title:
Reconstruction of the optical potential in the inverse quantum
  scattering. Application to the relativistic inelastic NN scattering

abstract:
  The numerical algorithm of the inverse quantum scattering is developed. This
algorithm is based on the Marchenko theory, and includes three steps. The first
one is the algebraic Pade approximation of the unitary S-matrix, what is
realized by solving a system of linear equations. Second step is the exact
solution of the Marchenko equation. The used approximant reduces it to another
system of linear equations. At this step we get the real-valued potential. It
is shown numerically that the developed algorithm is able not only to generate
the given S-matrix dependence, but converges to the initial potential. At third
step we construct the optical complex-valued potential which gives the needed
S-matrix. It is shown that the modern phase shift analysis data allow to
construct the nucleon-nucleon optical potentials of two kinds. These potentials
describe the deuteron properties and the phase shift analysis data up to 3 GeV
and they have different behavior at short distances. One is a repulsive core
potential and another is a Moscow attractive potential with forbidden states.


title:
Virtual photon asymmetry for confined, interacting Dirac particles with
  spin symmetry

abstract:
  We study the Bjorken x 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 bound to an infinitely
massive force center. The potential is chosen to have spin symmetry and a
linear radial dependence with spherical symmetry. The effect of interactions of
the struck constituent with the remainder of the target on the longitudinal
photon asymmetry is demonstrated. In particular, the small-x suppression of the
photon asymmetry observed in polarized deep inelastic scattering from the
proton is shown to be a consequence of these interactions. The effect of
p--wave components of the Dirac wave function, long known to give an important
contribution to the spin of hadrons, is explicitly demonstrated through their
interference with the s--wave term.


title:
Description of eta-distributions at RHIC energies in terms of the
  Ornstein-Uhlenbeck process and relativistic diffusion equations

abstract:
  Assuming the Ornstein-Uhlenbeck process and relativistic diffusion equations
with three sources at y = 0, we analyze eta-distributions of d+Au collision as
well as Au+Au collisions at sqrt{s_{NN}} = 130 GeV and 200 GeV.


title:
Renormalization of the Sigma-Omega model within the framework of U(1)
  gauge symmetry

abstract:
  It is shown that the Sigma-Omega model which is widely used in the study of
nuclear relativistic many-body problem can exactly be treated as an Abelian
massive gauge field theory. The quantization of this theory can perfectly be
performed by means of the general methods described in the quantum gauge field
theory. Especially, the local U(1) gauge symmetry of the theory leads to a
series of Ward-Takahashi identities satisfied by Green's functions and proper
vertices. These identities form an uniquely correct basis for the
renormalization of the theory. The renormalization is carried out in the
mass-dependent momentum space subtraction scheme and by the renormalization
group approach. With the aid of the renormalization boundary conditions, the
solutions to the renormalization group equations are given in definite
expressions without any ambiguity and renormalized S-matrix elememts are
exactly formulated in forms as given in a series of tree diagrams provided that
the physical parameters are replaced by the running ones. As an illustration of
the renormalization procedure, the one-loop renormalization is concretely
carried out and the results are given in rigorous forms which are suitable in
the whole energy region. The effect of the one-loop renormalization is examined
by the two-nucleon elastic scattering.


title:
Perturbative breaking of the pseudospin symmetry in the relativistic
  harmonic oscillator

abstract:
  We show that relativistic mean fields theories with scalar, $S$, and vector,
$V$, quadratic radial potentials can generate a harmonic oscillator with exact
pseudospin symmetry {\it and positive energy bound states} when $S=-V$. The
eigenenergies are quite different from those of the non-relativistic harmonic
oscillator. We also discuss a mechanism for perturbatively breaking this
symmetry by introducing a tensor potential. Our results shed light into the
intrinsic relativistic nature of the pseudospin symmetry, which might be
important in high density systems such as neutron stars.


title: Resonance states in 12C and alpha-particle condensation

abstract:
  The states with $J^\pi=0^+$, $2^+$, and $4^+$ of $^{12}$C with excitation
energies less than about 15 MeV are investigated with the alpha condensate wave
function with spatial deformation and by using the method of ACCC (analytic
continuation in the coupling constant) which is necessary for a proper
treatment of resonance states. The calculated energy and width of the recently
observed $2_2^+$ state are found to be well reproduced. The obtained $2_2^+$
wave function has a large overlap with a single condensate wave function of
$3\alpha$ gas-like structure. The density distribution is shown to be almost
the same as that of the $0_2^+$ state that is regarded as a $3\alpha$
Bose-condensed state, if the energy of the $2_2^+$ state is scaled down to the
same value as the one of the $0_2^+$ state. Furthermore, the kinetic energy,
nuclear interaction energy, and Coulomb interaction energy of the calculated
$2_2^+$ state are shown to be very similar to those of the $0_2^+$ state. We
conclude that the $2_2^+$ state has a structure similar to the $0_2^+$ state of
Bose-condensate character with a dilute $3\alpha$ gas-like structure. In
addition the resonance states, $0_3^+$, $0_4^+$, $4_2^+$, are also discussed.


title:
Some aspects of $\Theta^+$ parity determination in the reaction $\gamma
  N\to \Theta^+ \bar{K}\to N K \bar{K}$

abstract:
  We analyze the problem of how to determine the parity of the $\Theta^+$
pentaquark in the reaction $\gamma N\to K\Theta\to NK\bar{K}$, where $N=n,p$.
Our model calculations indicate that the contribution of the non-resonant
background of the reaction $\gamma N\to NK\bar{K}$ cannot be neglected, and
that suggestions to determine the parity based solely on the initial-stage
process $\gamma N\to K\Theta$ cannot be implemented cleanly. We discuss the
various mechanisms that contribute to the background, and we identify some spin
observables which are sensitive.


title: Flatte-like distributions and the a_0(980)/f_0(980) mesons

abstract:
  We explore the features of Flatte-like parametrizations. In particular, we
demonstrate that the large variation in the absolute values of the coupling
constants to the pi-eta (or pi-pi) and KKbar channels for the a_0(980) and
f_0(980) mesons that one can find in the literature can be explained by a
specific scaling behaviour of the Flatte amplitude for energies near the KKbar
threshold. We argue that the ratio of the coupling constants can be much better
determined from a fit to experimental data.


title:
Inclusive scattering data on light nuclei as a precision tool for the
  extraction of G_M^n

abstract:
  We demonstrate that refinements in the analysis of inclusive scattering data
on light nuclei enable the extraction of, generally accurate, values of the
neutron magnetic form factor G_M^n(Q^2). In particular, a recent
parametrization of ep inclusive resonance excitation enables a reliable
calculation of the inelastic background, and as a consequence a separation of
quasi-elastic and inelastic contributions. A far larger number of data points
than previously considered is now available for analysis and enables a more
reliable extraction of G_M^n from cross section and R_T data on D and He. The
achieved accuracy appears mainly limited by the present uncertainties in the
knowledge of proton form factors and by the accuracy of the data.


title: Hadron resonance probes of QGP

abstract:
  We discuss the indirect and direct role of the short-lived resonances as
probes of QGP freeze-out process. The indirect effect is the distortion of
stable single particle yields and spectra by contributions of decaying
resonances, which alter significantly the parameters obtained in fits to
experimental data. We than discuss the direct observation of short-lived
resonances as a probe of post-hadronization dynamics allowing to distinguish
between different hadronization models.


title: Numerical study of the hadron-quark mixed phase

abstract:
  The Coulomb screening effect and the finite-size effect such as surface
tension are figured out in the hadron-quark deconfinement phase transition. We
study the mixed phase of the quark droplets immersed in hadron matter. We see
that the droplet phase is mechanically unstable if the surface tension is
strong enough. Once the Coulomb potential is properly taken into account, we
could effectively satisfy the condition for charge chemical equilibrium in the
Maxwell construction. As a result, we suggest the Maxwell construction revives
the physical meaning effectively.


title:
Antisymmetrized Green's function approach to $(e,e')$ reactions with a
  realistic nuclear density

abstract:
  A completely antisymmetrized Green's function approach to the inclusive
quasielastic $(e,e')$ scattering, including a realistic one-body density, is
presented. The single particle Green's function is expanded in terms of the
eigenfunctions of the nonhermitian optical potential. This allows one to treat
final state interactions consistently in the inclusive and in the exclusive
reactions. Nuclear correlations are included in the one-body density. Numerical
results for the response functions of $^{16}$O and $^{40}$Ca are presented and
discussed.


title: Charmonium at LHC: Production, Propagation and Decay

abstract:
  The productions of muon pairs from the decay of heavy quarkonia have been
evaluated for different centrality of the nuclear collisions at LHC energies.
The effects of the various comover scenarios on the survival probability of the
heavy quarkonia have been considered. The effects of shadowing and comover
suppressions on the dilepton spectra originating from the decays of J/\psi is
found to be substantial. The dilepton yield from the thermal J/\psi has also
been estimated and found to be small.


title: Single-Particle Properties from Kohn-Sham Green's Functions

abstract:
  An effective action approach to Kohn-Sham density functional theory is used
to illustrate how the exact Green's function can be calculated in terms of the
Kohn-Sham Green's function. An example based on Skyrme energy functionals shows
that single-particle Kohn-Sham spectra can be improved by adding sources used
to construct the energy functional.


title: Soft triaxial rotor in the vicinity of $\gamma=\pi/6$ and its extensions

abstract:
  The collective Bohr hamiltonian is solved for the soft triaxial rotor around
$\gamma_0=\pi/6$ with a displaced harmonic oscillator potential in $\gamma$ and
a Kratzer-like potential in $\beta$. The properties of the spectrum are
outlined and a generalization for the more general triaxial case with
$0<\gamma<\pi/6$ is proposed.


title:
Asymmetries in the Non-Mesonic Weak Decay of Polarized
  Lambda-Hypernuclei

abstract:
  The non-mesonic weak decay of polarized Lambda-hypernuclei is studied for the
first time by taking into account, with a Monte Carlo intranuclear cascade
code, the nucleon final state interactions. A one-meson-exchange model is
employed to describe the Lambda N-> n N processes in a finite nucleus
framework. The relationship between the intrinsic Lambda asymmetry parameter
a_\Lambda and the asymmetry a^M_\Lambda accessible in experiments is discussed.
A strong dependence of a^M_\Lambda on nucleon final state interactions and
detection threshold is obtained. Our results for a^M_\Lambda are consistent
with ^{11}_\Lambda B and ^{12}_\Lambda C data but disagree with observations in
^5_\Lambda He.


title: The Thermodynamic Model for Nuclear Multifragmentation

abstract:
  A great many observables seen in intermediate energy heavy ion collisions can
be explained on the basis of statistical equilibrium. Calculations based on
statistical equilibrium can be implemented in microcanonical ensemble (energy
and number of particles in the system are kept fixed), canonical ensemble
(temperature and number of particles are kept fixed) or grand canonical
ensemble (fixed temperature and a variable number of particles but with an
assigned average). This paper deals with calculations with canonical ensembles.
A recursive relation developed recently allows calculations with arbitrary
precision for many nuclear problems. Calculations are done to study the nature
of phase transition in intermediate energy heavy ion collision, to study the
caloric curves for nuclei and to explore the possibility of negative specific
heat because of the finiteness of nuclear systems. The model can also be used
for detailed calculations of other observables not connected with phase
transitions, such as populations of selected isotopes in a heavy ion collision.
  The model also serves a pedagogical purpose. For the problems at hand, both
the canonical and grand canonical solutions are obtainable with arbitrary
accuracy hence we can compare the values of observables obtained from the
canonical calculations with those from the grand canonical. Sometimes, very
interesting discrepancies are found. To illustrate the predictive power of the
model, calculated observables are com$data from the central collisions of Sn
isotopes.


title:
Sensitivity of 8B breakup cross section to projectile structure in CDCC
  calculations

abstract:
  Given the Astrophysical interest of $^7$Be$(p,\gamma)^8$B, there have been
several experiments applying the Coulomb dissociation method for extracting the
capture rate. Measurements at Michigan State are dominated by $E1$
contributions but have a small $E2$ component. On the other hand, a lower
energy measurement at Notre Dame has a much stronger $E2$ contribution. The
expectation was that the two measurements would tie down the $E2$ and thus
allow for an accurate extraction of the $E1$ relevant for the capture process.
The aim of this brief report is to show that the $E2$ factor in breakup
reactions does not translate into a scaling of the $E2$ contribution in the
corresponding capture reaction. We show that changes to the $^8$B single
particle parameters, which are directly related to the $E2$ component in the
capture reaction, do not effect the corresponding breakup reactions, using the
present reaction theory.


title: Constraints on narrow exotic states from K+p and K0_Lp scattering data

abstract:
  We consider the effect of exotic S=+1 resonances Theta+ and Theta++ on K+p
elastic scattering data (total cross section) and the process K0_Lp-->K0_Sp.
Data near the observed Theta+(1540) are examined for evidence of additional
states. The width limit for a Theta++ state is reconsidered and shown to be
much less than 1 MeV.


title: Forward Production in d+Au Collisions by Parton Recombination

abstract:
  Hadron production at forward rapidities in d+Au collisions is studied in the
framework of parton recombination in the final state. Multiple scattering and
gluon saturation in the initial state are not explicitly considered. The
recombination of soft and shower partons is found to be important. The soft
parton densities are determined by extrapolation from the parametrization fixed
at \eta=0 with no unconstrained adjustments. The suppression of R_{CP} observed
at high \eta is understood as the simple consequence of the reduction of the
soft parton density on the deuteron side compared to that on the gold side. The
effect of momentum degradation responsible for baryon stopping is also
considered. The asymmetry of backward-to-forward spectra can be reproduced
within the same framework without any change in the basic physics.


title: Gauge dependence of calculations in relativistic Coulomb excitation

abstract:
  Before a quantum-mechanical calculation involving electromagnetic
interactions is performed, a choice must be made of the gauge to be used in
expressing the potentials. If the calculation is done exactly, the observable
results it predicts will be independent of the choice of gauge. However, in
most practical calculations approximations are made, which can destroy the
gauge invariance of the predictions. We compare here the results of
coupled-channel time-dependent relativistic Coulomb excitation calculations, as
performed in either Lorentz or Coulomb gauges. We find significant differences
when the bombarding energy per nucleon is $\geq$ 2 GeV, which indicates that
the common practice of relying completely on the Lorentz gauge can be
dangerous.


title: Nodal Lines in the Cranked HFB Overlap kernels

abstract:
  Norm overlap kernels of the cranked Hartree-Fock-Bogoliubov states are
studied in the context of angular momentum projection. In particular, the
geometrical distribution of nodal lines, i.e., one dimensional structures where
the overlap kernels possess null value, is investigated in the three
dimensional space defined by the Euler angles. It is important to know the
distribution of these nodal lines when one attempts to determine the phase of
norm overlap kernels.


title: Effective Interaction Techniques for the Gamow Shell Model

abstract:
  We apply a contour deformation technique in momentum space to the newly
developed Gamow shell model, and study the drip-line nuclei 5He, 6He and 7He. A
major problem in Gamow shell-model studies of nuclear many-body systems is the
increasing dimensionality of many-body configurations due to the large number
of resonant and complex continuum states necessary to reproduce bound and
resonant state energies. We address this problem using two different effective
operator approaches generalized to the complex momentum plane. These are the
Lee-Suzuki similarity transformation method for complex interactions and the
multi-reference perturbation theory method. The combination of these two
approaches results in a large truncation of the relevant configurations
compared with direct diagonalization. This offers interesting perspectives for
studies of weakly bound systems.


title: Quantum Monte Carlo Calculations of Light Nuclei

abstract:
  Variational Monte Carlo and Green's function Monte Carlo are powerful tools
for calculations of properties of light nuclei using realistic two-nucleon and
three-nucleon potentials. Recently the GFMC method has been extended to
multiple states with the same quantum numbers. The combination of the Argonne
v_18 two-nucleon and Illinois-2 three-nucleon potentials gives a good
prediction of many energies of nuclei up to 12C. A number of other recent
results are presented: comparison of binding energies with those obtained by
the no-core shell model; the incompatibility of modern nuclear Hamiltonians
with a bound tetra-neutron; difficulties in computing RMS radii of very weakly
bound nuclei, such as 6He; center-of-mass effects on spectroscopic factors; and
the possible use of an artificial external well in calculations of neutron-rich
isotopes.


title: Isoscaling of the Fission Fragments with Langevin Equation

abstract:
  Langevin equation is used to simulate the fission process of $^{112}$Sn +
$^{112}$Sn and $^{116}$Sn + $^{116}$Sn. The mass distribution of the fission
fragments are given by assuming the process of symmetric fission or asymmetric
fission with the Gaussian probability sampling. Isoscaling behavior has been
observed from the analysis of fission fragments of both reactions and the
isoscaling parameter $\alpha$ seems to be sensitive to the width of fission
probability and the beam energy.


title: QCD sum rules for nucleon two-point function in nuclear medium

abstract:
  We derive QCD sum rules from the nucleon two-point function in nuclear
medium, calculating its specral function in chiral perturbation theory to one
loop. Our calculation shows the inadequacy of the commonly used ansatz to
represent the two-point function as the sum of a nucleon pole term and a
spectral integral over the high energy continuum. We also point out that it is
the energy variable and not its square that must be used in writing the
dispersion integrals. The sum rules are obtained by equating terms linear in
nucleon number density of the spectral and operator representations of the
correlation function. We use them to predict the curent-nucleon coupling, in
good agreement with the value known from the vacuum sum rules. They also
predict a definite deviation of the four-quark condensate from its ground state
saturation value.


title:
The interparticle interaction and noncommutativity of conjugate
  operators in quantum mechanics II. Lightest nuclei

abstract:
  A new model for calculating the structure of bound states of interacting
particles is considered. The model takes into account the noncommutativity of
the space and impulse operators plus the correlation equations for the
indeterminacy of these quantities. The efficiency of the model is demonstrated
by specific calculations for some lightest nuclei.


title:
Predictions for Polarized-Beam/Vector-Polarized-Target Observables in
  Elastic Compton Scattering on the Deuteron

abstract:
  Motivated by developments at HIGS at TUNL that include increased photon flux
and the ability to circularly polarize photons, we calculate several
beam-polarization/target-spin dependent observables for elastic Compton
scattering on the deuteron. This is done at energies of the order of the pion
mass within the framework of Heavy Baryon Chiral Perturbation Theory. Our
calculation is complete to O(Q^3) and at this order there are no free
parameters. Consequently, the results reported here are predictions of the
theory. We discuss paths that may lead to the extraction of neutron
polarizabilities. We find that the photon/beam polarization asymmetry is not a
good observable for the purpose of extracting \alpha_n and \beta_n. However,
one of the double polarization asymmetries, \Sigma_x, shows appreciable
sensitivity to \gamma_{1n} and could be instrumental in pinning down the
neutron spin polarizabilities.


title:
Neutrino accompanied beta^-beta^-, beta^+beta^+, beta^+/EC and EC/EC
  processes within single state dominance hypothesis

abstract:
  The systematic study of (anti-)neutrino accompanied beta^-beta^-,
beta^+beta^+ decays and beta^+/EC, EC/EC electron captures is performed under
the assumption of single intermediate nuclear state dominance. The
corresponding half-lives are evaluated both for transitions to the ground state
as well as to the 0^+ and 2^+ excited states of final nucleus. It is stressed
that the hypothesis of single state dominance can be confirmed or ruled out by
the precision measurements of the differential characteristics of the
2nbb-decays of 100Mo and 116Cd as well as beta^+/EC electron capture in 106Cd,
130Ba and 136Ce.


title: Fluctuations in the Canonical Ensemble

abstract:
  The particle number and energy fluctuations in the system of charged
particles are studied in the canonical ensemble for non-zero net values of the
conserved charge. In the thermodynamic limit the fluctuations in the canonical
ensemble are different from the fluctuations in the grand canonical one. The
system with several species of particles is considered. We calculate the
quantum statistics effects which can be taken into account for the canonical
ensemble fluctuations in the infinite volume limit. The fluctuations of the
particle numbers in the pion-nucleon gas are considered in the canonical
ensemble as an example of the system with two conserved charges - baryonic
number and electric charge.


title: Baryonic mixing and production of hypernuclei

abstract:
  We address mixing of different baryonic states in hypernuclei and formation
of strange nuclei of various kinds. First, production of neutron-rich Lambda
hypernuclei by the (pi-,K+) reaction is considered, and one-step production via
baryonic admixtures in the final as well as in the initial state is discussed.
Then, the Lambda Lambda - Xi N mixing in p shell Lambda Lambda hypernuclei
exemplified by $^{12}_{\Lambda\Lambda}$Be is studied. The last topic is devoted
to production of Theta pentaquark nuclei (pentanuclei). We suggest a type of
reactions with recoilless Theta production.


title:
Study of dissipative dynamics in fission of hot nuclei using Langevin
  equation

abstract:
  The fission of highly excited compound nuclei formed in heavy ion induced
fusion reactions has emerged as a topic of considerable interest in the recent
years.
  Dissipative dynamical models based on the Langevin equation were developed
and were applied successfully for fission dynamics of highly excited heavy
nuclei. However, Wall Friction(WF), the standard version of nuclear friction
when incorporated in the Langevin dynamical model was not able to reproduce
simultaneously experimental data for both prescission neutron multiplicity and
fission probability. Consequently, an empirical reduction in the strength of
the wall friction was found necessary to reproduce the experimental numbers by
many workers. Interestingly, a modification of the wall friction was proposed
recently where the reduction was achieved microscopically. This modified
version is known as the chaos weighted wall friction(CWWF) which takes into
account non-integrability of single particle motion. The work in my thesis aims
at using this strongly shape dependent version of friction (CWWF) in the
Langevin dynamical model coupled with particle and gamma evaporation in order
to verify to what extent it can account for the experimental data of fission of
hot nuclei. The experimental data includes excitation functions of prescission
neutron multiplicity, fission probability as well as evaporation residue
cross-section of a number of nuclei. The importance of transients in nuclear
fission is also discussed. The present endeavour is an effort to obtain a clear
physical picture of nuclear dissipation which in turn will help in solving many
open problems related to collective motion, and in particular, nuclear fission.


title:
Angular distribution and azimuthal asymmetry for pentaquark production
  in proton-proton collisions

abstract:
  Angular distributions for production of the $\Theta^+$ pentaquark are
calculated for the collisions of polarized protons with polarized target
protons. We compare calculations based on different assumptions concerning spin
and parity ($J=1/2^\pm,3/2^\pm$) of the $\Theta^+$ state. For a wide class of
interactions the spin correlation parameters describing the asymmetric angular
distributions are calculated up to 250 MeV above production threshold. The
deviations from the near threshold behavior are investigated.


title: Statistical hadronization with resonances

abstract:
  We introduce the equilibrium and non-equilibrium statistical hadronization
picture of particle production in ultra-relativistic heavy ion collisions. We
describe the related physical reaction scenarios, and show how these can lead
to quark pair yield non-equilibrium. Using the SHARE1.2 program suite we
quantitatively model particle yields and ratios for RHIC-130 run.
  We study how experimental particle ratios can differentiate between model
scenarios, and discuss in depth the importance of hadronic resonances in
understanding of hadron production processes.


title:
Stability and structure of quark matter in a molecular dynamics
  framework

abstract:
  We study stability and structure of quark matters as a function of density in
a framework of molecular dynamics (MD). Using appropriate effective
interactions and the frictional cooling method, we search for the minimum
energy of the system. Transition from confined to deconfined phase is observed
at densities of 2 -- 3$\rho_0$, where $\rho_0$ is the nuclear matter saturation
density. The $uds$ matter becomes more stable than the charge-neutral $ud$
matter at 3$\rho_0$, but the $udd$ matter is the most stable even at high
density.


title: Transport analysis of K+ production in proton-nucleus reactions

abstract:
  The production of $K^+$ mesons in proton-nucleus collisions from 1.0 to 2.3
GeV is analyzed with respect to one-step nucleon-nucleon $(NN\to N Y K^+$) and
two-step $\Delta$-nucleon $(\Delta N \to K^+ Y N$) or pion-nucleon $(\pi N \to
K^+ Y $) production channels on the basis of a coupled-channel transport
approach (CBUU) including the kaon final-state-interactions (FSI).
Momentum-dependent potentials for the nucleon, hyperon and kaon in the final
state are included as well as $K^+$ elastic rescattering in the target nucleus.
The transport calculations are compared to the experimental $K^+$ spectra taken
at COSY-J\"ulich. Our systematic analysis of $K^+$ spectra from $^{12}C$,
$^{63}Cu$, $^{107}Ag$ and $^{197}Au$ targets as well as their momentum
differential ratios gives a repulsive $K^+$ potential of $20\pm 5 $ MeV at
normal nuclear matter density.


title: Kaon and Pion production in relativistic heavy-ion collisions

abstract:
  The BUU transport model is applied to study strangeness and pion production
in nucleus-nucleus collisions. Starting from proton induced reactions, we
further investigate Si+Au, Au+Au and Pb+Pb collisions in the energy range
between 2 and 40 A$\cdot$GeV and compare with data and with other transport
calculations. The $q \bar q$ annihilation, or resonance, channel simulated by
the string model in meson-nucleon collisions at $\sqrt{s} > 2$ GeV is
introduced. The importance of this channel for a good description of the
proton-nucleus data on $K^+$ production is demonstrated. We, furthermore, show
that the meson-meson collisions contribute significantly to the $K \bar K$
production in heavy-ion collisions above 5 A GeV and improve an agreement with
data on the $K^+/\pi^+$ ratio. Finally, we study the influence of the in-medium
modifications of the FRITIOF model on the pion and kaon production.


title: Excitations of the Quark- Gluon Plasma

abstract:
  We will discuss the spectrum of the eta mesons making use of the
Nambu-Jona-Lasinio (NJL) model supplemented with a model of confinement. We
will go on to discuss the properties of mesons at finite temperature and the
phenomenon of deconfinement. We will then discuss some excited states of the
quark-gluon plasma calculated in lattice QCD models.These resonances are
thought to be created in heavy-ion collisions.We consider the role these states
play in leading to a hydrodynamic description of the plasma at early stages of
its formation.


title:
D-state configurations in the electromagnetic form factors of the
  nucleon and the Delta(1232) resonance

abstract:
  The $\Delta-N$ electromagnetic transition form factors are calculated in the
Poincar\'e covariant quark model in three forms of relativistic kinematics.
Addition of $D-$state components to pure $S-$state model wave functions, chosen
so as to reproduce the empirical elastic electromagnetic nucleon form factors
with single constituent currents, brings the calculated $R_{EM}$ ratio for the
$\Delta(1232)\to N\gamma$ transition closer to the empirical values in instant
and point form kinematics. The calculated $R_{SM}$ ratio is insensitive to the
$D-$state component. In front form kinematics the substantial violation of the
angular condition for the spin 3/2 resonance transition amplitude in the
impulse approximation prevents a unique determination of $R_{EM}$ and $R_{SM}$,
both of which are very sensitive to $D-$state components. In no form of
kinematics do $D-$state deformations of the rest frame baryon wave functions
alone suffice for a description of the empirical values of these ratios.


title:
Leading-order Corrections of a Dynamical Model for Electromagnetic Pion
  Production Reactions

abstract:
  By applying a unitary transformation method, we have derived the
leading-order corrections on the effective Hamiltonian of a dynamical model
developed in Phys. Rev. C54, 2660 (1996) for electromagnetic pion production
reactions. The resulting energy-independent one-loop corrections on the baryon
masses and the gamma N -> Delta vertex interaction are associated with the
structure of the nucleon and Delta and have been calculated within a
constituent quark model. We find that the one-loop corrections on the magnetic
M1 transition of the gamma N -> Delta are very small, while their contributions
to the electric E2 and Coulomb C2 transitions are found to be in opposite signs
of that due to pion cloud effects associated with the scattering states. Our
results further indicate that the determination of the nonspherical L=2
components of the constituent quark wavefunctions of N and Delta from the
extracted empirical E2 and C2 form factors requires a rigorous and complete
calculation of meson cloud effects. We also find that the one-loop corrections
on the non-resonant pion production operator can resolve the difficulty in
describing the near threshold gamma p -> pi^0 p reaction. Possible future
developments are discussed.


title: Towards a Connection Between Nuclear Structure and QCD

abstract:
  As we search for an ever deeper understanding of the structure of hadronic
matter one of the most fundamental questions is whether or not one can make a
connection to the underlying theory of the strong interaction, QCD. We build on
recent advances in the chiral extrapolation problem linking lattice QCD at
relatively large ``light quark'' masses to the physical world to estimate the
scalar polarizability of the nucleon. The latter plays a key role in modern
relativistic mean-field descriptions of nuclei and nuclear matter (such as QMC)
and, in particular, leads to a very natural saturation mechanism. We
demonstrate that the value of the scalar polarizability extracted from the
lattice data is consistent with that needed for a successful description of
nuclei within the framework of QMC. In a very real sense this is the first hint
of a direct connection between QCD and the properties of finite nuclei.


title: Phase structure of the two-fluid proton-neutron system

abstract:
  The phase structure of a two-fluid bosonic system is investigated. The
proton-neutron interacting boson model (IBM-2) posesses a rich phase structure
involving three control parameters and multiple order parameters. The surfaces
of quantum phase transition between spherical, axially-symmetric deformed, and
SU*(3) triaxial phases are determined.


title: Hybrid stars that masquerade as neutron stars

abstract:
  We show that a hybrid (nuclear + quark matter) star can have a mass-radius
relationship very similar to that predicted for a star made of purely nucleonic
matter. We show this for a generic parameterization of the quark matter
equation of state, and also for an MIT bag model, each including a
phenomenological correction based on gluonic corrections to the equation of
state. We obtain hybrid stars as heavy as 2 M_solar for reasonable values of
the bag model parameters. For nuclear matter, we use the equation of state
calculated by Akmal, Pandharipande, and Ravenhall using many-body techniques.
Both mixed and homogeneous phases of nuclear and quark matter are considered.


title: Perturbative HFB model for many-body pairing correlations

abstract:
  We develop a perturbative model to treat the off-diagonal components in the
Hartree-Fock-Bogoliubov (HFB) transformation matrix, which are neglected in the
BCS approximation. Applying the perturbative model to a weakly bound nucleus
$^{84}$Ni, it is shown that the perturbative approach reproduces well the
solutions of the HFB method both for the quasi-particle energies and the radial
dependence of quasi-particle wave functions. We find that the non-resonant part
of the continuum single-particle state can acquire an appreciable occupation
probability when there exists a weakly bound state close to the Fermi surface.
This result originates from the strong coupling between the continuum particle
state and the weakly bound state, and is absent in the BCS approximation. The
limitation of the BCS approximation is pointed out in comparison with the HFB
and the present perturbative model.


title: Contribution of boundness and motion of nucleons to the EMC effect

abstract:
  The kinematical corrections to the structure function of nucleon in nucleus
due to the boundness and motion of nucleons arise from the excitation of the
doorway states for one-nucleon transfer reactions in the deep inelastic
scattering on nuclei.


title: Spin and Isospin Effects in the NN -> NK Lambda Reaction Near Threshold

abstract:
  The spin and isospin structure of the amplitudes and observables for K+Lambda
production in nucleon-nucleon collisions in the near-threshold region is
analysed. It is shown that, with reasonable values for the relative strengths
of the pi and rho terms in a meson-exchange model, one expects production on
the neutron to be significantly stronger than that on the proton. Negative
values of the spin-transfer coefficient D_NN are also predicted due to pi-rho
interference.


title:
Shortcuts to nuclear structure: lessons in Hartree-Fock, RPA, and the
  no-core shell model

abstract:
  While the no-core shell model is a state-of-the-art microscopic approach to
low-energy nuclear structure, its intense computational requirements lead us to
consider time-honored approximations such as the Hartree-Fock (HF)
approximation and the random phase approximation (RPA). We review RPA and point
out some common misunderstandings, then apply HF+RPA to the no-core shell
model. Here the main issue is appropriate treatment of contamination by
spurious center-of-mass motion.


title:
Dark Matter in the Cosmos - Its Direct Detection and the Role Of Nuclear
  Physics

abstract:
  Exotic dark matter together with dark energy or cosmological constant seem to
dominate in the Universe. An even higher density of such matter seems to be
gravitationally trapped in our Galaxy. The nature of dark matter can be
unveiled only, if it is detected in the laboratory. Thus the accomplishment of
this task is central to physics and cosmology. Current fashionable
supersymmetric models provide a natural dark matter candidate, which is the
lightest supersymmetric particle (LSP). Since the LSP is much heavier than the
proton, while its average energy is in the keV region, the most likely
possibility for its direct detection is via its elastic scattering with a
nuclear target. In order to evaluate the event rate one needs the nuclear
structure (form factor and/or spin response function) for the special nuclear
targets of experimental interest. Since the expected rates for
neutralino-nucleus scattering are expected to be small, one should exploit all
the characteristic signatures of this reaction. Such are: (i) In the standard
recoil measurements the modulation of the event rate due to the Earth's motion.
(ii) In directional recoil experiments the correlation of the event rate with
the sun's motion. One now has both modulation, which is much larger and depends
not only on time, but on the direction of observation as well, and a large
forward-backward asymmetry. (iii) In non recoil experiments gamma rays
following the decay of excited states populated during the Nucleus-LSP
collision. Branching ratios of about 6 percent are possible. (iv) novel
experiments in which one observes the electrons prodused during the collisionof
the LSP with the nucleus. Branching ratios of about 10 per cent are possible.


title: The compact star in the SU(3) sigma model

abstract:
  The linear chiral SU(3)*SU(3) model is applied to describe properties of the
compact star matter inside the quark, protoneutron and neutron star.The leads
to the neutron star with the value of maximum mass close to 1.5 solar mass and
radius 11 km and with the reduced value of proton fraction and very compact
hyperon core.


title: HFB calculations with a microscopic pairing interaction

abstract:
  Hartree-Fock-Bogolyubov (HFB) calculations making use of a recently proposed
microscopic effective pairing interaction are presented. The interaction was
shown to reproduce the pairing properties provided by the realistic $AV18$
force very accurately in infinite matter. Although finite-ranged and non-local,
it makes 3D HFB calculations in coordinate space tractable. As a first
application, basic pairing properties of calcium isotopes in their ground-state
are studied. By comparing the results with those obtained using a standard
Density-Dependent Delta Interaction, the crucial isovector character of the
microscopic interaction is highlighted.


title: eta-Nucleon Scattering Length and Effective Range uncertainties

abstract:
  The coupled eta-N, pi-N, gamma-N, 2pi-N system is described by a K-matrix
method. The parameters in this model are adjusted to get an optimal fit to
pi-N-->pi-N, pi-N-->eta-N, gamma-N-->pi-N and gamma-N-->eta-N data in an energy
range of about 100 MeV or so each side of the eta-threshold. Compared with our
earlier analysis, we now utilize recent Crystal Ball data. However, the outcome
confirms our previous result that the eta-nucleon scattering length (a) is
large with a value of 0.91(6)+i0.27(2) fm.


title: Neutrino Physics and Nuclear Axial Two-Body Interactions

abstract:
  We consider the counter-term describing isoscalar axial two-body currents in
the nucleon-nucleon interaction, L1A, in the effective field theory approach.
We determine this quantity using the solar neutrino data. We investigate the
variation of L1A when different sets of data are used.


title: Energy level displacement of excited np states of kaonic hydrogen

abstract:
  We compute the energy level displacement of the excited np states of kaonic
hydrogen within the quantum field theoretic and relativistic covariant model of
strong low-energy bar-KN interactions suggested in EPJA21, 11 (2004). For the
width of the energy level of the excited 2p state of kaonic hydrogen, caused by
strong low-energy interactions, we find Gamma_2p = 2 meV. This result is
important for the theoretical analysis of the X-ray yields in kaonic hydrogen.


title: Model Calculation of Effective Three-Body Forces

abstract:
  We propose a scheme for extracting an effective three-body interaction
originating from a two-nucleon interaction. This is based on the Q-box method
of Kuo and collaborators, where folded diagrams are obtained by differentiating
a sum of non-folded diagrams with respect to the starting energy. To gain
insight we have studied several examples using the Lipkin model where the
perturbative approach can be compared with exact results. Numerically the
three-body interactions can be significant and in a matrix example good
accuracy was not obtained simultaneously for both eigenvalues with two-body
interactions alone.


title: Thermal kaons production in the relativistic heavy ions collision

abstract:
  We study the thermal production of kaons in hot and dense symmetric and
asymmetric hypernuclear matter in the context of the modified quark-meson
coupling model. All the baryon species and kaons are treated as MIT bags that
interact with each other via the scalar mesons $\sigma,\sigma^*$ and the vector
mesons $\omega,\phi$ as well as the isovector meson $\rho$. Furthermore, in our
calculations, we use realistic sets of hyperon-hyperon (or $YY$) interactions
based on several versions of Nijmegen core potential models. We consider a
system of strange hadronic matter and kaons but with zero total net strangeness
of the system and conserved small negative fraction of the isospin-charge. We
find strange baryons as well as kaons are produced abundantly when the
temperature increases and approaches the critical temperature for the phase
transition to the quark-gluon plasma. Our results show that the kaons are
produced only thermally in the symmetric and asymmetric hypernuclear matter and
there is no signature for the onset of kaon condensation in the relativistic
heavy ions collision. The kaons appear in the system only by thermal
production. However, when the system cools down strange hadrons could survive.


title:
Nucleon and Pion Form Factors in Different Forms of Relativistic Quantum
  Mechanics

abstract:
  Calculations of form factors in different forms of relativistic kinematics
are presented. They involve the instant, front and point forms. In the two
first cases, different kinematical conditions are considered while in the
latter case, both a Dirac-inspired approach and a hyperplane-based one are
incorporated in our study. Numerical results are presented for the pion form
factors with emphasis on both the low and high Q**2 range. A new argument is
presented, explaining why some approaches do considerably much better than
other ones whenonly a single-particle current is considered.


title: Polarized Proton Pionic Capture in Deuterium as a Probe of 3N Dynamics

abstract:
  The proton analyzing power Ay in pion production reaction pd --> pi0 3He has
been calculated including one- and two-body meson production mechanisms with a
proper treatment of the three-nucleon dynamics and an accurate solution of the
3N bound-state problem for phenomenological two-nucleon potentials. In the
region around the Delta resonance, the structure of the analyzing power can be
understood once interference effects among amplitudes describing intermediate
Delta N formation in different orbital states are considered along with the
additional interference with the S-wave pion production amplitudes. Then, the
inclusion of three-nucleon dynamics in the initial state produces the structure
of the analyzing power that has been observed experimentally.


title: Quantum Opacity, the RHIC HBT Puzzle, and the Chiral Phase Transition

abstract:
  We present a relativistic quantum mechanical treatment of opacity and
refractive effects that allows reproduction of observables measured in two-pion
(HBT) interferometry and pion spectra at RHIC. The inferred emission duration
is substantial. The results are consistent with the emission of pions from a
system that has a restored chiral symmetry.


title: Recent Developments in the Lorentz Integral Transform (LIT) Method

abstract:
  Recent results on electromagnetic reactions into the continuum of systems
with A from 3 to 7 are presented. They have been obtained using the Lorentz
Integral Transform (LIT) method. The method is shortly reviewed, emphasizing
how all the results, though obtained with the sole ingredient of the N-N
potential, contain the full complicated dynamics of the A-body system, both in
the initial and in the final states.


title:
Improved radiative corrections for (e,e'p) experiments: Beyond the
  peaking approximation and implications of the soft-photon approximation

abstract:
  Analysing (e,e'p) experimental data involves corrections for radiative
effects which change the interaction kinematics and which have to be carefully
considered in order to obtain the desired accuracy. Missing momentum and energy
due to bremsstrahlung have so far always been calculated using the peaking
approximation which assumes that all bremsstrahlung is emitted in the direction
of the radiating particle. In this article we introduce a full angular Monte
Carlo simulation method which overcomes this approximation. The angular
distribution of the bremsstrahlung photons is reconstructed from H(e,e'p) data.
Its width is found to be underestimated by the peaking approximation and
described much better by the approach developed in this work.


title:
Neutron Fraction and Neutrino Mean Free Path Predictions in Relativistic
  Mean Field Models

abstract:
  The equation of state (EOS) of dense matter and neutrino mean free path
(NMFP) in a neutron star have been studied by using relativistic mean field
models motivated by effective field theory (ERMF). It is found that the models
predict too large proton fractions, although one of the models (G2) predicts an
acceptable EOS. This is caused by the isovector terms. Except G2, the other two
models predict anomalous NMFP. In order to minimize the anomaly, besides an
acceptable EOS, a large M* is favorable. A model with large M* retains the
regularity in the NMFP even for a small neutron fraction.


title: Missing Resonances in Kaon Photoproduction on the Nucleon

abstract:
  New kaon photoproduction data on a proton, gamma + p --> K+ + Lambda, are
analyzed using a multipole approach. The background terms are given in terms of
gauge invariant, crossing symmetric, Born diagrams with hadronic form factors,
while the resonances are parameterized using Breit-Wigner forms. Preliminary
results suggest a number of new resonances, as predicted by many quark model
studies. A comparison between the extracted multipoles and those obtained from
KAON-MAID is presented.


title:
Rescattering effects and two-step process in kaon photoproduction on the
  deuteron

abstract:
  Kaon photoproduction on the deuteron is investigated by considering YN and KN
rescattering and the two-step process gamma d --> pi NN --> KYN. A strong
enhancement in the total cross section is found from the two-step process. YN
rescattering has remarkable effects in the inclusive and exclusive cross
section, while the effect of KN rescattering is much less important.


title:
Microscopic analysis of T=1 and T=0 proton-neutron correlations in $N=Z$
  nuclei

abstract:
  The competition between the isovector (T=1) and isoscalar (T=0)
proton-neutron ($p-n$) correlations in $N=Z$ nuclei is investigated by
calculating their correlation energies with a realistic effective interaction
which reproduces observed nuclear properties very well, in a strict shell model
treatment. It is shown in the realistic shell model that the double-differences
of binding energies $(B(A+pn:T) + B(A) - B(A+p) - B(A+n))$ ($B(A)$ being the
binding energy) are good indicators of the T=1 and T=0 $p-n$ correlations. Each
of them, however, originates in plural kinds of correlations with T=1 or T=0.


title: Nuclear pairing from chiral pion-nucleon dynamics

abstract:
  We use a recently improved version of the chiral nucleon-nucleon potential at
next-to-next-to-leading order to calculate the $^1S_0$ pairing gap in
isospin-symmetric nuclear matter. The pairing potential consists of the
long-range one- and two-pion exchange terms and two short-distance NN-contact
couplings. We find that the inclusion of the two-pion exchange at
next-to-next-to-leading order reduces substantially the cut-off dependence of
the $^1S_0$ pairing gap determined by solving a regularised BCS equation. Our
results are close to those obtained with the universal low-momentum
nucleon-nucleon potential $V_{\rm low-k}$ or the phenomenological Gogny D1S
force.


title: A deformed QRPA formalism for single and two-neutrino double beta decay

abstract:
  We use a deformed QRPA formalism to describe simultaneously the energy
distributions of the single beta Gamow-Teller strength and the two-neutrino
double beta decay matrix elements. Calculations are performed in a series of
double beta decay partners with A = 48, 76, 82, 96, 100, 116, 128, 130, 136 and
150, using deformed Woods-Saxon potentials and deformed Skyrme Hartree-Fock
mean fields. The formalism includes a quasiparticle deformed basis and residual
spin-isospin forces in the particle-hole and particle-particle channels. We
discuss the sensitivity of the parent and daughter Gamow-Teller strength
distributions in single beta decay, as well as the sensitivity of the double
beta decay matrix elements to the deformed mean field and to the residual
interactions. Nuclear deformation is found to be a mechanism of suppression of
the two-neutrino double beta decay. The double beta decay matrix elements are
found to have maximum values for about equal deformations of parent and
daughter nuclei. They decrease rapidly when differences in deformations
increase. We remark the importance of a proper simultaneous description of both
double beta decay and single Gamow-Teller strength distributions. Finally, we
conclude that for further progress in the field it would be useful to improve
and complete the experimental information on the studied Gamow-Teller strengths
and nuclear deformations.


title: Gapless phases of color-superconducting matter

abstract:
  We discuss gapless color superconductivity for neutral quark matter in beta
equilibrium at zero as well as at nonzero temperature. Basic properties of
gapless superconductors are reviewed. The current progress and the remaining
problems in the understanding of the phase diagram of strange quark matter are
discussed.


title:
Intensity interferometry of thermal photons from relativistic heavy ion
  collisions

abstract:
  Intensity interferometry of thermal photons, having transverse momenta $k_T
\approx $ 0.1 -- 2.0 GeV, produced in relativistic collision of heavy nuclei is
studied. It is seen to provide an accurate information about the temporal and
spatial structure of the interacting system. The source dimensions and their
$k_T$ dependence revealed by the photon interferometry, display a richness not
seen in pion interferometry. We attribute this to difference in the source
functions, the fact that photons come out from every stage of the collision and
from every point in the system, and the fact that the rate of production of
photons is different for the quark-gluon plasma, which dominates the early hot
stage, and the hadronic matter which populates the last phase of the collision
dynamics. The usefulness of this procedure is demonstrated by an application to
collision of lead nuclei at the CERN SPS. Prediction for the transverse
momentum dependence of the sizes for SPS, RHIC, and LHC energies are given.


title: Regularization of singular terms in $N\bar{N}$ potential model

abstract:
  We suggest a method of singular terms regularization in potential model of
$N\bar{N}$ interaction. This method is free from any uncertainties, related to
the usual cut-off procedure and based on the fact, that in the presence of
sufficiently strong short-range annihilation $N$ and $\bar{N}$ never approach
close enough to each other. The effect of mentioned singular terms of OBE
potential, modified by annihilation is shown to be repulsive. The obtained
results for S- and P-wave scattering lengths are in agreement with existing
theoretical models.


title: Skewed recoil polarization in (e,e'p) reactions from polarized nuclei

abstract:
  The general formalism describing $\vec{A}(\vec{e},e'\vec{p})B$ reactions,
involving polarization of the electron beam, target and ejected proton, is
presented within the framework of the relativistic plane wave impulse
approximation for medium and heavy nuclei. It is shown that the simultaneous
measurement of the target and ejected proton polarization can provide new
information which is not contained in the separate analysis of the
$\vec{A}(\vec{e},e'p)B$ and $A(\vec{e},e'\vec{p})B$ reactions. The polarization
transfer mechanism in which the electron interacts with the initial nucleon
carrying the target polarization, making the proton exit with a fractional
polarization in a different direction, is referred to here as ``skewed
polarization''. The new observables characterizing the process are identified,
and written in terms of polarized response functions and asymmetries which are
of tensor nature. The corresponding half-off-shell single-nucleon responses are
analyzed using different prescriptions for the electromagnetic vertex and for
different kinematics. Numerical predictions are presented for selected
perpendicular and parallel kinematics in the case of $^{39}$K as polarized
target.


title:
Signature of Granular Structures by Single-Event Intensity
  Interferometry

abstract:
  The observation of a granular structure in high-energy heavy-ion collisions
can be used as a signature for the quark-gluon plasma phase transition, if the
phase transition is first order in nature. We propose methods to detect a
granular structure by the single-event intensity interferometry. We find that
the correlation function from a chaotic source of granular droplets exhibits
large fluctuations, with maxima and minima at relative momenta which depend on
the relative coordinates of the droplet centers. The presence of this type of
maxima and minima of a single-event correlation function at many relative
momenta is a signature for a granular structure and a first-order QCD phase
transition. We further observe that the Fourier transform of the correlation
function of a granular structure exhibits maxima at the relative spatial
coordinates of the droplet centers, which can provide another signature of the
granular structure.


title:
Near-threshold pion production with radioactive beams at the Rare
  Isotope Accelerator

abstract:
  Using an isospin- and momentum-dependent transport model we study
near-threshold pion production in heavy-ion collisions induced by radioactive
beams at the planned Rare Isotope Accelerator (RIA). We revisit the question of
probing the high density behavior of nuclear symmetry energy $E_{sym}(\rho)$
using the $\pi^-/\pi^+$ ratio. It is found that both the total and differential
$\pi^-/\pi^+$ ratios remain sensitive to the $E_{sym}(\rho)$ when the
momentum-dependence of both the isoscalar and isovector potentials are
consistently taken into account. Moreover, the multiplicity and spectrum of
$\pi^-$ mesons are found more sensitive to the $E_{sym}(\rho)$ than those of
$\pi^+$ mesons. Finally, effects of the Coulomb potential on the pion spectra
and $\pi^-/\pi^+$ ratio are also discussed.


title:
Low-energy constants and relativity in peripheral nucleon-nucleon
  scattering

abstract:
  In our recent works we derived a chiral $O(q^4)$ two-pion exchange
nucleon-nucleon potential (TPEP) formulated in a relativistic baryon (RB)
framework, expressed in terms of the so called low energy constants (LECs) and
functions representing covariant loop integrations. We showed that the
expansion of these functions in powers of the inverse of the nucleon mass
reproduces most of the terms of the TPEP derived from the heavy baryon (HB)
formalism, but such an expansion is ill defined and does not converge at large
distances. In the present work we perform a study of the phase shifts in
nucleon-nucleon ($NN$) scattering for peripheric waves ($L\geq 3$), which are
sensitive to the tail of the potential. We assess quantitatively the
differences between the RB and HB results, as well as variations due to
different values of the LECs. By demanding consistency between the LECs used in
$\pi N$ and $NN$ scattering we show how $NN$ peripheral phase shifts could
constrain these values. We demonstrate that this idea, first proposed by the
Nijmegen group, favors a smaller value for the LEC $c_3$ than the existing
ones, when considering the TPEP up to order $q^4$ in the chiral expansion.


title: Deconfinement energy threshold: analysis of hadron yields at 11.6 A GeV

abstract:
  We analyze the hadron yields obtained at the AGS in the range 11--11.6 A GeV
and discuss strategies to identify possible deconfinement at this energy scale.
These include consideration of chemical nonequilibrium at hadronization, and
the study of (multi)strange hadrons. We find that the totality of experimental
results available favors the interpretation as hadron freeze-out at the phase
boundary between confined and deconfined phase.


title: Dynamical response functions in correlated fermionic systems

abstract:
  Response functions in nuclear matter at finite temperature are considered
beyond the usual Hartree-Fock (HF) plus Random Phase Approximation (RPA)
scheme. The contributions due to the propagator for the dressed nucleons and
the corresponding vertex corrections are treated in a consistent way. For that
purpose a semi-realistic Hamiltonian is developed with parameters adjusted to
reproduce the nucleon self-energy as derived from realistic nucleon-nucleon
interactions. For a scalar residual interaction the resulting response
functions are very close to the RPA response functions. However, the collective
modes, if present, get an additional width due to the coupling to multi-pair
configurations. For isospin dependent residual interactions we find strong
modifications of isospin response functions due to multi-pair contributions in
the response function. Such a modification can lead to the disappearance of
collective spin or isospin modes in a correlated system and shall have an
effect on the absorption rate of neutrinos in nuclear matter.


title: Pion re-scattering operator in the S-matrix approach

abstract:
  The pion re-scattering operator for pion production, derived recently in
time-ordered perturbation theory, is compared with the one following from the
simple S-matrix construction. We show that this construction is equivalent to
the on-shell approximation introduced in previous papers. For a realistic NN
interaction, the S-matrix approach, and its simplified fixed
threshold-kinematics version, work well near threshold.


title: Energy Spectra of Anti-nucleons in Finite Nuclei

abstract:
  The quantum vacuum in a many-body system of finite nuclei has been
investigated within the relativistic Hartree approach which describes the bound
states of nucleons and anti-nucleons consistently. The contributions of the
Dirac sea to the source terms of the meson-field equations are taken into
account up to the one-nucleon loop and one-meson loop. The tensor couplings for
the $\omega$- and $\rho$-meson are included in the model. The overall nucleon
spectra of shell-model states are in agreement with the data. The calculated
anti-nucleon spectra in the vacuum differ about 20 -- 30 MeV with and without
the tensor-coupling effects.


title: Quark deconfinement and neutrino trapping in compact stars

abstract:
  We study the role played by neutrino trapping on the hadron star (HS) to
quark star (QS) conversion mechanism proposed recently by Berezhiani and
collaborators. We find that the nucleation of quark matter drops inside hadron
matter, and therefore the conversion of a HS into a QS, is strongly inhibit by
the presence of neutrinos.


title: Traces of Theta^+ pentaquark in K^+ nucleus dynamics

abstract:
  Long-standing anomalies in K^+ nucleus integral cross sections could be
resolved by extending the impulse-approximation t*rho optical-potential
framework to incorporate K^+ absorption on pairs of nucleons. Substantially
improved fits to the data at p(lab)=500-700 MeV/c are obtained. An upper bound
of 3.5 mb for the absorption cross section of K^+ per nucleon is derived. We
conjecture that the underlying microscopic absorption process is K^+ n N -->
Theta^+ N, where Theta^+(1540) is the newly discovered exotic Y=2, I=0, Z=1
pentaquark baryon, and estimate that the cross section for K^+ d --> Theta^+ p
is a fraction of millibarn. Comments are made on Theta^+ production reactions
on nuclei.


title:
Predicting the single-proton/neutron potentials in asymmetric nuclear
  matter

abstract:
  We discuss the one-body potentials for protons and neutrons obtained from
Dirac-Brueckner-Hartree-Fock calculations of neutron-rich matter, in particular
their dependence upon the degree of proton/neutron asymmetry. The closely
related symmetry potential is compared with empirical information from the
isovector component of the nuclear optical potential.


title: Anisotropic flow and jet quenching in ultra-relativistic U+U collisions

abstract:
  Full-overlap U+U collisions provide significantly larger initial energy
densities at comparable spatial deformation, and significantly larger
deformation and volume at comparable energy density, than semicentral Au+Au
collisions. We show quantitatively that this provides a long lever arm for
studying the hydrodynamic behavior of elliptic flow in much larger and denser
collision systems and the predicted non-linear path-length dependence of
radiative parton energy loss.


title:
Quasi-elastic barrier distribution as a tool for investigating unstable
  nuclei

abstract:
  The method of fusion barrier distribution has been widely used to interpret
the effect of nuclear structure on heavy-ion fusion reactions around the
Coulomb barrier. We discuss a similar, but less well known, barrier
distribution extracted from large-angle quasi-elastic scattering. We argue that
this method has several advantages over the fusion barrier distribution, and
offers an interesting tool for investigating unstable nuclei.


title:
Collective excitations in the inner crust of neutron stars : supergiant
  resonances

abstract:
  We investigate the nuclear collective excitations of Wigner-Seitz cells
containing nuclear clusters immersed in a gas of neutrons. This baryonic
non-uniform system is specific to the structure of inner crust matter of
neutron stars. The collective excitations are studied in the framework of a
spherical Hartree-Fock-Bogoliubov + Quasiparticle Random Phase Approximation,
formulated in coordinate representation. The calculations are done for two
representative Wigner-Seitz cells with baryonic density equal to 0.02 fm$^{-3}$
and 0.08 fm$^{-3}$. It is shown that the excitations with low multipolarities
are concentrated almost entirely in one strongly collective mode which exhausts
a very large fraction of the energy-weighted sum rule. Since these collective
modes are located at very low energies compared to the giant resonances in
standard nuclei, they may affect significantly the specific heat of baryonic
inner crust matter of neutron stars.


title:
Spin-orbit and tensor interactions in homogeneous matter of nucleons:
  accuracy of modern many-body theories

abstract:
  We study the energy per particle of symmetric nuclear matter and pure neutron
matter using realistic nucleon--nucleon potentials having non central tensor
and spin--orbit components, up to three times the empirical nuclear matter
saturation density, $\rho_0=0.16$ fm$^{-3}$. The calculations are carried out
within the frameworks of the Brueckner--Bethe--Goldstone (BBG) and Correlated
Basis Functions (CBF) formalisms, in order to ascertain the accuracy of the
methods. The two hole--line approximation, with the continuous choice for the
single particle auxiliary potential, is adopted for the BBG approach, whereas
the variational Fermi Hypernetted Chain/Single Operator Chain theory, corrected
at the second order perturbative expansion level, is used in the CBF one. The
energies are then compared with the available Quantum and Variational Monte
Carlo results in neutron matter and with the BBG, up to the three hole--line
diagrams. For neutron matter and potentials without spin--orbit components all
methods, but perturbative CBF, are in reasonable agreement up to $\rho\sim$ 3
$\rho_0$. After the inclusion of the LS interactions, we still find agreement
around $\rho_0$, whereas it is spoiled at larger densities. The spin--orbit
potential lowers the energy of neutron matter at $\rho_0$ by $\sim$ 3--4 MeV
per nucleon. In symmetric nuclear matter, the BBG and the variational results
are in agreement up to $\sim$ 1.5 $\rho_0$. Beyond this density, and in
contrast with neutron matter, we find good agreement only for the potential
having spin--orbit components.


title: Spectator theory for three-nucleon electromagnetic currents

abstract:
  In this talk I present some of the more recent developments within the
Covariant Spectator Theory. My focus will be on aspects of the derivation of
gauge invariant electromagnetic three-nucleon currents which are consistent
with the hadronic equations and with the basic assumptions of this framework.
Important dynamical ingredients of the three-nucleon currents are also
discussed, namely the three-nucleon bound state vertex function and the
two-nucleon interaction model they are derived from.


title: Analysis and Applications of the Generalised Dyson Mapping

abstract:
  Generalised Dyson boson-fermion mappings are considered. These are techniques
used in the analysis of the quantum many-body problem, and are instances of
so-called boson expansion methods. A generalised Dyson boson-fermion mapping is
a one-to-one linear but non-unitary operator that can be applied to vectors
representing the states of a many-fermion system. A vector representing a
fermion system maps onto a vector that represents a state of a many-body system
that contains both bosons and fermions. The motivation for doing such a mapping
is the hope that it will reveal some property of the system that simplifies its
analysis and that was hidden in the original form. The aims of this text are to
review the theory of generalized Dyson boson-fermion mappings and to find a
useful application for a generalized Dyson boson-fermion mapping, by
considering a non-trivial model, namely the Richardson model for
superconductivity. It is the first time that a boson expansion technique is
implemented for a system where the roles of both collective and non-collective
fermion pairs are important. The Dyson mapping uncovers non-trivial properties
of the system that aid the construction of time-independent as well as
time-dependent perturbation expansions. The time-independent expansions agree
with results that other authors have obtained through methods other than boson
expansions. The time-dependent expansions might in future prove useful in
understanding aspects of the dynamics of ultra-cold fermi gases, when
time-dependent magnetic fields are used to vary the atom-atom interaction
strenght.


title: Recent Developments in Lattice QCD

abstract:
  Recent trends in lattice QCD calculations and latest results are reviewed,
with particular emphasis on multiquark-states and the nucleon structure.


title: Direct Urca neutrino radiation from superfluid baryonic matter

abstract:
  Dense matter in compact stars cools efficiently by neutrino emission via the
direct Urca processes n -> p + e + nu and p + e -> n + nu. Below the pairing
phase transition temperature Tc these processes are suppressed - at
asymptotically low temperatures exponentially. We compute the emissivity of the
Urca process at one loop for temperatures T < Tc, in the case where the baryons
are paired in the 1S0 partial wave. The Urca process is suppressed linearly,
rather than exponentially, within the temperature range 0.1 < T/Tc < 1. The
charge-current Cooper pair-breaking process contributes up to 50% of the total
Urca emissivity in this temperature range.


title:
Nuclear vorticity and the low-energy nuclear response - Towards the
  neutron drip line

abstract:
  The transition density and current provide valuable insight into the nature
of nuclear vibrations. Nuclear vorticity is a quantity related to the
transverse transition current. In this work, we study the evolution of the
strength distribution, related to density fluctuations, and the vorticity
strength distribution, as the neutron drip line is approached. Our results on
the isoscalar, natural-parity multipole response of Ni isotopes, obtained by
using a self-consistent Skyrme-Hartree-Fock + Continuum RPA model, indicate
that, close to the drip line, the low-energy response is dominated by L>1
vortical transitions.


title:
Fluctuations in the Statistical Model of Relativistic Heavy Ion
  Collisions

abstract:
  Fluctuations in the statistical model of heavy ion collisions are studied.
The role of statistics, relativity, constraints, decaying resonances and
branching processes are investigated using this model. Also studied are
thermodynamic properties related to these fluctuations with specific concerns
centered around the behavior of the specific heat.


title: The nuclear pairing problem: new perspectives

abstract:
  The overview of the Exact Pairing technique based on the quasispin symmetry
is presented. Extensions of this method are discussed in relation to mean
field, quadrupole collectivity, electromagnetic transitions, and many-body
level density. Realistic calculations compared with experimental data are used
to support the methods as well as to emphasize the manifestations of pairing
correlations in nuclear many-body systems.


title: On the complexion of pseudoscalar mesons

abstract:
  A strongly momentum-dependent dressed-quark mass function is basic to QCD. It
is central to the appearance of a constituent-quark mass-scale and an
existential prerequisite for Goldstone modes. Dyson-Schwinger equation (DSEs)
studies have long emphasised this importance, and have proved that QCD's
Goldstone modes are the only pseudoscalar mesons to possess a nonzero leptonic
decay constant in the chiral limit when chiral symmetry is dynamically broken,
while the decay constants of their radial excitations vanish. Such features are
readily illustrated using a rainbow-ladder truncation of the DSEs. In this
connection we find (in GeV): f_{eta_c(1S)}= 0.233, m_{eta_c(2S)}=3.42; and
support for interpreting eta(1295), eta(1470) as the first radial excitations
of eta(548), eta'(958), respectively, and K(1460) as the first radial
excitation of the kaon. Moreover, such radial excitations have electromagnetic
diameters greater than 2fm. This exceeds the spatial length of lattices used
typically in contemporary lattice-QCD.


title: Effect of kinematics on final state interactions in (e,e'p) reactions

abstract:
  Recent data from experiment E97-006 at TJNAF using the 12C(e,e'p) reaction at
very large missing energies and momenta are compared to a calculation of
two-step rescattering.
  A comparison between parallel and perpendicular kinematics suggests that the
effects of final state interactions can be strongly reduced in the former case.


title: Deuteron-proton charge exchange reaction at small transfer momentum

abstract:
  The charge-exchange reaction pd -> npp at 1 GeV projectile proton energy is
studied. This reaction is considered in a special kinematics, when the transfer
momentum from the beam proton to fast outgoing neutron is close to zero. Our
approach is based on the Alt-Grassberger-Sandhas formulation of the
multiple-scattering theory for the three-nucleon system. The matrix inversion
method has been applied to take account of the final state interaction (FSI)
contributions. The differential cross section, tensor analyzing power
$C_{0,yy}$, vector-vector $C_{y,y}$ and vector-tensor $C_{y,xz}$ spin
correlation parameters of the initial particles are presented. It is shown,
that the FSI effects play a very important role under such kinematical
conditions. The high sensitivity of the considered observables to the
elementary nucleon-nucleon amplitudes has been obtained.


title: Fluctuations in the level density of a Fermi gas

abstract:
  We present a theory that accurately describes the counting of excited states
of a noninteracting fermionic gas. At high excitation energies the results
reproduce Bethe's theory. At low energies oscillatory corrections to the
many--body density of states, related to shell effects, are obtained. The
fluctuations depend non-trivially on energy and particle number. Universality
and connections with Poisson statistics and random matrix theory are
established for regular and chaotic single--particle motion.


title:
Electromagnetic strength of neutron and proton single-particle halo
  nuclei

abstract:
  Electromagnetic strength functions of halo nuclei exhibit universal features
that can be described in terms of characteristic scale parameters. For a
nucleus with nucleon+core structure the reduced transition probability, as
determined, e.g., by Coulomb dissociation experiments, shows a typical shape
that depends on the nucleon separation energy and the orbital angular momenta
in the initial and final states. The sensitivity to the final-state interaction
(FSI) between the nucleon and the core can be studied systematically by varying
the strength of the interaction in the continuum. In the case of neutron+core
nuclei analytical results for the reduced transition probabilities are obtained
by introducing the effective-range expansion. The scaling with the relevant
parameters is found explicitly. General trends are observed by studying several
examples of neutron+core and proton+core nuclei in a single-particle model
assuming Woods-Saxon potentials. Many important features of the neutron halo
case can be obtained from a square-well model. Rather simple analytical
formulas are found. The nucleon-core interaction in the continuum affects the
determination of astrophysical S factors at zero energy in the method of
asymptotic normalisation coefficients (ANC). It is also relevant for the
extrapolation of radiative capture cross sections to low energies.


title: Nuclear interactions from the renormalization group

abstract:
  We discuss how the renormalization group can be used to derive effective
nuclear interactions. Starting from the model-independent low-momentum
interaction V_{low k}, we successively integrate out high-lying particle and
hole states from momentum shells around the Fermi surface as proposed by
Shankar. The renormalization group approach allows for a systematic calculation
of induced interactions and yields similar contributions to the scattering
amplitude as the two-body parquet equations. We review results for the 1S0 and
3P2 superfluid pairing gaps as well as the spin dependence of effective
interactions in neutron matter. Implications for the cooling of neutron stars
are discussed.


title:
On the Eigenvalue Problem of the su(1,1)-Algebra and the Coupling Scheme
  of Two su(1,1)-Spins

abstract:
  After recapitulating the eigenvalue problem of the su(1,1)-algebra in the
conventional form, the same problem is treated in an unconventional form, in
which the eigenvalue is pure imaginary. Further, the coupling scheme of two
su(1,1)-spins is discussed in the framework of two possibilities, in which
certain new aspects appear. Finally, the coupling scheme developed in this
paper is applied to a concrete example, which will serve boson realization of
the so(4)- and the so(3,1)-algebra presented in the next paper.


title:
Particle-number conservation within self-consistent random-phase
  approximation

abstract:
  The self-consistent random-phase approximation (SCRPA) is reexamined within a
multilevel-pairing model with double degeneracy. It is shown that the
expressions for occupation numbers used in the original version of SCRPA
violate the particle number for non-symmetric particle-hole ($ph$) spectra. A
renormalization is introduced to restore the particle number, which leads to
the expressions of occupation numbers similar to those derived by Hara et al.
for the ph case. The results of calculations within the $ph$-symmetric case
show that this number-conserving SCRPA yields the energies of the ground state
and first excited state of the system with $\Omega+2$ particles relative to the
ground state of the system with $\Omega$ particles in close agreement with
those obtained within the original SCRPA. However it gives a slightly larger
correlation energy.


title: Nuclear giant resonances

abstract:
  This talk presents the recent status of theoretical and experimental studies
of giant resonances in nuclei with the emphasis on: (1) charge-exchange
Gamow-Teller resonance, (2) multiple-phonon resoanances, (3) giant dipole
resonances in highly excited nuclei, and (4) pygmy dipole resonances in neutron
rich nuclei. In particular, the description of these resonances within the
framework of the phonon damping model is discussed in detail.


title: A Note on the Eigenvalue Problem in the su(1,1)-Algebra

abstract:
  Normalization constant in the eigenstate appearing in the eigenvalue problem
of the su(1,1)-algebra is discussed. This normalization constant is expressed
in terms of the Gauss' hypergeometric series which is not absolutely
convergent. It is proved that this series is obtained as a certain limit of an
absolutely convergent series, which was conjectured in the previous paper.


title: A Possible Boson Realization of the so(4)- and the so(3,1)-Algebra

abstract:
  As natural extensions of the boson realizations of the su(2)- and the
su(1,1)-algebra, the so(4)- and the so(3,1)-algebras are presented in the form
of boson realizations with four kinds of boson operators. For each algebra, two
forms are discussed. One is constructed in terms of two sets of the boson
operators which play a role of spherical tensor with rank 1/2. The other is
based on the ranks 1 and 0. As a possible application, the Runge-Lenz-Pauli
vector, which is famous in the hydrogen atom, is derived with some aspects.


title: Jet quenching of massive quarks in a nuclear medium

abstract:
  Utilizing the generalized factorization of twist-4 processes, we derive the
modified heavy quark fragmentation function after considering the gluon
radiation induced by multiple scattering in DIS. It is found that the mass
effects of heavy quark may reduce the gluon formation time and change the
medium size dependence of heavy quark energy loss. The radiative energy loss is
also significantly suppressed relative to a light quark due to the dead-cone
effect.


title:
Coupled-channel analysis of collisional effects on HFS transitions in
  antiprotonic helium atoms

abstract:
  Collisions of metastable antiprotonic helium with atoms of medium induce
transitions between hyperfine structure sublevels as well as shifts and
broadenings of the microwave M1 spectral lines. We consider these phenomena in
the framework of a model with scalar and tensor interactions between
antiprotonic and ordinary helium atoms. S-matrix is obtained by solving
coupled-channels equations involving 4 HFS sublevels (F=L\pm 1/2, J=F\pm 1/2)
of the nL level and relative angular momenta up to l=5 at the kinetic energy
E<25 K. The calculated spin-flip cross sections are less than elastic ones by
four orders of value in the case \Delta J=\pm 1, and by seven orders of value
in the case \Delta F=\pm 1, \Delta J=0 or \Delta J=\pm 2. The considered cross
sections reveal a resonance behaviour at very low energy (E about 1 - 4 K
depending on the model parameters). At the density N=3\times 10^{20} cm^{-3}
and T=6 K we obtain the relaxation time =160 ns, the frequency shift \Delta\nu\
= 80 kHz and the frequency broadening \gamma \lesssim 5.9 MHz for M1 spectral
lines of the favored transitions (\Delta F=\pm 1, \Delta J=\pm 1). The results
are compatible with the recent experimental data obtained by a
laser-microwave-laser resonance method. With the temperature rising up to 25 K
the rate of relaxation \lambda=1/\tau as well as shift and broadening of the M1
microwave lines are lowered by a factor 1.5 - 2 reflecting the displacement of
a mean kinetic energy from the region of resonance scattering.


title: Anatomy of three-body decay I. Schematic models

abstract:
  Sequential three-body decay proceeds via spatially confined quasi-stationary
two-body configurations. Direct three-body decay populates the three-body
continuum without intermediate steps. The relative importance of these decay
modes is discussed in a schematic model employing only Coulomb or centrifugal
barrier potentials. Decisive dimensionless charge, mass and energy ratios are
derived. Sequential decay is usually favored for charged particles. Small
charge and small mass of high energy is preferably emitted first. Without
Coulomb potential the sequential decay is favored except when both resonance
energy and intermediate two-body energy are large.


title: Anatomy of three-body decay II. Decay mechanism and resonance structure

abstract:
  We use the hyperspherical adiabatic expansion method to discuss the the two
mechanisms of sequential and direct three-body decay. Both short-range and
Coulomb interactions are included. Resonances are assumed initially populated
by a process independent of the subsequent decay. The lowest adiabatic
potentials describe the resonances rather accurately at distances smaller than
the outer turning point of the confining barrier. We illustrate with realistic
examples of nuclei from neutron ($^{6}$He) and proton ($^{17}$Ne) driplines as
well as excited states of beta-stable nuclei ($^{12}$C).


title:
Nucleon Polarisabilities from Compton Scattering off the One- and
  Few-Nucleon System

abstract:
  These proceedings sketch how combining recent theoretical advances with data
from the new generation of high-precision Compton scattering experiments on
both the proton and few-nucleon systems offers fresh, detailed insight into the
Physics of the nucleon polarisabilities. A multipole-analysis is presented to
simplify their interpretation. Predictions from Chiral Effective Field Theory
with special emphasis on the spin-polarisabilities can serve as guideline for
doubly-polarised experiments below 300 MeV. The strong energy-dependence of the
scalar magnetic dipole-polarisability $\beta_{M1}$ turns out to be crucial to
understand the proton and deuteron data. Finally, a high-accuracy determination
of the proton and neutron polarisabilities shows that they are identical within
error-bars. For details and a better list of references, consult the given
references.


title: Nuclear structure of the exotic mass region along the rp process path

abstract:
  Isomeric states in the nuclei along the rapid proton capture process path are
studied by the projected shell model. Emphasis is given to two waiting point
nuclei 68Se and 72Kr that are characterized by shape coexistence. Energy
surface calculations indicate that the ground state of these nuclei corresponds
to an oblate-deformed minimum, while the lowest state at the prolate-deformed
minimum can be considered as a shape isomer. The impact of these isomer states
on isotopic abundance in x-ray bursts is studied in a multi-mass-zone x-ray
burst model by assuming an upper-lower limit approach.


title:
Electrodisintegration of $^3$He below and above deuteron breakup
  threshold

abstract:
  Recent advances in the study of electrodisintegration of 3He are presented
and discussed. The pair-correlated hyperspherical harmonics method is used to
calculate the initial and final state wave functions, with a realistic
Hamiltonian consisting of the Argonne v18 two-nucleon and Urbana IX
three-nucleon interactions. The model for the nuclear current and charge
operators retains one- and many-body contributions. Particular attention is
made in the construction of the two-body current operators arising from the
momentum-dependent part of the two-nucleon interaction. Three-body current
operators are also included so that the full current operator is strictly
conserved. The present model for the nuclear current operator is tested
comparing theoretical predictions and experimental data of pd radiative capture
cross section and spin observables.


title: Electromagnetic transitions for A=3 nuclear systems

abstract:
  Recent advances in the study of pd radiative capture in a wide range of
center-of-mass energy below and above deuteron breakup threshold are presented
and discussed.


title:
Modification of the pi-omega-rho vertex in nuclear medium and its
  influence on the dilepton production rate in relativistic heavy-ion
  collisions

abstract:
  In this PhD thesis we analyze the medium modification of the pi-omega-rho
coupling and subsequently discuss its possible influence on the dilepton
production rate in relativistic heavy-ion collisions. The first part of the
thesis is devoted to the medium modifications of the Dalitz decays from the
omega and rho mesons in nuclear matter. We use the relativistic field theory
formalism describing modifications of the coupling by one-loop Feynman diagrams
with nucleons and Delta(1232) isobars. We consider cases when the decaying
particle is at rest or at motion with respect to the medium. We investigate the
dependence of medium effects on the dilepton invariant mass and observe a
sizeable increase of the effective coupling constants compared to their vacuum
values. The effect grows with density. In the second part of the thesis we
apply our model to evaluate the influence of the medium effects on the dilepton
production from the Dalitz decays. In the calculations of the dilepton spectrum
we use the model of the hydrodynamic expansion of the fire cylinder. In our
comparison to the CERES dilepton data we take into account the experimental
cuts. The medium modifications enhance the effect of the Dalitz decays. It is
worth to point out that in the medium the rho decay due to the isospin
degeneracy becomes as important as the omega decay. The main new and original
results of the thesis are: 1. Significant in-medium increase of the
pi-omega-rho coupling constant. 2. Large enhancement of the Dalitz decays from
the omega and rho mesons in the range 0.2-0.6 GeV of the dilepton invariant
mass.


title:
Nonconservation of the Quantum Number K and Phase Transitions in Rapidly
  Rotating Nuclei

abstract:
  Three different effects observed in experiments with rotating
nuclei--backbending, noncollective quadrupole transitions between different
levels of the same band, and transitions that occur, in rapidly rotating
nuclei, from large-$K$ isomeric states immediately to the levels of a
rotational band despite their strong forbiddenness in $K$--are explained in
terms of nonconservation of the quantum number $K$ in such nuclei.


title: Tensor correlation in 4He and its Effect on the doublet splitting in 5He

abstract:
  We investigate the role of tensor correlation on the structures of
\nuc{4}{He} and its effect on the doublet splitting in \nuc{5}{He}. We perform
a configuration mixing calculation in the shell model type bases to represent
the tensor correlation for $^4$He. It is found that our model describes the
characteristics of the tensor correlation, which is represented by an admixture
of the $0s_{1/2}$ configuration with a spatially modified $0p_{1/2}$ orbit. For
$^5$He, we solve a coupled OCM equation for an extended $^4$He+$n$ model, while
taking into account the tensor correlation in the $^4$He cluster. It is shown
that the tensor correlation produces the Pauli blocking, in particular, for the
$J^\pi={1/2}^-$ state, and its effect causes about half of the p-wave doublet
splitting in $^5$He. This indicates that the strength of the effective
spin-orbit interaction should be reduced by about half from the conventional
one. We obtain a reliable $^4$He-$n$ interaction, including the tensor
correlation, which further improves the behavior of the $d$- and $f$-wave phase
shifts in the $^4$He+$n$ system.


title: Solutions of the Bohr hamiltonian, a compendium

abstract:
  The Bohr hamiltonian, also called collective hamiltonian, is one of the
cornerstone of nuclear physics and a wealth of solutions (analytic or
approximated) of the associated eigenvalue equation have been proposed over
more than half a century (confining ourselves to the quadrupole degree of
freedom). Each particular solution is associated with a peculiar form for the
$V(\beta,\gamma)$ potential. The large number and the different details of the
mathematical derivation of these solutions, as well as their increased and
renewed importance for nuclear structure and spectroscopy, demand a thorough
discussion. It is the aim of the present monograph to present in detail all the
known solutions in $\gamma-$unstable and $\gamma-$stable cases, in a taxonomic
and didactical way. In pursuing this task we especially stressed the
mathematical side leaving the discussion of the physics to already published
comprehensive material. The paper contains also a new approximate solution for
the linear potential, and a new solution for prolate and oblate soft axial
rotors, as well as some new formulae and comments, and an appendix on the
analysis of a few interesting numerical sequences appearing in this context.
The quasi-dynamical SO(2) symmetry is proposed in connection with the labeling
of bands in triaxial nuclei.


title:
Covariant Impulse Approximation for the study of the internal structure
  of composite particles

abstract:
  We present a brief review on the Impulse Approximation method to study
processes of scattering off composite particles. We first construct the model
in a non-relativistic fashion that enables us to extend the model to a
covariant Impulse Approximation, which is needed for the study of high momentum
transfer processes.


title:
Final-state interaction and recoil polarization in (e,e'p) reactions:
  comparison with the polarized target case

abstract:
  A study of the total cross section for polarized proton knockout in
$(e,e'{\vec p})$ reactions is carried out for the closed-shell nucleus
$^{40}$Ca. The dependence of FSI effects on polarization observables viewed as
functions of the nucleon polarization angles is analyzed and interpreted within
the basis of a semi-classical model for the orbit of the struck nucleon and
trajectory of the ejected nucleon. A comparison with the case of a $^{39}$K
polarized target and unpolarized protons is performed.


title: The shape of the nucleon

abstract:
  We show that all four of the nucleon form factors can be very well explained
using the manifestly covariant spectator theory. The nucleon is modeled as a
spherical state of three constituent quarks with electromagnetic form factors,
all determined by the fit to the data.


title: Coulomb breakup effects on the optical potentials of weakly bound nuclei

abstract:
  The optical potential of halo and weakly bound nuclei has a long range part
due to the coupling to breakup that damps the elastic scattering angular
distributions. In order to describe correctly the breakup channel in the case
of scattering on a heavy target, core recoil effects have to be taken into
account. We show here that core recoil and nuclear breakup of the valence
nucleon can be consistently taken into account. A microscopic absorptive
potential is obtained within a semiclassical approach and its characteristics
can be understood in terms of the properties of the halo wave function and of
the reaction mechanism. Results for the case of medium to high energy reactions
are presented.


title:
Electron-deuteron scattering in the equal-time formalism: beyond the
  impulse approximation

abstract:
  Using a three-dimensional formalism that includes relativistic kinematics,
the effects of negative-energy states, approximate boosts of the two-body
system, and current conservation, we calculate the electromagnetic form factors
of the deuteron up to Q^2 of 4 GeV^2. This is done using a dynamical boost for
two-body systems with spin. We first compute form factors in impulse
approxmation, but then also add an isoscalar meson-exchange current of pion
range that involves the gamma-pi contact operator associated with pseudovector
pi-N coupling. We also consider effects of the rho-pi-gamma meson-exchange
current. The experimentally measured quantities A, B, and t20 are calculated
over the kinematic range probed in recent Jefferson Laboratory experiments. The
rho-pi-gamma meson-exchange current provides significant strength in A at large
Q^2 and the gamma-pi contact-term exchange current shifts t20, providing good
agreement with the JLab data. Relativistic effects and the gamma-pi
meson-exchange current do not provide an explanation of the B observable, but
the rho-pi-gamma current could help to provide agreement if a nonstandard value
is used for the tensor rho-N coupling that enters this contribution.


title: J/psi transport in QGP and Pt distribution at SPS and RHIC

abstract:
  Combining the hydrodynamic equations for the QGP evolution and the transport
equation for the primordially produced $J/\psi$ in the QGP, we investigate the
$J/\psi$ transverse momentum distribution as well as its suppression in the
$\sqrt{s}$=17.3A GeV Pb-Pb collisions at SPS and $\sqrt{s}$=200A GeV Au-Au
collisions at RHIC. The two sets of equations are connected by the $J/\psi$
anomalous suppression induced by its inelastic scattering with gluons in the
QGP. The calculated centrality dependence of $J/\psi$ suppression and average
transverse momentum square agree well with the SPS data. From the comparison
with the coalescence model where charm quark is fully thermalized, our
calculated elliptical flow of the primordially produced $J/\psi$ is much
smaller. This may be helpful to differentiate the $J/\psi$ production
mechanisms in relativistic heavy ion collisions.


title:
Description of resonances in light nuclei using a microscopic cluster
  model

abstract:
  We investigate resonances in light halo nuclei using a fully microscopic
cluster model and the complex scaling method. We make use of the hermitian
representation of the complex scaling method. The general structure of the
cluster model is that of a correlation operator acting on a starting function
that describes a number of neutrons relative to an alpha-particle. The
correlation operator is expanded in terms of a small non-orthogonal set of
Gaussian basis states and we make use of a simplified, central but
state-dependent, interaction. The many-body integrals required for the
computation are evaluated by a variational Monte-Carlo algorithm. We show how
to obtain resonant states for both $^5$He and $^6$He.


title: $\Theta^+$ pentaquark in the nuclear medium

abstract:
  We study the interaction of the $\Theta^+$ pentaquark with nuclear matter
associated to the $KN$ decay channels and to the two meson cloud. We find that
the potential is attractive and could be strong enough to lead to the existence
of $\Theta^+$ nuclear bound states.


title: On stability of the neutron rich Oxygen isotopes

abstract:
  Stability with respect to neutron emission is studied for highly
neutron-excessive Oxygen isotopes in the framework of Hartree-Fock-Bogoliubov
approach with Skyrme forces Sly4 and Ska. Our calculations show increase of
stability around 40O.


title:
Isoscaling behavior in the Isospin dependent Quantum Molecular Dynamics
  model

abstract:
  The isoscaling behavior is investigated in the frame of Isospin dependent
Quantum Molecular Dynamics (IQMD) models. The isotopic yields ratio $Y_2$/$Y_1$
for reactions $^{48}Ca$+$^{48}Ca$ and $^{40}Ca+^{40}Ca$ at different entrance
channels are simulated and presented, the relationship between the isoscaling
parameter and the entrance channel is analyzed, the results show that $\alpha$
and $\beta$ reduce with the rise of incident energies and increase with the
impact parameter b, which can be attributed to the temperature varying of the
pre-fragments in different entrance channels. The relation of $\alpha$ and
symmetry-term coefficient $C_{sym}$ reveals that the chemical potential
difference $\triangle\mu$ is sensitive to the symmetry-term coefficient
$C_{sym}$.