title: Chiral dynamics in few-nucleon systems

abstract:
  We employ the chiral nucleon-nucleon potential derived using the method of
unitary transformation up to next-to-next-to-leading order (NNLO) to study
bound and scattering states in the two-nucleon system. The predicted partial
wave phase shifts and mixing parameters for higher energies and higher angular
momenta beyond the ones which are fitted are mostly well described for energies
below 300 MeV. Various deuteron properties are discussed. We also apply the
next-to-leading order (NLO) potential to 3N and 4N systems. The resulting 3N
and 4N binding energies are in the same range what is found using standard NN
potentials. Experimental low-energy 3N scattering observables are also very
well reproduced like for standard NN forces. Surprisingly the long standing
Ay-puzzle is resolved at NLO. The cut-off dependence of the scattering
observables is rather mild.


title:
Fourth Order Diffusion Monte Carlo Algorithms for Solving Quantum
  Many-Body Problems

abstract:
  By decomposing the important sampled imaginary time Schr\"odinger evolution
operator to fourth order with positive coefficients, we derived a number of
distinct fourth order Diffusion Monte Carlo algorithms. These sophisticated
algorithms require higher derivatives of the drift velocity and local energy
and are more complicated to program. However, they allowed very large time
steps to be used, converged faster with lesser correlations, and virtually
eliminated the step size error. We demonstrated the effectiveness of these
quartic algorithms by solving for the ground state properties of bulk liquid
helium.


title:
Neutron-Proton Differential Flow as a Probe of Isospin-Dependence of
  Nuclear Equation of State

abstract:
  The neutron-proton differential flow is shown to be a very useful probe of
the isospin-dependence of the nuclear equation of state (EOS). This novel
approach utilizes constructively both the isospin fractionation and the nuclear
collective flow as well as their sensitivities to the isospin-dependence of the
nuclear EOS. It also avoids effectively uncertainties associated with other
dynamical ingredients of heavy-ion reactions at intermediate energies.


title: Superdeformed Band in ^{36}Ar Described by Projected Shell Model

abstract:
  The projected shell model implements shell model configuration mixing in the
projected deformed basis. Our analysis on the recently observed superdeformed
band in $^{36}$Ar suggests that the neutron and proton 2-quasiparticle and the
4-quasiparticle bands cross the superdeformed ground band at the same angular
momentum. This constitutes a picture of band disturbance in which the first and
the second band-crossing, commonly seen at separate rotation frequencies in
heavy nuclei, occur simultaneously. We also attempt to understand the
assumptions of two previous theoretical calculations which interpreted this
band. Electromagnetic properties of the band are predicted.


title: Atomic effects in astrophysical nuclear reactions

abstract:
  Two models are presented for the description of the electron screening
effects that appear in laboratory nuclear reactions at astrophysical energies.
The two-electron screening energy of the first model agrees very well with the
recent LUNA experimental result for the break-up reaction $%
He3(He3,2p)He^{4}$, which so far defies all available theoretical models.
Moreover, multi-electron effects that enhance laboratory reactions of the CNO
cycle and other advanced nuclear burning stages, are also studied by means of
the Thomas-Fermi model, deriving analytical formulae that establish a lower and
upper limit for the associated screening energy. The results of the second
model, which show a very satisfactory compatibility with the adiabatic
approximation ones, are expected to be particularly useful in future
experiments for a more accurate determination of the CNO astrophysical factors.

categories: nucl-th astro-ph nucl-ex physics.atom-ph


title:
Effective Field Theory for Neutron-Deuteron Scattering: Higher Partial
  Waves

abstract:
  The phase shifts for the higher partial waves in the spin quartet and doublet
channel of nd scattering are presented at next-to-leading and
next-to-next-to-leading order in an effective field theory in which pions are
integrated out. The results agree with both phase shift analyses and potential
model calculations.


title: The Next Yukawa Phase of QCD at RHIC

abstract:
  QCD predicts the existence of a new partonic Yukawa phase above a critical
temperature $T_c\sim 150$ MeV. I review some of the key observables which will
be used in heavy ion reactions to search for this new phase at RHIC.
Systematics of collective observables ($N_{ch},E_\perp)$, flow patterns, meson
interferometry, jet quenching, and $J/\psi$ suppression are discussed. This
talk is updated with the first data from RHIC.


title:
Hyperon-Nucleon Final State Interaction in Kaon Photoproduction of the
  Deuteron

abstract:
  Final state hyperon-nucleon interaction in strangeness photoproduction of the
deuteron is investigated making use of the covariant reaction formalism and the
P-matrix approach to the YN system. Remarkably simple analytical expression for
the amplitude is obtained. Pronounced effects due to final state interaction
are predicted including the manifestation of the 2.13 GeV resonance.


title: Two-pion decay modes of the N*(1440) in n p -> d pi pi

abstract:
  A simple model for the n p -> d pi pi reaction has been developed. It is
shown that the deuteron momentum spectra measured at T_n = 795 MeV can be
understood in terms of the Roper excitation and its N pi pi decay modes. A
similar pattern, recently observed in p p -> p p pi+ pi-, can be explained in
the same way.


title: Two-Body Random Ensembles: From Nuclear Spectra to Random Polynomials

abstract:
  The two-body random ensemble (TBRE) for a many-body bosonic theory is mapped
to a problem of random polynomials on the unit interval. In this way one can
understand the predominance of 0+ ground states, and analytic expressions can
be derived for distributions of lowest eigenvalues, energy gaps, density of
states and so forth. Recently studied nuclear spectroscopic properties are
addressed.


title:
Equivalence of model space techniques and the renormalization group for
  a separable model problem

abstract:
  Lee-Suzuki similarity transformations and Krencigowa-Kuo folded diagrams are
two common methods used to derive energy independent model space effective
interactions for nuclear many-body systems. We demonstrate that these methods
are equivalent to a Renormalization Group (RG) analysis of a separable
potential model. The effective low-momentum potentials V_{eff} are shown to
give the same scaling equation that RG arguments predict. We find the new
result that the different model space techniques considered in this paper yield
a unique low-momentum V_{eff} when applied to the toy model problem.


title: Robust Nuclear Observables and Constraints on Random Interactions

abstract:
  The predictions of the IBM two-body random ensemble are compared to empirical
results on nuclei from Z=8 to 100. Heretofore unrecognized but robust empirical
trends are identified and related both to the distribution of valence nucleon
numbers and to the need for and applicability of specific, non-random
interactions. Applications to expected trends in exotic nuclei are discussed.


title: Asymmetry Effects on Nuclear Fragmentation

abstract:
  We show the possibility of extracting important information on the symmetry
term of the Equation of State ($EOS$) directly from multifragmentation
reactions using stable isotopes with different charge asymmetries. We study
n-rich and n-poor $Sn + Sn$ collisions at $50AMeV$ using a new stochastic
transport approach with all isospin effects suitably accounted for. For central
collisions a chemical component in the spinodal instabilities is clearly seen.
This effect is reduced in the neck fragmentation observed for semiperipheral
collisions, pointing to a different nature of the instability. In spite of the
low asymmetry tested with stable isotopes the results are showing an
interesting and promising dependence on the stiffness of the symmetry term,
with an indication towards an increase of the repulsion above normal density.


title: What can we learn from Nuclear Matter Instabilities?

abstract:
  We discuss the features of instabilities in binary systems, in particular,
for asymmetric nuclear matter. We show its relevance for the interpretation of
results obtained in experiments and in "ab initio" simulations of the reaction
between $^{124}Sn+^{124}Sn$ at 50AMeV.}


title: Nuclear fragmentation: sampling the instabilities of binary systems

abstract:
  We derive stability conditions of Asymmetric Nuclear Matter ($ANM$) and
discuss the relation to mechanical and chemical instabilities of general
two-component systems. We show that the chemical instability may appear as an
instability of the system against isoscalar-like rather than isovector-like
fluctuations if the interaction between the two constituent species has an
attractive character as in the case of $ANM$. This leads to a new kind of
liquid-gas phase transition, of interest for fragmentation experiments with
radioactive beams.


title:
On the uncertainty of hyperon couplings and the electrochemical
  potential in neutron star matter

abstract:
  Uncertainty of the hyperon couplings, in particular, that of the $\Sigma^-$,
in dense matter raises the question of the behavior of the electrochemical
potential in neutron star matter, which is crucial to the possible presence of
the kaon condensed phase. We show that regardless of this uncertainty, the
$\Lambda$ hyperon, whose coupling can be constrained by its binding in nuclear
matter and other observations, also aided by the $\Xi^-$, introduce a
saturation of the electrochemical potential just as the $\Sigma^-$ would
otherwise do, which tends to mitigate against kaon condensation. The maximum
possible mass of neutron stars appears to be $\sim 1.5 \msun$ independent of
the uncertainties.


title: Effect of in-medium properties on heavy-ion collisions

abstract:
  The properties of strange hadrons, i.e. of kaons and hyperons, in the nuclear
medium are discussed in connection with neutron star properties and
relativistic heavy-ion collisions. Firstly, the relevant medium modifications
of a kaon in a medium as provided by heavy-ion collisions is critically
examined within a coupled channel calculation. We demonstrate, that particle
ratios for kaons are not a sensitive probe of in-medium effects while the K-
flow is more suited to pin down the K- optical potential in dense matter.
Secondly, the interaction between hyperons is studied and may form bound states
which can be produced in relativistic heavy-ion collisions. Signals for the
detection of strange dibaryons by their decay topology and/or in the invariant
mass spectra are outlined.


title: Caloric Curves for small systems in the Nuclear Lattice Gas Model

abstract:
  For pedagogical reasons we compute the caloric curve for 11 particles in a
$3^3$ lattice. Monte-Carlo simulation can be avoided and exact results are
obtained. There is no back-bending in the caloric curve and negative specific
heat does not appear. We point out that the introduction of kinetic energy in
the nuclear Lattice Gas Model modifies the results of the standard Lattice Gas
Model in a profound way.


title:
Octupole deformations in actinides at high spins within the cranking
  Skyrme-Hartree-Fock approach

abstract:
  The cranked Skyrme III effective Hamiltonian is applied for the analysis of
the rotational dependence of the quadrupole and octupole moments in Ra, Th, and
U isotopes. A comparison of the intrinsic electric dipole moments calculated in
the model with available experimental and theoretical values is presented. It
is found that the non-axial octupole deformation $Y_{32}$ becomes favorable at
high spins for the actinide nuclei.


title:
Unfactorized versus factorized calculations for ^2H(e,e'p) reactions at
  GeV energies

abstract:
  In the literature, one often finds calculations of (e,e'p) reactions at GeV
energies using the factorization approach. Factorization implies that the
differential cross section can be written as the product of an off-shell
electron-proton cross section and a distorted missing momentum distribution.
While this factorization appears in the non-relativistic plane wave impulse
approximation, it is broken in a more realistic approach. The main source of
factorization breaking are final state interactions. In this paper, sources of
factorization breaking are identified and their numerical relevance is examined
in the reaction ^2H(e,e'p) for various kinematic settings in the GeV regime.
The results imply that factorization should not be used for precision
calculations, especially as unfactorized calculations are available.


title:
On the relativistic origin of the kink effect in the chain of Pb
  isotopes

abstract:
  We investigate the origin of the kink effect (KE) in the relativistic mean
field theory by transforming the single-particle Dirac equation into a
Schrodinger-like equation. It is found that relativistic self-consistent
effects as well as contributions from the rho meson determine the actual
structure of the KE. However, the spin-orbit force generated by the rho meson
has no significant influence on the KE.


title:
Two-neutron separation energies, binding energies and phase transitions
  in the interacting boson model

abstract:
  In the framework of the interacting boson model the three transitional
regions (rotational-vibrational, rotational-$\gamma$-unstable and,
vibrational-$\gamma$-unstable transitions) are reanalyzed. A new kind of plot
is presented for studying phase transitions in finite systems such as atomic
nuclei. The importance of analyzing binding energies and not only energy
spectra and electromagnetic transitions, describing transitional regions is
emphasized. We finally discuss a number of realistic examples.


title: Quark-Meson Coupling Model for a Nucleon

abstract:
  The quark-meson coupling model for a nucleon is considered. The model
describes a nucleon as an MIT bag, in which quarks are coupled to scalar and
vector mesons. A set of coupled equations for the quark and the meson fields
are obtained and are solved in a self-consistent way. It is shown that the mass
of a nucleon as a dressed MIT bag interacting with sigma- and omega-meson
fields significantly differs from the mass of a free MIT bag. A few sets of
model parameters are obtained so that the mass of a dressed MIT bag becomes the
nucleon mass. The results of our calculations imply that the self-energy of the
bag in the quark-meson coupling model is significant and needs to be considered
in doing the nuclear matter calculations.


title: Protoneutron Stars with Kaon Condensation and their Delayed Collapse

abstract:
  Properties of protoneutron stars are discussed in the context of kaon
condensation. Thermal and neutrino trapping effects are very important
ingredients to study them. By solving the TOV equation, we discuss the static
properties of protoneutron stars and the possibility of the delayed collapse
during their evolution.


title: Flow and the equation of state of nuclear matter

abstract:
  The status of flow in heavy-ion collisions and of inference of
hadronic-matter properties is reviewed.


title: Multi-channel phase-equivalent transformation and supersymmetry

abstract:
  Phase-equivalent transformation of local interaction is generalized to the
multi-channel case. Generally, the transformation does not change the number of
the bound states in the system and their energies. However, with a special
choice of the parameters, the transformation removes one of the bound states
and is equivalent to the multi-channel supersymmetry transformation recently
suggested by Sparenberg and Baye. Using the transformation, it is also possible
to add a bound state to the discrete spectrum of the system at a given energy
$E<0$ if the angular momentum at least in one of the coupled channels $l\ge 2$.


title: Few-Body Problems in Hadron Spectroscopy

abstract:
  Some rigorous results can be derived using a very simple approach to hadron
spectroscopy, in which a static potential is associated with non-relativistic
kinematics. Several regularities of the experimental spectrum are explained by
such models. It is underlined that certain methods developed for hadronic
physics have found applications in other fields, in particular atomic physics.
A few results can be extended to cases involving spin-dependent forces or
relativistic kinematics.


title:
ABSSM - a new field-theoretic method of describing scattering/production
  processes of composite particles by asymptotic in-/outgoing Bethe-Salpeter
  states

abstract:
  A new relativistic field-theoretic formalism called "Asymptotic
Bethe-Salpeter State Method" (ABSSM) is presented, which allows to calculate
both electromagnetic formfactors and hadronic scattering and production
amplitudes of elementary and composite systems (being described by
Bethe-Salpeter amplitudes) within one theoretical framework. The ABSSM is then
applied to the deuteron as a composite system of two nucleons.

categories: nucl-th cond-mat hep-ph math-ph math.MP physics.atom-ph


title: The Relativistic N-body Problem in a Separable Two-Body Basis

abstract:
  We use Dirac's constraint dynamics to obtain a Hamiltonian formulation of the
relativistic N-body problem in a separable two-body basis in which the
particles interact pair-wise through scalar and vector interactions. The
resultant N-body Hamiltonian is relativistically covariant. It can be easily
separated in terms of the center-of-mass and the relative motion of any
two-body subsystem. It can also be separated into an unperturbed Hamiltonian
with a residual interaction. In a system of two-body composite particles, the
solutions of the unperturbed Hamiltonian are relativistic two-body internal
states, each of which can be obtained by solving a relativistic
Schr\"odinger-like equation. The resultant two-body wave functions can be used
as basis states to evaluate reaction matrix elements in the general N-body
problem. We prove a relativistic version of the post-prior equivalence which
guarantees a unique evaluation of the reaction matrix element, independent of
the ways of separating the Hamiltonian into unperturbed and residual
interactions. Since an arbitrary reaction matrix element involves composite
particles in motion, we show explicitly how such matrix elements can be
evaluated in terms of the wave functions of the composite particles and the
relevant Lorentz transformations.


title: Kinetic equation with exact charge conservation

abstract:
  We formulate the kinetic master equation describing the production of charged
particles which are created or destroyed only in pairs due to the conservation
of their Abelian charge.Our equation applies to arbitrary particle
multiplicities and reproduces the equilibrium results for both canonical (rare
particles) and grand canonical (abundant particles) systems. For canonical
systems, the equilibrium multiplicity is much lower and the relaxation time is
much shorter than the naive extrapolation from the grand canonical ensemble
results. Implications for particle chemical equilibration in heavy-ion
collisions are discussed.


title:
Solution of the Faddeev-Yakubovsky equations using realistic NN and 3N
  interaction

abstract:
  We solve the Faddeev-Yakubovsky equations for 3N and 4N bound states based on
the most modern realistic nucleon-nucleon interactions. We include different
realistic 3N forces. It is shown that all 3N force models can remove the
underbinding of the triton and alpha-particle which one obtains with existing
NN interactions. The agreement of theoretical predictions and the experimental
binding energy is quite good and there is little room left for the action of
four-nucleon forces in the alpha-particle. The effect of 3N forces on the wave
function is investigated.


title:
Unified optical-model approach to low-energy antiproton annihilation on
  nuclei and to antiprotonic atoms

abstract:
  A successful unified description of $\bar p$ nuclear interactions near E=0 is
achieved using a $\bar p$ optical potential within a folding model, $V_{{\rm
opt}} \sim \bar v * {\rho}$, where a $\bar p p$ potential $\bar v$ is folded
with the nuclear density $\rho$. The potential $\bar v$ fits very well the
measured $\bar p p$ annihilation cross sections at low energies ($p_L < 200$
MeV/c) and the $1s$ and $2p$ spin-averaged level shifts and widths for the
$\bar p$H atom. The density-folded optical potential $V_{{\rm opt}}$ reproduces
satisfactorily the strong-interaction level shifts and widths over the entire
periodic table, for $A > 10$, as well as the few low energy $\bar p$
annihilation cross sections measured on Ne. Both $\bar v$ and $V_{{\rm opt}}$
are found to be highly absorptive, which leads to a saturation of reaction
cross sections in hydrogen and on nuclei. Predictions are made for $\bar p$
annihilation cross sections over the entire periodic table at these very low
energies and the systematics of the calculated cross sections as function of
$A$, $Z$ and $E$ is discussed and explained in terms of a Coulomb-modified
strong-absorption model. Finally, optical potentials which fit simultaneously
low-energy $\bar p - ^4$He observables for $E < 0$ as well as for $E > 0$ are
used to assess the reliability of extracting Coulomb modified $\bar p$ nuclear
scattering lengths directly from the data. The relationship between different
kinds of scattering lengths is discussed and previously published systematics
of the $\bar p$ nuclear scattering lengths is updated.


title:
Production of isoscalar pion pairs in the pd -> 3He pi pi reaction near
  threshold

abstract:
  The production near threshold of isoscalar pion pairs in the pd -> 3He(pi
pi)^0 reaction is estimated in a two-step model which successfully describes
the production of eta, omega and eta' mesons. A virtual pion beam, generated
through an NN -> d pi reaction on one of the nucleons in the deuteron, produces
a second pion via a pi N -> pi pi N reaction on the other nucleon. Using the
same scale factor as for heavy meson production, the model reproduces the total
pi^0 pi^0 production rate determined at an excess energy of 37 MeV. There are
some indications in the data for a suppression of events with low pi pi masses,
as in the pi^- p -> pi^0 pi^0 n reaction, and this is confirmed within the
model. The model suggests that a significant fraction of the charged pion
production in the p d -> 3He pi^+ pi^- reaction at Q=70 MeV might be associated
with isoscalar pion pairs, though this does not explain the strong dependence
observed on the pi^+ pi^- relative momentum angle.


title: Strangeness Equilibration at GSI Energies

abstract:
  We develop the notion of "broad-band equilibration" in heavy-ion processes
involving dense medium. Given density-dependent \Km-masses we show that the
equilibration at GSI energies claimed to hold in previous treatments down to
$\sim \rho_0/4$, can be replaced by a broad-band equilibration in which the
\Km-meson and hyperons are produced in an essentially constant ratio
independent of density. There are experimental indications that this also holds
for AGS energies. We then proceed to argue that {\it both} $K^+$ and $K^-$ must
get lighter in dense medium at some density $\rho >\rho_0$ due to the
decoupling of the vector mesons. As a consequence, kaon condensation in compact
stars could take place {\it before} chiral restoration since the sum of bare
quark masses in the kaon should lie below $\mu_e$. Another consequence of the
decoupling vector interactions is that the quasi-particle picture involving
(quasi)quarks, presumably ineffective at low densities, becomes more
appropriate at higher densities as chiral restoration is approached.


title: Short-range correlations in low-lying nuclear excited states

abstract:
  The electromagnetic transitions to various low-lying excited states of 16O,
48Ca and 208Pb are calculated within a model which considers the short-range
correlations. In general the effects of the correlations are small and do not
explain the required quenching to describe the data.


title: Parity Violating Measurements of Neutron Densities and Nuclear Structure

abstract:
  Parity violating electron nucleus scattering is a clean and powerful tool for
measuring the spatial distributions of neutrons in nuclei with unprecedented
accuracy. Parity violation arises from the interference of electromagnetic and
weak neutral amplitudes, and the $Z^0$ of the Standard Model couples primarily
to neutrons at low $Q^2$. Experiments are now feasible at existing facilities.
We show that theoretical corrections are either small or well understood, which
makes the interpretation clean. A neutron density measurement may have many
implications for nuclear structure, atomic parity nonconservation experiments,
and the structure of neutron stars.


title:
Review of existing breakup and transfer theories leading to continuum
  final states

abstract:
  This is a brief review of recent experimental and theoretical works aiming at
extracting spectroscopic information from quasielasic projectile breakup
reactions at intermediate energies.


title: RPA quasi-elastic responses in infinite and finite nuclear systems

abstract:
  Quasi-elastic responses in nuclear matter and in $^{12}$C and $^{40}$Ca
nuclei are calculated in ring approximation to investigate the finite size
effects on the electromagnetic quasi-elastic responses. A method to simulate
these effects in infinite systems calculations is proposed. The sensitivity of
the results to the various terms of the residual interaction is studied. The
results of nuclear matter RPA calculations are compared with those obtained in
ring approximation to evidence the importance of the exchange terms.


title:
Nucleon-deuteron elastic scattering as a tool to probe properties of
  three-nucleon forces

abstract:
  Faddeev equations for elastic Nd scattering have been solved using modern NN
forces combined with the Tucson-Melbourne two-pion exchange three-nucleon
force, with a modification thereof closer to chiral symmetry and the Urbana IX
three-nucleon force. Theoretical predictions for the differential cross section
and several spin observables using NN forces only and NN forces combined with
three-nucleon force models are compared to each other and to the existing data.
A wide range of energies from 3 to 200 MeV is covered. Especially at the higher
energies striking three-nucleon force effects are found, some of which are
supported by the still rare set of data, some are in conflict with data and
thus very likely point to defects in those three-nucleon force models.


title: Quark degrees of freedom in hadronic systems

abstract:
  Quantum Chromodynamics (QCD) is the theory of the strong interactions. We
review descriptions of hadronic systems motivated by QCD, analyzing the recent
controversy between gluonic and bosonic degrees of freedom under the prism of
the Cheshire Cat Principle. Our analysis leads to an optimal scheme to study
hadronic properties. We proceed to extend this low energy descriptions to the
deep inelastic regime.


title: Introduction to Effective Field Theory

abstract:
  An introduction to methods of effective field theory is given. Examples are
presented, including Rayleigh scattering from nonrelativistic quantum mechnics,
chiral perturbation theory/QCD as well as electromagnetic and weak interactions
of nucleons.


title: Shell Model Description of $^{158}$Gd

abstract:
  The pseudo-SU(3) model is used to describe the low-energy spectra as well as
$E2$ and $M1$ transition strengths in $^{158}$Gd. The Hamiltonian includes
spherical single-particle energies, the quadrupole-quadrupole and proton and
neutron pairing interactions, plus four rotor-like terms. The parameters of the
Hamiltonian were fixed by systematics with the rotor-like terms determined
through a least-squares analysis. The basis states are built as linear
combinations of SU(3) states which are the direct product of SU(3) proton and
neutron states with pseudo-spin zero. The calculated results compare favorably
with the available experimental data, which demonstrates the ability of the
model to describe such nuclei.


title: Hadronic interactions of the J/psi

abstract:
  We calculate the cross sections for reactions of the J/psi with light mesons.
We also evaluate its finite temperature spectral function. We investigate
separately the role of elastic and inelastic channels and we compare their
respective importance. We describe J/psi absorption channels that have not been
considered previously to our knowledge. The relevance of our study to heavy ion
collisions is discussed.


title: Ferromagnetism of Nuclear Matter in the Relativistic Approach

abstract:
  We study the spin-polarization mechanism in the highly dense nuclear matter
with the relativistic mean-field approach. In the relativistic Hartree-Fock
framework we find that there are two kinds of spin-spin interaction channels,
which are the axial-vector and tensor exchange ones. If each interaction is
strong and different sign, the system loses the spherical symmetry and holds
the spin-polarization in the high-density region. When the axial-vector
interaction is negative enough, the system holds ferromagnetism.


title:
Charge-dependent nucleon-nucleon potential from chiral effective field
  theory

abstract:
  We discuss charge symmetry and charge independence breaking in a chiral
effective field theory approach for few-nucleon systems based on a modified
Weinberg power counting. We construct a two-nucleon potential with bound and
scattering states generated by means of a properly regularized
Lippmann-Schwinger equation. We systematically introduce strong
isospin-violating and electromagnetic operators in the theory. We use standard
procedures to treat the Coulomb potential between two protons in momentum
space. We present results for phase shifts in the proton-proton, the
neutron-proton and the neutron-neutron systems. We discuss the various
contributions to charge dependence and charge symmetry breaking observed in the
nucleon-nucleon scattering lengths.


title: Reaction and break-up cross sections of 11Li at 0.8 and 0.28 GeV/u

abstract:
  In this paper we calculate reaction and breakup cross sections for the two-
neutron halo nucleus of $^{11}$Li using the optical limit of Glauber theory.
Calculations are presented and compared to experimental data at 0.8 and 0.28
GeV/u on a series of targets. The $^{11}$Li nucleus is described as a
three-body system, a core plus two neutrons, with a phenomenological
neutron-core potential and a density dependent neutron-neutron interaction of
zero range. Three different wave functions are constructed which have different
$(2s_{1/2})^2$ and $(1p_{1/2})^2$ two-neutron components but correspond to the
same binding energy close to the experimental value. We show that the agreement
with all the experimental observables is achieved only if the 11Li wave
function contains about 30% of $(2s_{1/2})^2$ configuration.


title: The Spectrum of Diquark Composites in Cold Dense QCD

abstract:
  The Bethe-Salpeter equations for spin zero diquark composites in the color
superconducting phase of $N_f=2$ and $N_f=3$ cold dense QCD are studied. The
explicit form of the spectrum of the diquarks with the quantum numbers of the
(pseudo-) Nambu-Goldstone bosons is derived.


title: Treatment of pairing correlations in nuclei close to drip lines

abstract:
  We discuss the HFB equations in coordinate representation,a suitable method
for handling the full effects of the continuous quasiparticle spectrum. We show
how the continuum HFB equations can be solved with the correct asymptotic
conditions instead of the discretization conditions which are commonly used in
the literature. The continuum HFB method is illustrated with a model where the
mean field and pairing field have simple forms. The relationship with the
continuum Hartree-Fock-BCS (HF-BCS) approximation is also discussed. Realistic
HFB and HF-BCS calculations based on Skyrme interactions are compared for the
case of a neutron-rich nucleus.


title:
Phase transitions in high energy heavy ion collisions within fluid
  dynamics

abstract:
  Recent advances in Fluid Dynamical modeling of heavy ion collisions are
presented, with particular attention to mesoscopic systems, QGP formation in
the pre FD regime and QGP hadronization coinciding with the final freeze-out.


title: Contemporary applications of Dyson-Schwinger equations

abstract:
  We illustrate the contemporary application of Dyson-Schwinger equations using
two examples: the calculation of pseudoscalar meson masses, an associated
model-independent mass formula and the approach to the heavy-quark limit; and
the study of nucleon observables, including a calculation of its mass, $M$, via
a covariant Fadde'ev equation and an estimate of pion-loop contributions to
$M$.


title: Dynamical Study of the Delta Excitation in N(e,e' pi) Reactions

abstract:
  The dynamical model developed in [Phys. Rev. C 54, 2660 (1996)] has been
applied to investigate the pion electroproduction reactions on the nucleon. It
is found that the model can describe to a very large extent the recent data of
p(e,e' pi^0) reaction from Jefferson Laboratory and MIT-Bates. The extracted
magnetic dipole(M1), electric dipole(E2), and Coulomb(C2) strengths of the
gamma N -> Delta transition are presented. It is found that the C2/M1 ratio
drops significantly with Q^2 and reaches about -13% at Q^2=4 (GeV/c)^2, while
the E2/M1 ratio remains close to the value \sim -3 % at the Q^2=0 photon point.
The determined M1 transition form factor drops faster than the usual dipole
form factor of the proton. We also find that the non-resonant interactions can
dress the gamma N -> Delta vertex to enhance strongly its strength at low Q^2,
but much less at high Q^2. Predictions are presented for future experimental
tests. Possible developments of the model are discussed.


title:
Relativistic mean field description for the shears band mechanism in
  $^{84}$Rb

abstract:
  For the first time, the Relativistic Mean Field (RMF) model is applied to the
shears band recently observed in $_{37}^{84}$Rb. Signals of the appearance of
the shears mechanism, such as smooth decreases of the shears angle and of the
$B$(M1)/$B$(E2) ratio with keeping the nearly constant tilt angle, are well
reproduced. Thus it is shown that the microscopic RMF model can nicely describe
the shears band in this nucleus.


title:
A boost to low energy nuclear reactions from preliminary elastic
  collisions (Carambole collisions)

abstract:
  In conventional nuclear experiments a beam of accelerated nuclei collides
with a target nucleus that is surrounded by other nuclei in a molecule, in
condensed matter, or in a plasma environment. It is shown that for low
collision energies possible nuclear reactions (including deuterium fusion) are
strongly boosted by the environment. The effect originates from a chain of
preliminary three elastic collisions which transform the projectile-target
experiment into one with colliding beams. Firstly, the projectile-target pair
of nuclei undergo elastic scattering in which the projectile shares its energy
and momentum with the target nucleus. Then the projectile and target nuclei
collide with different heavy nuclei from the environment. These latter
collisions change the velocities of the target and projectile nuclei and set
them again on the collision course. Finally, the same pair of nuclei collide
inelastically, this time giving rise to the nuclear reaction. The increased
energy of the target nucleus increases the relative velocity up to sqrt 2
times, resulting in a drastic exponential increase of the probability to
penetrate the Coulomb barrier and therefore sharply increasing the likelihood
of the nuclear reaction. Applications to laser-induced fusion are discussed.

categories: nucl-th cond-mat.mtrl-sci nucl-ex physics.plasm-ph


title:
"Colliding beam" enhancement mechanism of deuteron-deuteron fusion
  reactions in matter

abstract:
  We suggest a ``ping-pong'' mechanism of enhancement for fusion reactions
between a low energy external deuteron beam and the deuterons in a condensed
matter or molecular target. The mechanism is based on the possibility of
acceleration of a target deuteron by the Coulomb field of a projectile deuteron
with its subsequent rebound from a heavy atom in matter and the following
fusion of the two deuterons moving towards each other. This effectively
converts the fixed target process into a colliding beam reaction. In a simple
limiting case this reduces the negative penetrability exponent by a factor of
$\sqrt{2}$. We also discuss a contribution given by ``zero oscillations'' of a
bound target deuteron. The proposed mechanism is expected to be efficient in
compounds with target deuterons localized in the vicinity of heavy atoms.


title:
Nucleon number dependence of the onset of anomalous J/psi suppression
  and the dynamics of nuclear collisions

abstract:
  We point out that data on the onset of anomalous J/psi suppression as a
function of nucleon numbers A and B could provide information on the dynamics
of nuclear interactions. In particular the models of anomalous J/psi
suppression by Blaizot and Ollitrault (BO) and by Kharzeev, Lourenco, Nardi and
Satz (KLNS) are based on different assumptions on the dynamics of nuclear
collisions and lead to different predictions of the dependence of the onset of
anomalous J/psi suppression on nucleon numbers of colliding nuclei. The data on
this onset as function of A and B could become a tool for the study of the
dynamics of nuclear collisions and bring further evidence on J/psi suppression
by new form of hadronic matter, possibly Quark-Gluon Plasma.
  In particular we propose to study J/\psi suppression in A+Pb interaction with
nucleon number of A between 58 and 73 or a bit higher.


title: Phase Transitions in Dense Matter and Recent Topics of Neutron Stars

abstract:
  Core of neutron star consists of highly dense matter above normal nuclear
density, where phase transitions is expected to take place. We review some
phase transitions and recent topics of neutron stars.


title: Effective Field Theory in Nuclear Many-Body Physics

abstract:
  Recent progress in Lorentz-covariant quantum field theories of the nuclear
many-body problem (quantum hadrodynamics, or QHD) is discussed. The importance
of modern perspectives in effective field theory and density functional theory
for understanding the successes of QHD is emphasized.
  To appear in: 150 Years of Quantum Many-Body Theory: A conference in honour
of the 65th birthdays of John W. Clark, Alpo J. Kallio, Manfred L. Ristig, and
Sergio Rosati.


title:
P-Odd Asymmetry in the Deuteron Disintegration by Circularly Polarized
  Photons

abstract:
  We calculate P-odd difference of the total cross-sections of the deuteron
disintegration by left and right polarized photons. The relative magnitude of
this difference in the threshold region is about 10^{-7}. Its experimental
measurement would give valuable information on the weak nucleon-nucleon
interaction at short distances.


title: On the f Sum Rule and its Extensions

abstract:
  The $f$ sum rule is derived in a non-relativistic frame and connected, via
Ward Identities, to the low energy Thomson scattering. A generalisation to
isospin symmetry in the nuclear case is discussed and linked to the Meson
Exchange Currents. The extension to a fully relativistic theory is then
discussed and it is shown that the energy-weighted sum rule becomes a relation
between the particle-hole and particle-antiparticle emission. Moreover the
generalisation to isospin symmetry is also allowed and provides
non-perturbative results.


title: GDH2000 Convenor's Report: Spin Polarizabilities

abstract:
  The subject of low energy polarized Compton scattering from the proton, which
is characterized by phenomenological spin-polarizabilities, is introduced and
connection is made to new theoretical and experimental developments which were
reported to this meeting.


title: Quarks in nuclear medium

abstract:
  Using the quark-meson coupling (QMC) model we study nuclear matter from the
point of view of quark degrees of freedom. As the nucleon model we adopt the
MIT bag model and the relativistic constituent quark model, where a square well
and harmonic oscillator potentials are used to confine the quarks. We introduce
the Lorentz-vector type confining potential as well as the Lorentz-scalar type
one in order to examine how the vector confining potential contributes to the
properties of the nucleon and nuclear matter. Next, we perform a re-definition
of the scalar field in matter and transform the QMC model to a QHD-type model
with a non-linear scalar potential. The result obtained from QMC is then
compared with the potentials which are determined so as to fit various
properties of finite nuclei and nuclear matter in relativistic mean-field
models. The QMC model provides the parameters $\kappa \sim 20 - 40$ (fm$^{-1}$)
and $\lambda \sim 80 - 400$ for the standard, non-linear scalar potential. We
discuss a relationship between the QMC and QHD-type models in detail.


title:
Observing compact quark matter droplets in relativistic nuclear
  collisions

abstract:
  Compactness is introduced as a new method to search for the onset of the
quark matter transition in relativistic heavy ion collisions. That transition
supposedly leads to stronger compression and higher compactness of the source
in coordinate space. That effect could be observed via pion interferometry. We
propose to measure the compactness of the source in the appropriate principal
axis frame of the compactness tensor in coordinate space.


title: Nuclear Shadowing and the Optics of Hadronic Fluctuations

abstract:
  A coordinate space description of shadowing in deep-inelastic lepton-nucleus
scattering is presented. The picture in the laboratory frame is that of
quark-gluon fluctuations of the high-energy virtual photon, propagating
coherently over large light-cone distances in the nuclear medium. We discuss
the detailed dependence of the coherence effects on the invariant mass of the
fluctuation. We comment on the issue of possible saturation in the shadowing
effects at very small Bjorken-$x$.


title:
Nucleonic resonance excitations with linearly polarized photon in
  $\gamma p\to \omega p$

abstract:
  In this work, an improved quark model approach to the $\omega$ meson
photo-production with an effective Lagrangian is presented. The {\it t}-channel
{\it natural}-parity exchange is taken into account through the Pomeron
exchange, while the {\it unnatural}-parity exchange is described by the $\pi^0$
exchange. With a very limited number of parameters, the available experimental
data in the low energy regime can be consistently accounted for. We find that
the beam polarization observables show sensitivities to some {\it s}-channel
individual resonances in the $SU(6)\otimes O(3)$ quark model symmetry limit.
Especially, the two resonances $P_{13}(1720)$ and $F_{15}(1680)$, which belong
to the representation $[{\bf 56, ^2 8}, 2, 2, J]$, have dominant contributions
over other excited states. Concerning the essential motivation of searching for
"missing resonances" in meson photo-production, this approach provides a
feasible framework, on which systematic investigations can be done.


title: On the free volume in nuclear multifragmentation

abstract:
  In many statistical multifragmentation models the volume available to the $N$
nonoverlapping fragments forming a given partition is a basic ingredient
serving to the simplification of the density of states formula. One therefore
needs accurate techniques for calculating this quantity. While the direct
Monte-Carlo procedure consisting of randomly generating the fragments into the
freeze-out volume and counting the events with no overlapped fragments is
numerically affordable only for partitions with small $N$, the present paper
proposes a Metropolis - type simulation which allows accurate evaluations of
the free volume even for cases with large $N$. This procedure is used for
calculating the available volume for various situations. Though globally this
quantity has an exponential dependence on $N$, variations of orders of
magnitude for partitions with the same $N$ may be identified. A parametrization
based on the virial approximation adjusted with a calibration function,
describing very well the variations of the free volume for different partitions
having the same $N$ is proposed. This parametrization was successfully tested
within the microcanonical multifragmentation model from [Al. H. Raduta and Ad.
R. Raduta, Phys. Rev. C {\bf 55}, 1344 (1997); {\it ibid.}, {\bf 56}, 2059
(1997)]. Finally, it is proven that parametrizations of the free volume solely
dependent on $N$ are rather inadequate for multifragmentation studies producing
important deviations from the exact results.


title:
Asymptotic Behavior of Nucleon Electromagnetic Form Factors in Space-
  and Time-Like Regions

abstract:
  We compare the existing data about electromagnetic form factors of the proton
in the time-like region of momentum transfer (up to $q^2\simeq$ 14
(GeV/c)$^2$), with the corresponding data in the space-like region. From the
constrains given by the Phragm\`en-Lindel\"of theorem, it turns out that the
asymptotic regime can not be reached simultaneously for both form factors
(electric and magnetic) in the considered region of momentum transfer. The
angular dependence for the annihilation processes, such as
$\bar{p}+p\leftrightarrow e^++e^-$, is sensitive to the asymptotic properties
of form factors and to the two-photon physics in the time-like region.


title:
Rotations in isospace: a doorway to the understanding of neutron-proton
  superfluidity in N=Z nuclei

abstract:
  The $T$=2 excitations in even-even $N$=$Z$ nuclei are calculated within the
isospin cranked mean-field approach. The response of pairing correlations to
rotation in isospace is investigated. It is shown that whereas the isovector
pairing rather modestly modifies the single-particle moment of inertia in
isospace, the isoscalar pairing strongly reduces its value. This reduction of
the moments of inertia in isospace with respect to its rigid body value is a
strong indicator of collective isoscalar pairing correlations. Beautiful
analogies between the role of isovector pairing for the case of spatial
rotations and the role of isoscalar pairing for the case of iso-rotations are
underlined.


title: Phi^{zero}-N Bound State

abstract:
  We show that the QCD van der Waals attractive potential is strong enough to
bind a $\phi^{0}$ meson onto a nucleon inside a nucleus to form a bound state.
The direct experimental signature for such an exotic state is proposed in the
case of subthreshold $\phi^{0}$ meson photoproduction from nuclear targets. The
production rate is estimated and such an experiment is found to be feasible at
the Jefferson Laboratory.


title: Inclusive Particle Spectra at RHIC

abstract:
  A simulation is performed of the recently reported data from PHOBOS at
energies of 56 and 130 A GeV using the relativistic heavy ion cascade LUCIFER
which had previously given a good description of the NA49 inclusive spectra at
E=17.2 A GeV. The results compare well with these early measurements at RHIC.


title:
Long- and medium-range components of the nuclear force in quark-model
  based calculations

abstract:
  Quark-model descriptions of the nucleon-nucleon interaction contain two main
ingredients, a quark-exchange mechanism for the short-range repulsion and
meson-exchanges for the medium- and long-range parts of the interaction. We
point out the special role played by higher partial waves, and in particular
the 1F3, as a very sensitive probe for the meson-exchange part employed in
these interaction models. In particular, we show that the presently available
models fail to provide a reasonable description of higher partial waves and
indicate the reasons for this shortcoming.


title:
Elastic and radiative pi^+p scattering and properties of the Delta^{++}
  resonance

abstract:
  We study the Delta^{++} contributions to elastic and radiative \pi^+p
scattering within an effective Lagrangian model which incorporates the Delta,
N, rho and sigma meson degrees of freedom. This model provides a description of
the Delta resonance and its interactions that respects electromagnetic gauge
invariance and invariance under contact transformations when finite width
effects are incorporated. Following recent developments in the description of
unstable gauge bosons, we use a complex mass scheme to introduce the finite
width of the Delta^{++} without spoiling gauge invariance. The total cross
section of elastic \pi^+p scattering, whose amplitude exhibits the resonant
plus background structure of S-matrix theory, is used to fix the mass, width
and strong coupling of the \Delta resonance. The differential cross section of
elastic scattering is found in very good agreement with experimental data. The
magnetic dipole moment of the Delta^{++}, \mu_{Delta}, is left as the only
adjustable parameter in radiative \pi^+p scattering. From a fit to the most
sensitive configurations for photon emission in this process, we obtain
\mu_{\Delta} = (6.14 +-0.51)e/2m_p, in agreement with predictions based on the
SU(6) quark model.


title: Nuclear processes in magnetic fusion reactors with polarized fuel

abstract:
  We consider the processes $d +d \to n +{^3He}$, $d +{^3He} \to p +{^4He}$, $d
+{^3H} \to n +{^4He}$, ${^3He} +{^3He}\to p+p +{^4He}$, ${^3H} +{^3He}\to d
+{^4He}$, with particular attention for applications in fusion reactors. After
a model independent parametrization of the spin structure of the matrix
elements for these processes at thermal colliding energies, in terms of partial
amplitudes, we study polarization phenomena in the framework of a formalism of
helicity amplitudes. The strong angular dependence of the final nuclei and of
the polarization observables on the polarizations of the fuel components can be
helpful in the design of the reactor shielding, blanket arrangement etc..We
analyze also the angular dependence of the neutron polarization for the
processes $\vec d +\vec d \to n +{^3He}$ and $\vec d +\vec {^3H} \to n
+{^4He}$.


title: Semiclassical Calculation of Shell Effects in Deformed Nuclei

abstract:
  We summarize recent work in which the shell effect, which causes the onset of
the mass asymmetry in nuclear fission, could be explained semiclassically in
the framework of the periodic orbit theory. We also present new results for the
inclusion of a spin-orbit interaction in the semiclassical calculation of the
level density.


title:
Covariant nucleon electromagnetic form factors from the
  Goldstone-boson-exchange quark model

abstract:
  We present a study of proton and neutron electromagnetic form factors for the
recently proposed Goldstone-boson-exchange constituent quark model. Results for
charge radii, magnetic moments, and electric as well as magnetic form factors
are reported. The calculations are performed in a covariant framework using the
point-form approach to relativistic quantum mechanics. All the predictions by
the Goldstone-boson-exchange constituent quark model are found in remarkably
good agreement with existing experimental data.


title: Phases of QCD at High Baryon Density

abstract:
  We review recent work on the phase structure of QCD at very high baryon
density. We introduce the phenomenon of color superconductivity and discuss how
the quark masses and chemical potentials determine the structure of the
superfluid quark phase. We comment on the possibility of kaon condensation at
very high baryon density and study the competition between superfluid, density
wave, and chiral crystal phases at intermediate density.


title: At the edge of nuclear stability: nonlinear quantum amplifiers

abstract:
  We show that nuclear states lying at the edge of stability may show
enormously enhanced response to small perturbations. For example, a 0.1% change
in the strength of the strong nucleon-nucleon interaction can cause almost a
hundred times bigger change in the resonance energy of the 0+_2 state of 12C.


abstract:
  We show that nuclei lying at the edge of stability can behave as nonlinear
quantum amplifiers. A tiny change in the nucleon-nucleon interaction can
trigger a much bigger change in the binding energy of these systems, relative
to the few-cluster breakup threshold.


title:
Fine-tuning the basic forces of nature through the triple-alpha process
  in red giant stars

abstract:
  We show that the synthesis of carbon and oxygen through the triple-alpha
process in red giant stars is extremely sensitive to the fine details of the
nucleon-nucleon (N-N) interaction. A +/-0.5% change in the strength of the N-N
force would reduce either the carbon or oxygen abundance by as much as a factor
of 30-1000. This result may be used to constrain some fundamental parameters of
the Standard Model.


title: Microscopic calculations for solar nuclear reactions

abstract:
  We have studied the 4He(3He,gamma)7Be, 3He(3He,2p)4He, and 7Be(p,gamma)8B
reactions of the solar p-p chain, using microscopic cluster models. Among other
results, we showed that the 6Li+p channel has a nontrivial effect on the
7Be-producing reaction, that the existence of a resonance in 6Be close to the
3He+3He threshold is rather unlikely, and that the correlations between some
properties of 7Be/8B and the low-energy cross section of 7Be(p,gamma)8B might
help one to constrain the value of the S_17(0) astrophysical S-factor.


title: Chiral unitary approach to the K^- deuteron scattering length

abstract:
  Starting from a recent model where the Kbar N amplitudes are evaluated from
the chiral Lagrangians using a coupled channel unitary method, we evaluate here
the scattering length for K^- deuteron scattering. We find that the double
scattering contribution is very large compared to the impulse approximation and
that the charge exchange contribution of this rescattering is as large as the
sequential K^- scattering on the two nucleons. Higher order rescattering
corrections are evaluated using coupled channels with K^- and Kbar^0 within the
integral form of the fixed centre approximation to the Faddeev equations. The
higher order corrections involving intermediate pions and hyperons are found
negligible.


title:
Incorporating Radial Flow in the Lattice Gas Model for Nuclear
  Disassembly

abstract:
  We consider extensions of the lattice gas model to incorporate radial flow.
Experimental data are used to set the magnitude of radial flow. This flow is
then included in the Lattice Gas Model in a microcanonical formalism. For
magnitudes of flow seen in experiments, the main effect of the flow on
observables is a shift along the $E^*/A$ axis.


title: Dilepton production in proton-proton collisions at BEVALAC energies

abstract:
  The dilepton production in elementary ${pp\to e^{+}e^{-}X}$ reactions at
BEVALAC energies $T_{lab}=1\div 5$ GeV is investigated. The calculations
include direct ${e^{+}e^{-}}$ decays of the vector mesons $\rho ^{0}$, $\omega
$, and $\phi $, Dalitz decays of the $\pi ^{0}$-, $\eta $-, $% \rho $-, $\omega
$-, and $\phi $-mesons, and of the baryon resonances $% \Delta (1232),N(1520),$
$... $ . The subthreshold vector meson production cross sections in $pp$
collisions are treated in a way sufficient to avoid double counting with the
inclusive vector meson production. The vector meson dominance model for the
transition form factors of the resonance Dalitz decays $R\to e^{+}e^{-}N$ is
used in an extended form to ensure correct asymptotics which are in agreement
with the quark counting rules. Such a modification gives an unified and
consistent description of both $R\to N\gamma $ radiative decays and $R\to N\rho
(\omega)$ meson decays.
  The effect of multiple pion production on the experimental efficiency for the
detection of the dilepton pairs is studied. We find the dilepton yield in
reasonable agreement with the experimental data for the set of intermediate
energies whereas at the highest energy $T_{lab}=4.88$ GeV the number of
dilepton pairs is likely to be overestimated experimentally in the mass range
$M=300\div 700$ MeV.


title:
Nucleon-Nucleon Optical Potentials \and Fusion of $\pi$N, KN, $\pi\pi$
  and NN Systems

abstract:
  Several boson exchange potentials, describing the NN interaction $T_\ell\le
300$ MeV with high quality, are extended in their range of applicability as NN
optical models with complex local or separable potentials in r-space or as
complex boundary condition models. We determine in this work the separable
potential strengths or boundary conditions on the background of the Paris,
Nijmegen-I, Nijmegen-II, Reid93, AV18 and inversion potentials. Other hadronic
systems, $\pi$N, KN and $\pi\pi$, are studied with the same token. We use the
latest phase shift analyzes SP00, SM00 and FA00 by Arndt {\em et al.} as input
and thus extent the mentioned potential models from 300 MeV to 3 GeV . The
imaginary parts of the interaction account for loss of flux into direct or
resonant production processes. For a study of resonances and absorption the
partial waves wave functions with physical boundary conditions are calculated.
We display the energy and radial dependences of flux losses and radial
probabilities. The results lend quantitative support for the established mental
image of intermediate elementary particle formation in the spirit of fusion.


title: The NN Phase Shifts <3 GeV and Resonance Features

abstract:
  Solutions SP00, SM00 and FA00 of nucleon-nucleon (NN) phase shift analyzes by
Arndt et al. are used in optical model studies. The partial waves, single
channels J.leq.7 and coupled channels J.leq.6, are scrutinized. The radial
probability distributions and losses of flux are used to identify the known
Delta and N* resonances as well as anticipated other structures. The energy
interval extends to 3 GeV.


title:
Deuteron Compton scattering and electromagnetic polarizabilities of the
  nucleon

abstract:
  Differential cross section of deuteron Compton scattering has been calculated
using the Bonn NN-potential, a consistent set of meson-exchange currents and
seagulls, and lowest- and higher-order electromagnetic polarizabilities of the
nucleon. Estimates of the polarizabilities of the neutron are obtained from
recent experimental data.


title: The GDH sum rule for the Delta isobar: A possible anomaly?

abstract:
  The GDH sum rule is discussed for the Delta(1232) resonance. It is shown that
apart from ordinary excitations to higher-energy states, the sum rule contains
a large negative contribution due to de-excitation into the nucleon state.
Therefore, a fulfillment of the sum rule assumes a strong coupling of Delta^+
and Delta^0 to resonances of spin 5/2 and higher. Calculations performed in
quark models suggest that D15(1675) may be such a resonance. However, its
strength is found to be not sufficient for bringing the GDH sum rule to a
theoretically expected positive magnitude.


title: Interactions, Currents, and the Structure of Few-Nucleon Systems

abstract:
  Our current understanding of the structure of nuclei with up to A=8,
including energy spectra, electromagnetic form factors, and weak transitions,
is reviewed within the context of a realistic approach to nuclear dynamics
based on two- and three- nucleon interactions and associated electro-weak
currents. Low-energy radiative and weak capture reactions of astrophysical
relevance involving these light systems are also discussed.


title: Electromagnetic Structure of Few-Nucleon Systems: a Critical Review

abstract:
  Our current understanding of the structure of nuclei with up to A=8,
including energy spectra, electromagnetic form factors, and capture reactions,
is critically reviewed within the context of a realistic approach to nuclear
dynamics based on two- and three-nucleon interactions and associated
electromagnetic currents.


title:
Poissonian reducibility and thermal scaling within the lattice gas model
  and molecular dynamics model

abstract:
  The emission of clusters in the nuclear disassembly is investigated within
the framework of isospin dependent lattice gas model and classical molecular
dynamics model. As observed in the recent experimental data, it is found that
the emission of individual cluster is poissonian and thermal scaling is
observed in the linear Arrhenius plots made from the average multiplicity of
each cluster. The mass, isotope and charge dependent "emission barriers" are
extracted from the slopes of the Arrhenius plots and their possible physical
implications are investigated.


title:
J/psi absorption by pi and rho mesons in a meson exchange model with
  anomalous parity interactions

abstract:
  We reanalyze the dissociation process of the $J/\psi$ by $\pi$ and $\rho$
mesons into $D + \bar{D}$, $D^* + \bar{D}$, $D + \bar{D}^*$, and $D^* +
\bar{D}^*$ within a meson exchange model. In addition to the dissociation
mechanisms considered in the literature, we consider anomalous parity
interactions, whose couplings are constrained by heavy quark spin symmetry and
phenomenology. This opens new dissociation channels and adds new diagrams in
the previously considered processes. Compared to the previous results, we find
that these new additions have only a minor effect on the $\rho + J/\psi$ total
inelastic cross section, but reduce the one for $\pi + J/\psi$ by about 50 %
near the threshold.


title:
Hadron Structure Studied with the Electromagnetic Probe - from Giant
  Resonances to Meson Production

abstract:
  The development of theoretical photonuclear physics over the last 40 years is
illustrated by a few selected examples highlighting a number of important
issues like collective motion in nuclei, the role of subnuclear degrees of
freedom, relativity and meson production.


title: Effective Field Theory Power Counting at Finite Density

abstract:
  Effective field theory is applied to finite-density systems with an
unnaturally large scattering length, such as neutron matter. A new
organizational scheme is identified and connected with an expansion in inverse
powers of the number of space-time dimensions. This power counting allows for
analytic calculations in many-body systems and reproduces the hole-line
expansion of traditional nuclear physics.


title: Quark-meson coupling model for a nucleon

abstract:
  We considered the quark-meson coupling model for a nucleon. The model
describes a nucleon as an MIT bag, in which quarks are coupled to the scalar
and the vector mesons. A set of coupled equations for the quark and the meson
fields are obtained and are solved in a self-consistent manner. We show that
the mass of a dressed MIT bag interacting with $\sigma$- and $\omega$-meson
fields differs considerably from the mass of the free MIT bag. The effects of
the density-dependent bag constant are investigated. The results of our
calculations imply that the self-energy of the bag in the quark-meson coupling
model is significant and needs to be considered in doing the calculations for
nuclear matter or finite nuclei.


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

abstract:
  Here a short synthesis is presented of the work, developed in the last two
years by the Brescia Collaboration, on the phenomenology of antinucleon-nucleon
and antinucleon-nucleus annihilation at small momenta (below 300 MeV/c in the
laboratory), with special stress on the role of general principles.


title:
Production of hot nuclei in Fermi energy domain: from peripheral to
  central collisions

abstract:
  The production mechanism of highly excited nuclei in the Fermi energy domain
is investigated. A phenomenological approach, based on the exciton model, is
used for the description of pre-equilibrium emission. A model of deep inelastic
transfer is employed for the peripheral collisions in the post-pre-equilibrium
stage. An approach to describe more central collisions is proposed. A geometric
overlap formula is employed in a way suitable for given energy domain. A simple
geometric approach describing the interaction of participant and spectator
zones is used to determine the incomplete fusion channel. Excitation energies
of both fragments are determined. Results of the calculation are compared to
available experimental data and an overall satisfactorily agreement is
obtained. The model's ability to describe the production of the hot nuclei can
be employed in the study of multifragmentation and/or in the production of rare
beams.


title:
Isospin influences on particle emission and critical phenomenon in
  nuclear dissociation

abstract:
  Features of particle emission and critical point behavior are investigated as
functions of the isospin of disassembling sources and temperature at a moderate
freeze-out density for medium-size Xe isotopes in the framework of isospin
dependent lattice gas model. Multiplicities of emitted light particles,
isotopic and isobaric ratios of light particles show the strong dependence on
the isospin of the dissociation source, but double ratios of light isotope
pairs and the critical temperature determined by the extreme values of some
critical observables are insensitive to the isospin of the systems. Values of
the power law parameter of cluster mass distribution, mean multiplicity of
intermediate mass fragments ($IMF$), information entropy ($H$) and Campi's
second moment ($S_2$) also show a minor dependence on the isospin of Xe
isotopes at the critical point. In addition, the slopes of the average
multiplicites of the neutrons ($N_n$), protons ($N_p$), charged particles
($N_{CP}$), and IMFs ($N_{imf}$), slopes of the largest fragment mass number
($A_{max}$), and the excitation energy per nucleon of the disassembling source
($E^*/A$) to temperature are investigated as well as variances of the
distributions of $N_n$, $N_p$, $N_{CP}$, $N_{IMF}$, $A_{max}$ and $E^*/A$. It
is found that they can be taken as additional judgements to the critical
phenomena.


title: Open charm production in relativistic nucleus-nucleus collisions

abstract:
  We calculate excitation functions for open charm mesons in $Au+Au$ reactions
from AGS to RHIC energies within the HSD transport approach which is based on
string, quark, diquark ($q, \bar{q}, qq, \bar{q}\bar{q}$) and hadronic degrees
of freedom. The open charm cross sections from $pN$ and $\pi N$ reactions are
fitted to results from PYTHIA and scaled in magnitude to the available
experimental data. From our dynamical calculations we find an approximate
$m_T$-scaling for pions, kaons, $D$-mesons and $J/\Psi$ -- when discarding
final state elastic scattering of kaons and $\phi$-mesons with pions -- in
central collisions of $Au + Au$ at 160 A$\cdot$GeV (with an apparent slope of
176 MeV) without employing the assumption of a Quark-Gluon Plasma (QGP). We
demonstrate that this result is essentially due to a relative $m_T$-scaling in
$pp$ collisions at $\sqrt{s} \approx$ 17.3 GeV. At lower bombarding energies of
25 A$\cdot$GeV a suppression of $D$-mesons by a factor of $\sim$ 10 relative to
a global $m_T$-scaling with slope 143 MeV is expected. However, when
incorporating attractive $D$-meson self energies as suggested by QCD sum rules,
an approximate $m_T$-scaling is regained even at 25 A$\cdot$GeV. The effects of
$D$-meson rescattering and charmonium absorption are discussed, furthermore,
with respect to rapidity and transverse mass distributions in central
collisions of $Au + Au$ at 25, 160 A$\cdot$GeV and 21.3 A$\cdot$TeV.


title:
Ground-gamma band mixing and odd-even staggering in heavy deformed
  nuclei

abstract:
  It is proposed that the odd-even staggering (OES) in the $\gamma$- bands of
heavy deformed nuclei can be reasonably characterized by a discrete
approximation of the fourth derivative of the odd-even energy difference as a
function of angular momentum $L$. This quantity exhibits a well developed
staggering pattern (zigzagging behavior with alternating signs) in rare earth
nuclei and actinides with long $\gamma$- bands ($L\geq 10$). It is shown that
the OES can be interpreted reasonably as the result of the interaction of the
$\gamma$ band with the ground band in the framework of a Vector Boson Model
with SU(3) dynamical symmetry. The model energy expression reproduces
successfully the staggering pattern in all considered nuclei up to $L=12-13$.
The general behavior of the OES effect in rotational regions is studied in
terms of the ground--$\gamma$ band-mixing interaction, showing that strong OES
effect occurs in regions with strong ground--$\gamma$ band-mixing interaction.
The approach used allows a detailed comparison of the OES in $\gamma$ bands
with the other kinds of staggering effects in nuclei and diatomic molecules.


title: Zipf's Law in the Liquid Gas Phase Transition of Nuclei

abstract:
  Zipf's law in the field of linguistics is tested in the nuclear disassembly
within the framework of isospin dependent lattice gas model. It is found that
the average cluster charge (or mass) of rank $n$ in the charge (or mass) list
shows exactly inversely to its rank, i.e., there exists Zipf's law, at the
phase transition temperature. This novel criterion shall be helpful to search
the nuclear liquid gas phase transition experimentally and theoretically. In
addition, the finite size scaling of the effective phase transition temperature
at which the Zipf's law appears is studied for several systems with different
mass and the critical exponents of $\nu$ and $\beta$ are tentatively extracted.


title:
Barrier penetration and rotational damping of thermally excited
  superdeformed nuclei

abstract:
  We construct a microscopic model of thermally excited superdeformed states
that describes both the barrier penetration mechanism, leading to the decay-out
transitions to normal deformed states, and the rotational damping causing
fragmentation of rotational E2 transitions. We describe the barrier penetration
by means of a tunneling path in the two-dimensional deformation energy surface,
which is calculated with the cranked Nilsson-Strutinsky model. The individual
excited superdeformed states and associated E2 transition strengths are
calculated by the shell model diagonalization of the many-particle many-hole
excitations interacting with the delta-type residual two-body force. The effect
of the decay-out on the excited superdeformed states are discussed in detail
for $^{152}$Dy, $^{143}$Eu and $^{192}$Hg.


title:
First Order Kaon Condensation in Neutron Stars: Finite Size Effects in
  the Mixed Phase

abstract:
  We study the role of Coulomb and surface effects on the phase transition from
dense nuclear matter to a mixed phase of nuclear and kaon-condensed matter. We
calculate corrections to the bulk calculation of the equation of state (EOS)
and the critical density for the transition by solving explicitly for
spherical, cylindrical, and planar structures. The importance of Debye
screening in the determination of the charged particle profiles is studied in
some detail. We find that the surface and Coulomb contributions to the energy
density are small, but that they play an important role in the determination of
the critical pressure for the transition, as well as affecting the size and
geometry of favored structures. This changes the EOS over a wide range of
pressure and consequently increases the maximum mass by about 0.1 solar masses.
Implications for transport properties of the mixed phase are also discussed.


title: Comment on New Results for the Charged Pion Electromagnetic Form Factor

abstract:
  In the paper nucl-ex/0010009 by The Jefferson Lab F_pi Collaboration the new
results for the charged pion electromagnetic form factor are presented. The
approach given in our paper hep-ph/9811318, "On a possible estimation of the
constituent--quark parameters from Jefferson Lab experiments on the pion form
factor" makes it possible to estimate the mass of constituent quark from such
kind of experiment. Now this estimation gives M=0.21 GeV.


title:
Total 4He Photoabsorption Cross Section Revisited: Correlated HH versus
  Effective Interaction HH

abstract:
  Two conceptually different hyperspherical harmonics expansions are used for
the calculation of the total 4He photoabsorption cross section. Besides the
well known method of CHH the recently introduced effective interaction approach
for the hyperspherical formalism is applied. Semi-realistic NN potentials are
employed and final state interaction is fully taken into account via the
Lorentz integral transform method. The results show that the effective
interaction leads to a very good convergence, while the correlation method
exhibits a less rapid convergence in the giant dipole resonance region. The
rather strong discrepancy with the experimental photodisintegration cross
sections is confirmed by the present calculations.


title: Field Redefinitions at Finite Density

abstract:
  The apparent dependence of nuclear matter observables on off-shell properties
of the two-nucleon potential is re-examined in the context of the effective
field theory (EFT) approach. Finite density (thermodynamic) observables are
invariant under field redefinitions, which extends the well-known theorem about
the invariance of S-matrix elements. Simple examples demonstrate how field
redefinitions can shift contributions between purely off-shell two-body
interactions and many-body forces, leaving both scattering and finite-density
observables unchanged. If only the transformed two-body potentials are kept,
however, the nuclear matter binding curves will depend on the off-shell part
(generating ``Coester bands''). The correspondence between field redefinitions
and unitary transformations, which have traditionally been used to generate
``phase-equivalent'' nucleon-nucleon potentials, is also demonstrated.


title: Toy Model for Pion Production in Nucleon-Nucleon Collisions

abstract:
  We develop a toy model of pion production in nucleon-nucleon collisions that
reproduces some of the features of the chiral Lagrangian calculations. We
calculate the production amplitude and examine some common approximations.


title:
Electromagnetic isoscalar rho-pi-gamma exchange current and the
  anomalous action

abstract:
  Using modern data, we first refit constants needed to complete an anomalous
pi-rho-omega-a_1 Lagrangian obtained within the approach of hidden local
symmetries. Then we derive from this Lagrangian electromagnetic isoscalar
rho-pi-gamma and rho-a_1-gamma currents needed in calculations of the deuteron
electromagnetic form factors at large momentum transfers.


title: Nonexistence of a $\eta NN$ quasibound state

abstract:
  We have solved the Faddeev equations for $\eta d$ elastic scattering using
realistic separable interactions for the $NN$ and coupled $\eta N$-$\pi N$
subsystems. We found that including explicitly the pion channel in the integral
equations drastically reduces the attraction that is present in the system. As
a consequence, the existence of a $\eta NN$ quasibound state is excluded by the
modern $\eta N$ amplitude analysis.


title:
Multiplicity distributions associated to subthreshold events in
  heavy-ion collisions

abstract:
  Subthreshold events (pion production, for instance) at energies $E< m_{\pi}$
are treated as rare events. The associated multiplicity distribution $P_c (n)$
and the unconstrained distribution P(n), when there is no rare event-trigger,
are related by the model independent relation $P_c (n) = {n^2 \over
\average{n^2}} P(n)$. This relation, and in particular its improved version
inspired in clustering of nucleons, is in fair agreement with data. Moreover,
it allows to extract from the multiplicity data information on the number of
nucleons involved in meson production processes, occuring at energies below the
production threshold in free nucleon collisions.


title:
Simulation of Nucleus-Nucleus Interactions in the Framework of the
  FRITIOF Model at the Energy of 3.3 GeV/nucleon

abstract:
  The intranuclear cascade model overestimates the multiplicity of produced
mesons in nucleus-nucleus interactions without taking into account meson and
baryon resonance production. Inclusion of the resonances leads to decreasing
multiplicity of mesons, neutrons and protons. In order to overcome the problem,
it is proposed to use the FRITIOF model adapted to low energies in a
combination with the reggeon theory inspired model of nuclear destruction. It
is shown that the combination allows one to reproduce satisfactory the meson
and baryon yields in the nucleus-nucleus collisions at the energy of 3.3
GeV/nucleon. The combined model works faster than typical quantum molecular
dynamic model, and allows one to estimate the data needed for creation of
electro-nuclear amplifier.


title: Neutron stars in a class of non-linear relativistic models

abstract:
  We introduce in this work a class of relativistic models for nuclear matter
and neutron stars which exhibits a parameterization, through mathematical
constants, of the non-linear meson-baryon couplings. For appropriate choices of
the parameters, it recovers current QHD models found in the literature: Walecka
and the Zimanyi and Moszkowski models (ZM and ZM3). For other choices of the
parameters, the new models give very interesting and new physical results.We
have obtained numerical values for the maximum mass and radius of a neutron
star sequence, red-shift, hyperon populations, radial distribution of
particles, among other relevant static properties of these stellar objects. The
phenomenology of neutron stars in ZM models is presented and compared to the
phenomenology obtained in other versions of the Walecka model. We have found
that the ZM3 model is too soft and predicts a very small maximum neutron star
mass, $\sim0.72 M_\odot$. A strong similarity between the results of ZM-like
models and those with exponential couplings is noted. Sensibility of the
results to the specific choice of the values for the binding energy and
saturation density is pointed out. Finally, we discuss the very intense scalar
condensates found in the interior of neutron stars which may lead to negative
effective masses.


title: Study for the s-wave in ^{10}Li with analysis of cross-sections

abstract:
  We study the effect of s-wave cross-sections in $^{4}$He+$n$ and $^{9}$Li+$n$
elastic scattering reactions by using the Jost function method (JFM). In
$^{5}$He ($^{4}$He+$n$), the s-wave pole of the $S$-matrix does not contribute
so much to the total cross-section. On the other hand, in $^{10}$Li
($^{9}$Li+$n$), the s-wave component can not be neglected due to a relatively
strong attraction for the s-waves of the core+$n$ potential. It is shown that
the $^{9}$Li-$n$ potential, which is microscopically derived by taking into
account the pairing-blocking effect for a p-wave neutron, reproduces the s-wave
pole close to the $^{9}$Li+$n$ threshold and strongly enhances the s-wave
cross-section near the threshold.


title: Isovector multiphonon excitations in near spherical nuclei

abstract:
  The lowest isoscalar and isovector quadrupole and octupole excitations in
near spherical nuclei are studied within the the proton-neutron version of the
interacting boson model including quadrupole and octupole bosons (sdf-IBM-2).
The main decay modes of these states in near spherical nuclei are discussed.


title:
Symmetry-Unrestricted Skyrme-Hartree-Fock-Bogoliubov Calculations for
  Exotic Shapes in N=Z Nuclei from 64Ge to 84Mo

abstract:
  By performing fully 3D symmetry-unrestricted Skyrme-Hartree-Fock-Bogoliubov
calculations, we discuss shape coexistence and possibility of exotic
deformations simultaneously breaking the reflection and axial symmetries in
proton-rich N=Z nuclei: 64Ge, 68Se, 72Kr, 76Sr, 80Zr and 84Mo. Results of
calculation indicate that the oblate ground state of 68Se is extremely soft
against the Y33 triangular deformation, and that the low-lying spherical
minimum coexisting with the prolate ground state in 80Zr may be unstable
against the Y32 tetrahedral deformation.


title:
Transition to resonance-rich matter in heavy ion collisions at RHIC
  energies

abstract:
  The equilibration of hot and dense nuclear matter produced in the central
region in central Au+Au collisions at $\sqrt{s}=200$ AGeV is studied within the
microscopic transport model UrQMD. The pressure here becomes isotropic at $t
\approx 5$ fm/c. Within the next 15 fm/c the expansion of the matter proceeds
almost isentropically with the entropy per baryon ratio $S/A \approx 150$.
During this period the equation of state in the $(P,\epsilon)$-plane has a very
simple form, $P=0.15 \epsilon$. Comparison with the statistical model (SM) of
an ideal hadron gas reveals that the time of $\approx 20$ fm/$c$ may be too
short to attain the fully equilibrated state. Particularly, the fractions of
resonances are overpopulated in contrast to the SM values. The creation of such
a long-lived resonance-rich state slows down the relaxation to chemical
equilibrium and can be detected experimentally.


title: Odd-even mass differences in self-consistent Mean-Field calculations

abstract:
  The odd-even mass staggering (OES) of nuclei is analyzed in the context of
self-consistent mean-field calculations. The procedure developed allows to
understand the OES for spherical as well as for deformed nuclei. Comparison
with results at the Hartree-Fock level shows the non-perturbative effect on
this observable of the inclusion of pairing correlations.


title: Role of relativity and nucleon compositeness in few-body systems

abstract:
  Recent progress is reviewed in four areas where new experimental data have
been obtained: proton-proton bremsstrahlung, threshold pion production in
proton-proton collisions, elastic electron-deuteron scattering and deuteron
photodisintegration at several GeV photon energy. Relativistic effects are
expected to be significant in these processes. High energy photodisintegration
suggests that partonic behavior could be relevant in subamplitudes at large
momentum transfer.


title: Elastic p-3He and n-3H scattering with two- and three-body forces

abstract:
  We report on a microscopic calculation of n-3H and p-3He scattering employing
the Argonne v_{18} and v_8' nucleon-nucleon potentials with and without
additional three-nucleon force. An R-matrix analysis of the p-3He and n-3H
scattering data is presented. Comparisons are made for the phase shifts and a
selection of measurements in both scattering systems. Differences between our
calculation and the R-matrix results or the experimental data can be attributed
to only two partial waves (3P0 and 3P2). We find the effect of the Urbana IX
and the Texas-Los Alamos three-nucleon forces on the phase shifts to be
negligible.


title: Fock exchange terms in non-linear Quantum Hadrodynamics

abstract:
  We propose a method to introduce Fock term contributions in relativistic
models of fermions coupled to mesons, including self-interactions for the
mesonic fields. We show that effects on equilibrium properties and on the
dynamical response of the fermionic system can be consistently accounted for.
Some implications on equilibrium properties of asymmetric nuclear matter are
discussed.


title:
Fission barriers of neutron-rich and superheavy nuclei calculated with
  the ETFSI method

abstract:
  Using the ETFSI (extended Thomas-Fermi plus Strutinsky integral) method, we
have calculated the fission barriers of nearly 2000 exotic nuclei, including
all the neutron-rich nuclei up to A=318 that are expected to be relevant to the
r-process, and all the superheavy nuclei in the vicinity of N=184, with Z<=120.
Our calculations were performed with the Skyrme force SkSC4, which was
determined in the ETFSI-1 mass fit. For proton-deficient nuclei in the region
of N=184 we find the barriers to be much higher than previously believed, which
suggests that the r-process path might continue to mass numbers well beyond
300. For the superheavy nuclei we typically find barrier heights of 6-7 MeV.


title: Extrapolation of mean-field models to superheavy nuclei

abstract:
  The extrapolation of self-consistent nuclear mean-field models to the region
of superheavy elements is discussed with emphasis on the extrapolating power of
the models. The predictions of modern mean-field models are confronted with
recent experimental data. It is shown that a final conclusion about the
location of the expected island of spherical doubly-magic superheavy nuclei
cannot be drawn on the basis of the available data.


title:
Shift of the 2$^+_1$ state of $^{10}$Be in the ternary cold fission of
  $^{252}$Cf

abstract:
  Recent experimental data indicate that in the ternary cold fission of
$^{252}$Cf the energy of the first excited state of the accompanying light
cluster $^{10}$Be is decreased by an amount ranging between $\approx$ 6 and 26
keV. A model is proposed to calculate the shift of the vibrational 2$^+_1$
state in $^{10}$Be when its heavy companions are the even-even nuclei
$^{146}$Ba and $^{96}$Sr. The stiffness parameters of the $\beta$-vibrations
are calculated within the self-consistent Hartree-Fock method with BCS pairing
correlations taken into account, and its change is determined by the
interaction of the light cluster with the heavy fragments. The results are
pointing to a dependence of the shift magnitude and signature on the relative
distance between the three clusters and their mutual orientation. Eventually it
is the anharmonic perturbation of the spherical vibrator which is responsible
for obtaining a negative energy shift of the 2$^+_1$ state.


title:
Angular Momenta of Even-Even Fragments in the Neutronless Fission of
  $^{252}$Cf

abstract:
  The recent advent of experimental techniques in which the dynamical
characteristics of fission fragments are determined more accurately, prompted
us to investigate the angular momentum acquired by fragments in a model which
describes the cold(neutronless) fission of $^{252}$Cf as the decay of a giant
nuclear molecule. The molecular configuration is a consequence of the interplay
between the attractive nuclear part and the repulsive Coulomb+nuclear forces.
The basic ideea of the present approach is to separate the radial(fission)
modes describing the decay of the molecule from the modes associated to
transversal vibrations(bending) of the fragments. The distance between the
centers of the two fragments is fixed by the requirement that the energy
released in the fission reaction $Q$, equals the sum of quantum zero-energies
of radial and transversal modes and the total excitation energy $E^*$. Using a
semiclassical coupled channel formalism we computed the additional angular
momenta acquired by the fragments during their post-scission motion, and found
that the Coulomb excitation accounts for less than 10% of the final spins.


title:
Molecular Collective Vibrations in the Ternary Neutronless Fission of
  $^{252}$Cf

abstract:
  Based on a recent experimental finding which may suggest the existence of a
tri-nuclear molecular structure before the cold ternary fragmentation of
$^{252}$Cf takes place, we solved the eigenvalue problem of a certain class of
vibrations which are very likely to occur in these molecules. These
oscillations are the result of the joined action of rotations of the heavier
fragments and the transversal vibrations of the lighter spherical cluster with
respect to the fission axis. In the calculation of the interaction between the
heavier fragments we took into account higher multipole deformations, including
the hexadecupole one, and introduced a repulsive nuclear part to insure the
creation of a potential pocket in which a few molecular states can be
accommodated. The possibility to observe the de-excitation of such states is
discussed in connection with the molecular life-time.


title: Collective Modes of Tri-Nuclear Molecules

abstract:
  A geometrical model for tri-nuclear molecules is presented. An analytical
solution is obtained provided the nuclei, which are taken to be prolately
deformed, are connected in line to each other. Furthermore, the tri-nuclear
molecule is composed of two heavy and one light cluster, the later sandwiched
between the two heavy clusters. A basis is constructed in which Hamiltonians of
more general configurations can be diagonalized. In the calculation of the
interaction between the clusters higher multipole deformations are taken into
account, including the hexadecupole one. A repulsive nuclear core is introduced
in the potential in order to insure a quasi-stable configuration of the system.
The model is applied to three nuclear molecules, namely $^{96}$Sr + $^{10}$Be +
$^{146}$Ba, $^{108}$Mo + $^{10}$Be + $^{134}$Te and $^{112}$Ru + $^{10}$Be +
$^{130}$Sn.


title: Hadronic Decays of N and \Delta Resonances in a Chiral Quark Model

abstract:
  \pi and \eta decay modes of light baryon resonances are investigated within a
chiral quark model whose hyperfine interaction is based on Goldstone-boson
exchange. For the decay mechanism a modified version of the 3P0 model is
employed. Our primary aim is to provide a further test of the recently proposed
Goldstone-boson-exchange constituent quark model. We compare the predictions
for \pi and \eta decay widths with experiment and also with results from a
traditional one-gluon-exchange constituent quark model. The differences between
nonrelativistic and semirelativistic versions of the constituent quark models
are outlined. We also discuss the sensitivity of the results on the
parametrization of the meson wave function entering the 3P0 model.


title: Parity and time reversal violating nuclear polarizability

abstract:
  We propose a nuclear mechanism which can induce an atomic electric dipole
moment (EDM). Parity and time reversal violating (P,T-odd) nuclear forces
generate a mixed P,T-odd nuclear polarizability beta_{ik} (defined by an energy
shift U = -beta_{ik} E_{i}H_{k}, E is electric field and H magnetic field). The
interaction of atomic electrons with beta_{ik} produces an atomic EDM. We
performed an analytical calculation of the P,T-odd nuclear polarizability and
estimated the value for the induced atomic EDM. The measurements of atomic EDMs
can provide information about P,T-odd nuclear forces and test models of
CP-violation.


title: Chaos and isospin symmetry breaking in rotational nuclei

abstract:
  For nuclei with N = Z, the isospin degree of freedom is important and, for
deformed systems, rotational bands of different isospin may be expected at low
excitation energies. We have investigated, in a simple model space, the
influence of the isospin-breaking Coulomb interaction on the degree of
chaoticity of these rotational bands. The statistical measures used rely on an
analysis of level-spacing distributions, which are extremely difficult to
measure experimentally. We show, however, that the overlap intergrals between
states of similar frequency reflect well the degree of chaoticity. This
quantity is closely related to the experimentally more accessible gamma-decay
``spreading width''.


title:
Role of N*(1650) in the near threshold pp --> p Lambda K+ and pp --> p
  Sigma0 K+ reactions

abstract:
  We investigate the pp --> p Lambda K+ and pp --> p Sigma0 K+ reactions at
beam energies near their thresholds within an effective Lagrangian model, where
the strangeness production proceeds via the excitation of N*(1650), N*(1710),
and N*(1720) baryonic resonances. It is found that the $N^*$(1650) resonance
dominates both these reactions at near threshold energies. The contributions
from this resonance together with the final state interaction among the
outgoing particles are able to explain the observed beam energy dependence of
the ratio of the cross sections of the two reactions in the near threshold
region.


title:
Enhanced Strange Particle Yields - Signal of a Phase of Massless
  Particles ?

abstract:
  The yields of strange particles are calculated with the UrQMD model for
p,Pb(158 AGeV)Pb collisions and compared to experimental data. The yields are
enhanced in central collisions if compared to proton induced or peripheral
Pb+Pb collisions. The enhancement is due to secondary interactions.
Nevertheless, only a reduction of the quark masses or equivalently an increase
of the string tension provides an adequate description of the large observed
enhancement factors (WA97 and NA49). Furthermore, the yields of unstable
strange resonances as the Lambda_star(1520) resonance or the phi meson are
considerably affected by hadronic rescattering of the decay products.


title: Quantum Field Treatment of DCC Dynamics

abstract:
  A practical quantum-field treatment is developed for systems endowed with an
effective mass function depending on both space and time and a schematic
application illustrates the quantitative importance of quantum fluctuations in
the dynamics of disoriented chiral condensates.


title: Few-body resonances in light nuclei

abstract:
  We have localized several few-body resonances in light nuclei, using methods
which can properly handle two- or three-body resonant states. Among other
results, we predict the existence of a three-neutron resonance, small
spin-orbit splittings between the low-lying states in He-5 and Li-5, the
nonexistence of the soft dipole resonance in He-6, new 1+ states in Li-8 and
B-8, and the presence of a nonlinear amplification phenomenon in the 0+_2 state
of C-12.


title: Double-beta decay matrix elements for Ge-76

abstract:
  Double-beta decay matrix elements (ME) for $^{76}Ge$ are calculated with
different quasi random phase approximation (QRPA)-based methods. First, the ME
for the two-neutrino mode are computed using two choices for the single
particle (s.p.) basis: i) $2-4\hbar\omega$ full shells and ii) $3-4\hbar\omega$
full shells. When calculated with the renormalized QRPA (RQRPA) and full-RQRPA
their values are rather dependent on the size of the single particle basis
used, while calculated with proton-neutron QRPA (pnQRPA) and second-QRPA
approaches such a dependence was found to be small. The Ikeda sum rule was well
fulfilled within pnQRPA for both choices of the s.p. basis and with a good
approximation within second-QRPA, while the RQRPA and full-RQRPA methods give
deviations up to 21%. Further, the ME for the neutrinoless mode are calculated
with the pnQRPA, RQRPA and full-RQRPA methods. They all give close results for
the calculation with the smaller basis (i), while for the larger basis (ii),
the results differ significantly either from one method to another or within
the same method. Finally, using the most recent experimental limit for the
$0\nu\beta\beta$ decay half-life of $^{76}Ge$ a critical discussion on the
upper limits for the neutrino mass parameter obtained with different
theoretical approaches is given.


title: Hydrodynamic Models for Heavy-Ion Collisions, and beyond

abstract:
  A generic property of a first-order phase transition in equilibrium, and in
the limit of large entropy per unit of conserved charge, is the smallness of
the isentropic speed of sound in the ``mixed phase''. A specific prediction is
that this should lead to a non-isotropic momentum distribution of nucleons in
the reaction plane (for energies around 40 AGeV in our model calculation). On
the other hand, we show that from present effective theories for low-energy QCD
one does not expect the thermal transition rate between various states of the
effective potential to be much larger than the expansion rate, questioning the
applicability of the idealized Maxwell/Gibbs construction. Experimental data
could soon provide essential information on the dynamics of the phase
transition.


title: Observing Non-Gaussian Sources in Heavy-Ion Reactions

abstract:
  We examine the possibility of extracting non-Gaussian sources from
two-particle correlations in heavy-ion reactions. Non-Gaussian sources have
been predicted in a variety of model calculations and may have been seen in
various like-meson pair correlations. As a tool for this investigation, we have
developed an improved imaging method that relies on a Basis spline expansion of
the source functions with an improved implementation of constraints. We examine
under what conditions this improved method can distinguish between Gaussian and
non-Gaussian sources. Finally, we investigate pion, kaon, and proton sources
from the p-Pb reaction at 450 GeV/nucleon and from the S-Pb reaction at 200
GeV/nucleon studied by the NA44 experiment. Both the pion and kaon sources from
the S-Pb correlations seem to exhibit a Gaussian core with an extended,
non-Gaussian halo. We also find evidence for a scaling of the source widths
with particle mass in the sources from the p-Pb reaction.


title:
Isospin effects on rotational flow in intermediate energy heavy ion
  collisions

abstract:
  Within the framework of an isospin-dependent quantum molecular dynamics
model, the rotational flow in reactions of $^{58}$Fe + $^{58}$Fe and $^{58}$%
Ni + $^{58}$Ni at 40 MeV/nucleon for different impact parameters is
investigated by analyzing the mid-rapidity azimuthal distribution. The
rotational observables are also calculated semiquantitatively. For the first
time, it is found that the more neutron-rich system ($^{58}$Fe + $^{58}$Fe)
exhibits stronger rotational collective flow. This isospin dependence of
rotational collective flow is more appreciable in semi-peripheral collisions
and it is shown to mainly result from the isospin dependence of nucleon-nucleon
cross section rather than the symmetry energy. Meanwhile, it is indicated that
the rotational flow depends strongly on the impact parameter.


title:
Exploratory Calculations of the Effects of Higher Shell Admixtures on
  Static Electric Quadrupole and Magnetic Dipole Moments of Excited States

abstract:
  Using the interaction $Q \cdot Q ~+~ xV_{S.O.}$ where $V_{S.O.}$ is a
two-body spin-orbit interaction, we study the effects of varying x on the
static electric quadrupole and magnetic dipole moments of the $2^+_1$ and
$2^+_2$ states of $^{10}Be$. This is done both in the valence space $s^4p^6$
and in a larger space in which 2 $\hbar \omega$ excitations are allowed. In the
former case, for x=0, we have the Wigner Supermultiplet limit in which the
$2^+_1$ and $2^+_2$ states are degenerate and correspond to K=0 and K=2
rotational states, with equal and opposite static quadrupole moments. Turning
on the spin-orbit interaction with sufficient strength in the valence space
gives an energy splitting to the two $2^+$ states in accord with experiment.
When higher shell admixtures are allowed, we get quite a different behaviour as
a function of x than in the valence space. Of particular interest is a value of
x for which $Q(2^+_1)$ and $Q(2^+_2)$ both nearly vanish, and so does (somewhat
coincidentally) $\mu(2^+_1)$.