter show that a phase
transition takes place at a critical temperature around 180 MeV in which the
scalar mean fields $\sigma, \zeta$ take nonzero values at zero baryon density.
Furthermore, the bag contants of the baryons decrease significantly at and
above this critical temperature indicating the onset of quark deconfinement.
The present results imply that the onset of quark deconfinement in SU(3)
hypernuclear matter is much stronger than in SU(2) nuclear matter.


title: The inclusive 56Fe(nu_e,e-)56Co cross section

abstract:
  We study the 56Fe(nu_e,e^-)56Co cross section for the KARMEN neutrino
spectrum. The Gamow-Teller contribution to the cross section is calculated
within the shell model, while the forbidden transitions are evaluated within
the continuum random phase approximation. We find a total cross section of 2.73
x 10^-40 cm^2, in agreement with the data.


title: Isoscalar M1 and E2 Amplitudes in n+p -> d+gamma

abstract:
  The low energy radiative capture process n+p -> d+gamma provides a sensitive
probe of the two-nucleon system. The cross section for this process is
dominated by the isovector M1 amplitude for capture from the 1S0 channel via
the isovector magnetic moment of the nucleon. In this work we use effective
field theory to compute the isoscalar M1 and isoscalar E2 amplitudes that are
strongly suppressed for cold neutron capture. The actual value of the isoscalar
E2 amplitude is expected to be within 15% of the value computed in this work.
In contrast, due to the vanishing contribution of the one-body operator at
leading order and next-to-leading order, the isoscalar M1 amplitude is
estimated to have a large uncertainty. We discuss in detail the deuteron
quadrupole form factor and SD mixing.


title: Hadronic scattering of charmed mesons

abstract:
  The scattering cross sections of charm mesons with hadrons such as the pion,
rho meson, and nucleon are studied in an effective Lagrangian. In heavy ion
collisions, rescattering of produced charm mesons by hadrons affects the
invariant mass spectra of both charm meson pairs and dileptons resulting from
their decays. These effects are estimated for heavy ion collisions at SPS
energies and are found to be significant.


title: Q^2-Dependence of the Drell-Hearn-Gerasimov integral

abstract:
  The energy and four-momentum (Q^2) dependence of the photo-absorption cross
section on the proton is calculated for helicity -1/2 and -3/2 states. An
effective Lagrangian model is used, formulated in terms of meson and baryon
degrees of freedom, which obeys crossing symmetry, unitarity, Lorentz and gauge
invariance. The difference in the cross sections for the two helicity states,
the Drell-Hearn-Gerasimov integral $I_{DHG}(Q^2)$, is evaluated at different
$Q^2$. We find that at small momentum transfer the absolute value of
$I_{DHG}(Q^2)$ first increases to reach a maximum at $Q^2 \approx 0.05 GeV^2$
before decreasing at higher $Q^2$.


title: Quark-Gluon Plasma

abstract:
  An elementary introduction to the physics of quark-gluon plasma is given. We
start with a sketchy presentation of the Quantum Chromodynamics which is the
fundamental theory of strong interactions. The structure of hadrons built up of
quarks and gluons is briefly discussed with a special emphasis on the
confinement hypothesis. Then, we explain what is the quark-gluon plasma and
consider why and when the hadrons can dissolve liberating the quarks and
gluons. The heavy-ion collisions at high-energies, which provide a unique
opportunity to get a droplet of the quark-gluon plasma in the terrestrial
conditions, are described. We also consider the most promising experimental
signatures of the quark-gluon plasma produced in nucleus-nucleus collisions. At
the end, the perspectives of the quark-gluon plasma studies at the future
accelerators are mentioned.


title: Prompt muon-induced fission: a probe for nuclear energy dissipation

abstract:
  We solve the time-dependent Dirac equation for a muon which is initially
bound to a fissioning actinide nucleus. The computations are carried out on a
3-D cartesian lattice utilizing the Basis-Spline collocation method. The muon
dynamics is sensitive to the nuclear energy dissipation between the outer
fission barrier and the scission point. From a comparison with experimental
data we find a dissipated energy of about 10 MeV and a fission time delay due
to friction of order $2 \times 10^{-21}$ s.


title:
Hadronic Scatterings of Charm Mesons and Enhancement of Intermediate
  Mass Dileptons

abstract:
  The scattering effects of charm mesons by hadrons such as the pion, rho meson
and nucleon are studied in an effective Lagrangian, and are found to be
important in heavy ion collisions. At the CERN-SPS energies, hadronic
rescatterings are shown to harden the charm meson $m_T$ spectra, leading to a
significant enhancement of the yield of intermediate-mass dimuons from charm
meson decays.


title: ``Day 1'' Physics at RHIC: Predictions from RQMD

abstract:
  I discuss predictions based on the transport theoretical approach
``relativistic quantum molecular dynamics''. They can be tested rather soon by
the upcoming experiments at the Relativistic Heavy Ion Collider at BNL (RHIC).
Here I focus on the question whether hadronic observables are sensitive to the
Equation of State (EOS) in the ultradense matter. A new version of RQMD has
been developed recently in which the EOS can be varied, for instance like the
one observed in lattice gauge studies. It is found that -- somewhat
paradoxically -- the partial transparency of the two nuclei provides new
avenues to assess the influence of baryon number in hot matter. One of the
signals which are most sensitive to the dynamics is the directed flow of
nucleons. As a function of rapidity it changes its direction three times.
Surprisingly, even one of the most simple observables -- the average transverse
momenta or slopes -- displays some significant sensitivity to the EOS in the
phase transition region between hadronic and quark matter.


title: The Two-Nucleon Sector with Effective Field Theory

abstract:
  I present the results obtained for several observables in the two-nucleon
sector using effective field theory with KSW power-counting and dimensional
regularization. In addition to the phase shifts for nucleon-nucleon scattering,
several deuteron observables are discussed, including electromagnetic form
factors, polarizabilities, gamma+d -> gamma+d Compton scattering, and n+p ->
d+gamma. A detailed comparison between the effective field theory with pions,
the theory without pions, and effective range theory is made.


title:
Mean-field nuclear structure calculations on a Basis-Spline Galerkin
  lattice

abstract:
  Our goal is to carry out high-precision nuclear structure calculations in
connection with Radioactive Ion Beam Facilities. The main challenge for the
theory of drip line nuclei is that the outermost nucleons are weakly bound
(implying a large spatial distribution) and that these states are strongly
coupled to the particle continuum. For these reasons, the traditional basis
expansion methods fail to converge. We overcome these problems by representing
the nuclear Hamiltonian on a lattice utilizing the Galerkin method with
Basis-Spline test functions. We discuss tests of the numerical method and
applications to the deformed shell model, HF+BCS and HFB mean field theories.


title:
A coupled K-matrix description of the reactions pi+N -> pi+N, pi+N ->
  eta+N, gamma+N -> pi+N and gamma+N -> eta+N

abstract:
  The coupled pi+N, eta+N, gamma+N systems are described by a K-matrix method.
The parameters in this model are adjusted to get an optimal fit to pi+N ->
pi+N, pi+N -> eta+N, gamma+N -> pi+N and gamma+N -> eta+N data in an energy
range of about 100 MeV each side of the eta-threshold. The coupling of photons
to the N(1535) state is extracted and also an alternative to the current
S11(gamma+N -> pi+N) amplitudes suggested. Expansions are given for the eta-eta
and gamma-eta amplitudes in terms of the eta-momentum. Effects of interference
of this state with background potential interactions are discussed and
experimental consequences are indicated.


title:
One-particle exchange in the double folded potential in a semiclassical
  approximation

abstract:
  The one-particle exchange in the double folded model is analyzed. To this aim
the Extended Thomas-Fermi approach to the one-body density matrix is used. The
nucleon- nucleon force with Yukawa, Gauss and Coulomb-type form factors are
considered. The energy dependence of the exchange part of the double folded
potential is investigated and a comparison of the present approach with former
ones is carried out.


title:
A New Approach to y-scaling and the Universal Features of Scaling
  Functions and Nucleon Momentum Distributions

abstract:
  Some systematic general features of y-scaling structure functions, which are
essentially independent of detailed dynamics, are pointed out. Their physical
interpretation in terms of general characteristics, such as a mean field
description and nucleon-nucleon correlations, is given and their relationship
to the momentum distributions illustrated. A new relativistic scaling variable
is proposed which incorporates the momentum dependence of the excitation energy
of the (A-1) system, with the resulting scaling function being closely related
to the longitudinal momemtum distributions and being free from removal-energy
scaling violating effects.


title:
The $\Lambda\Lambda-\Xi N$ Coupling and the Binding Energy of
  $_{\Lambda\Lambda}^{6}}$He

abstract:
  To understand the difference between the value of the nn and Lambda-Lambda
two-body matrix elements, we examine the role of the coupling between the
Lambda-Lambda and Xi-N channels, first within the framework of SU(3), and
second in the numerical results for the binding energy of Lambda-Lambda 6He. We
find that it is essential to include the coupled channel nature of the BB
interaction as we proceed from strangeness zero to the strangeness -1 and -2
channels if we are to understand the relative magnitude of the two-body matrix
elements in the different strangeness channels.


title: Scalar meson exchange and the baryon spectra

abstract:
  We explore the role of a scalar meson exchange interaction between quarks in
a semirelativistic constituent quark model where the quarks are also subject to
a linear confinement. We search for a variational solution and study how the
spectrum evolves when the strength of the scalar meson exchange increases. Our
results have good implications on the description of the low-lying baryon
masses, especially on the long-standing problem of the relative position of the
first positive-parity (Roper resonance) and the first orbitally excited states.


title: Dilepton Production from Rho-Mesons in a Quark-Gluon Plasma

abstract:
  Assuming that rho-mesons exist in a quark-gluon plasma close to the QCD phase
transition, we calculate the dilepton production rate from quark-antiquark
annihilation via a rho-meson state using Vector Meson Dominance. The result is
compared to the rates from direct quark-antiquark annihilation and from pion
annihilation. Furthermore we discuss the suppression of low mass dileptons if
the quarks assume an effective mass in the quark-gluon plasma.


title:
Relativistic Calculations of Induced Polarization in $^{12}C$(e, e'
  \vec{p})$ Reactions

abstract:
  Relativistic calculations of the induced proton polarization in quasifree
electron scattering on $^{12}C$ are presented. Good agreement with the
experimental data of Woo et al. is obtained. The relativistic calculations
yield a somewhat better description of the data than the non-relativistic ones.
Differences between the two approaches are more pronounced at larger missing
momenta suggesting further experimental work in this region.


title: Influence of damping on the excitation of the double giant resonance

abstract:
  We study the effect of the spreading widths on the excitation probabilities
of the double giant dipole resonance. We solve the coupled-channels equations
for the excitation of the giant dipole resonance and the double giant dipole
resonance. Taking Pb+Pb collisions as example, we study the resulting effect on
the excitation amplitudes, and cross sections as a function of the width of the
states and of the bombarding energy.


title:
Ground-state properties of deformed proton emitters in the relativistic
  Hartree-Bogoliubov model

abstract:
  The Relativistic Hartree Bogoliubov (RHB) model is applied in the description
of ground-state properties of proton-rich odd-Z nuclei in the region $53 \leq Z
\leq 69$. The NL3 effective interaction is used in the mean-field Lagrangian,
and pairing correlations are described by the pairing part of the finite range
Gogny interaction D1S. The model predicts the location of the proton drip-line,
the ground-state quadrupole deformations and one-proton separation energies at
and beyond the drip-line, the deformed single-particle orbitals occupied by the
odd valence proton, and the corresponding spectroscopic factors. The results of
fully self-consistent RHB calculations are compared with available experimental
data, and with predictions of the macroscopic-microscopic mass model.


title: Spectator and participant decay in heavy ion collisions

abstract:
  We analyze the thermodynamical state of nuclear matter in transport
calculations of heavy--ion reactions. In particular we determine temperatures
and radial flow parameters from an analysis of fragment energy spectra and
compare to local microscopic temperatures obtained from an analysis of local
momentum space distributions. The analysis shows that the spectator reaches an
equilibrated freeze-out configuration which undergoes simultaneous
fragmentation. The fragments from the participant region, on the other hand, do
not seem to come from a common fragmenting source, but rather heavier fragments
seem to be formed earlier.


title:
Generalizing Phi-measure of event-by-event fluctuations in high-energy
  heavy-ion collisions

abstract:
  The Phi-measure of event-by-event fluctuations in high-energy heavy-ion
collisions corresponds to the second moment of the fluctuating quantity
distribution of interest. It is shown that the measure based on the third
moment preserves the properties of Phi but those related to the higher moments
do not. In particular, only the second and third moment measures are intensive
as thermodynamic quantities. The Phi_2- and Phi_3-measure of p_T-fluctuations
are computed for the hadron gas in equilibrium and the results are analyzed in
context of the experimental data.


title: Event-by-Event Fluctuations in Ultrarelativistic Heavy-Ion Collisions

abstract:
  Motivated by forthcoming experiments at RHIC and LHC, we study event-by-event
fluctuations in ultrarelativistic heavy-ion collisions in participant nucleon
as well as thermal models. The calculated physical observables, including
multiplicity, kaon to pion ratios, and transverse momenta agree well with
recent NA49 data at the SPS, and indicate that such studies do not yet reveal
the presence of new physics. Finally, we present a simple model of how a first
order phase transition can be signaled by very large fluctuations.