title: A different view of deep inelastic electron-proton scattering

abstract:
  Deep inelastic electron-proton scattering is analyzed in the target rest
frame using a theoretical approach suitable to describe many-body systems of
{\em bound} constituents subject to {\em interactions}. At large three-momentum
transfer $\magq$, this approach predicts the onset of scaling in the variable
$\yt=\nu$-$\magq$, where $\nu$ denotes the energy transfer. The present
analysis shows that the data, plotted at constant $\magq$, exhibit a remarkable
scaling behavior in $\yt$ and manifestly display the presence of sizable
interaction effects.


title:
Unblocking of the Gamow-Teller strength in stellar electron capture on
  neutron-rich Germanium isotopes

abstract:
  We propose a new model to calculate stellar electron capture rates for
neutron-rich nuclei. These nuclei are encountered in the core-collapse of a
massive star. Using the Shell Model Monte Carlo approach, we first calculate
the finite temperature occupation numbers in the parent nucleus. We then use
these occupation numbers as a starting point for calculations using the random
phase approximation. Using the RPA approach, we calculate electron capture
rates including both allowed and forbidden transitions. Such a hybrid model is
particularly useful for nuclei with proton numbers Z<40 and neutron numbers
N>40, where allowed Gamow-Teller transitions are only possible due to
configuration mixing by the residual interaction and by thermal unblocking of
$pf$-shell single-particle states. Using the even germanium isotopes Ge-68 to
Ge-76 as examples, we demonstrate that the configuration mixing is strong
enough to unblock the Gamow-Teller transitions at all temperatures relevant to
core-collapse supernovae.


title:
Negative heat capacities and first order phase transitions in nuclei and
  other mesoscopic systems

abstract:
  The origin of predicted and observed anomalies in caloric curves of nuclei
and other mesoscopic systems is investigated. It is shown that a
straightforward thermodynamical treatment of an evaporating liquid drop leads
to a backbending in the caloric curve and to negative specific heats in the two
phase coexistence region. The cause is found not in the generation of
additional surface, but in the progressive reduction of the drop's radius, and
surface, with evaporation.


title: The electromagnetic interaction of ultrarelativistic heavy ions

abstract:
  The validity of a delta-function approximation for the electromagnetic
interaction of relativistic heavy ions is investigated. The production of e+e-
pairs, with electron capture, is used as a test of the approximation.


title: Pair creation and plasma oscillations

abstract:
  We describe aspects of particle creation in strong fields using a quantum
kinetic equation with a relaxation-time approximation to the collision term.
The strong electric background field is determined by solving Maxwell's
equation in tandem with the Vlasov equation. Plasma oscillations appear as a
result of feedback between the background field and the field generated by the
particles produced. The plasma frequency depends on the strength of the initial
background field and the collision frequency, and is sensitive to the necessary
momentum-dependence of dressed-parton masses.


title: Space-time versus particle-hole symmetry in quantum Enskog equations

abstract:
  The non-local scattering-in and -out integrals of the Enskog equation have
reversed displacements of colliding particles reflecting that the -in and -out
processes are conjugated by the space and time inversions. Generalisations of
the Enskog equation to Fermi liquid systems are hindered by a request of the
particle-hole symmetry which contradicts the reversed displacements. We resolve
this problem with the help of the optical theorem. It is found that space-time
and particle-hole symmetry can only be fulfilled simultaneously for the
Bruckner-type of internal Pauli-blocking while the Feynman-Galitskii form
allows only for particle-hole symmetry but not for space-time symmetry due to a
stimulated emission of Bosons.

categories: nucl-th cond-mat.mes-hall cond-mat.str-el physics.flu-dyn physics.plasm-ph


title: Photoproduction of $\eta$-mesons off light nuclei

abstract:
  Photoproduction of $\eta$-mesons off deuteron is studied within the
Alt-Grassberger-Sandhas formalism for different parameters of $\eta N$
interaction. The calculations revealed peaks in the energy dependence of the
total cross-section.


title: Photonic Probes of the Deuteron in Effective Field Theory

abstract:
  I give a taste of recent progress in using chiral perturbation theory to
understand nucleon and deuteron structure.


title:
Parity Violation in Low-Energy np->d gamma and the Deuteron Anapole
  Moment

abstract:
  Parity violation in low-energy nuclear observables is included in the
pionless effective field theory. The model-independent relation between the
parity-violating asymmetry in polarized np -> d gamma and the non-nucleon part
of the deuteron anapole moment is discussed. The asymmetry in np -> d gamma
computed with KSW power-counting, and recently criticized by Desplanques, is
discussed.


title: In-medium spin-orbit NN potential in the Skyrme model

abstract:
  It is considered how spin-orbit potential for two nucleons is changed when
one of them is imbedded in nuclear matter. It is emphasized that there appears
new tipe of potential antisymmetric under nucleon spins which is proportional
to mass difference between free and imbedded nucleons. The longest range
behaviour of such potential is estimated.


title: Helicity Amplitudes and Sum Rules for Real and Virtual Photons

abstract:
  Results of the recently developed unitary isobar model (MAID) are presented
for helicity amplitudes, spin asymmetries, structure functions and relevant sum
rules for real and virtual photons in the resonance region. Our evaluation of
the energy-weighted integrals is in good agreement for the proton but shows big
discrepancies for the neutron.


title: The E2/M1 and C2/M1 ratios and form factors in N -> Delta transitions

abstract:
  A partial wave analysis of pion photoproduction has been obtained in the
framework of fixed-t dispersion relations valid from threshold up to 500 MeV.
In the resonance region we have precisely determined the electromagnetic
properties of the \Delta(1232) resonance, in particular the E2/M1 ratio
R_{EM}=(-2.5 +- 0.1) %. For pion electroproduction recent experimental data
from Mainz, Bates and JLab for Q^2 up to 4.0 (GeV/c)^2 have been analyzed with
two different models, an isobar model (MAID) and a dynamical model. The E2/M1
ratios extracted with these two models show, starting from a small and negative
value at the real photon point, a clear tendency to cross zero, and become
positive with increasing Q^2. This is a possible indication of a very slow
approach toward the pQCD region. The C2/M1 ratio near the photon point is found
as R_{SM}(0)=(-6.5 +- 0.5) %. At high Q^2 the absolute value of the ratio is
strongly increasing, a further indication that pQCD is not yet reached.


title: Comment on "Negative heat ..." by Moretto et al

abstract: The recent paper nucl-th/0012037 by Moretto et al. is commented


title:
One Body Density Matrix, Natural Orbits and Quasi Hole States in 16O and
  40Ca

abstract:
  The one body density matrix, momentum distribution, natural orbits and quasi
hole states of 16O and 40Ca are analyzed in the framework of the correlated
basis function theory using state dependent correlations with central and
tensor components. Fermi hypernetted chain integral equations and single
operator chain approximation are employed to sum cluster diagrams at all
orders. The optimal trial wave function is determined by means of the
variational principle and the realistic Argonne v8' two-nucleon and Urbana IX
three-nucleon interactions. The correlated momentum distributions are in good
agreement with the available variational Monte Carlo results and show the well
known enhancement at large momentum values with respect to the independent
particle model. Diagonalization of the density matrix provides the natural
orbits and their occupation numbers. Correlations deplete the occupation number
of the first natural orbitals by more than 10%. The first following ones result
instead occupied by a few percent. Jastrow correlations lower the spectroscopic
factors of the valence states by a few percent (~1-3%) and an additional ~8-12%
depletion is provided by tensor correlations. It is confirmed that short range
correlations do not explain the spectroscopic factors extracted from (e,e'p)
experiments. 2h-1p perturbative corrections in the correlated basis are
expected to provide most of the remaining strength, as in nuclear matter.


title: Quasi-SU(3) truncation scheme for odd-even sd-shell nuclei

abstract:
  The quasi-SU(3) symmetry, as found in shell model calculations, refers to the
dominance of the single particle plus quadrupole-quadrupole terms in the
Hamiltonian used to describe well deformed nuclei, and to the subspace relevant
in its diagonalization. It provides a very efficient basis truncation scheme.
It is shown that a small number of SU(3) coupled irreps, those with the largest
C_2 values within the direct product of the proton and neutron SU(3) irreps
with spin 0 and 1 (for even number of particles), and spin 1/2 and 3/2 for (for
odd number of nucleons), are enough to describe the low energy spectra and
B(E2) transition strengths of 21Ne, 23Na and 25Mg. A simple but realistic
Hamiltonian is employed. Results compare favorably both with experimental data
and with full shell model calculations. Limitations and possible improvements
of the schematic Hamiltonian are discussed.


title:
Degeneracies when T=0 Two Body Matrix Elements are Set Equal to Zero and
  Regge's 6j Symmetry Relations

abstract:
  The effects of setting all T=0 two body interaction matrix elements equal to
a constant (or zero) in shell model calculations (designated as $<T=0>=0$) are
investigated. Despite the apparent severity of such a procedure, one gets
fairly reasonable spectra. We find that using $<T=0>=0$ in single j shell
calculations degeneracies appear e.g. the $I={1/2} ^{-}$ and ${13/2}^{-}$
states in $^{43}$Sc are at the same excitation energies; likewise the
I=$3_{2}^{+}$,$7_{2}^{+}$,9$^{+}_{1}$ and 10$^{+}_{1}$ states in $^{44}$Ti. The
above degeneracies involve the vanishing of certain 6j and 9j symbols. The
symmetry relations of Regge are used to explain why these vanishings are not
accidental. Thus for these states the actual deviation from degeneracy are good
indicators of the effects of the T=0 matrix elements. A further indicator of
the effects of the T=0 interaction in an even - even nucleus is to compare the
energies of states with odd angular momentum with those that are even.


title:
From the Bethe-Salpeter equation to non-relativistic approaches with
  effective two-body interactions

abstract:
  It is known that binding energies calculated from the Bethe-Salpeter equation
in ladder approximation can be reasonably well accounted for by an
energy-dependent interaction, at least for the lowest states. It is also known
that none of these approaches gives results close to what is obtained by using
the same interaction in the so-called instantaneous approximation, which is
often employed in non-relativistic calculations. However, a recently proposed
effective interaction was shown to account for the main features of both the
Bethe-Salpeter equation and the energy-dependent approach. In the present work,
a detailed comparison of these different methods for calculating binding
energies of a two-particle system is made. Some improvement, previously
incorporated for the zero-mass boson case in the derivation of the effective
interaction, is also employed for massive bosons. The constituent particles are
taken to be distinguishable and spinless. Different masses of the exchanged
boson (including a zero mass) as well as states with different angular momenta
are considered and the contribution of the crossed two-boson exchange diagram
is discussed. With this respect, the role played by the charge of the exchanged
boson is emphasized. It is shown that the main difference between the
Bethe-Salpeter results and the instantaneous approximation ones are not due to
relativity as often conjectured.


title: Photoproduction of quasi-bound omega mesons in nuclei

abstract:
  We propose the (gamma,p) reaction as a means of producing possible
quasi-bound states of omega mesons in nuclei. We use an effective Lagrangian,
based on chiral SU(3) symmetry and vector meson dominance, in order to
construct the omega-nuclear potential. The contribution of bound omega states
is observable in the missing energy spectra of protons emitted in forward
direction for several nuclei.


title: Optical potentials for the antiproton nucleus interactions

abstract:
  The nuclear interactions of atomic and low energy antiprotons are studied.
Measurements of level shifts and widths in the lightest elements are analyzed
and compared with new results obtained in heavy nuclei. Simple geometric
properties of antiproton - nucleus interactions are demonstrated. Upon this
background one finds some anomalies that indicate strong energy dependence in
the subthreshold antiproton - nucleon interactions. The use of of antiproton in
studies of the nuclear surface is briefly discussed.


title:
Liquid-Drop Model and Quantum Resistance Against Noncompact Nuclear
  Geometries

abstract:
  The importance of quantum effects for exotic nuclear shapes is demonstrated.
Based on the example of a sheet of nuclear matter of infinite lateral
dimensions but finite thickness, it is shown that the quantization of states in
momentum space, resulting from the confinement of the nucleonic motion in the
conjugate geometrical space, generates a strong resistance against such a
confinement and generates restoring forces driving the system towards compact
geometries. In the liquid-drop model, these quantum effects are implicitly
included in the surface energy term, via a choice of interaction parameters, an
approximation that has been found valid for compact shapes, but has not yet
been scrutinized for exotic shapes.


title:
Faddeev description of two-hole one-particle motion and the
  single-particle spectral function

abstract:
  The Faddeev technique is employed to address the problem of describing the
influence of both particle-particle and particle-hole phonons on the
single-particle self-energy. The scope of the few-body Faddeev equations is
extended to describe the motion of two-hole one-particle (two-particle
one-hole) excitations. This formalism allows to sum both particle-particle and
particle-hole phonons, obtained separately in the Random Phase Approximation.
The appearance of spurious solutions for the present application of the Faddeev
method is related to the inclusion of a consistent set of diagrams. The
formalism presented here appears practical for finite nuclei and achieves a
simultaneous inclusion of particle-particle and particle-hole phonons to all
orders while the spurious solutions are properly eliminated.


title: A Microscopic Picture of Strangeness Production at the SPS

abstract:
  The microscopic origin of the strangeness enhancements observed in PbPb
collisions at the SPS is studied by testing the effects of three mechanisms.
First, the junction processes found in the HIJING/BBbar event generator are
reviewed showing that they can account for only part of the observed hyperon
enhancements. Second, the efficient final state chemical changing processes
(e.g. Lambda + K -> Xi + pi) are included by adding the General Cascade Program
(GCP) to HIJING/BBbar. While these processes are shown to further enhance
multistrange baryon production, HIJING/BBbar+GCP is still unable to fully
describe either the large hyperon yields or the increasing K+/pi+ ratio.
Finally, the addition of transient field fluctuations or ropes to
HIJING/BBbar+GCP is shown to be needed to account for the large hyperon yields
and for the behavior of the K+/pi+ ratio.


title: Density dependence of in-medium nucleon-nucleon cross sections

abstract:
  The lowest-order correction of the density dependence of in-medium
nucleon-nucleon cross sections is obtained from geometrical considerations of
Pauli-blocking effects. As a by-product, it is shown that the medium
corrections imply an 1/E energy dependence of the density-dependent term.


title: Single photons from Pb+Pb collisions at CERN SPS, QGP vs. hadronic gas

abstract:
  In a hydrodynamic model, we have analysed the direct photon data obtained by
the WA98 collaboration in 158 A GeV Pb+Pb collisions at CERN SPS. The
transverse expansion of the system was taken into account. Two scenarios (i)
formation of quark-gluon plasma and (ii) formation of hot hadronic gas were
considered. Equally well description to the data were obtained in both the
scenarios. However, hadronic gas scenario require very high initial temperature
($\sim$ 300 MeV) and it is difficult to conceive existence of hadron gas at
that high temperature. If the hadronic fluid has small radial velocity
(0.2c-0.3c) initially, the data are well explained in the hadronic gas scenario
with reasonable initial temperatures.


title: Renormalization of the weak hadronic current in the nuclear medium

abstract:
  The renormalization of the weak charge-changing hadronic current as a
function of the reaction energy release is studied at the nucleonic level. We
have calculated the average quenching factors for each type of current (vector,
axial vector and induced pseudoscalar). The obtained quenching in the axial
vector part is, at zero momentum transfer, 19% for the sd shell and 23% in the
fp shell. We have extended the calculations also to heavier systems such as
$^{56}$Ni and $^{100}$Sn, where we obtain stronger quenchings, 44% and 59%,
respectively. Gamow--Teller type transitions are discussed, along with the
higher order matrix elements. The quenching factors are constant up to roughly
60 MeV momentum transfer. Therefore the use of energy-independent quenching
factors in beta decay is justified. We also found that going beyond the zeroth
and first order operators (in inverse nucleon mass) does not give any
substantial contribution. The extracted renormalization to the ratio $C_P/C_A$
at q=100 MeV is -3.5%, -7.1$%, -28.6%, and +8.7% for mass 16, 40, 56, and 100,
respectively.


title: Effective Field Theory in Nuclear Physics

abstract:
  The Electromagnetic and Hadronic Physics sub-community of nuclear physics
held a town hall meeting at Jefferson Lab during November 30 to December 4 of
2000. This is is our combined contribution to the white paper that will result
from this meeting.


title:
Liquid-gas phase transition in nuclei in the relativistic Thomas-Fermi
  theory

abstract:
  The equation of state (EOS) of finite nuclei is constructed in the
relativistic Thomas-Fermi theory using the non-linear $\sigma-\omega -\rho$
model. The caloric curves are calculated by confining the nuclei in the
freeze-out volume taken to be a sphere of size about 4 to 8 times the normal
nuclear volume. The results obtained from the relativistic theory are not
significantly different from those obtained earlier in a non-relativistic
framework. The nature of the EOS and the peaked structure of the specific heat
$C_v$ obtained from the caloric curves show clear signals of a liquid-gas phase
transition in finite nuclei. The temperature evolution of the Gibbs potential
and the entropy at constant pressure indicate that the characteristics of the
transition are not too different from the first-order one.


title: Deuteron P-Wave in Elastic Backward Proton-Deuteron Scattering

abstract:
  The elastic backward proton-deuteron scattering is analyzed within a fully
covariant approach based on the invariant expansion of the reaction amplitude.
The method of calculation of any observables for any reaction mechanism is
developed. The cross section and spin observables, like tensor analyzing power
and polarization transfer coefficient etc., are investigated in explicit form
within framework of the impulse approximation using different kinds of the
relativistic deuteron wave function (DWF) with P-wave components. Our results
of numerical calculation for complete set of polarization observables are
compared with the experimental data and other calculations performed within
both the non-relativistic and relativistic approaches. An experimental
verification of the reaction mechanism is suggested by constructing some
combinations of different observables.


title: Neutrino Effects in Nucleosynthesis

abstract:
  The nucleosynthesis within a Type II supernova occurs in an intense neutrino
flux. I discuss some of the effects associated with neutrino interactions,
including direct synthesis in the neutrino process, the role of neutrinos in
controlling the r-process path and in postprocessing r-process products, and
neutrino oscillation connections.


title: On Charm Production near the Phase Boundary

abstract:
  We discuss aspects of the statistical hadronization model for the production
of mesons with open and hidden charm in ultra-relativistic nuclear collisions.
Emphasis is placed on what can be inferred from the dependence of the yield of
charmonia on the number of participants in the collisions.


title:
The role of Delta(1700) excitation and rho production in double pion
  photoproduction

abstract:
  Recent information on invariant mass distributions of the $\gamma
p\to\pi^+\pi^0 n$ reaction, where previous theoretical models had shown
deficiencies, have made more evident the need for new mechanisms, so far
neglected or inaccurately included. We have updated a previous model to include
new necessary mechanisms. We find that the production of the $\rho$ meson, and
the $\Delta(1700)$ excitation, through interference with the dominant terms,
are important mechanisms that solve the puzzle of the $\gamma p\to\pi^+\pi^0 n$
reaction without spoiling the early agreement with the $\gamma p\to\pi^+\pi^-
p$ and $\gamma p\to\pi^0\pi^0 p$ reactions.


title:
Polarization observables in elastic electron deuteron scattering
  including parity and time reversal violating contributions

abstract:
  The general formalism for polarization observables in elastic electron
deuteron scattering is extended to incorporate parity and time reversal
violating contributions. Parity violating effects arise from the interference
of $\gamma$ and $Z$ exchange as well as from the hadronic sector via a small
parity violating component in the deuteron. In addition we have allowed for
time reversal invariance violating contributions in the hadronic sector. Formal
expressions for the additional structure functions are derived, and their
decomposition into the various multipole contributions are given explicitly.


title: Baryons as Relativistic Bound States of Quark and Diquark

abstract:
  In this thesis a model framework for describing baryons as diquark-quark
bound states is presented which is formulated in an explicitly covariant
manner. The relativistic bound state problem for three quarks is considered.
Diquarks are introduced as separable correlations in the two-quark correlation
function and thereby baryons are described by a Bethe-Salpeter equation for
bound states of quark and diquark which interact by quark exchange. In analogy
to the meson spectrum, scalar and axialvector diquarks are considered to be the
most important two-quark configurations within baryons. The numerical solutions
of the covariant Bethe-Salpeter equation are subsequently employed in the
calculation of electromagnetic, strong and axial form factors of the nucleons.
The construction of the electromagnetic current operator in the diquark-quark
model respects gauge invariance. Invariance under chiral symmetry
transformations is slightly violated for vector diquarks have been neglected,
leading to a modest violation of the Goldberger-Treiman relation. The
possibility of an effective parametrization of confinement by suitable
modifications of the quark and diquark propagators is investigated. It is shown
that the modelling of confinement chosen here is suitable for the calculation
of the octet and devuplet spectrum and spacelike nucleon properties, but its
applicability breaks down for processes where large energies are transferred to
the nucleon as it is the case in certain meson production processes. Model
solutions for nucleon wave functions and observables are compared between the
full relativistic treatment and a widely used semi-relativistic approximation.
The considerable deviations in the results illustrate the inadequacy of
employing the semi-relativistic treatment.


title:
Hadrons in dense and hot matter: implications of chiral symmetry
  restoration

abstract:
  Recent developments on medium modifications of hadron properties in dense and
hot hadronic matter are discussed. I will focus in particular on the behavior
of spectral functions associated to collective scalar-isoscalar modes, kaons
and vector mesons from ordinary nuclear matter to highly excited matter
produced in relativistic heavy-ion collisions from SIS to SPS energies. Various
theoretical approaches are presented in connection with the interpretation of
experimental data. Special emphasis will be put on the role of chiral dynamics
and chiral symmetry restoration. I will discuss in particular to which extent
the broadening of the rho meson peak signals the onset of chiral symmetry
restoration.


title: Astrophysical factors:Zero energy vs. Most effective energy

abstract:
  Effective astrophysical factors for non-resonant astrophysical nuclear
reaction are invariably calculated with respect to a zero energy limit. In the
present work that limit is shown to be very disadvantageous compared to the
more natural effective energy limit. The latter is used in order to modify the
thermonuclear reaction rate formula so that it takes into account both plasma
and laboratory screening effects.


title:
Multi-electron SEFs for nuclear reactions involved in advanced stages of
  stellar evolution

abstract:
  Multi-electron screening effects encountered in laboratory astrophysical
reactions are investigated by considering the reactants Thomas-Fermi atoms. By
means of that model, previous studies are extended to derive the corresponding
screening enhancement factor (SEF), so that it takes into account ionization,
thermal, exchange and relativistic effects. The present study, by imposing a
very satisfactory constraint on the possible values of the screening energies
and the respective SEFs, corrects the current (and the future) experimental
values of the astrophysical factors associated with nuclear reactions involved
in advanced stages of stellar evolution.


title:
Validity of the Impulse Approximation and Quasielastic (e,e'p) Reactions
  from Nuclei

abstract:
  We assess the combined effect of ground-state correlations, meson-exchange
and isobar currents upon the cross sections for quasielastic (e,e'p) reactions
from nuclei. Four-momenta in the range 0.1 \leq Q^2 \leq 1 GeV^2 are addressed.
We observe that for $Q^2$ values exceeding 0.2 GeV^2, quasielastic conditions
and missing momenta below the Fermi momentum, the ground-state correlations and
two-body currents do not dramatically alter the $(e,e'p)$ predictions as they
are obtained in the impulse approximation. Moreover, deviations from the
impulse approximation exhibit a rather modest Q^2 dependence.


title:
Evaluation of cluster expansions and correlated one-body properties of
  nuclei

abstract:
  Three different cluster expansions for the evaluation of correlated one-body
properties of s-p and s-d shell nuclei are compared. Harmonic oscillator wave
functions and Jastrow type correlations are used, while analytical expressions
are obtained for the charge form factor, density distribution, and momentum
distribution by truncating the expansions and using a standard Jastrow
correlation function f. The harmonic oscillator parameter b and the correlation
parameter \beta have been determined by a least-squares fit to the experimental
charge form factors in each case. The information entropy of nuclei in
position-space (S_r) and momentum-space (S_k) according to the three methods
are also calculated. It is found that the larger the entropy sum S=S_r+S_k (the
information content of the system) the smaller the values of \chi^2. This
indicates that S is a criterion of the quality of a given nuclear model,
according to the maximum entropy principle. Only two exceptions to this rule,
out of many cases examined, were found. Finally an analytic expression for the
so-called "healing" or "wound" integrals is derived with the function f
considered, for any state of the relative two-nucleon motion and their values
in certain cases are computed and compared.


title: Cooling of Neutron Stars Revisited: Application of Low Energy Theorems

abstract:
  Cooling of neutrons stars proceeds mainly via neutrino emission;
  As an example we study the modified neutrino bremsstrahlung process $nn \to
nn\nu\bar{\nu}.$
  The radiated energy is small compared to other scales in the system.
  Hence one can use low-energy theorems to compute the neutrino emissivity in
terms of the non-radiative process, ie the on-shell $T$ matrix. We find that
the use of the $T-$matrix as compared to previous estimates based upon one pion
exchange leads a substantial reduction of the predicted emissivity.


title:
Momentum Space Integral Equations for Three Charged Particles: Diagonal
  Kernels

abstract:
  It has been a long-standing question whether momentum space integral
equations of the Faddeev type are applicable to reactions of three charged
particles, in particular above the three-body threshold. For, the presence of
long-range Coulomb forces has been thought to give rise to such severe
singularities in their kernels that the latter may lack the compactness
property known to exist in the case of purely short-range interactions.
Employing the rigorously equivalent formulation in terms of an
effective-two-body theory we have proved in a preceding paper [Phys. Rev. C
{\bf 61}, 064006 (2000)] that, for all energies, the nondiagonal kernels
occurring in the integral equations which determine the transition amplitudes
for all binary collision processes, possess on and off the energy shell only
integrable singularities, provided all three particles have charges of the same
sign, i.e., all Coulomb interactions are repulsive. In the present paper we
prove that, for particles with charges of equal sign, the diagonal kernels, in
contrast, possess one, but only one, nonintegrable singularity. The latter can,
however, be isolated explicitly and dealt with in a well-defined manner. Taken
together these results imply that modified integral equations can be
formulated, with kernels that become compact after a few iterations. This
concludes the proof that standard solution methods can be used for the
calculation of all binary (i.e., (in-)elastic and rearrangement) amplitudes by
means of momentum space integral equations of the effective-two-body type.


title: Non-localities and Fermi motion corrections in $K^-$ atoms

abstract:
  We evaluate the p-wave $K^-N$ amplitudes from the chiral Lagrangians and from
there construct the p-wave part of the $K^-$ nucleus optical potential plus a
small s-wave part induced from the elementary p-wave amplitude and the nuclear
Fermi motion. Simultaneously, the momentum and energy dependence of the s-wave
optical potential, previously developed, are taken into account and shown to
generate a small p-wave correction to the optical potential. All the
corrections considered are small compared to the leading s-wave potential, and
lead to changes in the shifts and widths which are smaller than the
experimental errors.
  A thorough study of the threshold region and low densities is conducted,
revealing mathematical problems for which a physical solution is given.


title:
Model-independent definition and determination of electromagnetic
  formfactors and multipole moments

abstract:
  A theoretical method for the systematic definition and determination of
Cartesian and spherical electromagnetic (onshell) formfactors and multipole
moments for particles or composite systems from electromagnetic Breit-frame
current distributions is presented. The method presented is free of sign
ambiguities and is not based on the underlying analytical substructure of the
electromagnetic current distributions. By construction the method contains all
higher order momentum derivative terms within the definition of electromagnetic
formfactors and multipole moments, which are not taken into account in a lot of
existing theoretical calculations.


title: Shell model study of the isobaric chains A=50, A=51 and A=52

abstract:
  Shell model calculations in the full pf-shell are carried out for the A=50,
51 and 52 isobars. The most frequently used effective interactions for the
pf-shell, KB3 and FPD6 are revisited and their behaviour at the N=28 and Z=28
closures examined. Cures to their -relatively minor- defaults are proposed, and
a new mass dependent version called KB3G is released. Energy spectra,
electromagnetic transitions and moments as well as beta decay properties are
computed and compared with the experiment and with the results of the earlier
interactions. A high quality description is achieved. Other miscellaneous
topics are addressed; the Coulomb energy differences of the yrast states of the
mirror pair 51Mn-51Fe and the systematics of the magnetic moments of the N=28
isotones.


title: A Relativistic Symmetry in Nuclei: Its origins and consequences

abstract:
  We review the status of quasi-degenerate doublets in nuclei, called
pseudospin doublets, which were discovered about thirty years ago and the
origins of which have remained a mystery, until recently. We show that
pseudospin doublets originate from an SU(2) symmetry of the Dirac Hamiltonian
which occurs when the sum of the scalar and vector potentials is a constant.
Furthermore, we survey the evidence that pseudospin symmetry is approximately
conserved in nuclear spectra and eigenfunctions and in nucleon-nucleus
scattering for a Dirac Hamiltonian with realistic nuclear scalar and vector
potentials.


title: Particle-Rotor Model Description of Doubly Odd Ta Isotopes

abstract:
  The doubly odd Ta isotopes are studied within the framework of the
particle-rotor model. The main aim of this study is to obtain information on
the neutron-proton interaction in deformed nuclei, with particular attention
focused on the role of the tensor force. To this end, both zero-range abd
finite-range phenomenological interactions are considered. Comparison of the
calculated results with experimental data provides evidence of the importance
of the tensor-force effects. We have also performed calculations using a
realistic two-body G matrix for the neutron proton interaction. Some
preliminary results are presented here.


title: Exact spinor-scalar bound states in a QFT with scalar interactions

abstract:
  We study two-particle systems in a model quantum field theory, in which
scalar particles and spinor particles interact via a mediating scalar field.
The Lagrangian of the model is reformulated by using covariant Green's
functions to solve for the mediating field in terms of the particle fields.
This results in a Hamiltonian in which the mediating-field propagator appears
directly in the interaction term. It is shown that exact two-particle
eigenstates of the Hamiltonian can be determined. The resulting relativistic
fermion-boson equation is shown to have Dirac and Klein-Gordon one-particle
limits. Analytic solutions for the bound state energy spectrum are obtained for
the case of massless mediating fields.


title: Structure functions for the three nucleon system

abstract:
  The spectral functions and light-cone momentum distributions of protons and
neutrons in 3He and 3H are given in terms of the three-nucleon wave function
for realistic nucleon-nucleon interactions. To reduce computational complexity,
separable expansions are employed for the nucleon-nucleon potentials. The
results for the light-cone momentum distributions suggest that they are not
very sensitive to the details of the two-body interaction, as long as it has
reasonable short-range repulsion. The unpolarised and polarised structure
functions are examined for both 3He and 3H in order to test the usefulness of
3He as a neutron target. It is found that the measurement of the spin structure
function of polarised 3H would provide a very clear test of the predicted
change in the polarised parton distributions of a bound proton.


title: Probing Isospin Dynamics in Halo Nuclei

abstract:
  Nuclear many-body theory is used to study nuclear matter and finite nuclei at
extreme isospin. In-medium interactions in asymmetric nuclear matter are
obtained from (Dirac-) Brueckner theory. Neutron skin formation in Ni and Sn
isotopes is investigated by relativistic mean-field calculations in DDRH theory
with density dependent meson-nucleon vertices. Applications to light nuclei are
discussed with special emphasis on pairing and core polarization in weakly
bound nuclei. Approaches accounting for continuum coupling in dripline pairing
and core polarization are presented. Calculations for the halo nuclei $^8$B,
$^{11}$Be and $^{19}$C show that shell structures are dissolving when the
driplines are approached. Relativistic breakup data are well described by
eikonal calculations.


title: Constraint Molecular Dynamics approach to Fermionic systems

abstract:
  We propose a Constraint Molecular Dynamics model for Fermionic system. In
this approach the equations of motion of wave packets for the nuclear many-body
problem are solved by imposing that the one-body occupation probability
$\bar{f}(r,p,t)$ can assume only values less or equal to 1. This condition
reflects the Fermionic nature of the studied systems and it is implemented with
a fast algorithm which allows also the study of the heaviest colliding system.
The parameters of the model have been chosen to reproduce the average binding
energy and radii of nuclei in the mass region $A=30\sim 208$. Some comparison
to data is given.


title:
p-Shell Nuclei and Two-Frequency Shell Model with a Realistic Effective
  Interaction

abstract:
  We have studied p-shell nuclei using a two-frequency shell-model approach
with an effective interaction derived from the Bonn-A nucleon-nucleon potential
by means of a G-matrix folded-diagram method. First, we briefly describe our
derivation of the effective interaction in a model space composed of harmonic
hoscillator wave functions with two different length parameters, b_in and
b_out, for the core and the valence orbits, respectively. Then we present some
selected results of our calculations. We show that a good agreement with
experiment is obtained, which is definitely better than that provided by a
standard one-frequency calculation. A comparison with results obtained from
large-basis shell-model calculations is also made.


title: Pion Interferometry at RHIC: Probing a thermalized Quark-Gluon-Plasma?

abstract:
  We calculate the Gaussian radius parameters of the pion-emitting source in
high energy heavy ion collisions, assuming a first order phase transition from
a thermalized Quark-Gluon-Plasma (QGP) to a gas of hadrons. Such a model leads
to a very long-lived dissipative hadronic rescattering phase which dominates
the properties of the two-pion correlation functions. The radii are found to
depend only weakly on the thermalization time tau_i, the critical temperature
T_c (and thus the latent heat), and the specific entropy of the QGP. The
dissipative hadronic stage enforces large variations of the pion emission times
around the mean. Therefore, the model calculations suggest a rapid increase of
R_out/R_side as a function of K_T if a thermalized QGP were formed.


title: Relativistic NN scattering equations without partial-wave decomposition

abstract:
  Relativistic quasi-potential equations describing NN scattering are compared.
Within the spectator formalism a cancellation is seen to occur between
retardation and negative-energy effects.


title: Few-Body Correlations in Fermi Systems

abstract:
  I present recent results on few-body correlations in nuclear matter at finite
temperatures and densities. In particular I focus on the four-body
correlations. The alpha-particle is the strongest bound state. The
investigation is done based on effective in-medium few-body equations that
consistently include self energy corrections and Pauli blocking effects. I
address the question of four-body condensates as well.


title: Charge-Exchange Reaction pD->n(pp) in the Bethe-Salpeter Approach

abstract:
  The deuteron charge - exchange reaction pD->n(pp) for the low values of
momentum transfer and small excitation energies of final pp - pair is
considered in the framework of Bethe - Salpeter approach. The method of
calculation of the observables is developed for the case, when the pp - pair is
in $^1S_0$ - state. The methodical numerical calculations of the differetial
cross sections and tensor analysing powers are presented. The reaction under
consideration is predicted to be a solid base for construction of the deuteron
tensor polarimeter at high energies, and also to obtain some additional
information about elementary nucleon - nucleon charge - exchange amplitude.


title: Multi-gap superfluidity in nuclear matter

abstract:
  It is shown that under lowering density or temperature a nucleon Fermi
superfluid can undergo a phase transition to a new superfluid state
corresponding to superposition of states with singlet-triplet (ST) and
triplet-singlet (TS) pairing of nucleons (in spin and isospin spaces). Such
states arise as a result of branching from one-gap solution of the
self-consistent equations, describing ST pairing of nucleons. The density and
temperature dependence of the order parameters for new two-gap solutions is
determined in the model with Skyrme effective forces.


title: Quark-meson coupling model with short-range quark-quark interactions

abstract:
  Short-range quark-quark correlations are introduced into the quark-meson
coupling (QMC) model phenomenologically. We study the effect of the
correlations on the structure of the nucleon in dense nuclear matter. With the
addition of correlations, the saturation curve for symmetric nuclear matter is
much improved at high density.


title: The q-Deformed NJL Model "Revisited"

abstract:
  In this work we investigate the chiral symmetry breaking in the q-deformed
version of the NJL Model and its consequent mass generation mechanism . We show
that the deformation of the NJL model, in the mean field approximation, may
take into account correlations that go beyond the mean field and, in a certain
limit, approaches the more realistic lattice calculations.


title: High $p_T$ Azimuthal Asymmetry in Non-central A+A at RHIC

abstract:
  The high $p_{\rm T}>3$ GeV azimuthal asymmetry, $v_2(p_{\rm T})$, in
non-central nuclear collisions at RHIC is shown to be a sensitive measure of
the initial parton density distribution of the produced quark-gluon plasma. A
generalization of the Gyulassy-Levai-Vitev (GLV) non-abelian energy loss
formalism including Bjorken 1+1D expansion as well as important kinematic
constraints is used.


title: Signatures of the quark gluon plasma: a personal overview

abstract:
  We first discuss, on a no-QGP basis, the two prominent indications of (a)
enhanced strangeness production and of (b) anomalous $J/\psi $-suppression: We
elaborate in particular on a recent idea of antihyperon production solely by
multi-mesonic reactions. As a possible source for an enhanced dissociation of
$c \bar{c}$ pairs we summarize the findings within the 'early'-comover
absorption scenario of prehadronic string excitations. As an exotic candidate
we then finally adress the stochastic formation of so called disoriented chiral
condensates: An experimentally feasible DCC, if it does exist, has to be a rare
event following an unusual and nontrivial distribution on an event by event
basis.


title:
Comment on `Charged Particle Ratio Fluctuation as a Signal for
  Quark-Gluon Plasma' and `Fluctuation Probes of Quark Deconfinement'

abstract:
  Charge fluctuations studied on event-by-event basis have been recently
suggested to provide a signal of the equilibrium quark-gluon plasma produced in
heavy-ion collisions at high energies. It is argued that the fluctuations
generated at the early collision stage when the energy is released can fake the
signal.


title: Mean-field models and superheavy elements

abstract:
  We discuss the performance of two widely used nuclear mean-field models, the
relativistic mean-field theory (RMF) and the non-relativistic
Skyrme-Hartree-Fock approach (SHF), with particular emphasis on the description
of superheavy elements (SHE). We provide a short introduction to the SHF and
RMF, the relations between these two approaches and the relations to other
nuclear structure models, briefly review the basic properties with respect to
normal nuclear observables, and finally present and discuss recent results on
the binding properties of SHE computed with a broad selection of SHF and RMF
parametrisations.


title: Nucleon Polarisabilities from Compton Scattering on the Deuteron

abstract:
  An analytic calculation of the differential cross section for elastic Compton
scattering on the deuteron at photon energies \omega in the range of 25-50 MeV
is presented to next-to-next-to-leading order, i.e. to an accuracy of \sim 3%.
The calculation is model-independent and performed in the low energy nuclear
Effective Field Theory without dynamical pions. The iso-scalar, scalar electric
and magnetic nucleon polarisabilities \alpha_0 and \beta_0 enter as free
parameters with a theoretical uncertainty of about 20%. Using data at
$\omega_{Lab}=49 MeV$ we find $\alpha_0=8.4\pm 3.0(exp)\pm 1.7(theor)$,
$\beta_0=8.9\pm 3.9(exp)\pm 1.8(theor)$, each in units of $10^{-4} fm^3$. With
the experimental constraint for the iso-scalar Baldin sum rule,
$\alpha_0=7.2\pm 2.1(exp)\pm 1.6(theor)$, $\beta_0=6.9\mp 2.1(exp)\mp
1.6(theor)$. A more accurate result can be achieved by: (i) better experimental
data, and (ii) a higher order theoretical calculation including contributions
from a couple of so far undetermined four-nucleon-two-photon operators.


title: Quantum Nucleardynamics as an SU(2)_N x U(1)_Z Gauge Theory

abstract:
  It is illustrated that quantum nucleardynamics (QND) as an SU(2)_N x U(1)_Z
gauge theory, which is generated from quantum chromodynamics (QCD) as an
SU(3)_C gauge theory through dynamical spontaneous symmetry breaking,
successfully describes nuclear phenomena at low energies. The proton and
neutron assigned as a strong isospin doublet are identified as a colorspin plus
weak isospin doublet. Massive gluon mediates strong interactions with the
effective coupling constant G_R/\sqrt{2} = g_n^2/8 M_G^2 \simeq 10 GeV^{-2}
just like Fermi weak constant G_F/\sqrt{2} = g_w^2/8 M_W^2 \simeq 10^{-5}
GeV^{-2} in the Glashow-Weinberg-Salam model where g_n and g_w are the coupling
constants and M_G and M_W are the gauge boson masses. Several explicit
evidences such as cross sections, lifetimes, nucleon-nucleon scattering,
magnetic dipole moment, nuclear potential, gamma decay, etc. are shown in
support of QND. The baryon number conservation is the consequence of the U(1)_Z
gauge theory and the proton number conservation is the consequence of the
U(1)_f gauge theory.


title: Off-Mass-Shell $\pi$N Scattering and $pp \to pp \pi^0$

abstract:
  We adapt the off-shell $\pi$N amplitude of the Tucson-Melbourne three-body
force to the half-off-shell amplitude of the pion rescattering contribution to
$pp \to pp \pi^0$ near threshold. This {\em pion} rescattering contribution,
together with the impulse term, provides a good description of the data when
the half-off-shell amplitude is linked to the phenomenological invariant
amplitudes obtained from meson factory $\pi$N scattering data.


title: Reworking the Tucson-Melbourne Three-Nucleon Potential

abstract:
  We introduce new values of the strength constants (i.e., $a$, $b$, $c$, and
$d$ coefficients) of the Tucson-Melbourne (TM) 2$\pi$ exchange three nucleon
potential. The new values come from contemporary dispersion relation analyses
of meson factory $\pi$N scattering data. We make variational Monte Carlo
calculations of the triton with the original and updated three-body forces to
study the effects of this update. We remove a short-range -- $\pi$-range part
of the potential due to the $c$ coefficient and discuss the effect on the
triton binding energy.


title: The u-d quark mass difference and nuclear charge symmetry breaking

abstract:
  The group theoretical analysis of the Coleman-Glashow tadpole picture of
"meson-mixing" is quantitatively reproduced by the u-d constituent quark mass
difference in quantum loop calculations of the self-energies of mesons. This
demonstration that the Coleman-Glashow scales can be directly calculated from
the constituent $u - d$ quark mass difference finishes the link between charge
symmetry breaking in low energy nuclear physics and the $u - d$ quark mass
difference in particle physics.


title: Darwin-Foldy term and proton charge radius

abstract:
  In this contribution we study the Dirac equation for a finite size proton in
an external electric field with explicit introduction of Dirac-Pauli form
factors. Our aim is twofold. On the one hand, we wish to study whether our
conclusions regarding the exact cancellation between Dirac form factor and
Foldy term contributions occurring for the neutron still hold for the proton.
On the other hand, we wish to clearly illustrate some of the specific features
of the description of a composite particle like the proton with the Dirac
equation.


title:
Vacuum polarization effects in hyperon rich dense matter -- a
  nonperturbative treatment

abstract:
  We derive the equation of state (EOS) for electrically charge neutral dense
matter using Quantum Hadrodynamics (QHD) model. This is carried out in a
nonperturbative manner including quantum corrections for baryons through a
realignment of vacuum with baryon-antibaryon condensates. This yields the
results of relativistic Hartree approximation of summing over baryonic tadpole
diagrams. The quantum corrections from the scalar meson is also taken into
account in a similar way. This leads to a softening of the equation of state
for the hyperonic matter. The formalism also allows us to do a self consistent
calculation of the in-medium sigma meson mass. The effects of such quantum
corrections on the composition of charge neutral dense matter is considered.
The effect of the resulting EOS on the structure of the neutron stars is also
studied.


title:
Meson-exchange $\pi N$ Models in Three-Dimensional Bethe-Salpeter
  Formulation

abstract:
  The pion-nucleon scattering is investigated by using several
three-dimensional reduction schemes of the Bethe-Salpeter equation for a model
Lagrangian involving $\pi$, $N$, $\Delta$, $\rho$, and $\sigma$ fields. It is
found that all of the resulting meson-exchange models can give similar good
descriptions of the $\pi N$ scattering data up to 400 MeV. However they have
significant differences in describing the $\pi NN$ and $\pi N\Delta$ form
factors and the $\pi N$ off-shell t-matrix elements. We point out that these
differences can be best distinguished by investigating the near threshold pion
production from nucleon-nucleon collisions and pion photoproduction on the
nucleon. The consequences of using these models to investigate various
pion-nucleus reactions are also discussed.


title: Relativistic and non-relativistic studies of nuclear matter

abstract:
  Recently we showed that while the tensor force plays an important role in
nuclear matter saturation in non-relativistic studies, it does not do so in
relativistic studies. The reason behind this is the role of $M^*$, the sum of
nucleon mass and its attractive self-energy in nuclear matter. Yet
nonrelativistic calculations at a certain level of approximation are far less
difficult than comparative relativistic calculation. Naturally the question
arises if one can modify a nonrelativistic method, say, the lowest order
Brueckner theory (LOBT), to reproduce approximately the results of a
relativistic calculation. While a many body effect, the role of $M^*$ is
intrinsically relativistic. It cannot be simulated by adding multi-body forces
in a nonrelativistic calculation. Instead, we examine if adding a set of
recipes to LOBT can be useful for the purpose. We point out that the
differences in the results arise principally from two reasons - first, the role
of $M^*$ and second, the disappearance in a relativistic treatment of the gap
in the hole and particle energy spectra, present in LOBT. In this paper we show
that LOBT, modified by {\it recipes} to remove these two reasons, generates
results quite close to those of Dirac-Brueckner theory.


title: New Forms of Deuteron Equations and Wave Function Representations

abstract:
  A recently developed helicity basis for nucleon-nucleon (NN) scattering is
applied to th e deuteron bound state. Here the total spin of the deuteron is
treated in such a helicity representation. For the bound state, two sets of two
coupled eigenvalue equations are developed, where the amplitudes depend on two
and one variable, respectively. Numerical illustrations based on the realistic
Bonn-B NN potential are given. In addition, an `operator form' of the deuteron
wave function is presented, and several momentum dependent spin densities are
derived and shown, in which the angular dependence is given analytically.


title: Phenomenology of kaonic atoms and other strange hadronic atoms

abstract:
  Recent optical-potential studies of the phenomenology of kaonic atoms are
reviewed. It is shown that the data can be fitted by a complex optical
potential with either a relatively shallow attractive component (about -50 MeV
at nuclear-matter density), as suggested by a self consistent application of
chirally motivated coupled-channels models, or a relatively deep attractive
component (about -180 MeV at nuclear-matter density) as suggested by a
mean-field extrapolation of a phenomenological low-density expansion. Both
classes of these optical potentials, due to their strongly absorptive
component, predict similarly structured relatively narrow `deeply bound'
kaonic-atom states with widths saturating at about 2 MeV. Possible formation
reactions are briefly discussed. The more speculative case for relatively
narrow deeply bound kaonic nuclear states is briefly mentioned. Recent works on
other strange hadronic atom systems, for the negatively charged Sigma and
Cascade hyperons, are also discussed.


title:
Coulomb versus nuclear break-up of 11Be halo nucleus in a non
  perturbative framework

abstract:
  The 11Be break-up is calculated using a non perturbative time-dependent
quantum calculation. The evolution of the neutron halo wave function shows an
emission of neutron at large angles for grazing impact parameters and at
forward angles for large impact parameters. The neutron angular distribution is
deduced for the different targets and compared to experimental data. We
emphasize the diversity of diffraction mechanisms, in particular we discuss the
interplay of the nuclear effects such as the towing mode and the Coulomb
break-up. A good agreement is found with experimental data.


title:
Nuclear isotope shifts within the local energy-density functional
  approach

abstract:
  The foundation of the local energy-density functional method to describe the
nuclear ground-state properties is given. The method is used to investigate
differential observables such as the odd-even mass differences and odd-even
effects in charge radii. For a few isotope chains of spherical nuclei, the
calculations are performed with an exact treatment of the Gor'kov equations in
the coordinate-space representation. A zero-range cutoff density-dependent
pairing interaction with a density-gradient term is used. The evolution of
charge radii and nucleon separation energies is reproduced reasonably well
including kinks at magic neutron numbers and sizes of staggering. It is shown
that the density-dependent pairing may also induce sizeable staggering and
kinks in the evolution of the mean energies of multipole excitations. The
results are compared with the conventional mean field Skyrme-HFB and
relativistic Hartree-BCS calculations. With the formulated approach, an
extrapolation from the pairing properties of finite nuclei to pairing in
infinite matter is considered, and the dilute limit near the critical point, at
which the regime changes from weak to strong pairing, is discussed.


title:
QCD sum rule analysis for light vector and axial-vector mesons in vacuum
  and nuclear matter

abstract:
  Extending previous work we study the constraints of QCD sum rules on mass and
width of light vector and axial-vector mesons in vacuum and in a medium with
finite nuclear density. For the latter case especially the effect of nuclear
pions leading to vector-axial-vector mixing is included in the analysis.


title:
A Realistic Description of Nucleon-Nucleon and Hyperon-Nucleon
  Interactions in the SU_6 Quark Model

abstract:
  We upgrade a SU_6 quark-model description for the nucleon-nucleon and
hyperon-nucleon interactions by improving the effective meson-exchange
potentials acting between quarks. For the scalar- and vector-meson exchanges,
the momentum-dependent higher-order term is incorporated to reduce the
attractive effect of the central interaction at higher energies. The
single-particle potentials of the nucleon and Lambda, predicted by the G-matrix
calculation, now have proper repulsive behavior in the momentum region q_1=5 -
20 fm^-1. A moderate contribution of the spin-orbit interaction from the
scalar-meson exchange is also included. As to the vector mesons, a dominant
contribution is the quadratic spin-orbit force generated from the rho-meson
exchange. The nucleon-nucleon phase shifts at the non-relativistic energies up
to T_lab=350 MeV are greatly improved especially for the 3E states. The
low-energy observables of the nucleon-nucleon and the hyperon-nucleon
interactions are also reexamined. The isospin symmetry breaking and the Coulomb
effect are properly incorporated in the particle basis. The essential feature
of the Lambda N - Sigma N coupling is qualitatively similar to that obtained
from the previous models. The nuclear saturation properties and the
single-particle potentials of the nucleon, Lambda and Sigma are reexamined
through the G-matrix calculation. The single-particle potential of the Sigma
hyperon is weakly repulsive in symmetric nuclear matter. The single-particle
spin-orbit strength for the Lambda particle is very small, in comparison with
that of the nucleons, due to the strong antisymmetric spin-orbit force
generated from the Fermi-Breit interaction.


title:
The Fate of Hadron Masses in Dense Matter: Hidden Local Symmetry and
  Color Flavor Locking

abstract:
  The notion that hadron masses scale according to the scaling of the quark
condensate in hadronic matter, partly supported by a number of observations in
finite nuclei, can be interpreted in terms of Harada-Yamawaki's ``vector
manifestation" (VM) of chiral symmetry. In this scenario, near chiral
restoration, the vector meson masses drop to zero {\it in the chiral limit}
with vanishing widths. This scenario appears to differ from the standard linear
sigma model scenario. We exploit a link between the VM and color-flavor locking
inferred by us from lattice data on quark number susceptibility (QNS) measured
as a function of temperature to suggest that local flavor symmetry gets mapped
to color gauge symmetry at the chiral phase transition.


title: Collisional Damping of Giant Monopole and Quadrupole Resonances

abstract:
  Collisional damping widths of giant monopole and quadrupole excitations for
$^{120}$Sn and $^{208}$Pb at zero and finite temperatures are calculated within
Thomas-Fermi approximation by employing the microscopic in-medium
cross-sections of Li and Machleidt and the phenomenological Skyrme and Gogny
forces, and are compared with each other. The results for the collisional
widths of giant monopole and quadrupole vibrations at zero temperature as a
function of the mass number show that the collisional damping of giant monopole
vibrations accounts for about 30-40% of the observed widths at zero
temperature, while for giant quadrupole vibrations it accounts for only 20-30%
of the observed widths of zero temperature.


title: Proton-Proton Fusion in Effective Field Theory to Fifth Order

abstract:
  The proton-proton fusion process p p->d e^+ nu_e is calculated at threshold
to fifth order in pionless effective field theory. There are two unknown
two-body currents contributing at the second and fourth orders. Combined with
the previous results for neutrino-deuteron and antineutrino-deuteron
scattering, computed to third order in the same approach, we conclude that a
10% measurement of reactor antineutrino-deuteron scattering measurement could
constrain the p p->d e^+ nu_e rate to ~7% while a ~3% measurement of nu_e d->
e^- p p could constrain the pp rate to ~2%.


title:
Anapole Moment and Other Constraints on the Strangeness Conserving
  Hadronic Weak Interaction

abstract:
  Standard analyses of low-energy NN and nuclear parity-violating observables
have been based on a pi-, rho-, and omega-exchange model capable of describing
all five independent s-p partial waves. Here a parallel analysis is performed
for the one-body, exchange-current, and nuclear polarization contributions to
the anapole moments of 133Cs and 205Tl. The resulting constraints are not
consistent, though there remains some degree of uncertainty in the nuclear
structure analysis of the atomic moments.


title: Excitation Spectrum in the Friedberg-Lee Model

abstract:
  The excitation spectrum of the nucleon with the spin 1/2 is examined by using
the Friedberg-Lee model containing the constituent quark and the scalar meson.
  An appropriate way of quantization for the non-linear meson field is employed
by taking account of the non-topological soliton existed in the classical
level.
  Our model space for the nucleon resonances includes the three-quark plus
one-meson state in addition to the pure three-quark state.
  The excitation spectrum in this model space shows that the positive parity
state appears as the first excited state associated with the 0s-excitation of
the scalar meson.
  The meson excitation also generates the additional negative parity state
apart from the well-known 0p-excitation of the quark.


title:
Boundary and expansion effects on two-pion correlation functions in
  relativistic heavy-ion collisions

abstract:
  We examine the effects that a confining boundary together with hydrodynamical
expansion play on two-pion distributions in relativistic heavy-ion collisions.
We show that the effects arise from the introduction of further correlations
due both to collective motion and the system's finite size. As is well known,
the former leads to a reduction in the apparent source radius with increasing
average pair momentum K. However, for small K, the presence of the boundary
leads to a decrease of the apparent source radius with decreasing K. These two
competing effects produce a maximum for the effective source radius as a
function of K.


title: Supernarrow Dibaryons Production in pd Interactions

abstract:
  An analysis of experimental data, obtained at the Proton Linear Accelerator
of INR, is carried out with the aim of searching for supernarrow dibaryons in
the pd->p+pX_1 and pd->p+dX_2 reactions. Dibaryons with masses 1904\pm 2,
1926\pm 2, and 1942\pm 2 MeV have been observed in invariant mass M_{pX_1}
spectra. In missing mass M_{X_1} spectra, the peaks at M_{X_1}=966\pm 2, 986\pm
2, and 1003\pm 2 MeV have been found. The analysis of the data obtained leads
to the conclusion that the observed dibaryons are supernarrow dibaryons, the
decay of which into two nucleons is forbidden by the Pauli exclusion principle.
A possible interpretation of exited nucleon states with small masses is
suggested.


title: The Canonical Nuclear Many-Body Problem as an Effective Theory

abstract:
  Recently it was argued that it might be possible treat the conventional
nuclear structure problem -- nonrelativistic point nucleons interacting through
a static and rather singular potential -- as an effective theory in a
shell-model basis. In the first half of this talk we describe how such a
program can be carried out for the simplest nuclei, the deuteron and 3He,
exploiting a new numerical technique for solving the self-consistent
Bloch-Horowitz equation. Some of the properties of proper effective theories
are thus illustrated and contrasted with the shell model. In the second half of
the talk we use these examples to return to a problem that frustrated the field
three decades ago, the possibility of reducing the effective interactions
problem to perturbation theory. We show, by exploiting the Talmi integral
expansion, that hard-core potentials can be systematically softened by the
introduction of a series of contact operators familiar from effective field
theory. The coefficients of these operators can be run analytically by a
renormalization group method in a scheme-independent way, with the introduction
of suitable counterterms. Once these coefficients are run to the shell model
scale, we show that the renormalized coefficients contain all of the
information needed to evaluate perturbative insertions of the remaining soft
potential. The resulting perturbative expansion is shown to converge in lowest
order for the simplest nucleus, the deuteron.


title:
Centrality Dependence of Hadron Multiplicities in Nuclear Collisions in
  the Dual Parton Model

abstract:
  We show that, even in purely soft processes, the hadronic multiplicity in
nucleus-nucleus interactions contains a term that scales with the number of
binary collisions. In the absence of shadowing corrections, this term dominates
at mid rapidities and high energies. Shadowing corrections are calculated as a
function of impact parameter and the centrality dependence of mid-rapidity
multiplicities is determined. The multiplicity per participant increases with
centrality with a rate that increases between SPS and RHIC energies, in
agreement with experiment.


title:
Coulomb corrections to $e^+ e^-$ production in ultra-relativistic
  nuclear collisions

abstract:
  The purpose of this paper is to explain the discrepancies existing in the
literature relative to $e^+e^-$ pair production in peripheral heavy ion
collisions at ultra-relativistic energies. A controversial issue is the
possible cancellation of Coulomb corrections to the Born term in the pair
production cross-section. Such a cancellation has been observed in a recent
approach based on finding retarded solutions of the Dirac equation, but does
not seem to hold in a perturbative approach. We show in this paper that the two
approaches are in fact calculating different observables: the perturbative
approach gives the exclusive cross-section of single pair production, while the
other method gives the inclusive cross-section.
  We have also performed a thorough study of the electron propagator in the
non-static background field of the two nuclei, the conclusion of which is that
the retarded propagator is in the ultra-relativistic limit a much simpler
object than the Feynman propagator, and can be calculated exactly.


title: The Strange Quark-Gluon Plasma

abstract:
  Strangeness flavor has turned out to be a very effective diagnostic tool of
relativistic heavy ion physics. The absolute yield provides information about
conditions arising in first instants of the interaction. Strange hadrons are
abundant allowing a precise study of the chemical freeze-out conditions in the
dense matter fireball. The thermal and chemical freeze-out universality seen in
strange hadrons confirms sudden hadronization as the breakup mechanism. A
plausible cause of sudden fireball breakup is the mechanical instability
arising when a quark-gluon plasma phase supercools deeply in its adiabatic
expansion. Applying these ideas, we interpret CERN-SPS and the first results on
hadronic particle ratios obtained at RHI


title:
The nuclear quadrupole moment of 57Fe from microscopic nuclear and
  atomic calculations

abstract:
  The nuclear quadrupole moment of the I=3/2- excited nuclear state of 57Fe at
14.41 keV, important in M\"ossbauer spectroscopy, is determined from the
large-scale nuclear shell-model calculations for 57Fe and also from the
electronic ab initio and density functional theory calculations including solid
state and electron correlation effects for the molecules Fe(CO)_5 and Fe(C_5
H_5)_2. Both independent methods yield very similar results. The recommended
value is 0.16(1) eb. The NQM of the isomeric 10+ in 54Fe has also been
calculated. The new value (0.5 eb), consistent with the perturbed angular
distribution data, is by a factor of two larger than the currently recommended
value.


title:
g-Factors and the Interplay of Collective and Single-Particle Degrees of
  Freedom in Superdeformed Mass-190 Nuclei

abstract:
  Interplay of collective and single-particle degrees of freedom is a common
phenomenon in strongly correlated many-body systems. Despite many successful
efforts in the study of superdeformed nuclei, there is still unexplored physics
that can be best understood only through the nuclear magnetic properties. We
point out that study of the gyromagnetic factor (g-factor) may open a unique
opportunity for understanding superdeformed structure. Our calculations suggest
that investigation of the g-factor dependence on spin and particle number can
provide important information on single-particle structure and its interplay
with collective motion in the superdeformed mass-190 nuclei. Modern
experimental techniques combined with the new generation of sensitive detectors
should be capable of testing our predictions.


title:
$\Delta(1232)$ Isobar Excitations in Nuclear Many-Body Systems derived
  from various NN Interactions

abstract:
  $\Delta$ isobar components in the nuclear many-body wave function are
investigated for the deuteron, light nuclei (${}^{16}O$) and infinite nuclear
matter within the framework of the coupled-cluster theory. The predictions
derived for various realistic models of the baryon-baryon interaction are
compared to each other. These include local ($V28$) and non-local meson
exchange potentials (Bonn$_{2000}$) but also a model recently derived by the
Salamanca group accounting for quark degrees of freedom. The characteristic
differences which are obtained for the $N\Delta$ and $\Delta\Delta$ correlation
functions are related to the approximation made in deriving the matrix elements
for the baryon-baryon interaction.


title: On the isospin dependence of the mean spin-orbit field in nuclei

abstract:
  By the use of the latest experimental data on the spectra of $^{133}$Sb and
$^{131}$Sn and on the analysis of properties of other odd nuclei adjacent to
doubly magic closed shells the isospin dependence of a mean spin-orbit
potential is defined. Such a dependence received the explanation in the
framework of different theoretical approaches.


title: Four-body DWBA calculations of the Coulomb breakup of 6He

abstract:
  We investigate the Coulomb breakup of the two-neutron halo nucleus 6He by
extending the framework of the finite range post form distorted wave Born
approximation theory introduced earlier for the description of the breakup of
one-neutron halo nuclei. The model can use the realistic three-body wave
function for the 6He ground state. Calculations have been performed for energy,
total and parallel momentum distributions of 4He fragment. The two-body
4He-neutron and neutron-neutron correlations have also been calculated. Our
results are compared with those of an adiabatic model of the Coulomb breakup
reactions. The two theories lead to almost identical results. Comparisons are
also made with the available experimental data. It is found that the pure
Coulomb breakup can describe the bulk of the data taken at below grazing
angles. However, a rigorous description of all the available data requires the
consideration of the nuclear breakup effects.


title: Antikaons in nuclei and dense nuclear matter

abstract:
  We present recent progress on the properties of antikaons in nuclei and dense
nuclear matter as obtained from two {\bar K}N interaction models: one based on
the lowest-order meson-baryon chiral lagrangian and the other derived from a
meson-exchange picture.


title: Chiral unitary theory: application to nuclear problems

abstract:
  In this talk we briefly describe some basic elements of chiral perturbation
theory, $\chi PT$, and how the implementation of unitarity and other novel
elements lead to a better expansion of the $T$ matrix for meson meson and meson
baryon interactions. Applications are then done to the $ \pi \pi $ interaction
in nuclear matter in the scalar and vector channels, antikaons in nuclei and
$K^-$ atoms, and how the $\phi$ meson properties are changed in a nuclear
medium.


title:
Higher order effects in electromagnetic dissociation of neutron halo
  nuclei

abstract:
  We investigate higher order effects in electromagnetic dissociation of
neutron halo nuclei using a simple and realistic zero range model for the
neutron-core interaction. In the sudden (or Glauber) approximation all orders
in the target-core interaction are taken into account. Small deviations from
the sudden approximation are readily calculated. We obtain very simple
analytical results for the next-to-leading order effects, which have a simple
physical interpretation. For intermediate energy electromagnetic dissociation,
higher order effects are generally small. We apply our model to Coulomb
dissociation of $^{19}$C at 67 A MeV. The analytical results are compared to
numerical results from the integration of the time-dependent Schroedinger
equation. Good agreement is obtained. We conclude that higher order
electromagnetic effects are well under control.


title: Relativistic corrections in (e,e'p) knockout reactions

abstract:
  A consistent comparison between nonrelativistic and relativistic descriptions
of the (e,e'p) reaction is presented. We use the nonrelativistic DWEEPY code
and develop a fully relativistic model starting from the effective Pauli
reduction for the scattering state and the relativistic mean field theory for
the bound state. Results for the 16O(e,e'p) differential cross section and
structure functions are compared in various kinematical conditions. A limit in
energy of the validity of the nonrelativistic approach is established. The
effects of spinor distortion and of the effective momentum approximation for
the scattering state are discussed. A satisfactory agreement with data of
differential cross sections, structure functions, and polarization observables
is achieved.


title:
Mutual heavy ion dissociation in peripheral collisions at
  ultrarelativistic energies

abstract:
  We study mutual dissociation of heavy nuclei in peripheral collisions at
ultrarelativistic energies. Earlier this process was proposed for beam
luminosity monitoring via simultaneous registration of forward and backward
neutrons in zero degree calorimeters at Relativistic Heavy Ion Collider.
Electromagnetic dissociation of heavy ions is considered in the framework of
the Weizsacker-Williams method and simulated by the RELDIS code. Photoneutron
cross sections measured in different experiments and calculated by the GNASH
code are used as input for the calculations of dissociation cross sections. The
difference in results obtained with different inputs provides a realistic
estimation for the systematic uncertainty of the luminosity monitoring method.
Contribution to simultaneous neutron emission due to grazing nuclear
interactions is calculated within the abrasion model. Good description of CERN
SPS experimental data on Au and Pb dissociation gives confidence in predictive
power of the model for AuAu and PbPb collisions at RHIC and LHC.


title: Relativistic unitary description of pi pi scattering

abstract:
  A unitary framework based on the Bakamjian-Thomas construction of
relativistic quantum mechanics is used to describe two-pion scattering from
threshold to 1400 MeV. The framework properly includes unitarity cuts for one-,
two- and three-hadron states and provides an excellent description of the
available data for pi pi phase shifts and inelasticities. The role and
importance of three-hadron cuts are calculated and discussed.


title: Fission widths of hot nuclei from Langevin dynamics

abstract:
  Fission dynamics of excited nuclei is studied in the framework of Langevin
equation. The one body wall-and-window friction is used as the dissipative
force in the Langevin equation. In addition to the usual wall formula friction,
the chaos weighted wall formula developed earlier to account for
nonintegrability of single-particle motion within the nuclear volume is also
considered here. The fission rate calculated with the chaos weighted wall
formula is found to be faster by about a factor of two than that obtained with
the usual wall friction. The systematic dependence of fission width on
temperature and spin of the fissioning nucleus is investigated and a simple
parametric form of fission width is obtained.


title:
Relativistic mean field approximation to the analysis of 16O(e,e'p)15N
  data at |Q^2|\leq 0.4 (GeV/c)^2

abstract:
  We use the relativistic distorted wave impulse approximation to analyze data
on 16O(e,e'p)15N at |Q^2|\leq 0.4 (GeV/c)^2 that were obtained by different
groups and seemed controversial. Results for differential cross-sections,
response functions and A_TL asymmetry are discussed and compared to different
sets of experimental data for proton knockout from p_{1/2} and p_{3/2} shells
in 16O. We compare with a nonrelativistic approach to better identify
relativistic effects. The present relativistic approach is found to accommodate
most of the discrepancy between data from different groups, smoothing a long
standing controversy.


title: Neutrino spectra from stellar electron capture

abstract:
  Using the recent shell model evaluation of stellar weak interaction rates we
have calculated the neutrino spectra arising from electron capture on pf-shell
nuclei under presupernova conditions. We present a simple parametrization of
the spectra which allows for an easy implementation into collapse simulations.
We discuss that the explicit consideration of thermal ensembles in the parent
nucleus broadens the neutrino spectra and results in larger average neutrino
energies. The capture rates and neutrino spectra can be easily modified to
account for phase space blocking by neutrinos which becomes increasingly
important during the final stellar collapse.


title:
A link of information entropy and kinetic energy for quantum many-body
  systems

abstract:
  A direct connection of information entropy $S$ and kinetic energy $T$ is
obtained for nuclei and atomic clusters, which establishes $T$ as a measure of
the information in a distribution. It is conjectured that this is a universal
property for fermionic many-body systems. We also check rigorous inequalities
previously found to hold between S and T for atoms and verify that they hold
for nuclei and atomic clusters as well. These inequalities give a relationship
of Shannon's information entropy in position-space with an experimental
quantity i.e. the rms radius of nuclei and clusters.


title: Reaction mechanisms for two-neutron halo breakup

abstract:
  We describe a reaction mechanism which is consistent with all available
experimental information of high energy three-body breakup processes. The
dominating channels are removal of one of the three halo particles leaving the
other two either undisturbed or absorbed. We compare with the commonly used
deceptive assumption of a decay through two-body resonance states. Our
predictions can be tested by measuring neutron-neutron invariant mass spectra.


title: Self-energy Effects in the Superfluidity of Neutron Matter

abstract:
  The superfluidity of neutron matter in the channel $^1 S_0$ is studied by
taking into account the effect of the ground-state correlations in the
self-energy. To this purpose the gap equation has been solved within the
generalized Gorkov approach. A sizeable suppression of the energy gap is driven
by the quasi-particle strength around the Fermi surface.


title: Asymmetry in $\vec{n} + p -> d + \gamma$

abstract:
  Heavy-baryon chiral perturbation theory (HBChPT) is applied to the asymmetry
$A_\gamma$ in $\vec{n} + p \to d + \gamma$ at threshold, which arises due to
the weak parity non-conserving interactions. Instead of appealing to Siegert's
theorem, transition operators up to next-to-leading chiral order are derived
and the corresponding amplitudes are evaluated with the Argonne $v_{18}$
wavefunctions. In addition to the impulse contribution, both parity-conserving
and parity-non-conserving two-body one-pion-exchange diagrams appear up to this
order. Our prediction for the asymmetry is $A_\gamma = - 0.10 \hpiNN$, which is
close to the Siegert's theorem based result, $A_\gamma \simeq -0.11 \hpiNN$.
This illustrates that HBChPT is effective in the parity-non-conserving physics.


title: Vector Meson Propagator and Baryon Current Conservation

abstract:
  If baryons couple only with $\omega $-mesons, one found the baryon spectral
function may be negative. We show this unacceptable result is caused by the
$k_\mu k_\nu $-terms in the $\omega $-meson propagator. Their contribution may
not vanish in approximate calculations which violate the baryon current
conserves. A rule is suggested, by which the calculated baryon spectral
function is well behaved.


title: Superfluid Phase Transitions in Dense Neutron Matter

abstract:
  The phase transitions in a realistic system with triplet pairing, dense
neutron matter, have been investigated. The spectrum of phases of the
$^3P_2-^3F_2$ model, which adequately describes pairing in this system, is
analytically constructed with the aid of a separation method for solving BCS
gap equation in states of arbitrary angular momentum. In addition to solutions
involving a single value of the magnetic quantum number (and its negative),
there exist ten real multicomponent solutions. Five of the corresponding
angle-dependent order parameters have nodes, and five do not. In contrast to
the case of superfluid $^3$He, transitions occur between phases with nodeless
order parameters. The temperature dependence of the competition between the
various phases is studied.


title:
Variational separable expansion scheme for two-body Coulomb-scattering
  problems

abstract:
  We present a separable expansion approximation method for Coulomb-like
potentials which is based on Schwinger variational principle and uses
Coulomb-Sturmian functions as basis states. The new scheme provides faster
convergence with respect to our formerly used non-variational approach.


title: Current Status of Quark Gluon Plasma Signals

abstract:
  Compelling evidence for the creation of a new form of matter has been claimed
to be found in Pb+Pb collisions at SPS. We discuss the uniqueness of often
proposed experimental signatures for quark matter formation in relativistic
heavy ion collisions. It is demonstrated that so far none of the proposed
signals like J\psi meson production/suppression, strangeness enhancement,
dileptons, and directed flow unambigiously show that a phase of deconfined
matter has been formed in SPS Pb+Pb collisions. We emphasize the need for
systematic future measurements to search for simultaneous irregularities in the
excitation functions of several observables in order to come close to pinning
the properties of hot, dense QCD matter from data.


title: A New Approach to Large-Scale Nuclear Structure Calculations

abstract:
  A new approach to large-scale nuclear structure calculations, based on the
Density Matrix Renormalization Group (DMRG), is described. The method is tested
in the context of a problem involving many identical nucleons constrained to
move in a single large-j shell and interacting via a pairing plus quadrupole
interaction. In cases in which exact diagonalization of the hamiltonian is
possible, the method is able to reproduce the exact results for the ground
state energy and the energies of low-lying excited states with extreme
precision. Results are also presented for a model problem in which exact
solution is not feasible.


title: SU(3) density matrix theory

abstract:
  The irreducible representations of the Lie algebra ${\frak su}$(3) describe
rotational bands in the context of the nuclear shell and interacting boson
models. The density matrices associated with ${\frak su}$(3) provide an
alternative theoretical framework for obtaining these bands. The ${\frak
su}$(3) density matrix formulation is mathematically simpler than
representation theory, yet it yields similar results. Bands are solutions to a
system of polynomial equations defined by the quadratic and cubic ${\frak
su}$(3) Casimirs. Analytic solutions are found in many physically important
cases including rotation about principal axes and spheroids. Numerical
solutions are reported in other cases including tilted rotors. The physics of
rotational bands is more transparent in the presented formalism. In
representation theory bands terminate because the space is finite-dimensional.
In ${\frak su}$(3) density matrix theory bands terminate when faster rotation
produces a spheroid rotating around its symmetry axis.


title:
State Dependent Effective Interaction for the Hyperspherical Formalism
  with Noncentral Forces

abstract:
  The recently developed effective interaction method for the hyperspherical
harmonic formalism is extended to noncentral forces. Binding energies and radii
of three- and four-body nuclei are calculated with AV6 and AV14 NN potentials.
Excellent results for the convergence of the expansion are found, particularly
for the three-nucleon system. Due to the higher density the convergence rate is
a bit slower for the alpha particle. In comparison to central potential models
there is only a very slight deterioration of the convergence due the tensor
force, while other potential terms have no visible effect on the convergence.
The obtained values for binding energy and radii also agree well with the
results in the literature obtained with other few-body techniques.


title:
Meson exchange in the weak decay of Lambda hypernuclei and the
  Gamma_n/Gamma_p ratio

abstract:
  We take an approach to the Lambda non-mesonic weak decay in nuclei based on
the exchange of mesons. The one pion and one kaon exchange are considered,
together with the exchange of two pions, either correlated, leading to an
important scalar-isoscalar exchange (sigma-like exchange), or uncorrelated (box
diagrams). Extra effects of omega exchange in the scalar-isoscalar channel are
also considered. Constraints of chiral dynamics are used to generate these
exchanges. A drastic reduction of the OPE results for the Gamma_n/Gamma_p ratio
is obtained and the new results are compatible with all present experiments
within errors. The absolute rates obtained for different nuclei are also in
good agreement with experiment.


title:
Chiral 3$\pi$-exchange NN-potentials: Results for dominant
  next-to-leading order contributions

abstract:
  We calculate in (two-loop) chiral perturbation theory the local NN-potentials
generated by the three-pion exchange diagrams with one insertion from the
second order chiral effective pion-nucleon Lagrangian proportional to the
low-energy constants $c_{1,2,3,4}$. The resulting isoscalar central potential
vanishes identically. In most cases these $3\pi$-exchange potentials are larger
than the ones generated by the diagrams involving only leading order vertices
due to the large values of $c_{3,4}$ (which mainly represent virtual
$\Delta$-excitation). A similar feature has been observed for the chiral
$2\pi$-exchange. We also give suitable (double-integral) representations for
the spin-spin and tensor potentials generated by the leading-order diagrams
proportional to $g_A^6$ involving four nucleon propagators. In these cases the
Cutkosky rule cannot be used to calculate the spectral-functions in the
infinite nucleon mass limit since the corresponding mass-spectra start with a
non-vanishing value at the $3\pi$-threshold. Altogether, one finds that chiral
$3\pi$-exchange leads to small corrections in the region $r\geq 1.4$ fm where
$1\pi$- and chiral $2\pi$-exchange alone provide a very good strong NN-force as
shown in a recent analysis of the low-energy pp-scattering data-base.


title: Predicting total reaction cross sections for nucleon-nucleus scattering

abstract:
  Nucleon total reaction and neutron total cross sections to 300 MeV for 12C
and 208Pb, and for 65 MeV spanning the mass range, are predicted using
coordinate space optical potentials formed by full folding of effective
nucleon-nucleon interactions with realistic nuclear ground state densities.
Good to excellent agreement is found with existing data.


title: Nucleon Compton Scattering in Chiral Effective Field Theories

abstract:
  Chiral effective field theories have a long history studying the process of
Compton scattering on the nucleon. In this contribution I want to focus on the
new developments that have occured since the last Chiral Dynamics conference in
Mainz 1997. I will focus exclusively on the spin-dependent sector, where most
of the recent work has been done.


title: Theory of the Nucleon Spin-Polarizabilities II

abstract:
  Following up on the plenary talk given by Ulf Mei{\ss}ner, I discuss a
generalization of the concept of nucleon spin-polarizabilities in terms of
multipole excitation/de-excitation and present an overview of the available
theoretical predictions for these elusive but interesting structure parameters
of the nucleon.


title: The nucleon-nucleon interaction

abstract:
  We review the major progress of the past decade concerning our understanding
of the nucleon-nucleon interaction. The focus is on the low-energy region
(below pion production threshold), but a brief outlook towards higher energies
is also given. The items discussed include charge-dependence, the precise value
of the $\pi NN$ coupling constant, phase shift analysis and high-precision NN
data and potentials. We also address the issue of a proper theory of nuclear
forces. Finally, we summarize the essential open questions that future research
should be devoted to.


title: Compton scattering from the proton at NLO in the chiral expansion

abstract:
  We present calculations of differential cross sections for Compton scattering
from the proton, using amplitudes calculated to fourth order in heavy baryon
chiral perturbation theory. We compare with available data up to 200 MeV. We
find that the agreement for angles below 90 degree is acceptable over the whole
energy range, but that at more backward angles the agreement decreases above
about 100 MeV, and fails completely above the photoproduction threshold.


title: Neutron electric dipole moment: Constituent-dressing and compositeness

abstract:
  Contributions to the neutron's EDM, are calculated using a well-constrained
Ansatz for the nucleon's Poincare' covariant Fadde'ev amplitude. The
momentum-dependent quark dressing amplifies the contribution from the
current-quarks' EDMs; and dressed-quark confinement and binding make
distinguishable the effect of the two CP and T violating interactions: i
gamma_5 sigma_{mu nu} (p_1-p_2)_nu and gamma_5 (p_1+p_2)_mu, where p_{1,2} are
the current-quarks' momenta. The value of |d_n| obtained using the
current-quark EDMs generated by a minimal three Higgs doublet model of
spontaneous CP violation is close to the current experimental upper bound.


title:
Relativistic Contributions to the Photon Asymmetry in Deuteron
  Photodisintegration

abstract:
  The cross section asymmetry $\Sigma$ in deuteron disintegration with linearly
polarized light is considered in the framework of the Bethe-Salpeter formalism.
Relativistic contributions to the asymmetry are investigated within the
approximation, which takes into account the one-body part of the
electromagnetic current operator and the dominant positive-energy partial
amplitudes of the Bethe-Salpeter vertex function of the deuteron.


title: Enhancement of $\phi$ mesons in Pb+Pb collisions at 158A GeV/c

abstract:
  Using a hadron-string cascade model LUCIAE, the $\phi$ meson production in
heavy ion collisions (Pb+Pb) and elementary collisions (p+p) were studied
systematically. Within the framework of the model, the experimentally measured
$\phi$ enhancement in Pb+Pb over p+p collisions can be mostly explained by the
collective effects in the gluon string emission and the reduction of the
s-quark suppression.


title: Non equilibrium effects in fragmentation

abstract:
  We study, using molecular dynamics techniques, how boundary conditions affect
the process of fragmentation of finite, highly excited, Lennard-Jones systems.
We analyze the behavior of the caloric curves (CC), the associated thermal
response functions (TRF) and cluster mass distributions for constrained and
unconstrained hot drops. It is shown that the resulting CC's for the
constrained case differ from the one in the unconstrained case, mainly in the
presence of a ``vapor branch''. This branch is absent in the free expanding
case even at high energies . This effect is traced to the role played by the
collective expansion motion. On the other hand, we found that the recently
proposed characteristic features of a first order phase transition taking place
in a finite isolated system, i.e. abnormally large kinetic energy fluctuations
and a negative branch in the TRF, are present for the constrained (dilute) as
well the unconstrained case. The microscopic origin of this behavior is also
analyzed.


title:
Topological susceptibility at zero and finite temperature in the
  Nambu-Jona-Lasinio model

abstract:
  We consider the three flavor Nambu-Jona-Lasinio model with the 't Hooft
interaction incorporating the U(1)_A anomaly. In order to set the coupling
strength of the 't Hooft term, we employ the topological susceptibility $\chi$
instead of the eta' meson mass. The value for $\chi$ is taken from lattice
simulations. We also calculate $\chi$ at finite temperature within the model.
Comparing it with the lattice data, we extract information about the behavior
of the U(1)_A anomaly at finite temperature. We conclude that within the
present framework, the effective restoration of the U(1)_A symmetry does not
necessarily take place even at high temperature where the chiral symmetry is
restored.


title:
Collectivity of the low-lying dipole strength in relativistic random
  phase approximation

abstract:
  The relativistic random phase approximation is applied in the analysis of the
evolution of the isovector dipole response in nuclei with a large neutron
excess. The self-consistent framework of relativistic mean-field theory, which
has been very successfully applied in the description of ground-state
properties of nuclei far from the valley of $\beta$-stability, is extended to
study the possible onset of low-energy collective isovector dipole modes in
nuclei with extreme isospin values.


title:
In-Medium Effective Pion Mass from Heavy-Baryon Chiral Perturbation
  Theory

abstract:
  Using heavy-baryon chiral perturbation theory, we have calculated all the
diagrams up to two-loop order which contribute to the S-wave pion self-energy
in symmetric nuclear matter. Some subtleties related to the definition of pion
fields are discussed. The in-medium pion mass is turned out to be increased by
only (5 - 6) per cents in normal nuclear matter density, without any off-shell
ambiguity.


title:
Pairing Properties In Relativistic Mean Field Models Obtained From
  Effective Field Theory

abstract:
  We apply recently developed effective field theory nuclear models in mean
field approximation (parameter sets G1 and G2) to describe ground-state
properties of nuclei from the valley of $\beta$-stability up to the drip lines.
For faster calculations of open-shell nuclei we employ a modified BCS approach
which takes into account quasi-bound levels owing to their centrifugal barrier,
with a constant pairing strength. We test this simple prescription by comparing
with available Hartree-plus-Bogoliubov results. Using the new effective
parameter sets we then compute separation energies, density distributions and
spin--orbit potentials in isotopic (isotonic) chains of nuclei with magic
neutron (proton) numbers. The new forces describe the experimental systematics
similarly to conventional non-linear $\sigma-\omega$ relativistic force
parameters like NL3.


title: Form factors and photoproduction amplitudes

abstract:
  We examine the use of phenomenological form factors in tree level amplitudes
for meson photoproduction. Two common recipes are shown to be fundamentally
incorrect. An alternate form consistent with gauge invariance and crossing
symmetry is proposed.


title: $e^+e^-$ production in $p A$ reactions at SIS energies

abstract:
  Detailed predictions for dilepton production from $p A$ reactions at SIS
energies are presented within a semi-classical BUU transport model that
includes the off-shell propagation of vector mesons nonperturbatively and
calculates the width of the vector mesons dynamically. Different scenarios of
in-medium modifications of vector mesons, such as collisional broadening and
dropping vector meson masses, are investigated and the possibilities for an
experimental observation of in-medium effects in $p A$ reactions at 1--4 GeV
are discussed for a variety of nuclear targets.


title: Effective nucleon mass in relativistic mean field theory

abstract:
  In the $\sigma$-$\omega$-$\rho$ model of the relativistic mean field theory
with nonlinear $\sigma$-meson self-interaction, the effective nucleon mass
$M^*$ is discussed with relation to the symmetry incompressibility $K_s$ of
nuclear matter, based on the model parameters fitted to nuclear matter
properties. It is shown that $M^*$ is larger than $0.73M$, if $K_s$ is assumed
to be negative and the nuclear matter incompressibility $K_0$ is kept less than
$300 MeV$. Furthermore, the field system is shown to be stable, as the
$\sigma$-meson self-interaction energy is lower bounded in this parameter
region.