title: Nuclear mass systematics using neural networks

abstract:
  New global statistical models of nuclidic (atomic) masses based on
multilayered feedforward networks are developed. One goal of such studies is to
determine how well the existing data, and only the data, determines the mapping
from the proton and neutron numbers to the mass of the nuclear ground state.
Another is to provide reliable predictive models that can be used to forecast
mass values away from the valley of stability. Our study focuses mainly on the
former goal and achieves substantial improvement over previous neural-network
models of the mass table by using improved schemes for coding and training. The
results suggest that with further development this approach may provide a
valuable complement to conventional global models.


title: The Evaluation of V_{ud}, Experiment and Theory

abstract:
  The value of the V_{ud} matrix element of the Cabibbo-Kobayashi-Maskawa (CKM)
matrix can be derived from nuclear superallowed beta decays, neutron decay, and
pion beta decay. We survey current world data for all three. Today, the most
precise value of V_{ud} comes from the nuclear decays; however, the precision
is limited not by experimental error but by the estimated uncertainty in
theoretical corrections. Experimental uncertainty does limit the neutron-decay
result, which, though statistically consistent with the nuclear result, is
approximately a factor of three poorer in precision. The value obtained for
$V_{ud}$ leads to a result that differs at the 98% confidence level from the
unitarity condition for the CKM matrix. We examine the reliability of the small
calculated corrections that have been applied to the data, and assess the
likelihood of even higher quality nuclear data becoming available to confirm or
deny the discrepancy. Some of the required experiments depend upon the
availability of intense radioactive beams. Others are possible today.


title: Determination of S17 from Systematic Analysis of 8B Coulomb Dissociation

abstract:
  Systematic analysis of 8B Coulomb dissociation with the Asymptotic
Normalization Coefficient (ANC) method is proposed to determine the
astrophysical factor S17 accurately. An important advantage of the analysis is
that uncertainties of the extracted S17 coming from the use of the ANC method
can quantitatively be evaluated, in contrast to previous analyses using the
Virtual Photon Theory (VPT). Calculation of measured spectra in dissociation
experiments is done by means of the method of Continuum-Discretized
Coupled-Channels (CDCC). From the analysis of 58Ni(8B,7Be+p)58Ni at 25.8 MeV,
S17=22.83 +/- 0.51(theo) +/- 2.28(expt) (eVb) is obtained; the ANC method
turned out to work in this case within 1% of error. Preceding systematic
analysis of experimental data at intermediate energies, we propose hybrid (HY)
Coupled-Channels (CC) calculation of 8B Coulomb dissociation, which makes
numerical calculation much simple, retaining its accuracy. The validity of the
HY calculation is tested for 58Ni(8B,7Be+p)58Ni at 240 MeV. The ANC method
combined with the HY CC calculation is shown to be a powerful technique to
obtain a reliable S17.


title:
Precise study of the Efimov three-particle spectrum and structure
  functions within variational approach

abstract:
  A precise study within variational approach of the basic properties of the
three-particle spectrum and structure functions with Gaussian potential near
the critical coupling constant of interaction where the Efimov effect takes
place is carried out. A method is developed to calculate highly excited states
with very small binding energies, and numerical analysis is carried out for the
ground and three excited energy states. For these states, one-particle density
distributions, formfactors, pair correlation functions, and momentum
distributions are calculated. It is found that the second excited state has
already all the basic features of a level from the infinite Efimov series. An
essential asymmetry is found in the position of energy levels with respect to
the critical constant point. A halo-type structure is revealed in the
one-particle density distributions, and formfactors are shown to have specific
dips of finite depth, the number of dips being equal to the number of the
state. The behaviour of pair correlation functions and momentum distributions
is studied for three-particle states.


title:
Relativistic Nucleon-Nucleon potentials using Dirac's constraint instant
  form dynamics

abstract:
  The formalism of two coupled Dirac equations within constraint instant form
dynamics is used to study the nucleon-nucleon interaction. The salient features
and the final Schroedinger type equation is given. Explicitly energy dependent
coupled channel potentials, for use in partial wave Schroedinger like
equations, with nonlinear and complicated derivative terms, result. We
developed the necessary numerics and study np and pp scattering phase shifts
for energies 0-3 GeV and the deuteron bound state. The interactions are
inspired by meson exchange of pi, eta, rho,omega and sigma mesons for which we
adjust coupling constants. This yields, in the first instant, high quality fits
to the Arndt phase shifts 0-300 MeV. Second, the potentials show a universal,
independent from angular momentum, core potential which is generated from the
relativistic meson exchange dynamics. Extrapolations towards higher energies,
up to 3 GeV, allow to separate a QCD dominated short range zone as well as
inelastic nucleon excitation mechanism contributing to meson production. A
local and/or nonlocal optical model, in addition to the meson exchange Dirac
potential, produces agreement between theoretical and data phase shifts. Third,
the 1S0, 3P0 and 3P1 partial waves elicit a fusion/scission, for T-Lab<1GeV,
and a fusion/fission, for T-Lab>1 GeV, mechanism for intermediate dibaryon
formation.


title:
Superallowed Beta Decay of Nuclei with A >or= 62: The Limiting Effect of
  Weak Gamow-Teller Branches

abstract:
  The most precise value of V_{ud}, which is obtained from superallowed nuclear
beta decay, leads to a violation of CKM unitarity by 2.2 sigma. Experiments are
underway on two continents to test and improve this result through decay
studies of odd-odd N = Z nuclei with A >or= 62. We show, in a series of
illustrative shell-model calculations, that numerous weak Gamow-Teller branches
are expected to compete with the superallowed branch in each of these nuclei.
Though the total Gamow-Teller strength is significant, many of the individual
branches will be unobservably weak. Thus, new techniques must be developed if
reliable ft-values are to be obtained with 0.1% precision for the superallowed
branches.


title: Pentaquark baryon production at the Relativistic Heavy Ion Collider

abstract:
  Production of pentaquark $\Theta^+$ baryons in central relativistic heavy ion
collisions is studied in a kinetic model. Assuming that a quark-gluon plasma is
produced in the collisions, we first determine the number of $\Theta^+$
produced from the quark-gluon plasma using a parton coalescence model, and then
take into consideration its production and absorption in subsequent hadronic
matter via the reactions $KN\leftrightarrow\Theta$,
$KN\leftrightarrow\pi\Theta$, and $\piN\leftrightarrow\bar K\Theta$. We find
that although the final $\Theta^+$ number is affected by hadronic interactions,
it remains sensitive to the initial number of $\Theta^+$ produced from the
quark-gluon plasma, particularly in the case of a small $\Theta^+$ width as
imposed by the $K^+N$ and $K^+d$ scattering data. Because of small baryon
chemical potential in the hot dense matter produced in these collisions, the
number of produced anti-$\Theta$ is only slightly smaller than that of
$\Theta^+$.


title:
Structure of cold nuclear matter at subnuclear densities by Quantum
  Molecular Dynamics

abstract:
  Structure of cold nuclear matter at subnuclear densities for the proton
fraction $x=0.5$, 0.3 and 0.1 is investigated by quantum molecular dynamics
(QMD) simulations. We demonstrate that the phases with slablike and rodlike
nuclei, etc. can be formed dynamically from hot uniform nuclear matter without
any assumptions on nuclear shape, and also systematically analyze the structure
of cold matter using two-point correlation functions and Minkowski functionals.
In our simulations, we also observe intermediate phases, which has complicated
nuclear shapes. It is found out that these phases can be characterized as those
with negative Euler characteristic. Our result implies the existence of these
kinds of phases in addition to the simple ``pasta'' phases in neutron star
crusts and supernova inner cores.
  In addition, we investigate the properties of the effective QMD interaction
used in the present work to examine the validity of our results. The resultant
energy per nucleon $\epsilon_{n}$ of the pure neutron matter, the proton
chemical $\mu_{p}^{(0)}$ in pure neutron matter and the nuclear surface tension
$E_{\rm surf}$ are generally reasonable in comparison with other nuclear
interactions.


title:
Ladder Dyson-Schwinger calculation of the anomalous gamma-3pi form
  factor

abstract:
  The anomalous processes, \gamma \to 3 \pi and \gamma \pi \to \pi\pi, are
investigated within the Dyson-Schwinger framework using the rainbow-ladder
approximation. Calculations reveal that a complete set of ladder diagrams
beyond the impulse approximation are necessary to reproduce the fundamental
low-energy theorem for the anomalous form factor. Higher momentum calculations
also agree with the limited form factor data and exhibit the same resonance
behavior as the phenomenological vector meson dominance model.


title: f_2, sigma, and 2-pi exchanges in rho meson photoproduction

abstract:
  The $\sigma$ meson exchange model for $\rho$ photoproduction at low energies
is re-examined and a new model is developed by considering explicit two-pion
exchange and the $f_2$ tensor meson exchange. The $f_2$ exchange model, which
is motivated by the low energy proton-proton elastic scattering, is constructed
by fully taking into account of the tensor structure of the $f_2$ meson
interactions. Phenomenological informations together with tensor meson
dominance and vector meson dominance assumptions are used to estimate the $f_2$
meson's coupling constants. For $2\pi$ exchange, the loop terms including
intermediate $\pi N$ and $\omega N$ channels are calculated using the coupling
constants determined from the study of pion photoproduction. It is found that
our model with $f_2$ and $2\pi$ exchanges can successfully replace the commonly
used $\sigma$ exchange model that suffers from the big uncertainty of the
coupling constants. We found that the two models can be distinguished by
examining the single and double spin asymmetries.


title:
Improving the convergence of the chiral expansion for nuclear forces II:
  low phases and the deuteron

abstract:
  Recently we have proposed a new cut-off scheme for pion loop integrals in the
two-pion exchange potential. This method allows for a consistent implementation
of constraints from pion-nucleon scattering and has been successfully applied
to peripheral nucleon-nucleon partial waves. We now consider low partial waves
in the non-perturbative regime, where the regularized Lippmann-Schwinger
equation has to be solved in order to generate the bound and scattering states.
We observe an improved description of most of the phase shifts when going from
next-to- to next-to-next-to-leading order in the chiral expansion. We also find
a good description of the deuteron properties. In addition, the new cut-off
scheme allows to avoid the presence of unphysical deeply bound states. We
discuss the cut-off dependence of the four-nucleon low-energy constants and
show that their numerical values can be understood in terms of resonance
saturation. This connects the effective field theory approach to boson exchange
phenomenology.


title:
A Test of the Calculability of a Three Body Relativistic, Cluster
  Decomposable, Unitary, Covariant Scattering Theory

abstract:
  In this work a calculation of the cluster decomposable formalism for
relativistic scattering as developed by Lindesay, Markevich, Noyes, and
Pastrana (LMNP) is made for an ultra-light quantum model. After highlighting
areas of the theory vital for calculation, a description is made of the process
to go from the general theory to an eigen-integral equation for bound state
problems, and calculability is demonstrated. An ultra-light quantum exchange
model is then developed to examine calculability.


title: K+ nucleon scattering and exotic S=+1 Baryons

abstract:
  The K+ nucleon elastic scattering process has been reexamined in light of
recent measurements which have found a narrow exotic S=+1 resonance in their KN
invariant mass distributions. We have analyzed the existing database in order
to consider the effect of a narrow state on fits to K+ nucleon observables.


title: Charm production from proton-proton collisions

abstract:
  We evaluate the cross sections for charmed hadron production from
proton-proton reactions $pp\to\bar D^0p\Lambda_c^+$ and $pp\to\bar
D^{*0}p\Lambda_c^+$ using a hadronic Lagrangian. With empirical coupling
constants and cutoff parameters in the form factors, sum of their cross
sections at center-of-mass energy of 11.5 GeV is about 1 $\mu$b and is
comparable to measured inclusive cross section for charmed hadron production
from proton-proton reactions. The cross section decreases to about 1 nb at 40
MeV above threshold.


title: What did we learn and what will we learn from hydrodynamics at RHIC?

abstract:
  A brief overview of the current status of hydrodynamic concepts applied to
ultra relativistic heavy-ion collisions is presented. Special emphasis is
placed on future prospects for extracting the thermodynamic properties and the
bulk features of the created medium from experimental observations.


title: The electric form factor of the neutron and its chiral content

abstract:
  Considering the nucleon as a system of confined valence quarks surrounded by
pions we derive a Galster-like parameterization of the neutron electric form
factor $G_E^n$. Furthermore, we show that the proposed parameterization can be
linked to properties of the pion cloud. By this, the high quality data for the
pion form factor can be used in predictions of $G_E^n$ in the low $Q^2$ region,
where the direct double polarization measurements are not available.


title: Three-body Coulomb breakup of 11Li in the complex scaling method

abstract:
  Coulomb breakup strengths of 11Li into a three-body 9Li+n+n system are
studied in the complex scaling method. We decompose the transition strengths
into the contributions from three-body resonances, two-body ``10Li+n'' and
three-body ``9Li+n+n'' continuum states. In the calculated results, we cannot
find the dipole resonances with a sharp decay width in 11Li. There is a low
energy enhancement in the breakup strength, which is produced by both the two-
and three-body continuum states. The enhancement given by the three-body
continuum states is found to have a strong connection to the halo structure of
11Li. The calculated breakup strength distribution is compared with the
experimental data from MSU, RIKEN and GSI.


title: Theory of fusion hindrance and synthesis of the superheavy elements

abstract:
  The two-step model for fusion reactions of massive systems is briefly
reviewed.By the use of fusion probabilities obtained by the model and of
survival probabilities obtained by the new statistical code, we predict residue
cross sections for 48Ca+actinide systems leading to superheavy elements with
Z=114, 116 and 118.


title: On Theoretical Problems in Synthesis of Superheavy Elements

abstract:
  Towards precise predictions of residue cross sections of the superheavy
elements, recent theoretical developments of reaction mechanisms are presented,
together with the remaining problems which give rise to ambiguities in absolute
values of cross sections predicted.


title:
Predictions of the residue cross-sections for the elements Z=113 and
  Z=114

abstract:
  An extremely good reproduction of experimental excitation function of the 1n
reactions producing Z=110,Z=111 and Z=112 is obtained by the two-step model and
the statistical decay code KEWPIE. Thus, an extension of the recipe permits us
to predict reliable values of the residue cross-sections of the elements Z=113
and Z=114 which will be a useful guide for planning of experiments.


title: KEWPIE: a dynamical cascade code for decaying exited compound nuclei

abstract:
  A new dynamical cascade code for decaying hot nuclei is proposed and
specially adapted to the synthesis of super-heavy nuclei. For such a case, the
interesting channel is the tiny fraction that will decay through particles
emission, thus the code avoids classical Monte-Carlo methods and proposes a new
numerical scheme. The time dependence is explicitely taken into account in
order to cope with the fact that fission decay rate might not be constant. The
code allows to evaluate both statistical and dynamical observables. Results are
successfully compared to experimental data.


title:
The Gamow-Teller Resonance in Finite Nuclei in the Relativistic Random
  Phase Approximation

abstract:
  Gamow-Teller(GT) resonances in finite nuclei are studied in a fully
consistent relativistic random phase approximation (RPA) framework. A
relativistic form of the Landau-Migdal contact interaction in the spin-isospin
channel is adopted. This choice ensures that the GT excitation energy in
nuclear matter is correctly reproduced in the non-relativistic limit. The GT
response functions of doubly magic nuclei $^{48}$Ca, $^{90}$Zr and $^{208}$Pb
are calculated using the parameter set NL3 and $g_0'$=0.6 . It is found that
effects related to Dirac sea states account for a reduction of 6-7 % in the GT
sum rule.


title: Correlations and Fluctuations, A Summary of Quark Matter 2002

abstract:
  Results for correlations and fluctuations presented at Quark Matter 2002 are
summarized. These results include Hanbury-Brown Twiss interferometry of a wide
variety of species, large scale fluctuations and correlations in $p_t$ and
multiplicity, and charge fluctuations and charge balance functions.


title: QCD sum rules for hyperon-nucleon interactions

abstract:
  We investigate the hyperon-nucleon interactions in the QCD sum rule starting
from the nucleon matrix element of the hyperon correlation function. Through
the dispersion relation, the correlation function in the operator product
expansion (OPE) is related with its integral over the physical energy region.
The dispersion integral around the hyperon-nucleon ($YN$) threshold is
identified as a measure of the interaction strength in the $YN$ channel. The
Wilson coefficients of the OPE for the hyperon correlation function are
calculated. The obtained sum rules relate $YN$ interaction strengths to the
nucleon matrix elements of the quark-gluon composite operators, which include
strange quark operators as well as up and down quark operators. It is found
that the $YN$ interaction strengths are smaller than the $NN$ interaction
strength since the nucleon matrix elements of strange quark operators are
smaller than those of up and down quark operators. Among $YN$ channels $\Lambda
N$ channel has stronger interaction than $\Sigma N$ and $\Xi N$ channels. Also
found is that the interaction strength is greater in the $\Sigma^+N$ ($\Xi^0
N$) channel than in the $\Sigma^-N$ ($\Xi^-N$) channel since the nucleon matrix
elements of up quark operators are greater than those of down quark operators.
The spin-dependent part is much smaller than the spin-independent part in the
$YN$ and $NN$ channels. The results of the sum rules are compared with those of
the phenomenological meson-exchange models.


title:
How big is the source that produces quark gluon plasma in heavy ion
  collisions?

abstract:
  We study, for the first time, the spatial extension of the
  "source" that produces quark gluon plasma (QGP) in ultra relativistic heavy
ion collisions. The longitudinal dimension is studied as a function of time as
the system evolves. The source size is found to exhibit a novel non-classical
feature.


title:
Linear Langevin Equation of Critical Fluctuation in Chiral Phase
  Transition

abstract:
  We derive the linear Langevin equation that describes the behavior of
critical fluctuation above the critical temperature of the chiral phase
transition in the Nambu-Jona-Lasinio model. The Langevin equation relaxes
exhibiting oscillation and shows thermalization. The relaxation becomes slower
as the system approaches the critical point(the critical slowing down). The
time correlation function also calculated using the Langevin equation shows
that there exists the same soft mode as the previous calculation in the linear
response theory.


title: Baryon spectroscopy on the lattice: recent results

abstract:
  Progress in determining the baryon spectrum using computer simulations of
quarks and gluons in lattice QCD are summarized and some future plans are
outlined.


title:
Solution of large scale nuclear structure problems by wave function
  factorization

abstract:
  Low-lying shell model states may be approximated accurately by a sum over
products of proton and neutron states. The optimal factors are determined by a
variational principle and result from the solution of rather low-dimensional
eigenvalue problems. Application of this method to sd-shell nuclei, pf-shell
nuclei, and to no-core shell model problems shows that very accurate
approximations to the exact solutions may be obtained. Their energies, quantum
numbers and overlaps with exact eigenstates converge exponentially fast as the
number of retained factors is increased.


title: Multiparton Tomography of Hot and Cold Nuclear Matter

abstract:
  Multiple parton interactions in relativistic heavy ion reactions result in
transverse momentum diffusion and medium induced non-Abelian energy loss of the
hard probes traversing cold and hot nuclear matter. A systematic study of the
interplay of nuclear effects on the $p_T \geq 2$ GeV inclusive hadron spectra
demonstrates that the competition between nuclear shadowing, multiple
scattering and jet quenching leads to distinctly different
enhancement/suppression of moderate and high-$p_T$ hadron production in $d+Au$
and $Au+Au$ collisions at RHIC. The associated increase of di-jet acoplanarity,
measured via the broadening of the back-to-back di-hadron correlation function,
provides an additional experimental tool to test the difference in the
dynamical properties of the media created in such reactions.


title: Cronin effect vs. geometrical shadowing in d+Au collisions at RHIC

abstract:
  Multiple initial state parton interactions in p(d)+Au collisions are
calculated in a Glauber-Eikonal formalism. The convolution of perturbative QCD
parton-nucleon cross sections predicts naturally the competing pattern of
low-pT suppression due geometrical shadowing, and a moderate-pT Cronin
enhancement of hadron spectra. The formal equivalence to recent classical
Yang-Mills calculations is demonstrated, but our approach is shown to be more
general in the large x>0.01 domain because it automatically incorporates the
finite kinematic constraints of both quark and gluon processes in the
fragmentation regions, and accounts for the observed spectra in elementary
pp-->\pi+X processes in the RHIC energy range, sqrt{s} = 20-200 GeV. The
Glauber-Eikonal formalism can be used as a baseline to extract the magnitude of
dynamical shadowing effects from the experimental data at differente
centralities and pseudo-rapidities.


title: Testing Chiral Dynamics in Pionic Atoms

abstract:
  The energy dependence of chirally expanded pi N isoscalar and isovector
amplitudes b_0(E) and b_1(E) respectively, for zero-momentum off shell pions
near threshold, is used to impose the minimal substitution requirement E -> E -
V_c on the properly constructed pion optical potential within a large-scale fit
to 100 pionic-atom data across the periodic table which also include the
recently established `deeply bound' pionic atoms of Pb and Sn. This fit cannot
be reconciled with the well known free-space values of the pi N threshold
amplitudes. In contrast, introducing the empirically known energy dependence
for on-shell pions leads to a better fit and to satisfactory values for the pi
N threshold amplitudes. The difference between these two approaches is briefly
discussed.


title: Exploring proton rich systems and Coulomb induced instabilities

abstract:
  The thermodynamic properties of proton rich systems are explored in a mean
field approach which is generated from a Skyrme interaction. The addition of
Coulomb interactions result in asymmetries which modify the chemical and
mechanical instability of the system and its equilibrium properties. These
properties are studied for systems with proton fraction $y$ on the proton
richer side of the valley of $\beta$-stability as well as the neutron rich
side. Coulomb induced instabilities lead to proton diffusion processes on the
proton richer side and also large asymmetries in chemical and mechanical
instabilities and coexistence curves. Considering the whole range of $0 \le y
\le 1$, we can study how the symmetry about $y=1/2$ is broken by asymmetric
interaction and we can also explicitly show that the role between proton and
neutron is exchanged around $y_E$. It is shown that there are two asymmetric
coexistence surfaces in $(y, P, T)$ space, one for $y < y_E$ and another for $y
> y_E$ and touching each other at $y_E$. These asymmetries in instabilities
show up as new branches, one for $y < y_E$ and one for $y > y_E$, and thus form
a closed loop in pressure versus $\rho$ for both chemical instability and
coexistence regions. The branch of $y > 1/2 > y_E$ was not previously
investigated since only the $y < 1/2$ region is usually considered. In our
simplified model, mechanical instability is still symmetric around a point $y_E
\ne 1/2$ even with Coulomb forces present.


title: Short-range three-nucleon forces and low-energy constants

abstract:
  The 3N forces due to pi-rho, pi-sigma and pi-omega exchanges following from
the nucleon Born diagrams and diagrams with an intermediate N^{*}(1440) are
re-analyzed. The cancellation between pi-sigma and pi-omega forces is rather
sensitive to the values of the coupling constants and to the form of the piNN
vertex. Experimental uncertainties in the parameters of the TM pi-pi potential
are assessed. They lead to uncertainties in theoretical predictions of the
triton binding energy of about 0.4 MeV. The low-energy limit of pi-sigma and
pi-omega potentials is performed. It defines the coupling constants of
effective contact piNNNN vertices, which are compared with the corresponding
contact vertices of Chiral Perturbation Theory.


title: Soft Pion Emission in DVCS

abstract:
  We examine soft-pion emission in deeply virtual Compton scattering. Contrary
to previous claims, we find that the amplitude for soft-pion emission is not
directly related to the generalized parton distributions in the nucleon.


title:
Cross sections for pentaquark baryon production from protons in
  reactions induced by hadrons and photons

abstract:
  Using hadronic Lagrangians that include the interaction of pentaquark
$\Theta^+$ baryon with $K$ and $N$, we evaluate the cross sections for its
production from meson-proton, proton-proton, and photon-proton reactions near
threshold. With empirical coupling constants and form factors, the predicted
cross sections are about 1.5 mb in kaon-proton reactions, 0.1 mb in rho-nucleon
reactions, 0.05 mb in pion-nucleon reactions, 20 $\mu$b in proton-proton
reactions, and 40 nb in photon-proton reactions.


title:
Two-neutrino double beta decay within Fully-Renormalized QRPA: Effect of
  the restoration of the Ikeda sum rule

abstract:
  The recently proposed Fully-Renormalized QRPA (FR-QRPA), which fullfils the
Ikeda sum rule (ISR) exactly, is applied to the two-neutrino double beta decay
of $^{76}$Ge, $^{82}$Se, $^{100}$Mo, $^{116}$Cd, $^{128}$Te and $^{130}$Xe. The
results obtained are compared with those of other approaches, standard QRPA and
self-consistent QRPA (SCQRPA). The similarities and the differences among the
methods are discussed. The influence of the restoration of the Ikeda sum rule
on the $2\nu\beta\beta$-decay amplitude is analyzed.


title: Counter Terms for Low Momentum Nucleon-Nucleon Interactions

abstract:
  There is much current interest in treating low energy nuclear physics using
the renormalization group (RG) and effective field theory (EFT). Inspired by
this RG-EFT approach, we study a low-momentum nucleon-nucleon (NN) interaction,
V_{low-k}, obtained by integrating out the fast modes down the scale ~2fm^{-1}.
Since NN experiments can only determine the effective interaction in the low
momentum region, our chief purpose is to find such an interaction for complex
nuclei whose typical momenta lie below this scale. In this paper we find that
V_{low-k} can be satisfactorily accounted for by the counter terms
corresponding to a short range effective interaction. The coefficients C_n of
the power series expansion C_n*k^n for the counter terms have been accurately
determined and results derived from several meson-exchange NN interaction
models are compared. The counter terms are found to be important for the S, P,
and D partial waves. Scaling behavior of the counter terms is also studied, and
we discuss the use of these methods for computing shell model matrix elements.


title:
Two-neutrino double beta decay of 76Ge within deformed QRPA: A new
  suppression mechanism

abstract:
  The effect of deformation on the two-neutrino double decay (2nbb-decay) for
ground state transition 76Ge -> 76Se is studied in the framework of the
deformed QRPA with separable Gamow-Teller residual interaction. A new
suppression mechanism of the 2nbb-decay matrix element based on the difference
in deformations of the initial and final nuclei is included. An advantage of
this suppression mechanism in comparison with that associated with ground state
correlations is that it allows a simultaneous description of the single beta
and the 2nbb-decay. By performing a detail calculation of the 2nbb-decay of
76Ge, it is found that the states of intermediate nucleus lying in the region
of the Gamow-Teller resonance contribute significantly to the matrix element of
this process.


title: Quantum chaos and nuclear mass systematics

abstract:
  The presence of quantum chaos in nuclear mass systematics is analyzed by
considering the differences between measured and calculated nuclear masses as a
time series described by the power law 1/ f^alpha. While for the liquid droplet
model plus shell corrections a quantum chaotic behavior alpha approx 1 is
found, errors in the microscopic mass formula have alpha approx 0.5, closer to
white noise. The chaotic behavior seems to arise from many body effects not
included in the mass formula.


title: DSEs, the pion, and related matters

abstract:
  We recapitulate on aspects of Dyson-Schwinger equation studies relevant to
pseudoscalar mesons: lattice confirmation of the DSE prediction that
propagators are nonperturbatively dressed in the infrared; and exact results,
e.g., in the chiral limit the leptonic decay constant vanishes for every
pseudoscalar meson except the pion.


title:
Contribution of the nucleon-hyperon reaction channels to K$^-$
  production in proton-nucleus collisions

abstract:
  The cross sections for producing K$^-$ mesons in nucleon-hyperon elementary
processes are estimated assuming one-pion exchange and using the experimentally
known pion-hyperon cross sections. The results are implemented in a transport
model which is applied to calculation of proton-nucleus collisions. In
significant difference to earlier estimates for heavy-ion collisions the
inclusion of the nucleon-hyperon cross section roughly doubles the K$^-$
production in near-threshold proton-nucleus collisions.


title: Warm stellar matter with deconfinement: application to compact stars

abstract:
  We investigate the properties of mixed stars formed by hadronic and quark
matter in $\beta$-equilibrium described by appropriate equations of state (EOS)
in the framework of relativistic mean-field theory. We use the non- linear
Walecka model for the hadron matter and the MIT Bag and the Nambu-Jona-Lasinio
models for the quark matter. The phase transition to a deconfined quark phase
is investigated. In particular, we study the dependence of the onset of a mixed
phase and a pure quark phase on the hyperon couplings, quark model and
properties of the hadronic model. We calculate the strangeness fraction with
baryonic density for the different EOS. With the NJL model the strangeness
content in the mixed phase decreases. The calculations were performed for T=0
and for finite temperatures in order to describe neutron and proto-neutron
stars. The star properties are discussed. Both the Bag model and the NJL model
predict a mixed phase in the interior of the star. Maximum allowed masses for
proto-neutron stars are larger for the NJL model ($\sim 1.9$ M$_{\bigodot}$)
than for the Bag model ($\sim 1.6$ M$_{\bigodot}$).


title:
Nuclear matter incompressibility coefficient in relativistic and
  nonrelativistic microscopic models

abstract:
  We systematically analyze the recent claim that nonrelativistic and
relativistic mean field (RMF) based random phase approximation (RPA)
calculations for the centroid energy E_0 of the isoscalar giant monopole
resonance yield for the nuclear matter incompressibility coefficient, K_{nm},
values which differ by about 20%. For an appropriate comparison with the RMF
based RPA calculations, we obtain the parameters for the Skyrme force used in
the nonrelativistic model by adopting the same procedure as employed in the
determination of the NL3 parameter set of an effective Lagrangian used in the
RMF model. Our investigation suggest that the discrepancy between the values of
K_{nm} predicted by the relativistic and nonrelativistic models is
significantly less than 20%.


title:
Analysis of Intermediate-Energy Nucleus-Nucleus Spallation, Fission, and
  Fragmentation Reactions with the LAQGSM code

abstract:
  The LAQGSM code has been recently developed at Los Alamos National Laboratory
to simulate nuclear reactions for proton radiography applications. We have
benchmarked our code against most available measured data both for
proton-nucleus and nucleus-nucleus interactions at incident energies from 10
MeV to 800 GeV and have compared our results with predictions of other current
models used by the nuclear community. Here, we present a brief description of
our code and show illustrative results obtained with LAQGSM for neutron spectra
measured recently by Nakamura's groups for reactions induced by light and
medium nuclei on targets from C to Pb at several incident energies from 95 to
600 MeV/nucleon and with the recent GSI measurements of spallation, fission,
and fragmentation yields from A+p and A+A reactions at incident energies near
and below 1 GeV/nucleon. Further necessary work is outlined.


title: Thermal shape fluctuation effects in the description of hot nuclei

abstract:
  The behavior of several nuclear properties with temperature is analyzed
within the framework of the Finite Temperature Hartree-Fock-Bogoliubov (FTHFB)
theory with the Gogny force and large configuration spaces. Thermal shape
fluctuations in the quadrupole degree of freedom, around the mean field
solution, are taken into account with the Landau prescription. As
representative examples the nuclei $^{164}$Er, $^{152}$Dy and $^{192}$Hg are
studied. Numerical results for the superfluid to normal and deformed to
spherical shape transitions are presented. We found a substantial effect of the
fluctuations on the average value of several observables. In particular, we get
a decrease in the critical temperature ($T_c$) for the shape transition as
compared with the plain FTHFB prediction as well as a washing out of the shape
transition signatures. The new values of $T_c$ are closer to the ones found in
Strutinsky calculations and with the Pairing Plus Quadrupole model Hamiltonian.


title:
Trinucleon photonuclear reactions with $\Delta$-isobar excitation:
  Processes below pion-production threshold

abstract:
  Radiative nucleon-deuteron capture and two- and three-body photo
disintegration of the three-nucleon bound state are described. The description
uses the purely nucleonic charge-dependent CD-Bonn potential and its
coupled-channel extension CD Bonn + $\Delta$. The $\Delta$-isobar excitation
yields an effective three-nucleon force and effective two- and three-nucleon
currents besides other $\Delta$-isobar effects; they are mutually consistent.
Exact solutions of three-particle equations are employed for the initial and
final states of the reactions. The current has one-baryon and two-baryon
contributions and couples nucleonic with $\Delta$-isobar channels.
$\Delta$-isobar effects on the observables are isolated. Shortcomings of the
theoretical description are discussed and their consequence for the calculation
of observables is estimated.


title: Proton-neutron pairing in the deformed BCS approach

abstract:
  We examine isovector and isoscalar proton-neutron pairing correlations for
the ground state of even-even Ge isotopes with mass number A=64-76 within the
deformed BCS approach. For N=Z 64Ge the BCS solution with only T=0
proton-neutron pairs is found. For other nuclear systems (N>Z) a coexistence of
a T=0 and T=1 pairs in the BCS wave function is observed. A problem of fixing
of strengths of isoscalar and isovector pairing interactions is addressed. A
dependence of number of like and unlike pairs in the BCS ground state on the
difference between number of neutrons and protons is discussed. We found that
for nuclei with N much bigger than Z the effect of proton-neutron pairing is
small but not negligible.


title:
Covariant Effective Field Theory for Nuclear Structure and Nuclear
  Currents

abstract:
  Recent progress in Lorentz-covariant quantum field theories of the nuclear
many-body problem (quantum hadrodynamics or QHD) is discussed. The effective
field theory studied here contains nucleons, pions, isoscalar scalar (\sigma)
and vector (\omega) fields, and isovector vector (\rho) fields. The theory
exhibits a nonlinear realization of spontaneously broken SU(2)_L \times SU(2)_R
chiral symmetry and has three desirable features: it uses the same degrees of
freedom to describe the nuclear currents and the strong-interaction dynamics,
it satisfies the symmetries of the underlying theory of QCD, and its parameters
can be calibrated using strong-interaction phenomena, like hadron scattering or
the empirical properties of finite nuclei. Moreover, it has recently been
verified that for normal nuclear systems, it is possible to expand the
effective Lagrangian systematically in powers of the meson fields (and their
derivatives) and to truncate the expansion reliably after the first few orders.
Using a mean-field version of the energy functional, accurate quantitative
results are obtained for the bulk and single-particle properties of medium- and
heavy-mass nuclei. The importance of modern perspectives in effective field
theory and density functional theory for understanding these successes of QHD
is emphasized. The inclusion of hadronic electromagnetic structure and of
nonanalytic terms in the energy functional is also considered briefly. As a
further application, weak-interaction currents are studied in the QHD
framework. The axial-vector current, evaluated through the leading order in the
field expansion, satisfies both PCAC and the Goldberger--Treiman relation, and
the corresponding vector and axial-vector charges satisfy the familiar chiral
charge algebra to all orders in the pion field.


title:
Chiral solitons in nuclei: Saturation, EMC effect and Drell-Yan
  experiments

abstract:
  The Chiral Quark-Soliton model of the nucleon contains a mechanism for an
attractive interaction between nucleons. This, along with the exchange of
vector mesons between nucleons, is used to compute the saturation properties of
infinite nuclear matter. This provides a new way to asses the effects of the
nuclear medium on a nucleon that includes valence and sea quarks. We show that
the model simultaneously describes the nuclear EMC effect and the related
Drell-Yan experiments.


title: Dynamical Correlation Length near the Chiral Critical Point

abstract:
  The dynamical evolution of small systems undergoing a chiral symmetry
breaking transition in the course of rapid expansion is discussed. The time
evolution of the dynamical correlation length for trajectories passing through
a second-order critical point is extracted. It is shown that while the maximum
value of the correlation length is bound from above by dynamical effects, the
time interval during which it is near its maximum grows steadily with the
system size and with decreasing expansion rate.


title: Effective field theory: A complete relativistic nuclear model

abstract:
  We analyzed the results for finite nuclei and infinite nuclear and neutron
matter using the standard $\sigma-\omega$ model and with the effective field
theory. For the first time, we have shown here quantitatively that the
inclusion of self-interaction of the vector mesons and the cross-interaction of
all the mesons taken in the theory explain naturally the experimentally
observed softness of equation of state without loosing the advantages of
standard $\sigma-\omega$ model for finite nuclei. Recent experimental
observations support our findings and allow us to conclude that without self-
and cross-interactions the relativistic mean field theory is incomplete.


title:
Elliptic flow of multi-strange particles: fragmentation, recombination
  and hydrodynamics

abstract:
  We study the elliptic flow $v_2$ of multi-strange hadrons such as the $\phi$,
$\Xi$ and $\Omega$ as a function of transverse momentum in the recombination
and fragmentation model and compare to a standard hydrodynamic calculation. We
find that the measurement of $v_2$ for the $\phi$ and $\Omega$ will allow for
the unambiguous distinction between parton recombination and statistical
hadro-chemistry to be the dominant process in hadronization at intermediate
transverse momenta.


title: Zone Determinant Expansions for Nuclear Lattice Simulations

abstract:
  We introduce a new approximation to nucleon matrix determinants that is
physically motivated by chiral effective theory. The method involves breaking
the lattice into spatial zones and expanding the determinant in powers of the
boundary hopping parameter.


title: Effects of Meson Mass Reduction on the Properties of Neutron Star Matter

abstract:
  We investigate the effects of meson-mass reduction on the properties of the
neutron star matter. We adopt the Brown-Rho scaling law to take into account
density dependence of meson masses in the quantum hadrodynamics, quark-meson
coupling and modified quark-meson coupling models. It is found that the
equation of state becomes stiff when the mass of meson is reduced in dense
medium. We discuss its implication on the properties of the neutron star.


title:
Spin Polarizabilities of the Nucleon from Polarized Low Energy Compton
  Scattering

abstract:
  As guideline for forthcoming experiments, we present predictions from Chiral
Effective Field Theory for polarized cross sections in low energy Compton
scattering for photon energies below 170 MeV, both on the proton and on the
neutron. Special interest is put on the role of the nucleon spin
polarizabilities which can be examined especially well in polarized Compton
scattering. We present a model-independent way to extract their energy
dependence and static values from experiment, interpreting our findings also in
terms of the low energy effective degrees of freedom inside the nucleon: The
polarizabilities are dominated by chiral dynamics from the pion cloud, except
for resonant multipoles, where contributions of the Delta(1232) resonance turn
out to be crucial. We therefore include it as an explicit degree of freedom. We
also identify some experimental settings which are particularly sensitive to
the spin polarizabilities.


title: Neutrino-nucleus reactions and effective field theory

abstract:
  Effetive field theory is believed to provide a useful framework for
describing low-energy nuclear phenomena in a model-independent fashion. I give
here a brief account of the basic features of this approach, some of its latest
developments, and examples of actual calculations carried out in this
framework.


title: Lowest Order Effective Field Theory for the weak $\Lambda N$ interaction

abstract:
  The $|\Delta S|=1$ $\Lambda N$ interaction, responsible for the decay of
hypernuclei, is studied by means of an Effective Field Theory where the long
range physics is described by pion and kaon exchange mechanisms, and its short
range counterpart is obtained from the most general non-derivative local
four-fermion interaction. We show that, including the Lowest Order Parity
Conserving contact terms, allows us to reproduce the total decay rates for
$^5_\Lambda {\rm He}$, $^{11}_\Lambda {\rm B}$ and $^{12}_\Lambda {\rm C}$ with
a reasonable value of ${\hat \chi^2}$, while in order to get a prediction for
the Parity Violating (PV) asymmetry compatible with experiments, we have to
include the Lowest Order PV contact pieces.


title: On eta-pi mixing close to the eta-Helium threshold

abstract:
  A K-matrix formalism is used to relate the amplitudes for the three reactions
pd --> 3He eta, pi- 3H --> 3He eta and pd --> 3H pi+. Free parameters are
fitted to the available experimental data and an extrapolation below the eta
3He threshold is made to see the origin of the eta 3He threshold enhancement.
The existence of a virtual -- and not a quasi-bound -- state finds support in
the data. The K-matrix permits a discussion of eta-pi mixing. A mixing
parameter of 0.010(5), i.e. a mixing angle theta =0.6(3) degrees, is extracted
from a best fit to the very recent pd --> 3He pi0 reaction data.


title:
Quark Molecular Model of the S=0 Strange Pentaquark (u-sbar)-(uds)
  Baryon Spectrum

abstract:
  We present a non-relativistic quark molecular model (QMM) of the strange
crypto-exotic pentaquark baryon spectrum motivated by the recent data showing
narrow, resonance enhancements in electromagnetic and hadronic production of
kaons. Our model assumes color octet bonded quark molecular clusters forming
exotic color singlet pentaquark baryons. We develop explicit molecular
pentaquark wavefunctions that exhibit color interchange and cluster fermion
antisymmetry. Our color electro-dynamics (CED) inspired Hamiltonian, which
includes confinement, one gluon exchange and color magnetic interactions, is a
natural generalization of the Isgur and Karl quark model Hamiltonian that
reproduces the conventional meson (q-qbar) and baryon (qqq) spectrumWe
introduce the idea of Color Magnetic Confinement (CMC) which is employed to
restrict the physical pentaquark spectrum and constrain the fundamental
constants (color gyromagnetic ratios) of the QMM-CED Hamiltonian. Comparing our
QMM spectrum predictions with the recent experimental data in associated
strangeness photo- and electro-production reactions, we identify 4 candidate
states that have masses and total widths consistent with exotic pentaquark
structure.


title:
The properties of the three-nucleon system with the dressed-bag model
  for nn interaction. I: New scalar three-body force

abstract:
  A multi-component formalism is developed to describe three-body systems with
nonstatic pairwise interactions and non-nucleonic degrees of freedom. The
dressed-bag model for $NN$ interaction based on the formation of an
intermediate six-quark bag dressed by a $\sigma$-field is applied to the $3N$
system, where it results in a new three-body force between the six-quark bag
and a third nucleon. Concise variational calculations of $3N$ bound states are
carried out in the dressed-bag model including the new three-body force. It is
shown that this three-body force gives at least half the $3N$ total binding
energy, while the weight of non-nucleonic components in the $^3$H and $^3$He
wavefunctions can exceed 10%. The new force model provides a very good
description of $3N$ bound states with a reasonable magnitude of the $\sigma NN$
coupling constant. The model can serve as a natural bridge between dynamical
description of few-nucleon systems and the very successful Walecka approach to
heavy nuclei and nuclear matter.


title:
The properties of the three-nucleon system with the dressed-bag model
  for $NN$ interaction. II: Coulomb and CSB effects

abstract:
  Coulomb and charge-symmetry breaking effects in the $^3$He ground state
within the dressed dibaryon model developed recently for $2N$ and $3N$ forces
are examined in detail. Particular attention has been paid to the Coulomb
displacement energy $\Delta E_C=E_B(^3{\rm H})- E_B(^3{\rm He})$ and rms charge
radii of $^3$H and $^3$He. A new scalar $3N$ force between the third nucleon a$
dibaryon is found to be very important for a correct description of the Coulomb
energy and rms charge radius in $^3$He. In view of the new results for $\Delta
E_C$ obtained here, the role of the effects of charge symmetry breaking in the
nuclear force is discussed.


title:
Cluster Properties and Particle Production in Relativistic Quantum
  Mechanics

abstract:
  I formulate a class of relativistic quantum mechanical models that satisfy
the cluster property and allow particle production. The models have a finite
number of bare-particle degrees of freedom. The class of models include
relativistic isobar models and the relativistic Lee model. I discuss elements
of the construction that may be relevant to treat the general case of an
infinite number of degrees of freedom.


title: Wavelets in Momentum-Space Scattering Calculations

abstract:
  We demonstrate that wavelet bases have features that make them advantageous
for solving momentum-space scattering integral equations. Using the example of
two nucleons interacting with the Malfliet-Tjon V interaction, we show it is
possible to reduce the size of the matrix representation of the
Lippmann-Scwhinger equation by 96% with a loss of accuracy of only a few parts
in a million. We also demonstrate that wavelet methods provide an accurate
means for treating the singularities that appear in the scattering integral
equations.


title: NN($^1S_0$) pairs in $^3$He and in p$^3$He backward elastic scattering

abstract:
  It is shown that the shoulder observed in the cross section of $p^3He$
backward elastic scattering at proton beam energies of 0.4 -- 0.7 GeV can be
explained by the mechanism of virtual $\pi$-meson production with a dominant
contribution from the subprocesses $pd^*\to ^3$He$ \pi^0$ and $p(pp)\to^3$He$
\pi^+$, where $d^*$ denotes the singlet deuteron and the $pp$ pair is in the
$^1S_0$ state. At high energies, 1-3 GeV, the mechanism of $np$-pair transfer
dominates and probes high-momentum $NN(^1S_0$) correlations in $^3$He.


title:
Effects of Dirac sea polarization on hadronic properties - A chiral
  SU(3) approach

abstract:
  The effect of vacuum fluctuations on the in-medium hadronic properties is
investigated using a chiral SU(3) model in the nonlinear realization. The
effect of the baryon Dirac sea is seen to modify hadronic properties and in
contrast to a calculation in mean field approximation it is seen to give rise
to a significant drop of the vector meson masses in hot and dense matter. This
effect is taken into account through the summation of baryonic tadpole diagrams
in the relativistic Hartree approximation (RHA), where the baryon self energy
is modified due to interactions with both the non-strange $(\sigma)$ and the
strange $(\zeta)$ scalar fields.


title: Chiral effective field theory of Delta(1232) and Compton scattering

abstract:
  A new power-counting scheme for a chiral effective field theory that includes
Delta degrees of freedom is briefly described and applied to the nucleon
Compton scattering.


title: Model Dependence of the Properties of S11 Baryon Resonances

abstract:
  The properties of baryon resonances are extracted from a complicated process
of fitting sophisticated, empirical models to data. The reliability of this
process comes from the quality of data and the robustness of the models
employed. With the large of amount of data coming from recent experiments, this
is an excellent time for a study of the model dependence of this extraction
process. A test case is chosen where many theoretical details of the model are
required, the S11 partial wave. The properties of the two lowest N* resonances
in this partial wave are determined using various models of the resonant and
non-resonant amplitudes.


title:
Traces of Thermalization from Transverse Momentum Fluctuations in
  Nuclear Collisions

abstract:
  Scattering of particles produced in Au+Au collisions at RHIC can wrestle the
system into a state near local thermal equilibrium. I illustrate how
measurements of the centrality dependence of the mean transverse momentum and
its fluctuations can exhibit this thermalization.


title: Pairing in nuclear systems with effective Gogny and V_low-k interactions

abstract:
  The pairing properties of nuclear systems are a sensitive probe of the
effective nucleon-nucleon interactions. We compare the 1S0 pairing gaps in
nuclear and neutron matter derived from the phenomenological Gogny interaction
and a renormalization group motivated low-momentum V_low-k interaction
extracted from realistic interactions. We find that the pairing gaps predicted
by these interactions are in an excellent agreement in a wide range of
sub-nuclear densities. The close agreement between the predictions of the
effective forces remains intact in the case where the single particle spectra
in neutron and nuclear matter are renormalized within the Hartree-Fock theory.


title: Finite Formation Time in Electro-Disintegration of Few-Body Nuclei

abstract:
  Inclusive and exclusive electro-disintegration of 2-H, 3-He and 4-He are
calculated within an approach where, besides the final state interaction (FSI),
also the finite formation time (FFT) of the hit hadron to its asymptotic
physical state is taken into account.


title:
Extracting a value of the slope of the neutron form factor $G_{En}(q^2)$
  at $q^2=0$ by reanalysis of the experimental data

abstract:
  A new value $b=0.0205\pm0.0017$ fm$^2$ of the slope of the neutron form
factor $G_{En}(q^2)$ at $q^2=0$ compatible with deuteron properties has been
extracted by using a linear relation between $b$ and $A^2_S(1+\eta^2)$ we found
for a class of nonlocal potential models having the experimental values of both
$r_D$ and $Q$. Another {\it model dependent} value $b^{\rm
MHKZ}=0.0206\pm0.0014$ fm$^2$, which is also compatible with deuteron
properties, has been determined by applying "constrained" unitary
transformations to the local MHKZ potential model. The sensitivity of a small
changes in the experimental values used for $r_D$ and $Q$ on the value obtained
for $b$ is also investigated.


title: Electron screening in the liquid-gas mixed phases of nuclear matter

abstract:
  Screening effects of electrons on inhomogeneous nuclear matter, which
includes spherical, slablike, and rodlike nuclei as well as spherical and
rodlike nuclear bubbles, are investigated in view of possible application to
cold neutron star matter and supernova matter at subnuclear densities. Using a
compressible liquid-drop model incorporating uncertainties in the surface
tension, we find that the energy change due to the screening effects broadens
the density region in which bubbles and nonspherical nuclei appear in the phase
diagram delineating the energetically favorable shape of inhomogeneous nuclear
matter. This conclusion is considered to be general since it stems from a
model-independent feature that the electron screening acts to decrease the
density at which spherical nuclei become unstable against fission and to
increase the density at which uniform matter becomes unstable against proton
clustering.


title: Radii of weakly bound three-body systems: halo nuclei and molecules

abstract:
  A renormalized three-body model with zero-range potential is used to estimate
the mean-square radii of three-body halo nuclei and molecular systems. The halo
nuclei ($^6$He, $^{11}$Li, $^{14}$Be and $^{20}$C) are described as point-like
inert cores and two neutrons. The molecular systems, with two helium atoms, are
of the type $^4$He$_2-$X, where X$=^4$He, $^6$Li, $^7$Li, or $^{23}$Na. The
estimations are compared with experimental data and realistic results.


title: Electroproduction of hadrons on nuclei at GeV energies

abstract:
  We investigate coherence length effects and hadron attenuation in lepton
scattering off nuclei in the kinematic regime of the HERMES experiment. The
elementary electron-nucleon interaction is described within the event generator
PYTHIA while a full coupled-channel treatment of the final state interactions
is included by means of a BUU transport model. The results of our calculations
are in good agreement with the experimentally measured transparency ratio of
incoherent rho0 electroproduction off Nitrogen and the multiplicity ratio R_M^h
for charged hadrons, pions, kaons, protons and anti-protons in deep inelastic
scattering off Nitrogen and Krypton targets.


title: $\Lambda N \to NN$ weak interaction in effective field theory

abstract:
  The nonleptonic weak $|\Delta S|=1$ $\Lambda N$ interaction, responsible for
the dominant nonmesonic decay of all but the lightest hypernuclei, is studied
in the framework of an effective field theory. The long-range physics is
described through tree-level exchange of the SU(3) Goldstone bosons, while the
short-range potential is parametrized in terms of the lowest-order contact
terms. We obtain reasonable fits to available weak hypernuclear decay rates and
quote the values for the parity-violating asymmetry as predicted by the present
effective field theory.


title:
Nuclear incompressibility using the density dependent M3Y effective
  interaction

abstract:
  A density dependent M3Y effective nucleon-nucleon (NN) interaction which was
based on the G-matrix elements of the Reid-Elliott NN potential has been used
to determine the incompressibity of infinite nuclear matter. The nuclear
interaction potential obtained by folding in the density distribution functions
of two interacting nuclei with this density dependent M3Y effective interaction
had been shown earlier to provide excellent descriptions for medium and high
energy $\alpha$ and heavy ion elastic scatterings as well as $\alpha$ and heavy
cluster radioactivities. The density dependent parameters have been chosen to
reproduce the saturation energy per nucleon and the saturation density of spin
and isospin symmetric cold infinite nuclear matter. The result of such
calculations for nuclear incompressibility using the density dependent M3Y
effective interaction based on the G-matrix elements of Reid-Elliott NN
potential predicts a value of about 300 MeV for nuclear incompressibility.


title:
M. Poincare visits Jefferson Lab: Relativistic Models of Few-Nucleon
  Systems

abstract:
  I discuss relativistic models of few-nucleon systems, with particular
emphasis on calculations of electron-deuteron scattering and the comparison of
these calculations with recent data from Jefferson Lab.


title: Entropy Production at RHIC

abstract:
  For central heavy ion collisions at the RHIC energy, the entropy per unit
rapidity dS/dy at freeze-out is extracted with minimal model dependence from
available experimental measurements of particle yields, spectra, and source
sizes estimated from two-particle interferometry. The extracted entropy
rapidity density is consistent with lattice gauge theory results for a
thermalized quark-gluon plasma with an energy density estimated from transverse
energy production at RHIC.


title: Spin asymmetries for confined Dirac particles

abstract:
  We study the Bjorken `x' (or equivalently Nachtmann `xi') dependence of the
virtual photon spin asymmetry in polarized deep inelastic scattering of
electrons from hadrons. We use an exactly solved relativistic potential model
of the hadron, treating the constituents as independent massless Dirac
particles confined to an infinitely massive force center. The importance of
including the p-wave components of the Dirac wave function is demonstrated.
Comparisons are made to the observed data on the proton by taking into account
the observed flavor dependence of the valence quark distribution functions.


title:
Nucleus-nucleus reaction cross-sections calculated for realistic nuclear
  matter distributions within the Glauber-Sitenko approach

abstract:
  Basing on the thickness (profile) function, previously obtained for the
realistic Fermi type distribution of nucleons in nuclei, calculations are made
of the microscopic eikonal phases of the nucleus-nucleus scattering and the
total reaction cross- sections. In so doing, the phase is deduced to the
one-dimensional integral provided that the Gaussian density distribution for
the projectile nucleus and an arbitrary shape of the thickness density for the
target nucleus are used. The problems of obtaining parameters of the "point"
nucleon density are considered. A possibility of approximating the realistic
densities by the "surface-matched" Gaussian functions and the dependence of
cross-sections on the nucleon-nucleon interaction radius are discussed. The
in-medium effects and the role of the trajectory distortion are studied.
Conclusions are made on physics of the process, and comparison with
experimental data is made with cross sections calculated by using the developed
method where no free parameters are introduced.


title:
Description of Chiral Doublets in $A\sim130$ Nuclei and the Possible
  Chiral Doublets in $A\sim100$ Nuclei

abstract:
  The chiral doublets for nuclei in $A\sim100$ and $A\sim130$ regions have been
studied with the particle-rotor model. The experimental spectra of chiral
partners bands for four N=75 isotones in $A\sim130$ region have been well
reproduced by the calculation with the configuration $\pi h_{11/2}\otimes\nu
h_{11/2}^{-1}$. The possible chiral doublets in $A\sim100$ region have been
predicted by the PRM model with the configuration $\pi g_{9/2}\otimes\nu
g_{9/2}^{-1}$ based on the analysis of the spectra, the $\omega$-I relation,
the $B(M1)$ and $B(E2)$ transition probabilities, and the structure of the wave
functions. The possible chiral doublets for nuclei with asymmetric particle and
hole configuration are also discussed.


title:
Structure of the Isovector Dipole Resonance in Neutron-Rich $^{60}Ca$
  Nucleus and Direct Decay from Pygmy Resonance

abstract:
  The structure of the isovector dipole resonance in neutron-rich calcium
isotope, $^{60}Ca$, has been investigated by implementing a careful treatment
of the differences of neutron and proton radii in the continuum random phase
approximation ($RPA$). The calculations have taken into account the current
estimates of the neutron skin. The estimates of the escape widths for direct
neutron decay from the pygmy dipole resonance ($PDR$) were shown rather wide,
implicating a strong coupling to the continuum. The width of the giant dipole
resonance ($GDR$) was evaluated, bringing on a detailed discussion about its
microscopic structure.


title: Mass modification of D-meson in hot hadronic matter

abstract:
  We evaluate the in-medium $D$ and $\bar D$-meson masses in hot hadronic
matter induced by interactions with the light hadron sector described in a
chiral SU(3) model. The effective Lagrangian approach is generalized to SU(4)
to include charmed mesons. We find that the D-mass drops substantially at
finite temperatures and densities, which open the channels of the decay of the
charmonium states ($\Psi^\prime$, $\chi_c$, $J/\Psi$) to $D \bar D$ pairs in
the thermal medium. The effects of vacuum polarisations from the baryon sector
on the medium modification of the $D$-meson mass relative to those obtained in
the mean field approximation are investigated. The results of the present work
are compared to calculations based on the QCD sum-rule approach, the
quark-meson coupling model, chiral perturbation theory, as well as to studies
of quarkonium dissociation using heavy quark potential from lattice QCD.


title: Observing Chiral Nonanalytic Behavior with FLIC Fermions

abstract:
  First results from lattice QCD revealing the chiral nonanalytic behavior of
nucleon and Delta baryon magnetic moments are presented. Numerical simulations
in the light quark mass regime employing the nonperturbatively O(a)-improved
conserved vector current are enabled via FLIC fermions. Quenched chiral
perturbation theory for the nucleon and Delta magnetic moments is derived to
next to next to leading nonanalytic order. Numerical simulation results for the
proton and Delta baryon magnetic moments in quenched QCD reveal dramatic
signatures of the quenched meson cloud, which are in accord with the
predictions of quenched chiral perturbation theory.


title: Nuclear Physics from QCD

abstract:
  Recent attempts to make direct contact between QCD and simple nuclear systems
are reviewed.


title: Exclusive $K^+$ production in proton-nucleus collisions

abstract:
  The exclusive $K^+$ meson production in a proton-nucleus collision, leading
to two body final states, is investigated in a fully covariant two-nucleon
model based on the effective Lagrangian picture. The explicit kaon production
vertex is described via creation, propagation and decay into relevant channel
of $N^*$(1650), $N^*$(1710) and $N^*$(1720) intermediate baryonic states in the
initial collision of the projectile nucleon with one of its target counterparts
which is modeled by the one-pion exchange process. The calculated cross
sections show strong sensitivity to the medium effects on pion propagator and
to the final hypernuclear state excited in the reaction.


title:
The $p(d,d^{\prime})$ Reaction and the $\sigma NN^{\ast}(1440)$ Coupling
  Constant

abstract:
  We make use of a $NN \to NN^*(1440)$ transition potential derived from a
quark-model in a parameter-free way, to study the Roper excitation diagram
contributing to the reaction $p(d,d^{\prime})$. We also determine the $\pi
NN^*(1440)$ and $\sigma NN^*(1440)$ coupling constants.


title: Thermal production of the $\rho$ meson in the $\pi^+\pi^-$ channel

abstract:
  Recent measurements of the pi^+pi^- invariant mass distribution at RHIC show
a shifted peak for the rho meson in 100A GeV in peripheral Au + Au and even in
p + p collisions. A recent theoretical study based on a picture of in-medium
production rates of pions, showed that a large shift could result from a
combination of the Boltzmann factor and the collisional broadening of the rho.
Here we argue that the two-pion density of states is the appropriate quantity
if one assumes a sudden break-up of the system. Methods for calculating the
density of states which include Bose effects are derived. The resulting
invariant mass distributions are significantly enhanced at lower masses and the
rho peak is shifted downward by ~ 35 MeV.


title: Coupled cluster approach to nuclear physics

abstract:
  Using many-body perturbation theory and coupled-cluster theory, we calculate
the ground-state energy of He-4 and O-16. We perform these calculations using a
no-core G-matrix interaction derived from a realistic nucleon-nucleon
potential. Our calculations employ up to two-particle-two-hole coupled-cluster
amplitudes.


title: Light-front time picture of few-body systems

abstract:
  The projection of the four-dimensional two-body Bethe-Salpeter equation at
the light-front hypersurface is discussed. Elimination of the relative time is
performed using a quasi-potential expansion, which is shown to be equivalent to
an infinite set of coupled equations for the Green's functions of the different
light-front Fock-states.


title:
Theoretical understanding of the nuclear incompressibility: where do we
  stand ?

abstract:
  The status of the theoretical research on the compressional modes of finite
nuclei and the incompressibility $K_\infty$ of nuclear matter, is reviewed. It
is argued that the recent experimental data on the Isoscalar Giant Monopole
Resonance (ISGMR) allow extracting the value of $K_\infty$ with an uncertainity
of about $\pm$ 12 MeV. Non-relativistic (Skyrme, Gogny) and relativistic mean
field models predict for $K_\infty$ values which are significantly different
from one another, namely $\approx$ 220-235 and $\approx$ 250-270 MeV
respectively. It is shown that the solution of this puzzle requires a better
determination of the symmetry energy at, and around, saturation. The role
played by the experimental data of the Isoscalar Giant Dipole Resonance (ISGDR)
is also discussed.


title: The Relativistic Dirac-Brueckner Approach to Nuclear Matter

abstract:
  An overview on the relativistic Dirac-Brueckner approach to the nuclear
many-body problem is given. Different approximation schemes are discussed, with
particular emphasis on the nuclear self-energy and the saturation mechanism of
nuclear matter. I will further discuss extensions of the standard approach,
amongst other things the inclusion of non-nucleonic degrees of freedom,
many-body forces and finally compare relativistic and non-relativistic
approaches.


title:
Quantum Phase Transitions in the Interacting Boson Model: Integrability,
  level repulsion and level crossing

abstract:
  We study the quantum phase transition mechanisms that arise in the
Interacting Boson Model. We show that the second-order nature of the phase
transition from U(5) to O(6) may be attributed to quantum integrability,
whereas all the first-order phase transitions of the model are due to level
repulsion with one singular point of level crossing. We propose a model
Hamiltonian with a true first-order phase transition for finite systems due to
level crossings.


title:
The U(5)-O(6) transition in the Interacting Boson Model and the E(5)
  critical point symmetry

abstract:
  The relation of the recently proposed E(5) critical point symmetry with the
interacting boson model is investigated. The large-N limit of the interacting
boson model at the critical point in the transition from U(5) to O(6) is
obtained by solving the Richardson equations. It is shown explicitly that this
algebraic calculation leads to the same results as the solution of the Bohr
differential equation with a $\beta^4$ potential.


title: Periodic orbit theory including spin degrees of freedom

abstract:
  We summarize recent developments of the semiclassical description of shell
effects in finite fermion systems with explicit inclusion of spin degrees of
freedom, in particluar in the presence of spin-orbit interactions. We present a
new approach that makes use of spin coherent states and a correspondingly
enlarged classical phase space. Taking suitable limits, we can recover some of
the earlier approaches. Applications to some model systems are presented.


title:
Nature of excited 0+ states in 158Gd described by the projected shell
  model

abstract:
  Excited 0+ states are studied in the framework of the projected shell model,
aiming at understanding the nature of these states in deformed nuclei in
general, and the recently observed 13 excited 0+ states in 158Gd in particular.
The model, which contains projected two- and four-quasiparticle states as
building blocks in the basis, is able to reproduce reasonably well the energies
for all the observed 0+ states. The obtained B(E2) values however tend to
suggest that these 0+ states might have a mixed nature of quasiparticle
excitations coupled to collective vibrations.


title: Three-Fluid Simulations of Relativistic Heavy-Ion Collisions

abstract:
  A relativistic 3-fluid 3D hydrodynamic model has been developed for
describing heavy-ion collisions at incident energies between few and $\sim$ 200
A$\cdot$GeV. In addition to two baryon-rich fluids which simulate mutually
decelerating counterflows of target and projectile nucleons, the new model
incorporates evolution of a third, retarded baryon-free fluid created by this
decelerated baryonic matter. Different equations of state, including those with
the deconfinement phase transition, are treated. A reasonable agreement with
experiment is illustrated by proton rapidity spectra, their dependence on
collision centrality and beam energy.


title:
Proton and neutron skins of light nuclei within the Relativistic Mean
  Field theory

abstract:
  The Relativistic Mean Field (RMF) theory is applied to the analysis of
ground-state properties of Ne, Na, Cl and Ar isotopes. In particular, we study
the recently established proton skin in Ar isotopes and neutron skin in Na
isotopes as a function of the difference between the proton and the neutron
separation energy. We use the TMA effective interaction in the RMF Lagrangian,
and describe pairing correlation by the density-independent delta-function
interaction. We calculate single neutron and proton separation energies,
quadrupole deformations, nuclear matter radii and differences between proton
radii and neutron radii, and compare these results with the recent experimental
data.


title: Pairing effect on the giant dipole resonance width at low temperature

abstract:
  The width of the giant dipole resonance (GDR) at finite temperature T in
Sn-120 is calculated within the Phonon Damping Model including the neutron
thermal pairing gap determined from the modified BCS theory. It is shown that
the effect of thermal pairing causes a smaller GDR width at T below 2 MeV as
compared to the one obtained neglecting pairing. This improves significantly
the agreement between theory and experiment including the most recent data
point at T = 1 MeV.


title: Temperature Dependent Neutron Scattering Sections for Polyethylene

abstract:
  This note presents neutron scattering cross sections for polyethylene at 296
K, 77 K and 4 K derived from a new scattering kernel for neutron scattering off
of hydrogen in polyethylene. The kernel was developed in ENDF-6 format as a set
of S(alpha,beta) tables using the LEAPR module of the NJOY94 code package. The
polyethylene density of states (from 0 to sub eV) adopted to derive the new
kernel is presented. We compare our calculated room temperature total
scattering cross sections and double differential cross sections at 232 meV at
various angles with the available experimental data (at room temperature), and
then extrapolate the calculations to lower temperatures (77K and 4K). The new
temperature dependent scattering kernel gives a good quantitative fit to the
available room temperature data and has a temperature dependence that is
qualitatively consistent with thermodynamics.


title: Compressibility, effective mass and density dependence in Skyrme forces

abstract:
  Generalized density dependence in Skyrme effective interactions is
investigated to get forces valid beyond the mean field approximation.
Preliminary results are presented for infinite symmetric and asymmetric nuclear
matter up to pure neutron matter.


title: EFT for electroweak processes of light nuclei

abstract:
  Recently we succeeded to make a reliable EFT prediction in a totally
parameter-free manner for the $S$ factors for the solar $pp$ and $hep$
processes, $p+p\to d + e^+ +\nu_e$ and $\He3+p \to \He4 + e^+ + \nu_e$. The
strategy used in there is to embed a highly sophisticated standard nuclear
physics approach (SNPA) exploiting realistic potentials into an EFT framework,
that we refer to as EFT*. Up to next-next-to-leading order in chiral expansion,
it turnes out that there is effectively only one counter-term relevant to this
process, the coefficient of which -- ($\hat d^R$) -- has been renormalized to
reproduce the experimental value of the tritium-beta decay. Our study has also
led to {\em very} accurate EFT calculations on two-body weak processes that
also receive contributions from the $\hat d^R$ term, $\mu-d$ capture rate, and
$\nu-d$ scattering cross section.


title:
A model of binary collisions dependence of jet quenching in nuclear
  collisions at ultrarelativistic energies

abstract:
  We describe a model of jet quenching in nuclear collisions at RHIC energies.
In the model, jet quenching is to be caused by the interruption of jet
formation by nucleons arriving at the position of jet formation in a time
shorter than the jet formation time. Our mechanism predicts suppression of
high-pt spectra also in d+Au reactions.


title: Nuclear profile dependence of elliptic flow from a parton cascade

abstract:
  The transverse profile dependence of elliptic flow is studied in a parton
cascade model. We compare results from the binary scaling profile to results
from the wounded nucleon scaling profile. The impact parameter dependence of
elliptic flow is shown to depend sensitively on the transverse profile of
initial particles, however, if elliptic flow is plotted as a function of the
relative multiplicity, the nuclear profile dependence disappears. The
insensitivity was found previously in a hydrodynamical calculation. Our
calculations indicate that the insensitivity is also valid with additional
viscous corrections. In addition, the minimum bias differential elliptic flow
is demonstrated to be insensitive to the nuclear profile of the system.


title:
Proton rich nuclei at and beyond the proton drip line in the
  Relativistic Mean Field theory

abstract:
  Ground state properties of proton-rich odd-$Z$ nuclei in the region $55\le Z
\le 73$ are studied in the relativistic mean field (RMF) theory. The RMF
equations are solved by using the expansion method in the Harmonic-Oscillator
basis. In the particle-particle channel, we use the state-dependent BCS method
with a zero-range $\delta$-force, which has been proved to be effective even
for neutron-rich nuclei. All the ground state properties, including the
one-proton separation energies, the ground state deformations, the last
occupied proton orbits and the locations of proton drip line, are calculated.
Good agreement with both the available experimental data and the predictions of
the RHB method are obtained.


title:
Role of in-medium hadrons in photon-nucleus reactions : shadowing and
  dilepton spectrum

abstract:
  We study the effect of in-medium hadronic properties in photon nucleus
interactions in the context of shadowing as well as the dilepton spectrum for
incident photon energies in the range 1.1- 3 GeV. A reasonable agreement with
the experimental data for shadowing is obtained in a scenario of downward
spectral shift of the hadrons. We show that distinguishable features for
in-medium changes of the hadronic properties can be observed experimentally
through the dilepton spectrum by judicious choice of target nuclei and incident
energy of photons.


title: Detection of Antineutrinos for Non-Proliferation

abstract:
  We discuss the feasibility of using the detection of electron antineutrinos
produced in fission to monitor the time dependence of the plutonium content of
nuclear power reactors. If practical such a scheme would allow world-wide,
automated monitoring of reactors and, thereby, the detection of certain
proliferation scenarios. For GW$_e$ power reactors the count rates and the
sensitivity of the antineutrino spectrum (to the core burn-up) suggest that
monitoring of the gross operational status of the reactor from outside the
containment vessel is feasible. As the plutonium content builds up in a given
burn cycle the total number of antineutrinos steadily drops and this variation
is quite detectable, assuming fixed reactor power. The average antineutrino
energy also steadily drops, and a measurement of this variation would be very
useful to help off set uncertainties in the total reactor power. However, the
expected change in the antineutrino signal from the diversion of a significant
quantity (SQ) of plutonium, which would typically require the diversion of as
little as a single fuel assemblies in a GW$_e$ reactor, would be very difficult
to detect.


title: Chiral effective field theory for few-nucleon systems

abstract:
  Some recent developments in the description of nuclear forces and
few--nucleon systems within the effective field theory approach are reviewed.


title: Some new perspectives on pairing in nuclei

abstract:
  Following a brief reminder of how the pairing model can be solved exactly, we
describe how this can be used to address two interesting issues in nuclear
structure physics. One concerns the mechanism for realizing superconductivity
in finite nuclei and the other concerns the role of the nucleon Pauli principle
in producing $sd$ dominance in interacting boson models of nuclei.


title: On the Lorentz structure of the symmetry energy

abstract:
  We investigate in detail the density dependence of the symmetry energy in a
relativistic description by decomposing the iso-vector mean field into
contributions with different Lorentz covariant properties. We find important
effects of the iso-vector, scalar channel (i.e. $\delta$-meson like) on the
high density behavior of the symmetry energy. Applications to static properties
of finite nuclei and to dynamic situations of heavy ion collisions are explored
and related to each other. The nuclear structure studies show only moderate
effects originating from the virtual $\delta$ meson. At variance, in heavy ion
collisions one finds important contributions on the reaction dynamics arising
from the different Lorentz structure of the high density symmetry energy when a
scalar iso-vector $\delta$ field is introduced. Particularly interesting is the
related neutron/proton effective mass splitting for nucleon transport effects
and for resonance and particle production around the threshold. We show that
the $\delta$-like channel turns out to be essential for the production of
pions, when comparing with experimental data, in particular for high momentum
selections.


title: Effect of color superconductivity on the mass and radius of a quark star

abstract:
  We compare quark stars made of color-superconducting quark matter to
normal-conducting quark stars. We focus on the most simple
color-superconducting system, a two-flavor color superconductor, and employ the
Nambu-Jona-Lasinio (NJL) model to compute the gap parameter and the equation of
state. By varying the strength of the four-fermion coupling of the NJL model,
we study the mass and the radius of the quark star as a function of the value
of the gap parameter. If the coupling constant exceeds a critical value, the
gap parameter does not vanish even at zero density. For coupling constants
below this critical value, mass and radius of a color-superconducting quark
star change at most by ca. 20% compared to a star consisting of
normal-conducting quark matter. For coupling constants above the critical value
mass and radius may change by factors of two or more.


title: Pentaquark baryon production from photon-neuteron reactions

abstract:
  Extending the hadronic Lagrangians that we recently introduced for studying
pentaquark $\Theta^+$ baryon production from meson-proton, proton-proton, and
photon-proton reactions near threshold to include the anomalous interaction
between $\gamma$ and $K^*K$, we evaluate the cross section for $\Theta^+$
production from photon-neutron reactions, in which the $\Theta^+$ was first
detected in the SPring-8 experiment in Japan and the CLAS experiment at Thomas
Jefferson National Laboratory. With empirical coupling constants and form
factors, and assuming that the decay width of $\Theta^+$ is 20 MeV, the
predicted cross section is found to have a peak value of about 280 nb, which is
substantially larger than that for $\Theta^+$ production from photon-proton
reactions.


title:
Rescattering contributions to final state interactions in (e,e'p)
  reactions

abstract:
  A semiclassical model is employed to study the effects of rescattering on
(e,e'p) cross sections. We consider a two-step process with the propagation of
an intermediate nucleon and use Glauber theory to account for the effects of
N--N scattering. This calculation has relevance for the analysis of data at
high missing energies. Of particular interest is the E97-006 experiment done at
JLab. It is found that rescattering is strongly reduced in parallel kinematics
and that the excitation of nucleon resonances is likely to give important
contributions to the final-state interactions in the correlated region.


title: Dyson-Schwinger Equations: An Instrument for Hadron Physics

abstract:
  Dyson-Schwinger equations furnish a Poincare' covariant approach to hadron
physics. They reveal that dynamical chiral symmetry breaking is tied to the
long-range behaviour of the strong interaction and make predictions
corroborated by modern lattice-QCD simulations. A hallmark in the contemporary
use of DSEs is the existence of a nonperturbative, symmetry preserving
truncation that enables the proof of exact results. The systematic error
associated with the truncation's leading term has been quantified and this
underpins an efficacious one-parameter model that is being employed to study
meson excited states.


title: The nuclear force problem: Are we seeing the end of the tunnel?

abstract:
  Embedded in the historical context, we review recent progress in the
development of nucleon-nucleon (NN) potentials based upon chiral effective
field theory. A major breakthrough is the construction of the first NN
potential at next-to-next-to-next-to-leading order (fourth order) of chiral
perturbation theory (ChPT). The accuracy of this potential concerning the
reproduction of the NN data below 290 MeV lab. energy is comparable to the one
of phenomenological high-precision potentials. Since NN potentials of order
three or less of ChPT are known to be deficient in quantitative terms, the
recent advances show that the fourth order of ChPT is necessary and sufficient
for a reliable NN potential derived from chiral effective Lagrangians. This
recent substantial progress raises hopes that we might be getting closer to a
solution of the nuclear force problem at low energies that has plagued the
community for more than half a century.


title:
Pion parameters in nuclear medium from chiral perturbation theory and
  virial expansion

abstract:
  We consider two methods to find the effective parameters of the pion
traversing a nuclear medium. One is the first order chiral perturbation
theoretic evaluation of the pion pole contribution to the two-point function of
the axial-vector current. The other is the exact, first order virial expansion
of the pion self-energy. We find that, although the results of chiral
perturbation theory are not valid at normal nuclear density, those from the
virial expansion may be reliable at such density. The latter predicts both the
mass-shift and the in-medium decay width of the pion to be small, of about a
few MeV.


title:
Isovector Collective Response Function of Nuclear Matter at Finite
  Temperature

abstract:
  We study isovector collective excitations in nuclear matter by employing the
linearized Landau-Vlasov equation with and without a non-Markovian binary
collision term at finite temperature. We calculate the giant dipole resonance
(GDR) strength function for finite nuclei using Steinwedel-Jensen model and
also by Thomas-Fermi approximation, and we compare them for 120Sn and 208Pb
with experimental results.


title: Recent Developments in Few-Nucleon Systems

abstract:
  N-d elastic scattering is studied at different energies using one of the
modern NN interactions, the Argonne v_{18} which explicitly includes the
magnetic moment interaction between two nucleons. This interaction, which has
been often neglected in the description of the few-nucleon continuum, produces
sizable modifications in some elastic observables. Its effects, as well as
those produced by the Coulomb potential, are analyzed as a function of energy.
The magnetic moment interaction produces appreciable effects in $p-d$
scattering at low energies butthey are very small above 10 MeV. Above 65 MeV
Coulomb effects can be observed only in specific observables as for example
$T_{21}$.


title: An Infrared Renormalization Group Limit Cycle in QCD

abstract:
  We conjecture that QCD can be tuned to an infrared limit cycle in the
three-nucleon system by adjusting the up and down quark masses to critical
values at which the binding energies of the deuteron and its spin-singlet
partner are tuned to zero. At the critical point, the triton would have
infinitely many arbitrarily-shallow excited states with the ratio of the
binding energies of successive states approaching a universal constant close to
515.


title:
Polarization observables in the $\gamma d\to\pi NN$ reaction in the
  $\Delta$(1232)-resonance region

abstract:
  Incoherent pion photoproduction on the deuteron in the
$\Delta$(1232)-resonance region is investigated with special emphasis on
polarization observables. For the elementary pion photoproduction operator an
effective Lagrangian model which includes the standard pseudovector Born terms
and a resonance contribution from the $\Delta$(1232)-excitation is used. Our
results for the elementary $\gamma N\to\pi N$ reaction are in good agreement
with recent experimental data and results of other theoretical calculations. A
general analysis of all possible polarization observables for the $\gamma d
\to\pi NN$ reaction with polarized photon beam and/or oriented deuteron target
is presented. The unpolarized differential cross section, photon asymmetry,
vector and tensor target asymmetries are predicted for forthcoming experiments.


title: Transport properties of isospin effective mass splitting

abstract:
  We investigate in detail the momentum dependence ($MD$) of the effective in
medium Nucleon-Nucleon ($NN$) interaction in the isovector channel. We focus
the discussion on transport properties of the expected neutron-proton ($n/p$)
effective mass splitting at high isospin density. We look at observable effects
from collective flows in Heavy Ion Collisions ($HIC$) of charge asymmetric
nuclei at intermediate energies. Using microscopic kinetic equation simulations
nucleon transverse and elliptic collective flows in $Au+Au$ collisions are
evaluated. In spite of the reduced charge asymmetry of the interacting system
interesting $isospin-MD$ effects are revealed. Good observables, particularly
sensitive to the $n/p$-mass splitting, appear to be the differences between
neutron and proton flows. The importance of more exclusive measurements, with a
selection of different bins of the transverse momenta ($p_t$) of the emitted
particles, is stressed. In more inclusive data a compensation can be expected
from different $p_t$-contributions, due to the microscopic $isospin-MD$
structure of the nuclear mean field in asymmetric matter.


title:
$^1 S_0$ pairing correlation in symmetric nuclear matter with Debye
  screening effects

abstract:
  The $^1 S_0$ pairing of symmetric nuclear matter is discussed in the frame
work of relativistic nuclear theory with Dyson-Schwinger equations (DSEs). The
in-medium nucleon and meson propagators are treated in a more self-consistent
way through meson polarizations. The screening effects on mesons due to
in-medium nucleon excitation are found to reduce the $^1S_0$ pairing gap and
shift remarkably the gap peak to low density region.

categories: nucl-th astro-ph cond-mat.str-el cond-mat.supr-con hep-ph


title: On the stability and the similarity of N=82 isotones

abstract:
  Here we study the stability and the similarity of all even $58\leq Z\leq 70,
N=82 isotones. We confirm the two decades old study of one of the authors (AA)
regarding the extra-ordinary stability and the similarity of these nuclei. We
present here a new evidence which shows very strongly the said magicity of
those nuclei and as such there exists a new ``plateau'' of magicity. Three well
studied theoretical models which have been successfully applied in nuclear
physics are used here to study the above phenomena. None of these model is able
to reproduce the similarity and the doubly magic character of these nuclei.
Therefore this hints at ``new physics'' in these N=82 isotones.


title: The double tetrahedron structure of the nucleus

abstract:
  Expanding a double tetrahedron formation of equal spheres arranged in fcc
structure correlation between the positions of the nucleons and quantum numbers
has been detected. The number of protons in the structure is not simply
consistent with all the corresponding quantum numbers but also bears the same
physical meaning as in quantum mechanics. The detected correlations between
lattice positions of the protons and quantum numbers raise the possibility the
solid nuclear structure might be able to provide an explanation for the single
particle properties of the nuclei.


title: Coupled collective motion in nuclear reactions

abstract:
  In this paper, we review the roles of collective modes in nuclear reactions.
We emphaize the strong couplings of various collective states with the monopole
and quadrupole motions. In inelastic excitation, these couplings can be seen as
an important source of anharmonicity in the multiphonon spectrum. In fusion
reaction, the breathing and quadrupole motions strongly affects the oscillation
of protons against neutrons. Finally, the modification of the collective
properties induced by a large amplitude dilution might be the origin of the
nuclear multifragmentation, directly related to the nuclear liquid-gas phase
transition. In the three cases we derive a coupling matrix element which
appears to be in good agreement.


title: Mean field at finite temperature and symmetry breaking

abstract:
  For an infinite system of nucleons interacting through a central spin-isospin
schematic force we discuss how the Hartree-Fock theory at finite temperature T
yields back, in the T=0 limit, the standard zero-temperature Feynman theory
when there is no symmetry breaking. The attention is focused on the mechanism
of cancellation of the higher order Hartree-Fock diagrams and on the dependence
of this cancellation upon the range of the interaction. When a symmetry
breaking takes place it turns out that more iterations are required to reach
the self-consistent Hartree-Fock solution, because the cancellation of the
Hartree-Fock diagrams of order higher than one no longer occurs. We explore in
particular the case of an explicit symmetry breaking induced by a constant,
uniform magnetic field B acting on a system of neutrons. Here we compare
calculations performed using either the single-particle Matsubara propagator or
the zero-temperature polarization propagator, discussing under which
perturbative scheme they lead to identical results (if B is not too large). We
finally address the issue of the spontaneous symmetry breaking for a system of
neutrons using the technique of the anomalous propagator: in this framework we
recover the Stoner equation and the critical values of the interaction
corresponding to a transition to a ferromagnetic phase.


title: Shape-invariance and Exactly Solvable Problems in Quantum Mechanics

abstract:
  Algebraic approach to the integrability condition called shape invariance is
briefly reviewed. Various applications of shape-invariance available in the
literature are listed. A class of shape-invariant bound-state problems which
represent two-level systems are examined. These generalize the Jaynes-Cummings
Hamiltonian. Coherent states associated with shape-invariant systems are
discussed. For the case of quantum harmonic oscillator the decomposition of
identity for these coherent states is given. This decomposition of identity
utilizes Ramanujan's integral extension of the beta function.


title:
Final state interaction effects in $\eta$ photoproduction on two- and
  three-body nuclei

abstract:
  The role of final state interaction in $\eta$ photoproduction on a deuteron
as well as on three-body nuclei is investigated within few-body scattering
theory. Deviation of the theory from the available experimental results is
briefly discussed.


title: Heavy Quark Energy Loss in Nuclear Medium

abstract:
  Multiple scattering, modified fragmentation functions and radiative energy
loss of a heavy quark propagating in a nuclear medium are investigated in
perturbative QCD. Because of the quark mass dependence of the gluon formation
time, the medium size dependence of heavy quark energy loss is found to change
from a linear to a quadratic form when the initial energy and momentum scale
are increased relative to the quark mass. The radiative energy loss is also
significantly suppressed relative to a light quark due to the suppression of
collinear gluon emission by a heavy quark.


title: Neutron Stars for Undergraduates

abstract:
  Calculating the structure of white dwarf and neutron stars would be a
suitable topic for an undergraduate thesis or an advanced special topics or
independent study course. The subject is rich in many different areas of
physics accessible to a junior or senior physics major, ranging from
thermodynamics to quantum statistics to nuclear physics to special and general
relativity. The computations for solving the coupled structure differential
equations (both Newtonian and general relativistic) can be done using a
symbolic computational package, such as Mathematica. In doing so, the student
will develop computational skills and learn how to deal with dimensions. Along
the way he or she will also have learned some of the physics of equations of
state and of degenerate stars.


title: Continuum coupled cluster expansion

abstract:
  We review the basics of the coupled-cluster expansion formalism for numerical
solutions of the many-body problem, and we outline the principles of an
approach directed towards an adequate inclusion of continuum effects in the
associated single-energy spectrum. We illustrate our findings by considering
the simple case of a single-particle quantum mechanics problem.


title:
Gamow-Teller transitions and deformation in the proton-neutron random
  phase approximation

abstract:
  We investigate reliability of Gamow-Teller transition strengths computed in
the proton-neutron random phase approximation, comparing with exact results
from diagonalization in full $0\hbar\omega$ shell-model spaces. By allowing the
Hartree-Fock state to be deformed, we obtain good results for a wide variety of
nuclides, even though we do not project onto good angular momentum. We suggest
that deformation is as important or more so than pairing for Gamow-Teller
transitions.


title: Physical Baryon Resonance Spectroscopy from Lattice QCD

abstract:
  We complement recent advances in the calculation of the masses of excited
baryons in quenched lattice QCD with finite-range regulated chiral effective
field theory enabling contact with the physical quark mass region. We examine
the P-wave contributions to the low-lying nucleon and delta resonances.