title:
Implications of Quark-Lepton Symmetry for Neutrino Masses and
  Oscillations

abstract:
  We identify a plausible scenario based on quark-lepton symmetry which
correlates long baseline oscillations with maximal mixing to sterile neutrinos.
The implication for the Sudbury Neutrino Observatory (SNO) is that the neutral
current signal will be found to suffer the same suppression from the Standard
Solar Model prediction as obtains for the charged current signal. Flavor mixing
among active neutrinos is expected to occur on shorter baselines with smaller
mixing amplitudes.


title: A New Mechanism for J/psi Suppression in Nuclear Collisions

abstract:
  We present new results based on an improved version of the Glauber model,
used to describe the nuclear absorption of J/psi in reactions between nuclei at
high energy. The excitation of the colour degrees of freedom of nucleons, due
to collisions mediated by one-gluon exchange, is taken into account. It is
found that the proposed mechanism leads to larger nuclear absorption of J/psi
than previously considered.


title: Moments of inertia for multi-quasiparticle configurations

abstract:
  Tilted-axis cranking calculations have been performed for multi-quasiparticle
states in well deformed A$\approx$180 nuclei. In the limit of zero pairing, not
only are the calculated moments of inertia substantially smaller than for rigid
rotation, but also they are close to the experimental values. The moments of
inertia are found to be insensitive to dynamic pair correlations.


title: eta d scattering in the region of the S11 resonance

abstract:
  We have studied the reaction eta d -> eta d close to threshold within a
nonrelativistic three-body formalism. We considered several eta N and NN
models, in particular potentials with separable form, fitted to the low-energy
eta N and NN data to represent the two-body interactions. We found that with
realistic two-body interactions a quasibound state does not exist in this
system, although there is an enhancement of the cross section by one order of
magnitude, in the region near threshold, which is a genuine three-body effect
not predicted within the impulse approximation.


title:
Radiative Corrections to Elastic Electron-Proton Scattering for
  Polarized Electrons

abstract:
  We analyze the radiative correction to high energy elastic electron-proton
scattering of polarized electrons. We show that if the approximations inherent
in the calculations developed by Tsai and given in the work of Mo and Tsai,
which have been used in the analysis of almost all experimental data pertaining
to medium and high energy elastic electron scattering for the past three
decades, are maintained, then the same radiative correction applies both in the
case of initially polarized and unpolarized electrons.


title: Radiative Corrections to Electron-Proton Scattering

abstract:
  The radiative corrections to elastic electron-proton scattering are analyzed
in a hadronic model including the finite size of the nucleon. For initial
electron energies above 8 GeV and large scattering angles, the proton vertex
correction in this model increases by at least two percent the overall factor
by which the one-photon exchange (Rosenbluth) cross section must be multiplied.
The contribution of soft photon emission is calculated exactly. Comparison is
made with the generally used expressions previously obtained by Mo and Tsai.
Results are presented for some kinematics at high momentum transfer.


title:
Light Front Quantization--A Technique for Relativistic and Realistic
  Nuclear Physics

abstract:
  Applications of relativistic light front dynamics to computing wave functions
of heavy nuclei are reviewed. The motivation for this is the desire to find
wave functions, expressed in terms of the plus-momentum variable, that simplify
the analyses of high energy experiments such as deep inelastic scattering,
Drell-Yan production, (e,e') and (p,p').Some examples of ordinary quantum
mechanics are solved to show that the formalism is tractable. Light-front
quantization is reviewed briefly and applied to: infinite nuclear matter within
the mean field approximation; a simple static source theory; finite nuclei
using the mean field approximation; low-energy pion-nucleon scattering using a
chiral Lagrangian; nucleon-nucleon scattering, within the one boson exchange
approximation; and, infinite nuclear matter including the effects of
two-nucleon correlations. Standard good results for nuclear saturation
properties are obtained, with a possible improvement in the computed nuclear
compressibility. Manifest rotational invariance is not used as an aid in doing
calculations, but it does emerge in the results. It seems that nuclear physics
can be done in a manner in which modern nuclear dynamics is respected, boost
invariance in the $z$-direction is preserved, and in which rotational
invariance is maintained. A salient feature is that $\omega,\sigma$ and $\pi$
mesons are important constituents of nuclei. It seems possible to find
Lagrangians that yield reasonable descriptions of nuclear deep inelastic
scattering and Drell-Yan reactions. Furthermore, the presence of the $\sigma$
and $\omega$ mesons could provide a nuclear enhancement of the ratio of the
cross sections for longitudinally and transversely polarized virtual photons in
accord with recent measurements by the HERMES collaboration.


title: Pairing correlation involving the continuum states

abstract:
  The Hartree-Fock-Bogoliubov equation for the ground states of even-even
atomic nuclei is solved using the canonical representation in the coordinate
space for zero range interactions like the Skyrme force. The gradient method is
improved for faster convergence to the solutions under constraint of
orthogonality between canonical orbitals. Necessity of the cut-off of the
pairing interaction is shown even when the number of the canonical orbitals are
restricted. A repulsive dependence of the interaction on the pairing density is
introduced as an implementation of the cut-off which leaves the HFB super
matrix state-independent.


title: Hartree-Fock-Bogoliubov for deformed neutron-rich nuclei

abstract:
  The two-basis method to solve the HFB for deformed nuclei in coordinate space
is examined concerning the precision of the density tail. Small cutoff energies
are shown to give rise to ripples in the tail, whose wave length corresponds to
the cutoff momentum. More precise solutions require higher cutoff energies,
which result in HFB matrices of larger dimensions. To circumvent the difficulty
of the large dimension, we employ another method to solve the HFB ---the
natural-orbital method introduced originally for spherical nuclei--- to apply
it to deformed nuclei. The method can be successfully implemented with a
three-dimensional Cartesian mesh representation.


title: Low energy onset of nuclear shadowing in photoabsorption

abstract:
  The early onset of nuclear shadowing in photoabsorption at low photon
energies has recently been interpreted as a possible signature of a decrease of
the rho meson mass in nuclei. We show that one can understand this early onset
within simple Glauber theory if one takes the negative real part of the rho N
scattering amplitudes into account, corresponding to a higher effective mass of
the rho meson in nuclear medium.


title:
Single-Particle and Collective Motion for Proton-Rich Nuclei on the
  Astrophysical rp-Process Path

abstract:
  Based on available experimental data, a new set of Nilsson parameters is
proposed for proton-rich nuclei with proton or neutron numbers $28\leq N\leq
40$. The resulting single-particle spectra are compared with those from
relativistic and non-relativistic mean field theories. Collective excitations
in some even--even proton-rich nuclei in the upper $pf$ shell are investigated
using the Projected Shell Model with the new Nilsson basis. It is found that
the regular bands are sharply disturbed by band crossings involving $1g_{9/2}$
neutrons and protons. Physical quantities for exploring the nature of the band
disturbance and the role of the $1g_{9/2}$ single-particle are predicted, which
may be tested by new experiments with radioactive beams.


title:
The role of electron-screening deformations in solar nuclear fusion
  reactions and the solar neutrino puzzle

abstract:
  Thermonuclear fusion reaction rates in the solar plasma are enhanced by the
presence of the electron cloud that screens fusing nuclei. The present work
studies the influence of electron screening deformations on solar reaction
rates in the framework of the Debye-Huckel model. These electron-ion cloud
deformations, assumed here to be static and axially symmetric, are shown to be
able to considerably influence the solar neutrino fluxes of the pp and the CNO
chains, with reasonable changes in the macroscopic parameters of the standard
solar model (SSM) . Various known deformation sources are discussed but none of
them is found strong enough to have a significant impact on the SSM neutrino
fluxes.


title:
Effect of Cluster Formation on Isospin Asymmetry in the Liquid-Gas Phase
  Transition Region

abstract:
  Nuclear matter within the liquid-gas phase transition region is investigated
in a mean-field two-component Fermi-gas model. Following largely analytic
considerations, it is shown that: (1) Due to density dependence of asymmetry
energy, some of the neutron excess from the high-density phase could be
expelled into the low-density region. (2) Formation of clusters in the gas
phase tends to counteract this trend, making the gas phase more liquid-like and
reducing the asymmetry in the gas phase. Flow of asymmetry between the
spectator and midrapidity region in reactions is discussed and a possible
inversion of the flow direction is indicated.


title:
Three-Body-Cluster Effects on Lambda Single-Particle Energies in
  _{Lambda}^{17}O and_{Lambda}^{41}Ca

abstract:
  A method for a microscopic description of Lambda hypernuclei is formulated in
the framework of the unitary-model-operator approach. A unitarily transformed
hamiltonian is introduced and given in a cluster expansion form. The structure
of three-body-cluster terms are discussed especially on the Lambda
single-particle energy. The Lambda single-particle energies including the
three-body-cluster contributions are calculated for the 0s_{1/2}, 0p_{3/2} and
0p_{1/2} states in_{Lambda}^{17}O, and for the 0s_{1/2}, 0p_{3/2}, 0p_{1/2},
0d_{5/2}, 0d_{3/2} and 1s_{1/2} states in_{Lambda}^{41}Ca, using the Nijmegen
soft-core (NSC), NSC97a-f, the Juelich A (J A) and J B hyperon-nucleon
interactions. It is indicated that the three-body-cluster terms bring about
sizable effects in the magnitudes of the Lambda single-particle energies, but
hardly affect the Lambda spin-orbit splittings.


title: Equilibration within a semiclassical off-shell transport approach

abstract:
  Equilibration times for nuclear matter configurations -- modelling
intermediate and high energy nucleus-nucleus collisions -- are evaluated within
the semiclassical off-shell transport approach developed recently. The
transport equations are solved for a finite box in coordinate space employing
periodic boundary conditions. The off-shell transport model is shown to give
proper off-shell equilibrium distributions in the limit $t \to \infty$ for the
nucleon and $\Delta$-resonance spectral functions. We find that equilibration
times within the off-shell approach are only slightly enhanced as compared to
the on-shell limit for the momentum configurations considered.


title:
Solution of the Skyrme-Hartree-Fock equations in the Cartesian deformed
  harmonic-oscillator basis. (III) HFODD (v1.75r): a new version of the program

abstract:
  We describe the new version (v1.75r) of the code HFODD which solves the
nuclear Skyrme-Hartree-Fock problem by using the Cartesian deformed
harmonic-oscillator basis. Three minor errors that went undetected in the
previous version have been corrected. The new version contains an interface to
the LAPACK subroutine ZHPEV. Several methods of terminating the Hartree-Fock
iteration procedure, and an algorithm that allows to follow the diabatic
configurations, have been implemented.


title: Threshold $pp\to pp\pi^0$ up to one-loop accuracy

abstract:
  The $pp\to pp\pi^0$ cross section near threshold is computed up to one-loop
order including the initial and final state interactions using the hybrid heavy
baryon chiral perturbation theory and the counting rule a la Weinberg. With the
counter terms whose coefficients are fixed by the resonance-saturation
assumption, we find that the one-loop contributions are as important as the
tree-order contribution and bring the present theoretical estimation of the
total cross section close to the experimental data. The short-ranged
contributions are controlled by means of a cutoff, and a mild cutoff dependence
is observed when all diagrams of the given chiral order are summed. To the
order treated, however, the expansion is found to converge rather slowly,
calling for further studies of the process.


title:
On the choice of colliding beams to study deformation effects in
  relativistic heavy ion collisions

abstract:
  It has been suggested that collisions between deformed shapes will lead to
interesting effects on various observables such as K production and elliptic
flow. Simple formulae can be written down which show how to choose the
colliding beams which will maximise the effects of deformation.


title:
Limits on the low energy antinucleon-nucleus annihilations from the
  Heisenberg principle

abstract:
  We show that the quantum uncertainty principle puts some limits on the
effectiveness of the antinucleon-nucleus annihilation at very low energies.
This is caused by the fact that the realization a very effective short-distance
reaction process implies information on the relative distance of the reacting
particles. Some quantitative predictions are possible on this ground, including
the approximate A-independence of antinucleon-nucleus annihilation rates.


title: Cluster states in nuclei as representations of a U(n+1) group

abstract:
  We propose a description of cluster states in nuclei in terms of
representations of unitary algebras U(n+1), where n is the number of space
degrees of freedom. Within this framework, a variety of situations including
both vibrational and rotational spectra, soft and rigid configurations,
identical and non-identical constituents can be described. As an example, we
show how the method can be used to study alpha-clustering configurations in 12C
with point group symmetry D(3h).


title: Kaon Condensation in Proto-Neutron Star Matter

abstract:
  We study the equation of state (EOS) of kaon-condensed matter including the
effects of temperature and trapped neutrinos. It is found that the order of the
phase transition to a kaon-condensed phase, and whether or not Gibbs' rules for
phase equilibrium can be satisfied in the case of a first order transition,
depend sensitively on the choice of the kaon-nucleon interaction. The main
effect of finite temperature, for any value of the lepton fraction, is to mute
the effects of a first order transition, so that the thermodynamics becomes
similar to that of a second order transition. Above a critical temperature,
found to be at least 30--60 MeV depending upon the interaction, the first order
transition disappears. The phase boundaries in baryon density versus lepton
number and baryon density versus temperature planes are delineated. We find
that the thermal effects on the maximum gravitational mass of neutron stars are
as important as the effects of trapped neutrinos, in contrast to previously
studied cases in which the matter contained only nucleons or in which hyperons
and/or quark matter were considered. Kaon-condensed EOSs permit the existence
of metastable neutron stars, because the maximum mass of an initially hot,
lepton-rich protoneutron star is greater than that of a cold, deleptonized
neutron star. The large thermal effects imply that a metastable protoneutron
star's collapse to a black hole could occur much later than in previously
studied cases that allow metastable configurations.


title: Compton scattering in a unitary approach with causality constraints

abstract:
  Pion-loop corrections for Compton scattering are calculated in a novel
approach based on the use of dispersion relations in a formalism obeying
unitarity. The basic framework is presented, including an application to
Compton scattering. In the approach the effects of the non-pole contribution
arising from pion dressing are expressed in terms of (half-off-shell) form
factors and the nucleon self-energy. These quantities are constructed through
the application of dispersion integrals to the pole contribution of loop
diagrams, the same as those included in the calculation of the amplitudes
through a K-matrix formalism. The prescription of minimal substitution is used
to restore gauge invariance. The resulting relativistic-covariant model
combines constraints from unitarity, causality, and crossing symmetry.


title:
Spin-Orbit Splitting in Non-Relativistic and Relativistic
  Self-Consistent Models

abstract:
  The splitting of single-particle energies between spin-orbit partners in
nuclei is examined in the framework of different self-consistent approachs,
non-relativistic as well as relativistic. Analytical expressions of spin-orbit
potentials are given for various cases. Proton spin-orbit splittings are
calculated along some isotopic chains (O, Ca, Sn) and they are compared with
existing data. It is found that the isotopic dependence of the relativistic
mean field predictions is similar to that of some Skyrme forces while the
relativistic Hartree-Fock approach leads to a very different dependence due to
the strong non-locality.


title: SU(3) Symmetry and Scissors Mode Vibrations in Nuclei

abstract:
  We show that a nearly perfect SU(3) symmetry emerges from an extended
Projected Shell Model. Starting from a deformed potential we construct separate
bases for neutron and proton collective rotational states by exact angular
momentum projection. These rotational states are then coupled by diagonalizing
a residual pairing plus quadrupole interaction. The states obtained exhibit a
one-to-one correspondence with an SU(3) spectrum up to high angular momentum
and excitation, and their wave functions have a near-maximal overlap with the
SU(3) states. They can also be classified as rotational bands built on
spin-1$\hbar$ phonon excitations, which may correspond to a geometrical
scissors mode and its generalizations. This work is a direct demonstration that
numerical angular momentum projection theory extends the Elliott's original
idea to heavy nuclear systems.

categories: nucl-th math-ph math.MP nucl-ex physics.atm-clus


title: From meson-nucleon scattering to vector mesons in nuclear matter

abstract:
  We employ meson-nucleon scattering data to deduce the properties of the
low-mass vector mesons in nuclear matter, and present results for the $\rho$
and $\omega$ in-medium spectral functions. The corresponding thermal emission
rate for lepton pairs is also discussed.


title:
Quantum interference in the e^+e^- decays of rho^0 and omega-mesons
  produced in pi^- p reactions

abstract:
  The study of the pi^- p -> rho^0 n and pi^- p -> omega n amplitudes close and
below the vector meson production threshold (1.2< sqrt(s) <1.8 GeV) reveals a
rich dynamics arising from the presence of specific baryon resonances in this
energy range. The interference pattern of the e^+e^- decays of the rho^0 and
omega mesons produced in pi^- p reactions reflects directly this dynamics. We
discuss this interference pattern in the pi^- p -> e^+e^- n reaction as
function of the total center of mass energy sqrt(s). We emphasize the
importance of an experimental study of this reaction, which could be made with
the HADES detector and the available pion beam at GSI.


title: Observing Quark-Gluon Plasma with Strange Hadrons

abstract:
  We review the methods and results obtained in an analysis of the experimental
heavy ion collision research program at nuclear beam energy of 160-200A GeV. We
study strange, and more generally, hadronic particle production experimental
data. We discuss present expectations concerning how these observables will
perform at other collision energies. We also present the dynamical theory of
strangeness production and apply it to show that it agrees with available
experimental results. We describe strange hadron production from the
baryon-poor quark-gluon phase formed at much higher reaction energies, where
the abundance of strange baryons and antibaryons exceeds that of nonstrange
baryons and antibaryons.


title: Level Densities by Particle-Number Reprojection Monte Carlo Methods

abstract:
  A particle-number reprojection method is applied in the framework of the
shell model Monte Carlo approach to calculate level densities for a family of
nuclei using Monte Carlo sampling for a single nucleus. In particular we can
also calculate level densities of odd-even and odd-odd nuclei despite a new
sign problem introduced by the projection on an odd number of particles. The
method is applied to level densities in the iron region using the complete
$pf+g_{9/2}$-shell. The single-particle level density parameter $a$ and the
backshift parameter $\Delta$ are extracted by fitting the microscopically
calculated level densities to the backshifted Bethe formula. We find good
agreement with experimental level densities with no adjustable parameters in
the microscopic calculations. The parameter $a$ is found to vary smoothly with
mass and does not show odd-even effects. The calculated backshift parameter
$\Delta$ displays an odd-even staggering effect versus mass and is in better
agreement with the experimental data than are the empirical values.


title: Correlation energy of the pairing Hamiltonian

abstract:
  We study the correlation energy associated with the pair fluctuations in BCS
theory. We use a schematic two-level pairing model and discuss the behavior of
the correlation energy across shell closures, including the even-odd
differences. It is shown that the random phase approximation (RPA) to the
ground state energy reproduces the exact solutions quite well both in the
normal fluid and in the superfluid phases. In marked contrast, other methods to
improve the BCS energies such as Lipkin-Nogami method, only work when the
strength of a pairing interaction is large. We thus conclude that the RPA
approach is better for a systematic theory of nuclear binding energies.


title: Rho-Nucleon Tensor Coupling and Charge-Exchange Resonances

abstract:
  The Gamow-Teller resonances are discussed in the context of a self-consistent
RPA, based on the relativistic mean field theory. We inquire on the possibility
of substituting the phenomenological Landau-Migdal force by a microscopic
nucleon-nucleon interaction generated from the rho-nucleon tensor coupling. The
effect of this coupling turns out to be very small when the short range
correlations are not taken into account, but too large when these correlations
are simulated by the simple extraction of the contact terms from the resulting
nucleon-nucleon interaction.


title: Vacuum structure in QCD and Correlation functions

abstract:
  We discuss here a model of QCD vacuum in terms of quark antiquark and gluon
condensates alongwith their fluctuations. The correlation functions of hadronic
currents in such a vacuum are evaluated to extract hadron properties. The
presence of fluctuations of the condensates are emphasized. The structure of
vacuum is then generalised to finite temperatures to study correlation
functions at finite temperatures. Finally, we discuss the vacuum structure at
finite densities with diquark condensates in a Nambu JonaLasinio type model.
The coupled mass gap and superconducting gap equations are solved
selfconsistently. For certain parameters of the model nontrivial solutions of
both the gap equations are obtained. The equation of state is also computed.


title:
Odd-even staggering of binding energies as a consequence of pairing and
  mean-field effects

abstract:
  Odd-even staggering of binding energies is studied in finite fermion systems
with pairing correlations. We discuss contributions of the pairing and
mean-field to the staggering, and we construct the binding-energy filters which
measure the magnitude of pairing correlations and the effective single-particle
spacings in a given system The analysis is based on studying several
exactly-solvable many-body Hamiltonians as well as on the analytical formulas
that can be applied in the weak and strong pairing limits.


title: Color Dynamics On Phase Space

abstract:
  We describe the properties of quark matter at zero temperature and finite
baryon densities within microscopic Vlasov/molecular dynamics approaches. We
use an inter-quark Richardson's potential consistent with the indications of
Lattice QCD calculations. The color degrees of freedom are explicitly taken
into account.
  We explicitly demonstrate that the Vlasov approach alone is insufficient in
the hadronization region. In order to overcome this problem we prepare the
initial condition for many events using molecular dynamics with frictional
cooling and a Thomas-Fermi approximation to the Fermi motion.
  These events are averaged and propagated in time using the Vlasov approach.
  We find some evidence for a second order phase transition from nuclear to
quark matter at high baryon densities. An order parameter suitable to describe
the phase transition is discussed. At low densities the quark condensate into
approximately color white clusters (nucleon).


title:
Is it possible to reconstruct the freeze-out duration of heavy-ion
  collisions using tomography?

abstract:
  We investigate what conditions allow us to extract the relative distribution
of freeze-out space and time points in an arbitrary reference frame using
tomography and source imaging. The source function may be extracted from the
two-particle correlation function measured in heavy-ion collisions using
imaging techniques. This imaged source function is related to the relative
distribution of freeze-out space and time points through a generalization of
the Radon transform found in tomography. Using tomography, the imaged source
function may be converted into the relative freeze-out distribution in the
frame of interest. We describe how the tomography may be performed in practice.


title: Tilted Pion Sources from Azimuthally Sensitive HBT Interferometry

abstract:
  Intensity interferometry in noncentral heavy ion collisions provides access
to novel information on the geometry of the effective pion-emitting source. We
demonstrate analytically that, even for vanishing pair momentum, the cross
terms $R_{ol}^2$ and $R_{sl}^2$ of the HBT correlation function in general show
a strong first harmonic in their azimuthal dependence. The strength of this
oscillation characterizes the tilt of the major axis of the spatial emission
ellipsoid away from the direction of the beam. Event generator studies indicate
that this tilt can be large (>20 degrees) at AGS energies which makes it by far
the most significant azimuthally sensitive HBT signal at these energies.
Moreover, transport models suggest that for pions this spatial tilt is directed
opposite to the tilt of the directed flow ellipsoid in momentum space. A
measurement of the azimuthal dependence of the HBT cross terms $R_{ol}^2$ and
$R_{sl}^2$ thus probes directly the physical origin of directed pion flow.


title:
The Use of Nuclear Beta-decay as a Test of Bulk Neutrinos in Extra
  Dimensions

abstract:
  Theories which include neutrinos in large extra dimensions can be constrained
by nuclear beta decay experiments. We examine universality of beta decay
strengths of Fermi transitions. From this we find that the extra dimensional
Yukawa coupling for a higher dimensional scale of 10 TeV, and two extra
dimensions can be constrained to y < 1. Kinematic implications are also
discussed. In particular, an extra dimensional scenario will produce a tritium
decay endpoint spectrum with a different shape than that for just one massive
state.


title: Kaon-baryon coupling constants in the QCD sum rule approach

abstract:
  We improve our previous QCD sum rule calculation on G(KN\Lambda) and
G(KN\Sigma) coupling constants by including the contributions from higher
dimensional condensates, <\bar{q} g_s \sigma \cdot G q> and <\bar{q}q>
<(\alpha_s /\pi) G^2>, in the OPE. It is found that the contribution of these
condensates is non-negligible compared to that of the quark condensates. Using
a best-fit analysis we find |G(KN\Lambda)| = 2.49 $\pm$ 1.25 and |G(KN\Sigma)|
= 0.395 $\pm$ 0.377.


title:
Nuclear Multifragmentation in the Non-extensive Statistics - Canonical
  Formulation

abstract:
  We apply the canonical quantum statistical model of nuclear
multifragmentation generalized in the framework of recently proposed Tsallis
non-extensive thermostatistics for the description of nuclear
multifragmentation process. The test calculation in the system with A=197
nucleons show strong modification of the 'critical' behaviour associated with
the nuclear liquid-gas phase transition for small deviations from the
conventional Boltzmann-Gibbs statistical mechanics.


title: Borromean Binding of Three or Four Bosons

abstract:
  We estimate the ratio $R=g_{3}/g_{2}$ of the critical coupling constants
$g_{2}$ and $g_{3}$ which are required to achieve binding of 2 or 3 bosons,
respectively, with a short-range interaction, and examine how this ratio
depends on the shape of the potential. Simple monotonous potentials give
$R\simeq 0.8$. A wide repulsive core pushes this ratio close to R=1. On the
other hand, for an attractive well protected by an external repulsive barrier,
the ratio approaches the rigorous lower bound $R=2/3$. We also present results
for N=4 bosons, sketch the extension to $N>4$, and discuss various
consequences.


title:
Generating new solutions for relativistic transverse flow at the softest
  point

abstract:
  Using the method of prolongation we generate new solutions from a simple
particular solution for relativistic transverse flow with cylindrical symmetry
in 1+3 dimensions. This is an extension of the longitudinal Bjorken flow ansatz
and can be applied among others during first order phase transition in an
expanding system. The prolongated solution allows for tracing back the flow
profile from a transverse flow conjectured at the end of phase transition at
CERN SPS heavy ion collisons.


title: LOCV calculation for Beta-stable matter at finite temperature

abstract:
  The method of lowest-order constrained variational, which predicts reasonably
the nuclear matter semi-empirical data is used to calculate the equation of
state of beta-stable matter at finite temperature. The Reid soft-core with and
without the N-$\Delta$ interactions which fits the N-N scattering data as well
as the $UV_{14}$ potential plus the three-nucleon interaction are considered in
the nuclear many-body Hamiltonian. The electron and muon are treated
relativistically in the total Hamiltonian at given temperature, to make the
fluid electrically neutral and stable against beta decay. The calculation is
performed for a wide range of baryon density and temperature which are of
interest in the astrophysics. The free energy, entropy, proton abundance, etc.
of nuclear beta-stable matter are calculated.
  It is shown that by increasing the temperature, the maximum proton abundance
is pushed to the lower density while the maximum itself increases as we
increase the temperature. The proton fraction is not enough to see any
gas-liquid phase transition. Finally we get an overall agreement with other
many-body techniques, which are available only at zero temperature.


title: Relativistic Approach to Isoscalar Giant Resonances in 208Pb

abstract:
  We calculate the longitudinal response of 208Pb using a relativistic
random-phase approximation to three different parameterizations of the Walecka
model with scalar self-interactions. From a nonspectral calculation of the
response-that automatically includes the mixing between positive- and
negative-energy states-we extract the distribution of strength for the
isoscalar monopole, dipole, and high-energy octupole resonances. We employ a
consistent formalism that uses the same interaction in the calculation of the
ground state as in the calculation of the response. As a result, the
conservation of the vector current is strictly maintained throughout the
calculation. Further, at small momentum transfers the spurious dipole
strength-associated with the uniform translation of the center-of-mass-gets
shifted to zero excitation energy and is cleanly separated from the sole
remaining physical fragment located at an excitation energy of about 24 MeV; no
additional dipole strength is observed. The best description of the collective
modes is obtained using a ``soft'' parameterization having a compression
modulus of K=224 MeV.


title: How unique is the Asymptotic Normalisation Coefficient (ANC) method?

abstract:
  The asymptotic normalisation coefficients (ANC) for the vertex $^{10}$B $\to$
$^9$Be + p is deduced from a set of different proton transfer reactions at
different energies. This set should ensure the peripheral character of the
reaction and availability of data for the elastic channels. The problems
associated with the characteristics of the data and the analysis are discussed.
For a subgroup of the set of available data, the uniqueness property of the
extracted ANC is fulfilled. However, more measurements are needed before a
definite conclusion can be drawn.


title:
Hot nuclear matter in the modified quark-meson coupling model with
  quark-quark correlations

abstract:
  Short-range quark-quark correlations in hot nuclear matter are examined
within the modified quark-meson coupling model (MQMC) by adding repulsive
scalar and vector quark-quark interactions. Without these correlations, the bag
radius increases with the baryon density. However when the correlations are
introduced the bag size shrinks as the bags overlap. Also as the strength of
the scalar quark-quark correlation is increased, the decrease of the effective
nucleon mass $M^{*}_N$ with the baryonic density is slowed down and tends to
saturate at high densities. Within this model we study the phase transition
from the baryon-meson phase to the quark-gluon plasma (QGP) phase with the
latter modeled as an ideal gas of quarks and gluons inside a bag. Two models
for the QGP bag parameter are considered. In one case, the bag is taken to be
medium-independent and the phase transition from the hadron phase to QGP is
found to occur at 5-8 times ordinary nuclear matter density for temperatures
less than 60 MeV. For lower densities, the transition takes place at higher
temperature reaching up to 130 MeV at zero density. In the second case, the QGP
bag parameter is considered medium-dependent as in the MQMC model for the
hadronic phase. In this case, it is found that the phase transition occurs at
much lower densities.


title: Fluctuation of Voids in Hadronization at Phase Transition

abstract:
  Starting from the recognition that hadrons are not produced smoothly at phase
transition, the fluctuation of spatial patterns is investigated by finding a
measure of the voids that exhibits scaling behavior. The Ising model is used to
simulate a cross-over in quark-hadron phase transition. A threshold in hadron
density is used to define a void. The dependence of the scaling exponents on
that threshold is found to provide useful information on some properties of the
hadronization process. The complication in heavy-ion collision introduces the
possibility of configuration mixing, which can also be studied in this
approach. Numerical criteria on the scaling exponents have been found that can
be used to discriminate phase-transition processes from other hadronization
processes having nothing to do with critical phenomena.


title:
Dynamical Screening and Radiative Parton Energy Loss in a Quark-gluon
  Plasma

abstract:
  Dynamical screening in the magnetic part of the one-gluon exchange
interaction is included in the study of radiative energy loss of a fast parton
propagating inside a quark-gluon plasma. As a result the final radiative energy
loss is about twice as large as when only the electric part of one-gluon
exchange interaction is considered. A non-perturbative magnetic screening mass
is also used in the estimate of the mean-free-path of parton scattering in a
hot QCD matter.


title: Double giant dipole resonances in time-dependent density-matrix theory

abstract:
  The strength functions of the DGDRs in 16O and 40Ca are calculated using an
extended version of TDHF known as the time-dependent density-matrix theory
(TDDM). The calculations are done in a self-consistent manner, in which the
same Skyrme force as that used for the mean-field potential is used as the
residual interaction to calculate two-body correlations. It is found that the
DGDR in 16O has a large width due to the Landau damping, although the centroid
energy of the DGDR is close to twice the energy of the GDR calculated in RPA.
The DGDR in 40Ca is found more harmonic than that in 16O.


title:
Inelastic photon scattering and the magnetic moment of the $\Delta$
  (1232) resonance

abstract:
  The reaction $\gamma+p\to\gamma'+p+\pi^0$ has been suggested as a means to
deduce the $\Delta^+$ magnetic moment. The cross section for this process is
estimated in both the constituent quark model and an effective Lagrangian
procedure. The resulting total cross section is of the order 5-10 nb, which is
at the limit of present experimental capabilities.


title:
Statistical analysis of light fragment production from medium energy
  proton-induced reactions

abstract:
  The light fragment production reactions for 10 MeV to 3 GeV protons incident
on O-16, Al-27, Fe, Nb-93, and Ag are analyzed by a combination of an
intranuclear cascade model and a generalized evaporation model which includes
light nuclei up to Mg as ejectiles. It is concluded that evaporation is the
dominant process by which particles lighter than or equal to Be are produced
from targets heavier than O.


title:
Theory of doorway states for one-nucleon transfer reactions. II.
  Model-independent study of nuclear correlation effects

abstract:
  The correlation effects in nuclei owing to which the nuclear wave functions
are different from the Slater determinants are studied on the basis of the
original theory. The calculated numbers of nucleons out of the nuclear
Fermi-surface are in reasonable agreement with the finding from the
high-momentum components of the nucleon momentum distributions in nuclei. The
problems concerning the nuclear binding energy are also discussed.


title:
Photon-Photon and Pomeron-Pomeron Processes in Peripheral Heavy Ion
  Collisions

abstract:
  We estimate the cross sections for the production of resonances, pion pairs
and a central cluster of hadrons in peripheral heavy-ion collisions through
two-photon and double-pomeron exchange, at energies that will be available at
RHIC and LHC. The effect of the impact parameter in the diffractive reactions
is introduced, and imposing the condition for realistic peripheral collisions
we verify that in the case of very heavy ions the pomeron-pomeron contribution
is indeed smaller than the electromagnetic one. However, they give a
non-negligible background in the collision of light ions. This diffractive
background will be more important at RHIC than at LHC.


title: Dispersive effects in neutron matter superfluidity

abstract:
  The explicit energy dependence of the single particle self-energy (dispersive
effects), due to short range correlations, is included in the treatment of
neutron matter superfluidity. The method can be applied in general to strong
interacting fermion systems, and it is expected to be valid whenever the
pairing gap is substantially smaller than the Fermi kinetic energy. The results
for neutron matter show that dispersive effects are strong in the density
region near the gap closure.


title:
Projectile structure effects in the Coulomb breakup of one-neutron halo
  nuclei

abstract:
  We investigate the Coulomb breakup of neutron rich nuclei 11Be and
(19,17,15)C within a theory developed in the framework of Distorted Wave Born
Approximation. Finite range effects are included by a local momentum
approximation, which allows incorporation of realistic wave functions for these
nuclei in our calculations. Energy and angular as well as parallel momentum
distributions of the fragments emitted in the breakup of these nuclei on heavy
targets have been calculated using several structure models for their ground
state. Comparison with the available experimental data shows that the results
are selective about the ground state wave function of the projectile. Our
investigations confirm that the nuclei 11Be, 19C and 15C have a one-neutron
halo structure in their ground states. However, for 17C such a structure
appears to be less likely. Calculations performed within our method have also
been compared with those from an adiabatic model and the results are discussed.


title: Isoscalar dipole mode in relativistic random phase approximation

abstract:
  The isoscalar giant dipole resonance structure in $^{208}$Pb is calculated in
the framework of a fully consistent relativistic random phase approximation,
based on effective mean-field Lagrangians with nonlinear meson self-interaction
terms. The results are compared with recent experimental data and with
calculations performed in the Hartree-Fock plus RPA framework. Two basic
isoscalar dipole modes are identified from the analysis of the velocity
distributions. The discrepancy between the calculated strength distributions
and current experimental data is discussed, as well as the implications for the
determination of the nuclear matter incompressibility.


title: On dipole compression modes in nuclei

abstract:
  Isoscalar dipole strength distributions in spherical medium- and heavy-mass
nuclei are calculated within random phase approximation (RPA) or quasiparticle
RPA. Different Skyrme-type interactions corresponding to incompressibilities in
the range 200 - 250 MeV are used. The results are discussed in comparison with
existing data on isoscalar giant dipole resonances. Two main issues are raised,
firstly the calculated giant resonance energies are somewhat higher than the
observed ones, and secondly a sizable fraction of strength is predicted below
20 MeV which needs to be experimentally confirmed.


title: Fragment Formation and Phase Transitions in Heavy Ion Collisions

abstract:
  We investigate the thermodynamical properties of nuclear matter in heavy ion
collisions, in particular with respect to questions of thermodynamical
instability, phase transitions and fragmentation. For this we analyze results
of relativistic transport calculations of Au+Au collisons at intermediate
energies, separately for spectator and participant matter. On one hand, we
determine local thermodynamical variables from the analysis of the local
momentum distribution; on the other, we analyze fragment energy spectra in a
blast model scenario. We find that the spectator represents an instable,
equilibrized fragmenting source, while in the participant no such common source
can be identified. Our results compare well with experimental determinations of
temperatures and flow velocities.


title:
Momentum conservation and local field corrections for the response of
  interacting Fermi gases

abstract:
  We reanalyze the recently derived response function for interacting systems
in relaxation time approximation respecting density, momentum and energy
conservation. We find that momentum conservation leads exactly to the local
field corrections for both cases respecting only density conservation and
respecting density and energy conservation. This rewriting simplifies the
former formulae dramatically. We discuss the small wave vector expansion and
find that the response function shows a high frequency dependence of
$\omega^{-5}$ which allows to fulfill higher order sum rules. The momentum
conservation also resolves a puzzle about the conductivity which should only be
finite in multicomponent systems.

categories: nucl-th cond-mat.str-el physics.plasm-ph quant-ph


title: Surface Tension between Kaon Condensate and Normal Nuclear Matter Phase

abstract:
  We calculate for the first time the surface tension and curvature coefficient
of a first order phase transition between two possible phases of cold nuclear
matter, a normal nuclear matter phase in equilibrium with a kaon condensed
phase, at densities a few times the saturation density. We find the surface
tension is proportional to the difference in energy density between the two
phases squared. Furthermore, we show the consequences for the geometrical
structures of the mixed phase region in a neutron star.


title: Event-by-event physics in relativistic heavy ion collisions

abstract:
  Motivated by forthcoming experiments at RHIC and LHC, and results from SPS, a
review is given of the present state of event-by-event fluctuations in
ultrarelativistic heavy-ion collisions. Fluctuations in particle
multiplicities, ratios, transverse momenta, rapidity, etc. are calculated in
participant nucleon as well as thermal models. The physical observables,
including multiplicity, kaon to pion ratios, and transverse momenta agree well
with recent NA49 data at the SPS, and indicate that such studies do not yet
reveal the presence of new physics. Predictions for RHIC and LHC energies are
given. The centrality dependence with and without a phase transition to a
quark-gluon plasma is discussed - in particular, how the physical quantities
are expected to display a qualitative different behavior in case of a phase
transition, and can be signaled by anomalous fluctuations and correlations in a
number of observables.


title:
A meson-exchange model of the associated photoproduction of vector
  mesons and N*(1440) resonances

abstract:
  We discuss the photoproduction of omega- and rho0-mesons off protons in the
particular channel where the target proton is excited to a Roper resonance
N*(1440). We propose a simple meson-exchange model for these processes in order
to evaluate their cross sections near threshold and at low momentum transfers.
It is suggested in particular that the differential cross section for the
associated photoproduction of a rho0-meson and a Roper resonance in these
kinematic conditions could provide direct information on the strength of the
scalar-isoscalar excitation of the N*(1440) and hence on the magnitude of an
effective sigma N N*(1440) coupling. The latter quantity is poorly known and of
much interest for the nuclear many-body problem.


title: Reduction of superfluid gap by scattering

abstract:
  The effect nucleon dressing by scattering on the pairing gap in nuclear
matter is discussed. Numerical results from self-consistent T-matrix
calculations are compared to quasi-particle approximations. The dominant effect
of scattering can be accounted for by a renormalization of the quasi-particle
strength. The exponential sensitivity of the pairing gap and the critical
temperature on the pairing strength makes it strongly dependent on many-body
effects.


title: Invariant Manifolds and Collective Coordinates

abstract:
  We introduce suitable coordinate systems for interacting many-body systems
with invariant manifolds. These are Cartesian in coordinate and momentum space
and chosen such that several components are identically zero for motion on the
invariant manifold. In this sense these coordinates are collective. We make a
connection to Zickendraht's collective coordinates and present certain
configurations of few-body systems where rotations and vibrations decouple from
single-particle motion. These configurations do not depend on details of the
interaction.


title: Pion-nucleon interaction in a covariant hadron-exchange model

abstract:
  We develop a relativistic covariant and unitary description of the
pion-nucleon interaction in a hadron-exchange model. The model is based on the
solution of a dimensionally reduced (quasipotential) Bethe-Salpeter equation
for the partial-wave off-shell $\pi N$ scattering amplitudes with the potential
consisting of the field-theoretical $s$- and $u$-channel nucleon, Roper, Delta,
$D_{13}$, $S_{11}$ exchanges, and the $t$-channel $\rho$ and $\sigma$ meson
exchanges. The contributions of the spin-3/2 Delta and $D_{13}$ resonances are
treated within the Rarita-Schwinger formalism and different forms of the $\pi
N\Delta$ vertex are investigated. The free parameters of the model are fitted
to the $\pi N$ phase-shift data of the KH80 and SM95 partial-wave analyses in
the region up to 600 MeV pion kinetic energy. The resulting on-shell solution
provides a good description of the $\pi N$ scattering lengths, as well as the
energy behavior of the S, P, and D partial waves. The sensitivity of the phase
shifts on various model-dependent effects is examined.


title: Antisymmetry in Strangeness -1 and -2 Three-Baryon Systems

abstract:
  Using the generalized Pauli principle by adding particle labels to the usual
space and spin labels a symmetric Hamiltonian and a corresponding antisymmetric
wavefunction is constructed for systems of three baryons in the strangeness
sectors $S=-1$ and -2. Applications are the $\Xi NN-\Lambda\Lambda N$ and
$NN\Lambda -NN\Sigma$ systems.
  Minimal sets of generalized coupled Faddeev equations for breakup and
rearrangement operators as well as (possible) bound states are derived which
have the ordinary Pauli principle among identical particles built in. The
equations found confirm our previous sets of coupled Faddeev equations for
those systems whose derivation was carried through for distinguishable
particles and not using the generalized Pauli principle.


title:
Ground-$\gamma$ band coupling in heavy deformed nuclei and SU(3)
  contraction limit

abstract:
  We derive analytic expressions for the energies and $B(E2)$-transition
probabilities in the states of the ground and $\gamma$ bands of heavy deformed
nuclei within a collective Vector-Boson Model with SU(3) dynamical symmetry. On
this basis we examine the analytic behavior of the SU(3) energy splitting and
the B(E2) interband transition ratios in the SU(3) contraction limits of the
model. The theoretical analyses outline physically reasonable ways in which the
ground-$\gamma$ band coupling vanishes. The experimental data on the lowest
collective states of even-even rare earth nuclei and actinides strongly support
the theoretical results. They suggest that a transition from the
ground-$\gamma$ band coupling scheme to a scheme in which the ground band is
situated in a separate irreducible representation of SU(3) should be realized
towards the midshell regions. We propose that generally the SU(3) group
contraction process should play an important role for such a kind of
transitions in any collective band coupling scheme in heavy deformed nuclei.


title:
Does localization occur in a hierarchical random-matrix model for
  many-body states?

abstract:
  We use random-matrix theory and supersymmetry techniques to work out the
two-point correlation function between states in a hierarchical model which
employs Feshbach's chaining hypothesis: Classes of many-body states are
introduced. Only states within the same or neighboring classes are coupled. We
assume that the density of states per class grows monotonically with class
index. The problem is mapped onto a one-dimensional non-linear sigma model. In
the limit of a large number of states in each class we derive the critical
exponent for the growth of the level density with class index for which
delocalization sets in. From a realistic modelling of the class-dependence of
the level density, we conclude that the model does not predict Fock-space
localization in nuclei.


title: Total cross section for p-d breakup below 30 MeV

abstract:
  The total cross section for p-d breakup is studied in terms of the elastic
S-matrix through the unitary condition. Calculations using the complex Kohn
variational method along with the Pair Correlated Hyperspherical Harmonic basis
are presented. The results have been restricted to energies below Ep=30 MeV
where Coulomb effects are expected to be sizable and are compared to the
existing data. Two different measurements have been found in the literature: 40
years ago, Gibbons and Macklin (1959); and 26 years ago, Carlosn et al. (1973).
The calculations are found to be in reasonable agreement with these old data,
though a discrepancy is observed near the deuteron breakup threshold. Moreover,
a detailed analysis of the contributions to the observable from different
partial waves has been presented. Unexpectedly, the main contribution for a
wide range of energies has been detected in the J=3/2- state.


title: Quark Condensate in the Deuteron

abstract:
  We study the changes produced by the deuteron on the QCD quark condensate by
means the Feynman-Hellmann theorem and find that the pion mass dependence of
the pion-nucleon coupling could play an important role. We also discuss the
relation between the many body effect of the condensate and the meson exchange
currents, as seen by photons and pions. For pion probes, the many-body term in
the physical amplitude differs significantly from that of soft pions, the one
linked to the condensate. Thus no information about the many-body term of the
condensate can be extracted from the pion-deuteron scattering length. On the
other hand, in the Compton amplitude, the relationship with the condensate is a
more direct one.


title: Soliton excitations as emitted clusters on nuclear surfaces

abstract:
  This work reports on calculations of the deformation energy of a nucleus plus
an emitted cluster as a soliton moving on its surface. The potential barrier
against the emission of a soliton is calculated within the
macroscopic-microscopic method. The outer turning point of the barrier
determines limitations on the geometrical and kinematical parameters for the
formation of a surface soliton. For large asymmetry, the two-center shell model
is used to assign a structure to the soliton. Calculations for
$^{248}$N\lowercase{o} with the emission of a $^{40}$C\lowercase{a} soliton are
reported; likewise for $^{224}$T\lowercase{h} with the emission of $^{16}$O.
Except for necked shapes at the very first stages of soliton formation, the
greatest portion of the deformation path displays rather compact configurations
with large neck radii. These shape sequences correspond to allowable soliton
velocities. Close to and just beyond the touching point configuration, where
the shape becomes concave, the width and the velocity of the soliton approach
zero. The calculations suggest that the emission of a $^{40}$C\lowercase{a}
structure is quite probable due to a low potential barrier, whereas the
emission of an $^{16}$O type soliton is rather unlikely due to the higher
penetration barrier.


title: Capture of alpha Particles by Isospin-Symmetric Nuclei

abstract:
  The reaction rates for alpha capture processes on self-conjugate nuclei in
the mass range A=20-40 have been investigated. The rates were calculated using
the statistical model code NON-SMOKER taking into account isospin suppression
rules. These theoretical predictions are compared with rates derived from the
available experimental data about the alpha capture reactions taking also into
account additional experimental information from different reaction channels
populating the alpha unbound states of the self-conjugate compound nuclei.


title:
Preserving the gauge invariance of meson production currents in the
  presence of explicit final-state interactions

abstract:
  A comprehensive formalism is developed to preserve the gauge invariance of
currents describing the photo- or electroproduction of mesons off the nucleon
when the final-state interactions of mesons and nucleons is taken into account
explicitly. Replacing exchange currents by auxiliary currents, it is found that
all contributions due to explicit final-state interactions are purely
transverse and do not contain a Kroll-Ruderman-type contact current. The
relation of the present formulation to tree-level-type prescriptions is shown.


title:
Important role of the spin-orbit interaction in forming the 1/2^+
  orbital structure in Be isotopes

abstract:
  The structure of the second 0^+ state of ^{10}Be is investigated using a
microscopic $\alpha+\alpha+n+n$ model based on the molecular-orbit (MO) model.
The second 0^+ state, which has dominantly the (1/2^+)^2 configuration, is
shown to have a particularly enlarged $\alpha-\alpha$ structure. The kinetic
energy of the two valence neutrons occupying along the $\alpha-\alpha$ axis is
reduced remarkably due to the strong $\alpha$ clustering and, simultaneously,
the spin-orbit interaction unexpectedly plays important role to make the energy
of this state much lower. The mixing of states with different spin structure is
shown to be important in negative-parity states. The experimentally observed
small-level spacing between 1^- and 2^- (~ 300 keV) is found to be an evidence
of this spin-mixing effect. ^{12}{Be} is also investigated using
$\alpha+\alpha+4n$ model, in which four valence neutrons are considered to
occupy the (3/2^-)^2(1/2^+)^2 configuration. The energy surface of ^{12}Be is
shown to exhibit similar characteristics, that the remarkable $\alpha$
clustering and the contribution of the spin-orbit interaction make the binding
of the state with (3/2^-)^2(1/2^+)^2 configuration properly stronger in
comparison with the closed p-shell (3/2^-)^2(1/2^-)^2 configuration.


title:
The role of $\nu$-induced reactions on lead and iron in neutrino
  detectors

abstract:
  We have calculated cross sections and branching ratios for neutrino induced
reactions on ^{208}Pb and ^{56}Fe for various supernova and
accelerator-relevant neutrino spectra. This was motivated by the facts that
lead and iron will be used on one hand as target materials in future neutrino
detectors, on the other hand have been and are still used as shielding
materials in accelerator-based experiments. In particular we study the
inclusive ^{56}$Fe(\nu_e,e^-)$^{56}Co and ^{208}$Pb(\nu_e,e^-)$^{208}Bi cross
sections and calculate the neutron energy spectra following the decay of the
daughter nuclei. These reactions give a potential background signal in the
KARMEN and LSND experiment and are discussed as a detection scheme for
supernova neutrinos in the proposed OMNIS and LAND detectors. We also study the
neutron-emission following the neutrino-induced neutral-current excitation of
^{56}Fe and ^{208}Pb.


title: The structure of the nucleon

abstract:
  These lectures give an introduction to the structure of the nucleon as seen
with the electromagnetic probe. Particular emphasis is put on the form factors,
the strangeness content, Compton scattering and polarizabilities, pion photo-
and electroproduction, the spin structure and sum rules. The existing data are
compared to predictions obtained from chiral perturbation theory, dispersion
theory and effective Lagrangians.


title: The pion charge radius from charged pion electroproduction

abstract:
  We analyze a low-energy theorem of threshold pion electroproduction which
allows one to determine the charge radius of the pion. We show that at the same
order where the radius appears, pion loops induce a correction to the momentum
dependence of the longitudinal dipole amplitude $L_{0+}^{(-)}$. This
model-independent correction amounts to an increase of the pion charge radius
squared from the electroproduction data by about 0.26~fm$^2$. It sheds light on
the apparent discrepancy between the recent determination of the pion radius
from electroproduction data and the one based on pion-electron scattering.


title:
Debye screening and Meissner effect in a three-flavor color
  superconductor

abstract:
  I compute the gluon self-energy in a color superconductor with three flavors
of massless quarks, where condensation of Cooper pairs breaks the color and
flavor SU(3)_c x U(3)_V x U(3)_A symmetry of QCD to the diagonal subgroup
SU(3)_{c+V}. At zero temperature, all eight electric gluons obtain a Debye
screening mass, and all eight magnetic gluons a Meissner mass. The Debye as
well as the Meissner masses are found to be equal for the different gluon
colors. These masses determine the coefficients of the kinetic terms in the
effective theory for the low-energy degrees of freedom. Their values agree with
those obtained by Son and Stephanov.


title:
A two-pion exchange three-nucleon force based on a realistic pi-N
  interaction

abstract:
  The contribution of a $\pi \pi$-exchange three-body force to the
three-nucleon binding energy is calculated in terms of a $\pi N$ amplitude. The
latter is based on a meson-theoretical model of $\pi N$ interaction developed
by the J\"ulich group. Similar to a previous study based on simple
phenomenological $\pi N$ potentials a very small effect of the resulting
three-body force is found. Possible origins of the two-orders-of-magnitude
descrepancy between the present result and the values obtained for the
Tucson-Melbourne three-body force are investigated. Evidence is provided that
this discrepancy is most likely due to strikingly different off-shell
properties of the $\pi N$ amplitudes underlying the two approaches.


title: Realistic Calculation of the hep Astrophysical Factor

abstract:
  The astrophysical factor for the proton weak capture on 3He is calculated
with correlated-hyperspherical-harmonics bound and continuum wave functions
corresponding to a realistic Hamiltonian consisting of the Argonne v18
two-nucleon and Urbana-IX three-nucleon interactions. The nuclear weak charge
and current operators have vector and axial-vector components, that include
one- and many-body terms. All possible multipole transitions connecting any of
the p-3He S- and P-wave channels to the 4He bound state are considered. The
S-factor at a p-3He center-of-mass energy of 10 keV, close to the Gamow-peak
energy, is predicted to be 10.1 10^{-20} keV b, a factor of five larger than
the standard-solar-model value. The P-wave transitions are found to be
important, contributing about 40 % of the calculated S-factor.


title: Quark-Hadron Phase Transitions in Young and Old Neutron Stars

abstract:
  The mixed phase of quarks and hadrons which might exist in the dense matter
encountered in the varying conditions of temperature and trapped neutrino
fraction in proto-neutron stars is studied. The extent that the mixed phase
depends upon the thermodynamical parameters as well as on the stiffness of
matter in the hadronic and quark phases is discussed. We show that hadronic
equations of state that maximize the quark content of matter at a given {\it
density} generally minimize the extent of the mixed phase region in a neutron
star of a given mass, and that only in extreme cases could a pure quark star
result. For both the Nambu Jona-Lasinio and MIT bag quark models, neutrino
trapping inhibits the appearance of a mixed phase which leads to possible
proto-neutron star metastability. The main difference between the two quark
models is the small abundance of strange quarks in the former. We also
demonstrate that $\partial T/\partial n<0$ along adiabats in the quark-hadron
mixed phase, opposite to what is found for the kaon condensates-hadron mixed
phase. This could lead to core temperatures which are significantly lower in
stars containing quarks than in those not containing quarks.


title:
Baryon distribution for high energy heavy ion collisions in a parton
  cascade model

abstract:
  The baryon distribution is studied by using a parton cascade model which is
based on pQCD incorporating hard partonic scattering and dynamical
hadronization scheme. In order to study baryon distribution,baryonic cluster
formation is newly implemented as well as hadronic higher resonance states from
parton/beam cluster decay. The net baryon number and charged hadron
distributions are calculated with different $K$-factors in which parameters are
fixed by elementary $p\bar p$ data at $E_{c.m.}=200$ GeV. It is found that
baryon stopping behavior at SPS and RHIC energies are not consequence of hard
parton scattering but soft processes.


title: Transport with three-particle interaction

abstract:
  Starting from a point - like two - and three - particle interaction the
kinetic equation is derived. While the drift term of the kinetic equation turns
out to be determined by the known Skyrme mean field the collision integral
appears in two - and three - particle parts. The cross section results from the
same microscopic footing and is naturally density dependent due to the three -
particle force. By this way no hybrid model for drift and cross section is
needed for nuclear transport. Besides the mean field correlation energy the
resulting equation of state has also a two - and three - particle correlation
energy which are both calculated analytically for the ground state. These
energies contribute to the equation of state and lead to an occurrence of a
maximum at 3 times nuclear density in the total energy.

categories: nucl-th cond-mat.stat-mech cond-mat.str-el physics.plasm-ph


title: Fine structure of alpha decay in odd nuclei

abstract:
  Using an alpha decay level scheme, an explanation for the fine structure in
odd nuclei is evidenced by taking into account the radial and rotational
couplings between the unpaired nucleon and the core of the decaying system. It
is stated that the experimental behavior of the alpha decay fine structure
phenomenon is directed by the dynamical characteristics of the system.


title: Neutron matter with a model interaction

abstract:
  An infinite system of neutrons interacting by a model pair potential is
considered. We investigate a case when this potential is sufficiently strong
attractive, so that its scattering length tends to infinity. It appeared, that
if the structure of the potential is simple enough, including no finite
parameters, reliable evidences can be presented that such a system is
completely unstable at any finite density. The incompressibility as a function
of the density is negative, reaching zero value when the density tends to zero.
If the potential contains a sufficiently strong repulsive core then the system
possesses an equilibrium density. The main features of a theory describing such
systems are considered.


title: The alpha-particle in nuclear matter

abstract:
  Among the light nuclear clusters the alpha-particle is by far the strongest
bound system and therefore expected to play a significant role in the dynamics
of nuclei and the phases of nuclear matter. To systematically study the
properties of the alpha-particle we have derived an effective four-body
equation of the Alt-Grassberger-Sandhas (AGS) type that includes the dominant
medium effects, i.e. self energy corrections and Pauli-blocking in a consistent
way. The equation is solved utilizing the energy dependent pole expansion for
the sub system amplitudes. We find that the Mott transition of an
alpha-particle at rest differs from that expected from perturbation theory and
occurs at approximately 1/10 of nuclear matter densities.


title:
Relativistic predictions of quasielastic proton-nucleus spin observables
  based on a complete Lorentz invariant representation of the NN scattering
  matrix

abstract:
  Within the framework of the relativistic plane wave impulse approximation
(RPWIA), complete sets of quasielastic $(\vec{p}, \vec{p}^{'})$ and $(\vec{p},
\vec{n})$ spin observables are calculated employing a general Lorentz invariant
representation of the NN scattering matrix (referred to as the IA2
representation). The use of a complete representation eliminates the
arbitrariness of a previously-used five-term parameterization (commonly called
the IA1 representation) and allows for the correct incorporation of
effective-mass-type medium effects within the RPWIA framework and within the
context of the Walecka model. For quasielastic scattering from a $^{40}$Ca
target at incident proton energies between 200 and 500 MeV, we investigate the
sensitivity of complete sets of spin observables to effective nucleon masses
for both IA1 and IA2 representations. In general it is seen that the IA1
representation may overestimate the importance of nuclear medium effects,
whereas the IA2-based predictions nearly correspond to values for free
nucleon-nucleon scattering.


title: Behavior of the diffractive cross section in hadron-nucleus collisions

abstract:
  A phenomenological analysis of diffractive dissociation of nuclei in
proton-nucleus and meson-nucleus collisions is presented. The theoretical
approach employed here is able to take into account at once data of the HELIOS
and EHS/NA22 collaborations that exhibit quite different atomic mass
dependences. Possible extensions of this approach to hard diffraction in
nuclear processes are also discussed.


title: Dynamical model for Pion - Nucleon Bremsstrahlung

abstract:
  A dynamical model based on effective Lagrangians is proposed to describe the
bremsstrahlung reaction $ \pi N \to \pi N \gamma$ at low energies. The
$\Delta(1232)$ degrees of freedom are incorporated in a way consistent with
both, electromagnetic gauge invariance and invariance under contact
transformations. The model also includes the initial and final state
rescattering of hadrons via a T-matrix with off-shell effects. The $\pi N
\gamma$ differential cross sections are calculated using three different
T-matrix models and the results are compared with the soft photon
approximation, and with experimental data. The aim of this analysis is to test
the off-shell behavior of the different T-matrices under consideration.


title: Limitations of the number selfconsistent Random Phase Approximation

abstract:
  The Quasiparticle Random Phase Approximation equations are solved taking into
account the Pauli Principle at the expectation value level, and allowing
changes in the mean field occupation numbers to minimize the energy while
having the correct number of particles in the correlated vacuum. The study of
Fermi pn excitations in $^{76}$Ge using a realistic Hilbert space shows that
the pairing energy gaps in the modified mean field are diminished up to one
half of the experimental value when strong proton-neutron correlations are
present. Additionally, the Ikeda sum rule for Fermi transitions is violated due
to the lack of scattering terms in the phonon operators. These results call for
a critical revision of the double beta decay half-lives estimated using the
QRPA extensions when standard QRPA calculations collapse.


title:
Generalized Gerasimov-Drell-Hearn Sum Rule for the Proton-Neutron
  Difference in Chiral Perturbation Theory

abstract:
  Applications of the chiral expansion to generalize the Gerasimov-Drell-Hearn
sum rule for finite $Q^2$ are discussed. The observation of several authors
that the corrections to the leading order contributions are large and limit the
applicability to a very small range in $Q^2$, are valid when considering the
sum rule for protons and neutrons, separately. When using the proton-neutron
difference, the chiral expansion may be valid to considerably higher momentum
transfers where hadronic degrees of freedom at large distances may connect up
with quark and gluon degrees of freedom. This could mark the first time that
nucleon structure is decribed by fundamental theory from large to small
distances.


title: Collective states in nuclei and many-body random interactions

abstract:
  Low-lying collective states in nuclei are investigated in the framework of
the interacting boson model using an ensemble of random many-body interactions.
It is shown that whenever the number of bosons is sufficiently large compared
to the rank of the interactions, the spectral properties are characterized by a
dominance of L(P)=0(+) ground states and the occurrence of both vibrational and
rotational band structures. This indicates that these features represent a
general and robust property of the collective model space.


title: Tables of internal conversion coefficients for superheavy elements

abstract:
  The internal conversion coefficients for the elements 104 <= Z <= 126 are
presented.


title:
Studying the $\omega$ properties in pA collisions via the
  $\omega{\to}\pi^0\gamma$ decay

abstract:
  Within transport calculations we study the production and decay of
$\omega$-mesons in $pA$ reactions at COSY energies including elastic and
inelastic ${\omega}N$ rescattering, the $\omega{\to}\pi^0\gamma$ Dalitz decay
as well as $\pi^0 N$ rescattering. The resulting invariant $\pi^0 \gamma$ mass
distributions indicate that in-medium modifications of the $\omega$-meson may
be observed experimentally.


title:
An Effective Approach to VMD at One Loop Order and the Departures from
  Ideal Mixing for Vector Mesons

abstract:
  We examine the mechanisms producing departures from ideal mixing for vector
mesons within the context of the Hidden Local Symmetry (HLS) model. We show
that kaon loop transitions between the ideal combinations of the $\omega$ and
$\phi$ mesons necessitate a field transformation in order to get the mass
eigenstates. It is shown that this transformation is close to a rotation for
processes involving, like meson decays, on--shell $\omega$ and $\phi$ mesons.
The HLS model predicts a momentum dependent, slowly varying mixing angle
between the ideal states. We examine numerically the consequences of this for
radiative and leptonic decays of light mesons. The mean $\omega-\phi$ mixing
angle is found smaller than its ideal value; this is exhibited separately in
radiative and in leptonic decays. Effects of nonet symmetry breaking in the
vector sector are compared to those produced by the field rotation implied by
the HLS model.


title:
Chiral Symmetry Restoration at Nonzero Temperature in the SU(3) \times
  SU(3) Linear Sigma Model

abstract:
  We study patterns of chiral symmetry breaking at zero temperature and its
subsequent restoration at nonzero temperature within the $SU(3)_{r} \times
SU(3)_{\ell}$ linear sigma model. Gap equations for the masses of the scalar
and pseudoscalar mesons and the non-strange and strange quark condensates are
systematically derived in the Hartree approximation via the
Cornwall-Jackiw-Tomboulis formalism. In the chiral limit, the chiral symmetry
restoring transition is found to be first order, as predicted by universality
arguments. Taking the experimental values for the meson masses, however, the
transition is crossover. The absence of the $U(1)_A$ anomaly is found to drive
this transition closer to being first order. At large temperatures, the mixing
angles between octet and singlet states approach ideal flavor mixing.


title:
Pseudovector versus pseudoscalar coupling in kaon photoproduction -
  revisited

abstract:
  The question of pseudovector versus pseudoscalar coupling schemes for the
kaon-hyperon-nucleon interaction is re-examined for the reaction $\gamma p\to
K^+ \Lambda$ in several isobaric models. These models typically include Born
terms, $K^*$- and $K_1$-exchange in the t-channel, and a few different
combinations of spin-1/2 baryon resonances in the $s$- and $u$-channels. The
coupling constants are obtained by fitting to a large data set. We find that
both pseudoscalar and pseudovector couplings can allow for a satisfactory
description of the present database. The resulting coupling constants,
$g_{K\Lambda N}$ and $g_{K\Sigma N}$, in the pseudovector coupling scheme are
smaller than those predicted using flavor SU(3) symmetry, but consistent with
the values obtained in a QCD sum rule calculation.


title: Chiral aspects of hadron structure

abstract:
  Chiral loop corrections for hadronic properties are considered in a
constituent quark model. It is emphasized that the correct implementation of
such corrections requires a sum over intermediate hadronic states. The leading
non-analytic corrections are very important for baryon magnetic moments and
explain the failure of the sum rule
$(\mu_{\Sigma^{+}}+2\mu_{\Sigma^{-}})/\mu_{\Lambda}=-1$ predicted by the
constituent quark model.


title: Nonaxial octupole deformations in light N=Z nuclei at high spins

abstract:
  High spin states of ^{32}S$ and ^{56}Ni are investigated by means of the
cranking Hartree-Fock method with the Gogny interaction without imposing a
restriction on the axial reflection symmetry. It was found that a non-axial
octupole deformation of the Y_{31} type becomes important in the yrast states
of ^{32}S. A similar effect is predicted for the nucleus ^{56}Ni.


title:
Particles in classically forbidden area, neutron skin and halo, and pure
  neutron matter in Ca isotopes

abstract:
  The nucleon density distributions and the thickness of pure neutron matter in
Ca isotopes were systematically studied using the Skyrme-Hartree-Fock model
(SHF) from the $\beta$-stability line to the neutron drip-line. The pure
neutron matter, related with the neutron skin or halo, was shown to depend not
only on the Fermi levels of the neutrons but also on the orbital angular
momentum of the valence neutrons. New definitions for the thickness of pure
neutron matter are proposed.


title: Strangeness production from $\pi N$ collisions in nuclear matter

abstract:
  Kaon production in pion-nucleon collisions in nuclear matter is studied in
the resonance model. To evaluate the in-medium modification of the reaction
amplitude as a function of the baryonic density we introduce relativistic,
mean-field potentials for the initial, final and intermediate mesonic and
baryonic states. These vector and scalar potentials were calculated using the
quark-meson coupling (QMC) model. The in-medium kaon production cross sections
in pion-nucleon interactions for reaction channels with $\Lambda$ and $\Sigma$
hyperons in the final state were calculated at the baryonic densities
appropriate to relativistic heavy ion collisions. Contrary to earlier work
which has not allowed for the change of the cross section in medium, we find
that the data for kaon production are consistent with a repulsive $K^+$-nucleus
potential.


title: Pion - Nucleon Bremsstrahlung beyond the Soft-Photon approximation

abstract:
  A dynamical model based on effective Lagrangians is proposed to describe the
bremsstrahlung reaction $ \pi N \to \pi N \gamma$ at low energies. The
$\Delta(1232)$ degrees of freedom are incorporated in a way consistent with
both, electromagnetic gauge invariance and invariance under contact
transformations. The model also includes the initial and final state
rescattering of hadrons via a T-matrix with off the momentum-shell effects. The
double differential distribution of photons is computed for three different
T-matrix models and the results are compared with the soft photon
approximation, and with experimental data. The aim of this analysis is to test
the off-shell behaviour of the different T-matrices under consideration.
Finally an alternative simpler dynamical model that incorporates the unstable
character of the isobar-$\Delta(1232)$ through a complex mass, is presented. As
we will see it is suitable for the study of the magnetic moment of the
resonance.


title: Renormalization Group Improved Gap Equation for Color Superconductors

abstract:
  The renormalization group is used to resum leading logarithmic contributions
of the form alpha_s^{n+1} beta_0^n log^n (Delta/mu) to the gap equation
appropriate for high density QCD. The scale dependence of the strong coupling
constant alpha_s increases the gap by a factor of exp(33/16 (pi^2/4 - 1)) ~ 20
in the small coupling limit.


title: Internal conversion coefficients for superheavy elements

abstract:
  The internal conversion coefficients (ICC) were calculated for all atomic
subshells of the elements with 104<=Z<=126, the E1...E4, M1...M4
multipolarities and the transition energies between 10 and 1000 keV. The atomic
screening was treated in the relativistic Hartree-Fock-Slater model. The Tables
comprising almost 90000 subshell and total ICC were recently deposited at LANL
preprint server.


title:
The Longitudinal and Transverse responses in inclusive electron
  scattering within the RPA framework

abstract:
  The longitudinal and transverse nuclear responses to inclusive electron
scattering reactions are analyzed within the Random Phase Approximation (RPA)
framework. Several residual interactions are considered and it is shown that
the exchange terms in the RPA make very difficult to find an effective residual
interaction capable of reproducing simultaneously the quasielastic peak of both
the longitudinal and transverse responses. By means of a simplified model it is
illustrated that the residual interaction used in a ring approximation must
fulfill some restrictions in order to qualitatively reproduce the full RPA
results.


title: Color superconductivity in cold, dense quark matter

abstract:
  We review what is different and what is similar in a color superconductor as
compared to an ordinary BCS superconductor. The parametric dependence of the
zero-temperature gap on the coupling constant differs in QCD from that in BCS
theory. On the other hand, the transition temperature to the superconducting
phase is related to the zero-temperature gap in the same way in QCD as in BCS
theory.


title: Shell model description of 16O(p,gamma)17F and 16O(p,p)16O reactions

abstract:
  We present shell model calculations of both the structure of 17F and the
reactions 16O(p,gamma)17F, 16O(p,p)16O. We use the ZBM interaction which
provides a good description of the properties of 16O and neighbouring nuclei
and, in particular it takes account for the complicated correlations in
coexisting low-lying states of 16O.


title:
Neutron density distributions for atomic parity nonconservation
  experiments

abstract:
  The neutron distributions of Cs, Ba, Yb and Pb isotopes are described in the
framework of relativistic mean-field theory. The self-consistent ground state
proton and neutron density distributions are calculated with the relativistic
Hartree-Bogoliubov model. The binding energies, the proton and neutron radii,
and the quadrupole deformations are compared with available experimental data,
as well as with recent theoretical studies of the nuclear structure corrections
to the weak charge in atomic parity nonconservation experiments.


title: Possible Striking Signals for a Quark-Gluon Plasma at RHIC

abstract:
  We believe that one can have serious reservations as to whether heavy ion
collisions (e.g. 100 GeV/n Au + 100 GeV/n Au) can lead to Thermal and Chemical
equilibrium over large regions (particularly if it is assumed this happens
whenever QGP is produced at RHIC-that is if it is produced). It is at present
not clear that the collision dynamics and times available will lead to this. An
alternate scenario proposed by Van Hove where localized in rapidity bubbles of
plasma may well be more probable, and may well occur at least some of the time,
and some of the time mainly survive to the final state. If this occurs we have
developed a series of event generators to extend and describe these phenomena.
A Van Hove type[6,7] spherical bubble at eta=0 is embedded in a resonable event
generator in qualitative agreement with Hijing etc[12]. The plasma bubble
hadronized at a temperature of 170 Mev according to the model developed by
Koch, Muller and Rafelski[21]. The amount of available bubble energy is
selected by that in a small central circular cross-section of radius approx
1.3fm or 2.5fm in 100 Gev/n Au+AU, central events The results predict Possible
Striking Signals for a QGP.
  We are also applying these techniques to investigating Kharzeev and Pisarski
bubbles of metastable vacua with odd CP.


title: Gradient Terms in the Microscopic Description of K-Atoms

abstract:
  We analyze the spectra of kaonic atoms using optical potentials withnon-local
(gradient) terms. The magnitude of the non-local termsfollows from a self
consistent many-body calculation of the kaon selfenergy in nuclear matter,
which is based on s-wave kaon nucleoninteractions. The optical potentials
exhibit strong non-linearitiesin the nucleon density and sizeable non-local
terms. We find that thenon-local terms are quantitatively important in the
analysis of thespectra and that a phenomenologically successful description can
be obtained for p-wave like optical potentials. It is suggested that
themicroscopic form of the non-local interaction terms is
obtainedsystematically by means of a semi-classical expansion of the
nucleusstructure. The resulting optical potential leads to less pronounced
non-local effects.


title: Effective chiral theory of kaon-nucleon scattering

abstract:
  We apply the relativistic chiral SU(3) Lagrangian density to kaon-nucleon
scattering imposing constraints from the pion-nucleon s- and p-wave threshold
parameters at chiral order $Q^2$. The s and u channel decouplet baryon exchange
is included explicitly and is found to play a crucial role in understanding the
empirical s- and p-wave nuclear kaon dynamics quantitatively.


title: On the $\Lambda$ to $\Sigma^0$ ratio from proton-proton collisions

abstract:
  We compare the recent COSY data on the total $pp{\to}p\Lambda{K^+}$ and
$pp{\to}p\Sigma^0{K^+}$ cross sections with the predictions from two boson
exchange models that either are based solely on $\pi$ and $K$ exchange or
include $\pi$, $\eta$ and $\rho$ exchange as well as the virtual excitation of
intermediate baryon resonances. Both models are found to reproduce the data
after the inclusion of final state hyperon-nucleon interactions. Thus, within
the experimental uncertainties, both models also roughly reproduce the strong
dependence of the $\Lambda$ to $\Sigma^0$ ratio as a function of the excess
energy near threshold, as well as at higher energies.


title: Modern nuclear force predictions for the alpha particle

abstract:
  We present new calculations of the $\alpha$-particle which are based on the
most modern nucleon-nucleon interactions alone and combined with the
Tucson-Melbourne or the Urbana IX three-nucleon interaction. Results for the
binding energies and some properties of the wavefunction are given. On that
phenomenological level little room is left for the action of a possible
four-nucleon force.


title: Dynamical constraints on phase transitions

abstract:
  The numerical solutions of nonlocal and local Boltzmann kinetic equations for
the simulation of central heavy ion reactions are parameterized in terms of
time dependent thermodynamical variables in the Fermi liquid sense. This allows
one to discuss dynamical trajectories in phase space. The nonequilibrium state
is characterized by non-isobaric, non-isochoric etc. conditions, shortly called
iso-nothing conditions. Therefore a combination of thermodynamical observables
is constructed which allows one to locate instabilities and points of possible
phase transition in a dynamical sense. We find two different mechanisms of
instability, a short time surface - dominated instability and later a spinodal
- dominated volume instability. The latter one occurs only if the incident
energies do not exceed significantly the Fermi energy and might be attributed
to spinodal decomposition. In contrast the fast surface explosion occurs far
outside the spinodal region and pertains also in the cases where the system
develops too fast to suffer a spinodal decomposition and where the system
approaches equilibrium outside the spinodal region.


title:
Statistical Model Description of $K^+$ and $K^-$ Production between 1 -
  10 AGeV

abstract:
  The excitation functions of $K^+$ and $K^-$ mesons in heavy ion collisions
are studied within a statistical model assuming chemical and thermal
equilibrium with exact strangeness conservation. At low incident energies the
associate production of kaons, i.e. the production of a K+ together with a
hyperon and the production of a K- together with a K+, implies specific
features: different threshold energies and different dependences of K+ and K-
yields on baryon number density. It is shown that the experimentally observed
equality of the $K^+$ and $K^-$ rates at energies $\sqrt{s} - \sqrt{s_{th}}
\leq 0$ is due to a crossing of the two excitation functions. Furthermore, the
independence of the $K^+$ to $K^-$ ratio on the number of participating
nucleons observed at 1 and 10 $A\cdot$GeV is consistent with this model.


title: Is the analysis of flow at the CERN SPS reliable?

abstract:
  Several heavy ion experiments at SPS have measured azimuthal distributions of
particles with respect to the reaction plane. These distributions are deduced
from two-particle azimuthal correlations under the assumption that they result
solely from correlations with the reaction plane. In this paper, we investigate
other sources of azimuthal correlations: transverse momentum conservation,
which produces back-to-back correlations, resonance decays, HBT correlations
and final state interactions. These correlations increase with impact
parameter: most of them vary with the multiplicity N like 1/N. When they are
taken into account, the experimental results of the NA49 collaboration at SPS
are significantly modified. These correlations might also explain an important
fraction of the pion directed flow observed by WA98. Data should be reanalyzed
taking into account carefully these non--flow correlations.


title: Single particle spectrum and binding energy of nuclear matter

abstract:
  In non-relativistic Brueckner calculations of nuclear matter, the
self-consistent single particle potential is strongly momentum dependent. To
simplify the calculations, a parabolic approximation is often used in the
literature. The variation in the binding energy value introduced by the
parabolic approximation is quantitatively analyzed in detail. It is found that
the approximation can introduce an uncertainty of 1-2 MeV near the saturation
density.


title:
Parity violation in reactions with B- and Li- nuclei using polarized
  thermal neutrons

abstract:
  Parity violation in the $(n,\alpha)$ reactions on $^6$Li and $^{10}$B nuclei
and in the $\gamma$-transition between two lowest levels of $^7$Li nucleus is
discussed. It appears that the effects (neutral currents contribution in
particular) are measurable due to the large values of the neutron cross
sections. This holds promise for the theoretical extraction of the constants of
the weak NN potential because of the relative simplicity of the investigated
systems.


title:
In-Plane Elliptic Flow of Resonance Particles in Relativistic Heavy-Ion
  Collisions

abstract:
  We analyze the second Fourier coefficient $v_2$ of the pion azimuthal
distribution in non-central heavy-ion collisions in a relativistic hydrodynamic
model. The exact treatment of the decay kinematics of resonances leads to
almost vanishing azimuthal anisotropy of pions near the midrapidity, while the
matter elliptic flow is in-plane at freeze-out. In addition, we reproduce the
rapidity dependence of $v_2$ for pions measured in non-central Pb + Pb
collisions at 158$A$ GeV. This suggests that resonance particles as well as
stable particles constitute the in-plane flow and are important ingredients for
the understanding of the observed pion flow.


title:
Renormalization of the f0(980) and a0(980) scalar resonances in a
  nuclear medium

abstract:
  The meson meson interaction in the scalar sector in the presence of a nuclear
medium is studied with particular attention to the change of the properties of
the f0(980) and a0(980) resonances. By using a chiral unitary approach which
generates the f0 and a0 resonances and reproduces their free properties, we
find that the position of the resonances in the medium is barely changed but
their widths are considerably broadened. New many body corrections generating
from higher orders in the chiral Lagrangian plus the contribution from N*h
excitations, not considered before in connection with the pion-pion interaction
in the nuclear medium, are also investigated.


title: Hyperon-hyperon interactions and properties of neutron matter

abstract:
  We present results from Brueckner-Hartree-Fock calculatons for beta stable
neutron star matter with nucleonic and hyperonic degress degrees of freedom,
employing the most recent parametrizations of the baryon-baryon interaction of
the Nijmegen group. It is found that the only strange baryons emergin in beta
stable matter up to total barionic densities of 1.2 fm^-3 are $\Sigma^-$ and
$\Lambda$. The corresponding equations of state are then used to compute
properties of neutron stars such as masses and radii.


title: Nuclear structure from random interactions

abstract:
  Low-lying states in nuclei are investigated using an ensemble of random
interactions. Both in the nuclear shell model and in the interacting boson
model we find a dominance of $J^P=0^+$ ground states. It is shown that this
feature is not due to time reversal symmetry. In the shell model, evidence is
found for the occurrence of pairing properties, and in the interacting boson
model for both vibrational and rotational band structures. Our results suggest
that these features represent general and robust properties of the model space,
and do not depend on details of the interactions.


title: Chiral Three-Nucleon Forces from p-wave Pion Production

abstract:
  Production of p-wave pions in nucleon-nucleon collisions is studied according
to an improved power counting that embodies the constraints of chiral symmetry.
Contributions from the first two non-vanishing orders are calculated. We find
reasonable convergence and agreement with data for a spin-triplet cross section
in $pp\to pp\pi^0$,with no free parameters. Agreement with existing data for a
spin-singlet cross section in $pp\to pn\pi^+$ constrains a short-range operator
shown recently to contribute significantly to the three-nucleon potential.


title: Algebraic Models of Hadron Structure II. Strange Baryons

abstract:
  The algebraic treatment of baryons is extended to strange resonances. Within
this framework we study a collective string-like model in which the radial
excitations are interpreted as rotations and vibrations of the strings. We
derive a mass formula and closed expressions for strong and electromagnetic
decay widths and use these to analyze the available experimental data.


title:
Calculation of Exclusive Cross Sections with the Lorentz Integral
  Transform Method

abstract:
  The longitudinal structure function of the d(e,e'p) exclusive cross section
is calculated with the Lorentz integral transform method. In this approach
final state interaction is fully taken into account, but without using a final
state wave function. Cross sections are obtained via the inversion of the
transform. It is shown that the inversion results are very stable. The
comparison to a conventional calculation with an explicit np final state wave
function shows that the obtained results are also very precise. Thus the method
opens up the possibility to obtain exclusive cross sections for reactions with
more than two particles, where it is generally very difficult to calculate the
exact final state wave function.


title: Chiral properties of hadron correlators in nuclear matter

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


title: A number projected model with generalized pairing interaction

abstract:
  A mean-field model with a generalized pairing interaction that accounts for
neutron-proton pairing is presented. Both the BCS as well as number-projected
solutions of the model are presented. For the latter case the Lipkin-Nogami
projection technique was extended to encompass the case of non-separable
proton-neutron systems. The influence of the projection on various pairing
phases is discussed. In particular, it is shown that number-projection allows
for mixing of different pairing phases but, simultanously, acts destructively
on the proton-neutron correlations. The basic implications of proton-neutron
pairing correlations on nuclear masses are discussed. It is shown that these
correlations may provide a natural microscopic explanation of the Wigner energy
lacking in mean-field models. A possible phase transition from isovector to
isoscalar pairing condensate at high angular momenta is also discussed. In
particular predictions for the dynamical moments of inertia for the
superdeformed band in $^{88}$Ru are given.


title: Proton-Proton Fusion in Effective Field Theory

abstract:
  The rate for the fusion process $p + p \ra d + e^+ + \nu_e$ is calculated
using non-relativistic effective field theory. Including the four-nucleon
derivative interaction, results are obtained in next-to-leading order in the
momentum expansion. This reproduces the effects of the effective range
parameter. Coulomb interactions between the incoming protons are included
non-perturbatively in a systematic way. The resulting fusion rate is
independent of specific models and wavefunctions for the interacting nucleons.
At this order in the effective Lagrangian there is an unknown counterterm which
limits the numerical accuracy of the calculated rate given by the squared
reduced matrix element $\Lambda^2(0) = 7.37$. Assuming the counterterm to have
a natural magnitude, we estimate the accuracy of this result to be 6\% - 8\%.
This is consistent with previous nuclear physics calculations based on
effective range theory and inclusion of axial two-body weak currents. The true
magnitude of the counterterm can be determined from a precise measurement of
the cross-section for low-energy neutrino scattering on deuterons.


title: Nucleon-nucleon elastic scattering to 3 GeV

abstract:
  A partial-wave analysis (PWA) of NN elastic scattering data has been
completed. This analysis covers an expanded energy range, from threshold to a
laboratory kinetic energy of 3 GeV, in order to include recent elastic pp
polarized scattering measurements performed at SATURNE II. Results of the
energy-dependent fit are compared with single-energy solutions and Saclay
amplitudes obtained via the direct-reconstruction approach. We also comment on
the status of Eps1 in the low-energy region.