title:
Indication of a Co-Existing Phase of Quarks and Hadrons in Nucleus -
  Nucleus Collisions

abstract:
  The variation of average transverse mass of identified hadrons with charge
multiplicity have been studied for AGS, SPS and RHIC energies. The observation
of a plateau in the average transverse mass for multiplicities corresponding to
SPS energies is attributed to the formation of a co-existence phase of quark
gluon plasma and hadrons. A subsequent rise for RHIC energies may indicate a
deconfined phase in the initial state. Several possibilities which can affect
the average transverse mass are discussed. Constraints on the initial
temperature and thermalization time have been put from the various experimental
data available at SPS energies.


title:
Charge exchange operators sum rules and proton-neutron T=0 and T=1
  pairing interactions

abstract:
  We study sum rules for charge exchange operators of the Gamow-Teller and
Fermi type and explore what can be learned from them about proton-neutron
pairing in T=0 and T=1 channels. We consider both energy weighted (EWSR) and
non-energy weighted (NEWSR) sum rules. We use a schematic Hamiltonian to stress
the distinctive roles of T=1 and T=0 pair interactions and correlations in the
sum rules. Numerical results for 44Ti are presented for both schematic and
realistic interactions.


title:
Two-pion exchange nucleon-nucleon potential:O(q^4) relativistic chiral
  expansion

abstract:
  We present a relativistic procedure for the chiral expansion of the two-pion
exchange component of the $NN$ potential, which emphasizes the role of
intermediate $\pi N$ subamplitudes. The relationship between power counting in
$\pi N$ and $NN$ processes is discussed and results are expressed directly in
terms of observable subthreshold coefficients. Interactions are determined by
one- and two-loop diagrams, involving pions, nucleons, and other degrees of
freedom, frozen into empirical subthreshold coefficients. The full evaluation
of these diagrams produces amplitudes containing many different loop integrals.
Their simplification by means of relations among these integrals leads to a set
of intermediate results. Subsequent truncation to $O(q^4)$ yields the
relativistic potential, which depends on six loop integrals, representing
bubble, triangle, crossed box, and box diagrams. The bubble and triangle
integrals are the same as in $\pi N$ scattering and we have shown that they
also determine the chiral structures of box and crossed box integrals.
Relativistic threshold effects make our results to be not equivalent with those
of the heavy baryon approach. Performing a formal expansion of our results in
inverse powers of the nucleon mass, even in regions where this expansion is not
valid, we recover most of the standard heavy baryon results. The main
differences are due to the Goldberger-Treiman discrepancy and terms of
$O(q^3)$, possibly associated with the iteration of the one-pion exchange
potential.


title: Color Superconductivity in Compact Stars and Gamma Ray Bursts

abstract:
  We study the effects of color superconductivity on the structure and
formation of compact stars. We show that it is possible to satisfy most of
recent observational boundaries on masses and radii if a diquark condensate
forms in a hybrid or a quark star. Moreover, we find that a huge amount of
energy, of the order of $10^{53}$ erg, can be released in the conversion from a
(metastable) hadronic star into a (stable) hybrid or quark star, if the
presence of a color superconducting phase is taken into account. Accordingly to
the scenario proposed in Astrophys.J.586(2003)1250, the energy released in this
conversion can power a Gamma Ray Burst. This mechanism can explain the recent
observations indicating a delay, of the order of days or years, between a few
Supernova explosions and the subsequent Gamma Ray Burst.


title: Regularity and Chaos in low-lying 2+ states of even-even nuclei

abstract:
  Using all the available empirical information, we analyse the spacing
distributions of low-lying 2+ levels in even-even nuclei by comparing them with
a theoretical distribution characterized by a single parameter (the chaoticity
parameter f). We use the method of Bayesian inference. We show that the
necessary unfolding procedure generally leads to an overestimate of f. We find
that f varies strongly with the ratio of the excitation energies of the first
4+ and 2+ levels and assumes particularly small values in nuclei that have one
of the dynamical symmetries of the Interacting Boson Model.


title:
The Goldstone bosons in the pairing Hamiltonian: the path integral
  approach

abstract:
  As a first step to derive the IBM from a microscopic nuclear hamiltonian, we
bosonize the pairing hamiltonian in the framework of the path integral
formalism respecting both the particle number conservation and the Pauli
principle. Special attention is payed to the role of the Goldstone bosons. We
construct the saddle point expansion which reproduces the sector of the
spectrum associated to the addition or removal of nucleon pairs.


title: The alpha decay of deformed superheavy elements

abstract:
  The interaction potential between the alpha particle and the deformed parent
nucleus was used for description of the decay of superheavy nuclei. It consists
of centrifugal, nuclear and Coulomb parts suitably modified for deformed
nuclei. The significant effect of various shapes of barriers obtained for
deformed parent nuclei on calculated alpha half-life times were shown. The
finally calculated half-life times due to the spontaneous alpha decay for
superheavy elements were compared with the results obtained from other models
and the experimental data.


title: Nuclear Isospin Diffusivity

abstract:
  The isospin diffusion and other irreversible phenomena are discussed for a
two-component nuclear Fermi system. The set of Boltzmann transport equations,
such as employed for reactions, are linearized, for weak deviations of a system
from uniformity, in order to arrive at nonreversible fluxes linear in the
nonuniformities. Besides the diffusion driven by a concentration gradient, also
the diffusion driven by temperature and pressure gradients is considered.
Diffusivity, conductivity, heat conduction and shear viscosity coefficients are
formally expressed in terms of the responses of distribution functions to the
nonuniformities. The linearized Boltzmann-equation set is solved, under the
approximation of constant form-factors in the distribution-function responses,
to find concrete expressions for the transport coefficients in terms of
weighted collision integrals. The coefficients are calculated numerically for
nuclear matter, using experimental nucleon-nucleon cross sections. The isospin
diffusivity is inversely proportional to the neutron-proton cross section and
is also sensitive to the symmetry energy. At low temperatures in symmetric
matter, the diffusivity is directly proportional to the symmetry energy.


title: Oblique-Basis Calculations for $^{44}$Ti

abstract:
  The spectrum and wave functions of $^{44}$Ti are studied in oblique-basis
calculations using spherical and SU(3) shell-model states. Although the results
for $^{44}$Ti are not as good as those previously reported for $^{24}$Mg, due
primarily to the strong spin-orbit interaction that generates significant
splitting of the single-particle energies that breaks the SU(3) symmetry, a
more careful quantitative analysis shows that the oblique-basis concept is
still effective. In particular, a model space that includes a few SU(3)
irreducible representations, namely, the leading irrep (12,0) and next to the
leading irrep (10,1) including its spin S=0 and 1 states, plus spherical
shell-model configurations (SSMC) that have at least two valence nucleons
confined to the $f_{7/2}$ orbit -- the SM(2) states, provide results that are
compatible with SSMC with at least one valence nucleon confined to the
$f_{7/2}$ orbit -- the SM(3) states.


title:
A note on the time evolution of the fission decay width under the
  influence of dissipation

abstract:
  The claim put forward in a recent paper by B. Jurado, K.-H. Schmidt and J.
Benlliure that the transient effect of nuclear fission may be described simply
as a relaxation process in the upright oscillator around the potential minimum
is refuted. Some critical remarks on the relevance of this effect in general
are added.


title: Everything you always wanted to know about SUSY, but were afraid to ask

abstract:
  New experimental tests of nuclear supersymmetry are suggested. They involve
the measurement of one- and two-nucleon transfer reactions between nuclei that
belong to the same supermultiplet. These reactions provide a direct test of the
`fermionic' sector, i.e. of the operators that change a boson into a fermion or
vice versa. We present some theoretical predictions for the supersymmetric
quartet of nuclei: 194Pt, 195Pt, 195Au and 196Au.


title:
A Possible Form of the Orthogonal Set in Six Kinds of Boson Operators
  --In Relation to the su(2)- and its Relevant Algebras--

abstract:
  With the aim of constructing coherent states for many-body systems consisting
of six kinds of boson operators, a possible form of the orthogonal set is
presented in terms of monomial with respect to state generating operators. In
connection with the su(3)-, the su(2)-, the su(2,1)- and the su(1,1)-algebras,
four types of the orthogonal set are discussed.


title:
Note on the Orthogonal Set in Six Kinds of Boson Operators --In Relation
  to the su(1,1)- and its Relevant Algebras--

abstract:
  Following the basic idea proposed by the present authors in recent paper, a
possible form of the orthogonal set for many-body system consisting of six
kinds of boson operators is developed. In contrast to the recent paper, in
which the su(2)-algebra plays a central role, in this paper, the
su(1,1)-algebra is in a central position. The orthogonal set obtained in this
paper is expressed in terms of monomial with respect to the state generating
operators.


title: Expansion rates at RHIC

abstract:
  A detailed description of the temporal evolution of the thermodynamic fields
in heavy ion collisions is presented within a hydrodynamic framework.
Particular attention is devoted to the evolution of the collective flow fields
and their space-time gradients.


title:
Improving the convergence of the chiral expansion for nuclear forces I:
  Peripheral phases

abstract:
  We study the two-pion exchange potential at next-to-next-to-leading order in
chiral effective field theory. We propose a new cut-off scheme for the pion
loop integrals based on spectral function regularization. We show that this
method allows for a consistent implementation of constraints from pion-nucleon
scattering. It leads to a much improved description of the partial waves with
angular momentum l \geq 2 as compared to the calculation utilizing dimensional
regularization.


title:
Number of states with fixed angular momentum for identical fermions and
  bosons

abstract:
  We present in this paper empirical formulas for the number of angular
momentum I states for three and four identical fermions or bosons. In the cases
with large I we prove that the number of states with the same ${\cal M}$ and n
but different J is identical if $I \ge (n-2)J - {1/2} (n-1)(n-2)$ for fermions
and $I \ge (n-2)J$ for bosons, and that the number of states is also identical
for the same ${\cal M}$ but different n and J if ${\cal M} \le $min(n, 2J+1 -
n) for fermions and for ${\cal M} \le $min(n, 2J) for bosons. Here ${\cal M}
=I_{max}-I$, n is the particle number, and J refers to the angular momentum of
a single-particle orbit for fermions, or the spin L carried by bosons.


title:
Generalization of the $N_pN_n$ scheme to non-yrast levels of even-even
  nuclei

abstract:
  In this paper we present the systematics of excitation energies for even-even
nuclei in two regions: the 50$<$Z$\le$66, 82$<$N$\le$104 region, and the
66$<$Z$<$82, 82$<$N$\le$104 region. Using the $N_pN_n$ scheme, we obtain
compact trajectories for the ground band as well as quasi-$\beta$ and
quasi-$\gamma$ bands.
  This suggests that the $N_pN_n$ scheme is useful even if one extends it to
non-yrast levels, and thus can serve as a general tool to disclose new types of
structural evolution for higher excitations, besides the yrast states which
have been investigated extensively. It is highlighted that deformations in
non-yrast quasibands of nuclei with $Z \sim 80$ and $N \sim 104$ are often very
different from those in the ground bands.


title:
Angular momentum I ground state probabilities of boson systems
  interacting by random interactions

abstract:
  In this paper we report our systematic calculations of angular momentum $I$
ground state probabilities ($P(I)$) of boson systems with spin $l$ in the
presence of random two-body interactions. It is found that the P(0) dominance
is usually not true for a system with an odd number of bosons, while it is
valid for an even number of bosons, which indicates that the P(0) dominance is
partly connected to the even number of identical particles. It is also noticed
that the $P(I_{max})$'s of bosons with spin $l$ do not follow the 1/N ($N=l+1$,
referring to the number of independent two-body matrix elements) relation. The
properties of the $P(I)$'s obtained in boson systems with spin $l$ are
discussed.


title:
Electromagnetic Dissociation as a Tool for Nuclear Structure and
  Astrophysics

abstract:
  Coulomb dissociation is an especially simple and important reaction
mechanism. Since the perturbation due to the electric field of the (target)
nucleus is exactly known, firm conclusions can be drawn from such measurements.
Electromagnetic matrixelements and astrophysical S-factors for radiative
capture processes can be extracted from experiments. We describe the basic
elements of the theory of nonrelativistic and relativistic electromagnetic
excitation with heavy ions. This is contrasted to electromagnetic excitation
with leptons (electrons), with their small electric charge and the absence of
strong interactions. We discuss various approaches to the study of higher order
electromagnetic effects and how these effects depend on the basic parameters of
the experiment. The dissociation of neutron halo nuclei is studied in a zero
range model using analytical methods. We also review ways how to treat nuclear
interactions, show their characteristics and how to avoid them (as far as
possible). We review the experimental results from a theoretical point of view.
Of special interest for nuclear structure physics is the appearence of low
lying electric dipole strength in neutron rich nuclei. Applications of Coulomb
dissociation to some selected radiative capture reactions relevant for nuclear
astrophysics are discussed. The Coulomb dissociation of 8B is relevant for the
solar neutrino problem. The potential of the method especially for future
investigations of (medium) heavy exotic nuclei for nuclear structure and
astrophysics is explored. We conclude that the Coulomb dissociation mechanism
is theoretically well understood, the potential difficulties are identified and
can be taken care of. Many interesting experiments have been done in this field
and many more are expected in the future.


title:
Spin-orbit induced backflow in neutron matter with auxiliary field
  diffusion Monte Carlo

abstract:
  The energy per particle of zero-temperature neutron matter is investigated,
with particular emphasis on the role of the $\vec L\cdot\vec S$ interaction. An
analysis of the importance of explicit spin--orbit correlations in the
description of the system is carried out by the auxiliary field diffusion Monte
Carlo method. The improved nodal structure of the guiding function, constructed
by explicitly considering these correlations, lowers the energy. The proposed
spin--backflow orbitals can conveniently be used also in Green's Function Monte
Carlo calculations of light nuclei.


title: Fusion and Breakup of Halo Nuclei

abstract:
  We discuss the effect of the coupling to the break-up channel on the total
fusion involving a halo nucleus with a heavy target. We show that there is a
competition between the hindrance arising from this coupling, mostly at above
barrier energies, and the enhancement which ensues at sub-barrier energies
owing to the static effect of the extended matter distribution and the coupling
to the soft modes.


title:
Generalized q-Deformed Symplectic sp(4) Algebra for Multi-shell
  Applications

abstract:
  A multi-shell generalization of a fermion representation of the q-deformed
compact symplectic sp_q(4) algebra is introduced. An analytic form for the
action of two or more generators of the Sp_q(4) symmetry on the basis states is
determined and the result used to derive formulae for the overlap between
number preserving states as well as for matrix elements of a model Hamiltonian.
A second-order operator in the generators of Sp_q(4) is identified that is
diagonal in the basis set and that reduces to the Casimir invariant of the
sp(4) algebra in the non-deformed limit of the theory. The results can be used
in nuclear structure applications to calculate beta-decay transition
probabilities and to provide for a description of pairing and higher-order
interactions in systems with nucleons occupying more than a single-j orbital.


title: Quark Coalescence and Elliptic Flow of Charm Hadrons

abstract:
  Elliptic flow of charm hadrons is investigated based on the quark coalescence
model. Due to the large difference between the charm quark and light quark
masses, hadrons containing both light and charm quarks show a qualitatively
different $v_2(p_\perp)$ from hadrons containing only light quarks. Simple
relations are proposed to infer quark elliptic flow from those of hadrons. The
effects of the finite momentum spread of hadron wavefunctions are also studied,
and are found to be small for charm hadrons.


title:
Higher-order calculations of electron-deuteron scattering in nuclear
  effective theory

abstract:
  Motivated by recent advances in the application of effective field theory
techniques to light nuclei we revisit the problem of electron-deuteron
scattering in these approaches. By sidestepping problems with the description
of electron-nucleon scattering data in effective field theories, we show that
the effective theory expansion for deuteron physics converges well over a wide
range of momentum transfers. The resultant description of the physics of the
two-nucleon system is good up to virtual photon momenta of order 700 MeV.


title:
Dibaryon systems in the quark mass density- and temperature-dependent
  model

abstract:
  Using the quark mass density- and temperature-dependent model, we have
studied the properties of the dibaryon systems. The binding energy, radius and
mean lifetime of Omega-Omega and Omega-Xi are given. We find the dibaryons
Omega-Omega, Omega-Xi are metastable at zero temperature, but the strong decay
channel for Omega-Omega opens when temperature arrives at 129.3MeV. It is shown
that our results are in good agreement with those given by the chiral S(3)
quark model.


title: P- and T-violating Schiff moment of the Mercury nucleus

abstract:
  The Schiff moment of the $^{199}$Hg nucleus was calculated using finite range
P- and T-violating weak nucleon-nucleon interaction. Effects of the core
polarization were considered in the framework of RPA with effective residual
forces.


title: Many-body effects in nuclear structure

abstract:
  We calculate, for the first time, the state-dependent pairing gap of a finite
nucleus (120Sn) diagonalizing the bare nucleon-nucleon potential (Argonne v14)
in a Hartree-Fock basis (with effective k-mass m_k eqult to 0.7 m), within the
framework of the BCS approximation including scattering states up to 800 MeV
above the Fermi energy to achieve convergence. The resulting gap accounts for
about half of the experimental gap. We find that a consistent description of
the low-energy nuclear spectrum requires, aside from the bare nucleon-nucleon
interaction, not only the dressing of single-particle motion through the
coupling to the nuclear surface, to give the right density of levels close to
the Fermi energy (and thus an effective mass m* approximately equal to m), but
also the renormalization of collective vibrational modes through vertex and
self-energy processes, processes which are also found to play an essential role
in the pairing channel, leading to a long range, state dependent component of
the pairing interaction. The combined effect of the bare nucleon-nucleon
potential and of the induced pairing interaction arising from the exchange of
low-lying surface vibrations between nucleons moving in time reversal states
close to the Fermi energy accounts for the experimental gap.


title: Unifying aspects of light- and heavy-systems

abstract:
  Dyson-Schwinger equations furnish a Poincare' covariant framework within
which to study hadrons. A particular feature is the existence of a
nonperturbative, symmetry preserving truncation that enables the proof of exact
results. Key to the DSE's efficacious application is their expression of the
materially important momentum-dependent dressing of parton propagators at
infrared length-scales, which is responsible for the magnitude of
constituent-quark masses and the length-scale characterising confinement in
bound states. A unified quantitative description of light- and heavy-quark
systems is achieved by capitalising on these features.


title:
Application of the Adiabatic Selfconsistent-Collective-Coordinate Method
  to a Solvable Model of Prolate-Oblate Shape Coexistence

abstract:
  The adiabatic selfconsistent collective coordinate method is applied to an
exactly solvable multi-O(4) model which simulates nuclear shape coexistence
phenomena. Collective mass and dynamics of large amplitude collective motions
in this model system are analysed, and it is shown that the method can well
describe the tunneling motions through the barrier between the prolate and
oblate local minima in the collective potential. Emergence of the doublet
pattern is well reproduced.


title:
Angular asymmetries in the reactions pp \to d\pi^+\eta and pn \to
  d\pi^0\eta and a_0-f_0 mixing

abstract:
  The reactions pp\to d\pi^+\eta and pn\to d\pi^0\eta are of special interest
for investigating the a_0(980) (J^P=0^+) resonance in the process NN \to da_0
\to d\pi\eta. We study some aspects of those reactions within a general
formalism and also in a concrete phenomenological model. In particular, it is
shown that the presence of nonresonant (i.e. without excitation of the a_0
resonance) contributions to these reactions yields nonvanishing values for
specific polarization observables, i.e. to effects like those generated by
a_0-f_0 mixing. An experimental determination of these observables for the
reaction pp\to d\pi^+\eta would provide concrete information on the magnitude
of those nonresonant contributions to \pi\eta production. We discuss also the
possibility of extracting information about a_0-f_0 mixing from the reaction pn
\to d\pi^0\eta with polarized proton beam.


title:
Microscopic calculation of the spin-dependent neutron scattering lengths
  on 3He

abstract:
  We report on the spin.dependent neutron scattering length on 3He from a
microscopic calculation of p-3H, n-3He, and d-2H scattering employing the
Argonne v18 nucleon-nucleon potential with and without additional three-nucleon
force. The results and that of a comprehensive R-matrix analysis are compared
to a recent measurement. The overall agreement for the scattering lengths is
quite good. The imaginary parts of the scattering lengths are very sensitive to
the inclusion of three-nucleon forces, whereas the real parts are almost
insensitive.


title:
Electromagnetic dissociation of 8B and the astrophysical S factor for
  7Be(p,gamma)8B

abstract:
  We present S factor data obtained from the Coulomb dissociation of 83
MeV/nucleon 8B, and analyze 7Be longitudinal momentum distributions measured at
44 and 81 MeV/nucleon using a potential model, first-order perturbation theory,
and dynamical solution of the time-dependent Schroedinger equation. Comparing
our results with independent continuum-discretized coupled channels
calculations, we study the reaction model and beam energy dependence of the E2
contribution to the dissociation cross section. By fitting radiative capture
and Coulomb breakup data taken below relative energies of 400 keV with
potential models constrained by 7Li + n and 7Be + p elastic scattering data, we
examine the mutual consistency of recent S17 measurements and obtain a
recommended value for S17(0) of 18.6 +/- 0.4 (experimental) +/- 1.1
(extrapolation) eV b (1 sigma). This result is in good agreement with recent
experimental determinations of the asymptotic normalization coefficient of the
valence proton wave function in 8B.


title:
Many-body approach to proton emission and the role of spectroscopic
  factors

abstract:
  The process of proton emission from nuclei is studied by utilizing the
two-potential approach of Gurvitz and Kalbermann in the context of the full
many-body problem. A time-dependent approach is used for calculating the decay
width. Starting from an initial many-body quasi-stationary state, we employ the
Feshbach projection operator approach and reduce the formalism to an effective
one-body problem. We show that the decay width can be expressed in terms of a
one-body matrix element multiplied by a normalization factor. We demonstrate
that the traditional interpretation of this normalization as the square root of
a spectroscopic factor is only valid for one particular choice of projection
operator. This causes no problem for the calculation of the decay width in a
consistent microscopic approach, but it leads to ambiguities in the
interpretation of experimental results. In particular, spectroscopic factors
extracted from a comparison of the measured decay width with a calculated
single-particle width may be affected.


title: Thermal Radiation from Nucleons and Mesons

abstract:
  Thermal photon emission rates due to meson-nucleon interactions have been
evaluated. An exhaustive set of reactions involving p(\bar p), n(\bar n), rho,
omega, a_1, pi and eta is seen to provide a sizeable contribution to the
emission rate from hot hadronic matter. Contributions from baryonic resonances
are found to be negligibly small.


title:
Development of particle multiplicity distributions using a general form
  of the grand canonical partition function and applications to L3 and H1 Data

abstract:
  Various phenomenological models of particle multiplicity distributions are
discussed using a general form of a unified model which is based on the grand
canonical partition function and Feynman's path integral approach to
statistical processes. These models can be written as special cases of a more
general distribution which has three control parameters which are $a$, $x$,
$z$. The relation to these parameters to various physical quantities are
discussed. A connection of the parameter $a$ with Fisher's critical exponent
$\tau$ is developed. Using this grand canonical approach, moments, cumulants
and combinants are discussed and a physical interpretation of the combinants
are given and their behavior connected to the critical exponent $\tau$. Various
physical phenomena such as hierarchical structure, void scaling relations, KNO
scaling features, clan variables, and branching laws are shown in terms of this
general approach. Several of these features which were previously developed in
terms of the negative binomial distribution are found to be more general. Both
hierarchical structure and void scaling relations depend on the Fisher exponent
$\tau$. Applications of our approach to the charged particle multiplicity
distribution in jets of L3 and H1 data are given. It is shown that just looking
at the mean and fluctuation of data is not enough to distinguish these
distributions or the underlying mechanism. The mean, fluctuation and third
cummulant of distribution determine three parameters $x$, $z$, $a$. We find
that a generalized random work model fits the data better than the widely used
negative binomial model.


title:
Comment on "Negative heat capacities and first order phase transitions
  in nuclei" by L.G. Moretto et al

abstract:
  In a recent paper L.G. Moretto et al [nucl-th/0208024] claim that the
negative heat capacities presented in our previously published paper
\cite{PRL2000} are "artifacts" coming from the use of periodic boundary
conditions in the Lattice-Gas calculations. We stress in this comment that this
claim is wrong: in ref. \cite{PRL2000} we did not use periodic boundary
conditions and anyhow the boundary conditions are irrelevant for the
statistical ensemble used in \cite{PRL2000}. The second claim of
[nucl-th/0208024] is that, because of the Coulomb repulsion, systems "with A>60
should present no anomalous negative heat capacities". We show that this
conclusion is contradicted by exact Lattice-gas simulations including Coulomb
forces which present negative heat capacities even for A>200.


title: Generator Coordinate Truncations

abstract:
  We investigate the accuracy of several schemes to calculate ground-state
correlation energies using the generator coordinate technique. Our test-bed for
the study is the $sd$ interacting boson model, equivalent to a 6-level
Lipkin-type model. We find that the simplified projection of a triaxial
generator coordinate state using the $S_3$ subgroup of the rotation group is
not very accurate in the parameter space of the Hamiltonian of interest. On the
other hand, a full rotational projection of an axial generator coordinate state
gives remarkable accuracy. We also discuss the validity of the simplified
treatment using the extended Gaussian overlap approximation (top-GOA), and show
that it works reasonably well when the number of boson is four or larger.


title: On the linear term in the nuclear symmetry energy

abstract:
  The nuclear symmetry energy calculated in the RPA from the pairing plus
symmetry force Hamiltonian with equidistant single-nucleon levels is for mass
number A=48 approximately proportional to T(T+1.025), where T is the isospin
quantum number. An isovector character of the pair field assumed to produce the
observed odd-even mass staggering is essential for this result. The RPA
contribution to the symmetry energy cannot be simulated by adding to the
Hartree-Fock-Bogolyubov energy a term proportional to the isospin variance in
the Bogolyubov quasiparticle vacuum, and there are significant corrections to
the approximation which consist in adding half the isocranking angular
velocity. The present calculation employs a smaller single-nucleon level
spacing than used in a previous investigation of the model.


title: Deformation Energy Minima at Finite Mass Asymmetry

abstract:
  A very general saddle point nuclear shape may be found as a solution of an
integro-differential equation without giving apriori any shape parametrization.
By introducing phenomenological shell corrections one obtains minima of
deformation energy for binary fission of parent nuclei at a finite (non-zero)
mass asymmetry. Results are presented for reflection asymmetric saddle point
shapes of thorium and uranium even-mass isotopes with A=226-238 and A=230-238
respectively.


title:
Search for delays between unlike particle emissions in relativistic
  heavy-ion collisions

abstract:
  The possibilities of unlike particle correlations for a study of particle
delays and spatial shifts in relativistic heavy ion collisions are
demonstrated. This report represents the unpublished Ref. [4] in the paper by
S. Voloshin et al., Phys. Rev. Lett. {\bf 79} (1977) 4766; the report abstract
was submitted to the conference Quark Matter'97.


title: Searching for space-time asymmetries in particle production

abstract:
  The possibilities of unlike particle correlations for a study of the
space-time asymmetries in particle production, including the sequence of
particle emission, are demonstrated.


title:
Searching for multi-boson effects and space-time asymmetries in particle
  production

abstract:
  The influence of the multi-boson effects on pion multiplicities, single-pion
spectra and two-pion correlation functions is discussed in terms of an
analytically solvable model. It is argued that spectacular multi-boson effects
are likely to be observed only in the rare events containing sufficiently high
density fluctuations. The possibilities of unlike particle correlations for a
study of the space-time asymmetries in particle production, including the
sequence of particle emission, are demonstrated.


title:
On the physical significance of q-deformation to isovector pairing
  interactions in nuclei

abstract:
  The quantum deformation concept is applied to a study of isovector pairing
correlations in nuclei of the mass 40<A<100 region. While the non-deformed (q
-> 1) limit of the theory provides a reasonable global estimate for strength
parameters of the pairing interaction, the results show that the q-deformation
plays a significant role in understanding higher-order effects in the
interaction.


title: Cluster-Impact Fusion and Effective Deuteron Temperature

abstract:
  Temperature and kinematic line broadening are the primary contributions to
the width of the proton energy spectrum measured in cluster-impact fusion
experiments. By ascertaining these two contributions, we have determined an
effective temperature for the high-velocity deuteron component that is
responsible for the measured fusion yield. The extracted effective temperature
is substantially higher than conventional estimates., and implies that
cluster-impact fusion is hot fusion on an atomic scale. The proton spectrum
rules out contaminants in explaining the high yield.


title: Spin symmetry in the anti-nucleon spectrum

abstract:
  We discuss spin and pseudo-spin symmetry in the spectrum of single nucleons
and single anti-nucleons in a nucleus. As an example we use relativistic mean
field theory to investigate single anti-nucleon spectra. We find a very well
developed spin symmetry in single anti-neutron and single anti-proton spectra.
The dominant components of the wave functions of the spin doublet are almost
identical. This spin symmetry in anti-particle spectra and the pseudo-spin
symmetry in particle spectra have the same origin. However it turns out that
the spin symmetry in anti-nucleon spectra is much better developed than the
pseudo-spin symmetry in normal nuclear single particle spectra.


title:
eta-Nucleus interactions and in-medium properties of N*(1535) in chiral
  models

abstract:
  The properties of eta-nucleus interaction and their experimental consequences
are investigated with eta-nucleus optical potentials obtained by postulating
the N*(1535) dominance for eta-N system. The N*(1535) properties in nuclear
medium are evaluated by two kinds of chiral effective models based on distinct
pictures of N*(1535). We find that these two models provide qualitatively
different optical potentials of the eta meson, reflecting the in-medium
properties of N*(1535) in these models. In order to compare these models in
physical observables, we calculate spectra of (d,3He) reactions for the eta
mesic nucleus formation with various kinds of target nuclei. We show that the
(d,3He) spectra obtained in these models are significantly different and are
expected to be distinguishable in experiments.


title: Corrections to deuterium hyperfine structure due to deuteron excitations

abstract:
  We consider the corrections to deuterium hyperfine structure originating from
the two-photon exchange between electron and deuteron, with the deuteron
excitations in the intermediate states. In particular, the motion of the two
intermediate nucleons as a whole is taken into account. The problem is solved
in the zero-range approximation. The result is in good agreement with the
experimental value of the deuterium hyperfine splitting.


title:
Central and tensor components of three-nucleon forces in low-energy
  proton-deuteron scattering

abstract:
  Contributions of three-nucleon forces (3NF) to proton-deuteron scattering
observables at energies below the deuteron breakup threshold are studied by
solving the Faddeev equation that includes the Coulomb interaction. At E_p=3.0
MeV, we find that the central part of a two-pion exchange 3NF removes the
discrepancy between measured cross sections and the calculated ones by
two-nucleon forces, and improves the agreement with T_{22} experimental data.
However, the tensor part of the 3NF fails in reproducing data of the analyzing
power T_{21} by giving worse agreement between the measured and the calculated.
Detailed examinations of scattering amplitudes suggest that a P-wave
contribution in spin quartet tensor amplitudes has unsuitable sign for
reproducing the T_{21} data.


title:
Low-Energy Direct Capture in the 8Li(n,gamma)9Li and 8B(p,gamma)9C
  Reactions

abstract:
  The cross sections of the 8Li(n,gamma)9Li and 8B(p,gamma)9C capture reactions
have been analyzed using the direct capture model. At low energies which is the
astrophysically relevant region the capture process is dominated by E1
transitions from incoming s-waves to bound p-states. The cross sections of both
mirror reactions can be described simultaneously with consistent potential
parameters, whereas previous calculations have overestimated the capture cross
sections significantly. However, the parameters of the potential have to be
chosen very carefully because the calculated cross section of the
8Li(n,gamma)9Li reaction depends sensitively on the potential strength.


title: Kinematical classification of two-pion production on the nucleon

abstract:
  We give a full kinematical classification of all the tree-level two-pion
photoproduction processes on the nucleon, which consists of seventeen diagrams.
It suggests a method of analysis of two-pion data with little model bias.


title:
Comparison of Nuclear Suppression Effects on Meson Production at High
  p_T and p_L

abstract:
  The medium effect on the pion distribution at high $p_T$ in $AA$ collisions
is compared to that of the pion distribution at high $p_L$ in $pA$ collisions.
Both the suppression of the spectra and the energy losses of the measured pions
are studied. Although the medium effect on $p_T$ is larger than on $p_L$, the
difference is found surprisingly to be not as big as one would naively expect.


title:
Towards a practical approach for self-consistent large amplitude
  collective motion

abstract:
  We investigate the use of an operatorial basis in a self-consistent theory of
large amplitude collective motion. For the example of the
pairing-plus-quadrupole model, which has been studied previously at
equilibrium, we show that a small set of carefully chosen state-dependent basis
operators is sufficient to approximate the exact solution of the problem
accuratly. This approximation is used to study the interplay of quadrupole and
pairing degrees of freedom along the collective path for realistic examples of
nuclei. We show how this leads to a viable calculational scheme for studying
nuclear structure, and discuss the surprising role of pairing collapse.


title: Time-Reversal Violating Schiff Moment of 225Ra

abstract:
  We use the Skyrme-Hartree-Fock method, allowing all symmetries to be broken,
to calculate the time-reversal-violating nuclear Schiff moment (which induces
atomic electric dipole moments) in the octupole-deformed nucleus 225Ra. Our
calculation includes several effects neglected in earlier work, including self
consistency and polarization of the core by the last nucleon. We confirm that
the Schiff moment is large compared to those of reflection-symmetric nuclei,
though ours is generally a few times smaller than recent estimates.


title: Shapes of the Proton

abstract:
  A model proton wave function, constructed using Poincare invariance, and
constrained by recent electromagnetic form factor data, is used to study the
shape of the proton. Spin-dependent quark densities are defined as matrix
elements of density operators in proton states of definite spin-polarization,
and shown to have an infinite variety of non-spherical shapes. For high
momentum quarks with spin parallel to that of the proton, the shape resembles
that of a peanut, but for quarks with anti-parallel spin the shape is that of a
bagel.


title: Nuclear Astrophysics in Rare Isotope Facilities

abstract:
  I discuss a few of the recent developments in nuclear reactions at very low
energies with emphasis on the role of radioactive beam facilities.


title: Spinodal in asymmetric nuclear matter

abstract:
  The phase diagram of nuclear matter is quite rich - it shows such phenomena
as phase-transitions, formation of condensates, clustering, etc. From the
analysis of the spinodal instability, one can learn about the region of
liquid-gas coexistence in nuclear matter at low densities and finite isospin
asymmetries. In a recent paper, we have shown that asymmetric nuclear matter at
sub-nuclear densities should undergo only one type of instability. The
associated order parameter is dominated by the isoscalar density and so the
transition is of liquid-gas type. The instability goes in the direction of a
restoration of the isospin symmetry leading to a fractionation phenomenon.


title: Blast-wave snapshots from RHIC

abstract:
  I present fits with the so-called blast-wave model to single-particle spectra
and HBT correlations from Au+Au collisions at a CMS energy of 130 AGeV. There
is only little choice of freeze-out temperature and transverse flow velocity
for which the model fits both the identified spectra and the correlation radii
just well enough not to be excluded. The observed steep M_t dependence of
R_side leads to a temperature which it is problematic to interpret. The
applicability of the model for the freeze-out description is thus questioned.


title: Hadrons in Nuclei

abstract:
  Changes of hadronic properties in dense nuclear matter as predicted by theory
have usually been investigated by means of relativistic heavy-ion reactions. In
this talk I show that observable consequences of such changes can also be seen
in more elementary reactions on nuclei. Particular emphasis is put on a
discussion of photonuclear reactions; examples are the dilepton production at
$\approx 1$ GeV and the hadron production in nuclei at 10 - 20 GeV virtual
photon energies. The observable effects are expected to be as large as in
relativistic heavy-ion collisions and can be more directly related to the
underlying hadronic changes.


title: On the Excitation of Double Giant Resonances in Heavy Ion Reactions

abstract:
  The interplay of nuclear and Coulomb processes in the inelastic excitation of
single- and double-phonon giant resonances in heavy ion collisions is studied
within a simple reaction model. Predominance of the Coulomb excitation
mechanism on the population of the single-phonon and, on the contrary,
predominance of the nuclear excitation for the double-phonon is evidenced. The
effect of the spreading of the strength distribution of the giant resonances on
the excitation process is analyzed, showing sizeable modifications in the case
of Coulomb dominated processes.


title: Searching for Quark-Gluon Plasma(QGP) Bubble effects at RHIC/LHC

abstract:
  Since the early eighties, we have shared with Leon Van Hove the following
view. That if a QGP were produced in high energy heavy ion colliders, that its
hadronization products would likely come from small localized in phase space
bubbles of plasma. We develop a model based on HIJING, to which we added a ring
of adjoining multiple bubbles in the central rapidity region. Our simulations
were designed to be tested by the forthcoming RHIC STAR detector data for 65
GeV/n Au colliding with 65 GeV/n Au. We took into account background and
resonance effects to allow a direct comparison with the data. Later 100 GeV/n
Au colliding with 100 GeV/n Au and LHC data could also test these ideas. We
used two charged particle correlation's as a sensitive method to test for
bubbles.


title:
An interpretation of saturation phenomena as Glauber-Gribov multiple
  parton scatterings

abstract:
  We compare two formalism that describe minijet production in pA and AA
collisions: pQCD supplemented by Glauber-Gribov multiple semihard parton
scatterings (pQCD+Glauber), and the Colour Glass Condensate (CGC). We argue
that in a suitable limit they are equivalent to each other, the PQCD+Glauber
model being more accurate from a numerical point of view. Finally, we analyze
RHIC data on Au-Au integrated charged multiplicities in the pQCD+Glauber
framework, and conclude that at least at central rapidity there is no sign of
gluon saturation.


title: The 2p-2h electromagnetic response in the quasielastic peak and beyond

abstract:
  The contribution to the nuclear transverse response function R_T arising from
two particle-two hole (2p-2h) states excited through the action of
electromagnetic meson exchange currents (MEC) is computed in a fully
relativistic framework. The MEC considered are those carried by the pion and by
Delta degrees of freedom, the latter being viewed as a virtual nucleonic
resonance. The calculation is performed in the relativistic Fermi gas model in
which Lorentz covariance can be maintained. All 2p-2h many-body diagrams
containing two pionic lines that contribute to R_T are taken into account and
the relative impact of the various components of the MEC on R_T is addressed.
The non-relativistic limit of the MEC contributions is also discussed and
compared with the relativistic results to explore the role played by relativity
in obtaining the 2p-2h nuclear response.


title:
Influence of the Pauli principle on the dynamics of the Quark-Gluon
  Plasma

abstract:
  A simple parton cascade model for the ultra-relativistic nucleus-nucleus
collisions is proposed to investigate the Pauli blocking at the transition from
hadronic to partonic state, i.e. QGP. A boost invariant study of the Pauli
blocking is implemented in the Monte Carlo simulation for the first time. It
turns out that the higher reaction energy the stronger the partonic Pauli
effect is. It amounts to about ten percent at SPS and RHIC energies but nearly
reaches twenty percent at LHC energy. Thus the effect is relevant to the
formation and evolution of the quark-gluon plasma.


title:
Isovector Giant Dipole Resonance of Stable Nuclei in a Consistent
  Relativistic Random Phase Approximation

abstract:
  A fully consistent relativistic random phase approximation is applied to
study the systematic behavior of the isovector giant dipole resonance of nuclei
along the $\beta$-stability line in order to test the effective Lagrangians
recently developed. The centroid energies of response functions of the
isovector giant dipole resonance for stable nuclei are compared with the
corresponding experimental data and the good agreement is obtained. It is found
that the effective Lagrangian with an appropriate nuclear symmetry energy,
which can well describe the ground state properties of nuclei, could also
reproduce the isovector giant dipole resonance of nuclei along the
$\beta$-stability line.


title:
Intermediate energy Coulomb excitation as a probe of nuclear structure
  at radioactive beam facilities

abstract:
  The effects of retardation in the Coulomb excitation of radioactive nuclei in
intermediate energy collisions (Elab ~100 MeV/nucleon) are investigated. We
show that the excitation cross sections of low-lying states in 11Be,
{38,40,42}S and {44,46}Ar projectiles incident on gold and lead targets are
modified by as much as 20% due to these effects. The angular distributions of
decaying gamma-rays are also appreciably modified.


title:
Spin effects and baryon resonance dynamics in phi-meson photoproduction
  at few GeV

abstract:
  The diffractive $\phi$-meson photoproduction amplitude is dominated by the
Pomeron exchange process and contains the terms that govern the spin-spin and
spin-orbital interactions.
  We show that these terms are responsible for the spin-flip transitions at
forward photoproduction angles and appear in the angular distributions of
$\phi\to K^+K^-$ -decay in reactions with unpolarized and polarized photon
beams.
  At large momentum transfers, the main contribution to the $\phi$-meson
photoproduction is found to be due to the excitation of nucleon resonances.
  Combined analysis of $\omega$ and $\phi$ photoproduction indicates strong
OZI-rule violation in $\phi NN^*$ - couplings.
  We also show that the spin observables are sensitive to the dynamics of
$\phi$-meson photoproduction at large angles and could help distinguish
different theoretical models of nucleon resonances.
  Predictions for spin effects in $\phi$-meson photoproduction are presented
for future experimental tests.


title: Supernova Neutrinos

abstract:
  I describe how the signals corresponding to the supernova $\nu_e$ and
$\bar{\nu}_e$ (charged current reactions) as well as all active neutrinos
(neutral current reactions) can be separately observed in various existing
detectors. These observations would make it possible to determine the flux and
average energy (or temperature) for each of these three neutrino signal
components. I argue that all these quantities are needed in order to understand
the interplay between the so far poorly known supernova neutrino emission
process and the neutrino oscillations.


title: Beyond the known baryon resonances

abstract:
  eta photoproduction data on the proton up to E=2 GeV are interpreted within a
chiral constituent quark formalism, which embodies all known three and four
star resonances. This study confirms the need for a new S11 resonance, with
M=1.780 GeV and Gamma=280 MeV, already introduced in investigating lower energy
data.


title: On the uncertainty in the $0\nu\beta\beta$ decay nuclear matrix elements

abstract:
  The nuclear matrix elements $M^{0\nu}$ of the neutrinoless double beta decay
($0\nu\beta\beta$) are evaluated for $^{76}$Ge,$^{100}$Mo, $^{130}$Te, and
$^{136}$Xe within the Renormalized Quasiparticle Random Phase Approximation
(RQRPA) and the simple QRPA. Three sets of single particle level schemes are
used, ranging in size from 9 to 23 orbits. When the strength of the
particle-particle interaction is adjusted so that the $2\nu\beta\beta$ decay
rate is correctly reproduced, the resulting $M^{0\nu}$ values become
essentially independent on the size of the basis, and on the form of different
realistic nucleon-nucleon potentials. Thus, one of the main reasons for
variability of the calculated $M^{0\nu}$ within these methods is eliminated.


title: Negative specific heat in a thermodynamic model of multifragmentation

abstract:
  We consider a soluble model of multifragmentation which is similar in spirit
to many models which have been used to fit intermediate energy heavy ion
collision data. In this model $c_v$ is always positive but for finite nuclei
$c_p$ can be negative for some temperatures and pressures. Furthermore,
negative values of $c_p$ can be obtained in canonical treatment. One does not
need to use the microcanonical ensemble. Negative values for $c_p$ can persist
for systems as large as 200 paticles but this depends upon parameters used in
the model calculation. As expected, negative specific heats are absent in the
thermodynamic limit.


title: Low-energy operators in effective theories

abstract:
  Modern effective-theory techniques are applied to the nuclear many-body
problem. A novel approach is proposed for the renormalization of operators in a
manner consistent with the construction of the effective potential. To test
this approach, a one-dimensional, yet realistic, nucleon-nucleon potential is
introduced. An effective potential is then constructed by tuning its parameters
to reproduce the exact effective-range expansion and a variety of bare
operators are renormalized in a fashion compatible with this construction.
Predictions for the expectation values of these effective operators in the
ground state reproduce the results of the exact theory with remarkable accuracy
(at the 0.5% level). This represents a marked improvement over a widely
practiced approach that uses effective interactions but retains bare operators.
Further, it is shown that this improvement is more impressive as the operator
becomes more sensitive to the short-range structure of the potential. We
illustrate the main ideas of this work using the elastic form factor of the
deuteron as an example.


title:
Statistical description with anisotropic momentum distributions for
  hadron production in nucleus-nucleus collisions

abstract:
  The various experimental data at AGS, SPS and RHIC energies on hadron
particle yields for central heavy ion collisions are investigated by employing
a generalized statistical density operator, that allows for a well-defined
anisotropic local momentum distribution for each particle species, specified by
a common streaming velocity parameter. The individual particle ratios are
rather insensitive to a change in this new intensive parameter. This leads to
the conclusion that the reproduction of particle ratios by a statistical
treatment does not imply the existence of a fully isotropic local momentum
distribution at hadrochemical freeze-out, i.e. a state of almost complete
thermal equilibrium.


title: Critical-Point Symmetry in a Finite System

abstract:
  At a critical point of a second order phase transition the intrinsic energy
surface is flat and there is no stable minimum value of the deformation.
However, for a finite system, we show that there is an effective deformation
which can describe the dynamics at the critical point. This effective
deformation is determined by minimizing the energy surface after projection
onto the appropriate symmetries. We derive analytic expressions for energies
and quadrupole rates which provide good estimates for these observables at the
critical point.


title:
High-$p_T$ Hadron Spectra, Azimuthal Anisotropy and Back-to-Back
  Correlations in High-energy Heavy-ion Collisions

abstract:
  The observed suppression of high-$p_T$ hadron spectra, finite azimuthal
anisotropy, disappearance of jet-like back-to-back correlations, and their
centrality dependence in $Au+Au$ collisions at RHIC are shown to be
quantitatively described by jet quenching within a pQCD parton model. The
difference between $h^{\pm}$ and $\pi^0$ suppression in intermediate $p_T$ is
consistent with the observed $(K+p)/\pi$ enhancement which should disappear at
$p_T>6$ GeV/$c$. The suppression of back-to-back correlations is shown to be
directly related to the medium modification of jet fragmentation functions(FF).


title:
Detailed Analysis of the Chiral Unitary Model for Meson-Baryon
  Scattering with Flavor SU(3) Breaking Effects

abstract:
  We study s-wave meson-baryon scattering using the chiral unitary model. We
consider $1/2^{-}$ baryon resonances as quasibound states of the low lying
mesons ($\pi,K,\eta$) and baryons ($N,\Lambda,\Sigma,\Xi$). In previous works,
the subtraction constants which appear in loop integrals were found to largely
depend on the channels, and it was necessary to fit these constants to
reproduce the data. In order to extend this model to all channels with fewer
parameters, we introduce flavor SU(3) breaking interactions in the framework of
chiral perturbation theory. It is found, however, that the observed SU(3)
breaking in meson-baryon scattering cannot be explained by the present SU(3)
breaking interactions. The role and importance of the subtraction constants in
the present framework are discussed.


title: Partial Dynamical Symmetry as an Intermediate Symmetry Structure

abstract:
  We introduce the notion of a partial dynamical symmetry for which a
prescribed symmetry is neither exact nor completely broken. We survey the
different types of partial dynamical symmetries and present empirical examples
in each category.


title: Critical Points in Nuclei and Interacting Boson Model Intrinsic States

abstract:
  We consider properties of critical points in the interacting boson model,
corresponding to flat-bottomed potentials as encountered in a second-order
phase transition between spherical and deformed $\gamma$-unstable nuclei. We
show that intrinsic states with an effective $\beta$-deformation reproduce the
dynamics of the underlying non-rigid shapes. The effective deformation can be
determined from the the global minimum of the energy surface after projection
onto the appropriate symmetry. States of fixed $N$ and good O(5) symmetry
projected from these intrinsic states provide good analytic estimates to the
exact eigenstates, energies and quadrupole transition rates at the critical
point.


title: Latest results from lattice QCD for the Roper resonance

abstract:
  The present status of the Roper resonance in lattice QCD is reviewed. Some of
the latest lattice results are discussed with particular emphasis on a large
systematic error stemming from the finite size effect. These results suggest
that the Roper resonance can be described by the simple three quark excitation
of sizable extent.


title: Dilepton production in heavy ion collisions at intermediate energies

abstract:
  We present a unified description of the vector meson and dilepton production
in elementary and in heavy ion reactions. The production of vector mesons
($\rho,\omega$) is described via the excitation of nuclear resonances ($R$).
The theoretical framework is an extended vector meson dominance model (eVMD).
The treatment of the resonance decays $R\longmapsto NV$ with arbitrary spin is
covariant and kinematically complete. The eVMD includes thereby excited vector
meson states in the transition form factors. This ensures correct asymptotics
and provides a unified description of photonic and mesonic decays. The
resonance model is successfully applied to the $\omega$ production in $p+p$
reactions. The same model is applied to the dilepton production in elementary
reactions ($p+p, p+d$). Corresponding data are well reproduced. However, when
the model is applied to heavy ion reactions in the BEVALAC/SIS energy range the
experimental dilepton spectra measured by the DLS Collaboration are
significantly underestimated at small invariant masses. As a possible solution
of this problem the destruction of quantum interference in a dense medium is
discussed. A decoherent emission through vector mesons decays enhances the
corresponding dilepton yield in heavy ion reactions. In the vicinity of the
$\rho/\omega$-peak the reproduction of the data requires further a substantial
collisional broadening of the $\rho$ and in particular of the $\omega$ meson.


title:
Non-Scissors-Mode Behaviour of Isovector Magnetic Dipole Orbital
  Transitions Involving Isospin Transfer

abstract:
  We study the response of isovector orbital magnetic dipole (IOMD) transitions
to the quadrupole-quadrupole ($Q \cdot Q$) interaction, to the
isospin-conserving pairing interaction (ICP) and to combinations of both. We
find qualitatively different behaviours for transitions in which the final
isospin differs from the initial isospin versus cases where the two isospins
are the same. For $N=Z$ even-even nuclei with $J^{\pi}=0^+, T=0$ ground states
such as $^8Be$ and $^{20}Ne$, the summed $T=0 \to T=1$ IOMD from the ground
state to all the $J=1, T=1$ states in the $0 \hbar \omega$ space does not
vanish when the $Q \cdot Q$ interaction is turned off. The pairing interaction
(ICP) alone leads to a finite transition rate. For nuclei with $J=0^+, T=1$
ground states such as $^{10}Be$ and $^{22}Ne$, the summed $T=1 \to T=1$ IOMD
$does$ vanish when the $Q \cdot Q$ interaction is turned off, as is expected in
a good scissors-mode behaviour. However this is not the case for the
corresponding sum of the $T=1 \to T=2$ IOMD transitions. In $^{22}Ne$ (but not
in $^{10}Be$) the sum of the $T=1 \to T=2$ IOMD transitions is remarkably
insensitive to the strengths of both the $Q \cdot Q$ and the ICP interactions.
In $^{22}Ne$ an energy weighted-sum is similarly insensitive. All our
calculations were carried out in the $0 \hbar \omega$ space.


title: BBN and Lambda_QCD

abstract:
  Big Bang Nucleosynthesis (BBN) has increasingly become the tool of choice for
investigating the permitted variation of fundamental constants during the
earliest epochs of the Universe. Here we present a BBN calculation that has
been modified to permit changes in the QCD scale, Lambda_QCD. The primary
effects of changing the QCD scale upon BBN are through the deuteron binding
energy, B_D, and the neutron-proton mass difference, delta-m_np, which both
play crucial roles in determining the primordial abundances. In this paper, we
show how a simplified BBN calculation allows us to restrict the nuclear data we
need to just B_D and delta-m_np yet still gives useful results so that any
variation in Lambda_QCD may be constrained via the corresponding shifts in B_D
and delta-m_np by using the current estimates of the primordial deuterium
abundance and helium mass fraction. The simplification predicts the helium-4
and deuterium abundances to within 1% and 50% respectively when compared with
the results of a standard BBN code. But Lambda_QCD also affects much of
remaining required nuclear input so this method introduces a systematic error
into the calculation and we find a degeneracy between B_D and delta-m_np. We
show how increased understanding of the relationship of the pion mass and/or
B_D to other nuclear parameters, such as the binding energy of tritium and the
cross section of T + D -> He4 + n, would yield constraints upon any change in
B_D and delta-m_np at the 10% level.


title:
Alternative Size and Lifetime Measurements for High-Energy Heavy-Ion
  Collisions

abstract:
  Two-Particle correlations based on the interference of identical particles
has provided the chief means for determining the shape and lifetime of sources
in relativistic heavy ion collisions. Here, Strong and Coulomb induced
correlations are shown to provide equivalent information.


title: Net charge fluctuation and string fragmentation

abstract:
  We present simulation results of net charge fluctuation in $Au+Au$ collisions
at $\sqrt{s_{nn}}$=130 GeV from a dynamic model, JPCIAE. The calculations are
done for the quark-gluon phase before hadronization, the pion gas, the
resonance pion gas from $\rho$ and $\omega$ decays and so on. The simulations
of the charge fluctuation show that the discrepancy exists between the dynamic
model and the thermal model for a pion gas and a resonance pion gas from $\rho$
and $\omega$ decays while the simulated charge fluctuation of the quark-gluon
phase is close to the thermal model prediction. JPCIAE results of net charge
fluctuation in the hardonic phase are nearly 4-5 times larger than one for the
quark-gluon phase, which implies that the charge fluctuation in the quark-gluon
phase may not survive the hadronization (string fragmentation) as implemented
in JPCIAE.


title: Electromagnetic response of confined Dirac particles

abstract:
  The eigenstates of a single massless Dirac particle confined in a linear
potential are calculated exactly by direct solution of the Dirac equation. The
electromagnetic structure functions are calculated from the Dirac wave
functions of the ground and excited states of the particle by coupling to its
conserved vector current. We obtain the longitudinal and transverse structure
functions as a function of y=nu-q, where nu and q are the energy and momentum
transferred to the target in its rest frame. At values of q>~2.5 GeV, much
larger than the characteristic energy scale ~440 MeV of the confining
potential, the response exhibits y scaling, a generalization of Bjorken
scaling. We compare the exact structure functions with those obtained from the
ground state wave functions in the plane wave impulse approximation. The
deviation from the Callan-Gross relation is compared with the parton model
prediction.


title:
Beyond-mean-field-model analysis of low-spin normal-deformed and
  superdeformed collective states of S32, Ar36, Ar38 and Ca40

abstract:
  We investigate the coexistence of spherical, deformed and superdeformed
states at low spin in S32, Ar36, Ar38 and Ca40. The microscopic states are
constructed by configuration mixing of BCS states projected on good particle
number and angular momentum. The BCS states are themselves obtained from
Hartree-Fock BCS calculations using the Skyrme interaction SLy6 for the
particle-hole channel, and a density-dependent contact force in the pairing
channel. The same interaction is used within the Generator Coordinate Method to
determine the configuration mixing and calculate the properties of even-spin
states with positive parity. Our calculations underestimate moments of inertia.
Nevertheless, for the four nuclei, the global structural properties of the
states of normal deformation as well as the recently discovered superdeformed
bands up to spin 6 are correctly reproduced with regard to both the energies
and the transition rates.


title:
The Contribution of the Light Quark Condensate to the Pion-Nucleon Sigma
  Term

abstract:
  There has been a discrepancy between values of the pion-nucleon sigma term
extracted by two different methods for many years. Analysis of recent high
precision pion-nucleon data has widened the gap between the two determinations.
It is argued that the two extractions correspond to different quantities and
that the difference between them can be understood and calculated.


title: Magnetic moments of the N(1535) resonance in the chiral unitary model

abstract:
  We calculate the magnetic moments of the N(1535) resonance using the chiral
unitary model, where the resonance is dynamically generated in the scatterings
of the lowest-lying mesons and baryons. We obtain the magnetic moments of the
resonance as +1.1 and -0.25 for p(1535) and n(1535), respectively, in units of
the nuclear magneton. We discuss the origin of these numbers within the chiral
unitary model, then we compare the present results with those of the quark
model and the chiral doublet model. The possibility to observe the magnetic
moments in experiments is also investigated.


title: Parton coalescence at RHIC

abstract:
  Using a covariant coalescence model, we study hadron production in
relativistic heavy ion collisions from both soft partons in the quark-gluon
plasma and hard partons in minijets. Including transverse flow of soft partons
and independent fragmentation of minijet partons, the model is able to describe
available experimental data on pion, kaon, and antiproton spectra. The
resulting antiproton to pion ratio is seen to increase at low transverse
momenta and reaches a value of about one at intermediate transverse momenta, as
observed in experimental data at RHIC. A similar dependence of the antikaon to
pion ratio on transverse momentum is obtained, but it reaches a smaller value
at intermediate transverse momenta. At high transverse momenta, the model
predicts that both the antiproton to pion and the antikaon to pion ratio
decrease and approach those given by the perturbative QCD. Both collective flow
effect and coalescence of minijet partons with partons in the quark-gluon
plasma affect significantly the spectra of hadrons with intermediate transverse
momenta. Elliptic flows of protons, Lambdas, and Omegas have also been
evaluated from partons with elliptic flows extracted from fitting measured pion
and kaon elliptic flows, and they are found to be consistent with available
experimental data.


title: Wavelet Notes

abstract:
  Wavelets are a useful basis for constructing solutions of the integral and
differential equations of scattering theory. Wavelet bases efficiently
represent functions with smooth structures on different scales, and the matrix
representation of operators in a wavelet basis are well-approximated by sparse
matrices. The basis functions are related to solutions of a linear
renormalization group equation, and the basis functions have structure on all
scales. Numerical methods based on this renormalization group equation are
discussed. These methods lead to accurate and efficient numerical
approximations to the scattering equations. These notes provide a detailed
introduction to the subject that focuses on numerical methods. We plan to
provide periodic updates to these notes.


title: Isomeric and hyperdeformed states at high spin for light nuclei

abstract:
  We present a macroscopic model for the energy of rotation nuclei which has
several refinements relative to the rotating liquid drop model. The most
important features are the inclusion of the shell correction and using a new
family of triaxial compact and creviced shapes to describe transition of the
system from one sphere to a two separated spheres. With this model we calculate
the properties of point of equilibrium corresponding to nuclear ground states,
isomeric states and fission saddle-points. The model is applied to the nuclei
56Ni, 48Cr and 80Zr. The results obtained allowed to explain the light compound
nuclear system fission phenomena and predict the existence of hyperdeformed
states at very high spins.


title: Correlation femtoscopy of multiparticle processes

abstract:
  Recent results on particle momentum and spin correlations are discussed in
view of the role played by the effects of quantum statistics, including
multiboson and coherence phenomena, and final state interaction. Particularly,
it is demonstrated that the latter allows for (i) correlation femtoscopy with
unlike particles; (ii) study of the relative space--time asymmetries in the
production of different particle species (e.g., relative time delays or spatial
shifts due to collective flows); (iii) study of the particle strong interaction
hardly accessible by other means (e.g., in two-lambda system).


title:
Modern nuclear force predictions for the neutron-deuteron scattering
  lengths

abstract:
  The nd doublet and quartet scattering lengths have been calculated based on
the modern NN and 3N interactions. We also studied the effect of the
electromagnetic interactions in the form introduced in AV18. Switching them off
for the various nuclear force models leads to shifts of up to +0.04 fm for
doublet scattering length, which is significant for present day standards. The
electromagnetic effects have also a noticeable effect on quartet scattering
length, which otherwise is extremely stable under the exchange of the nuclear
forces. For the current nuclear force models there is a strong scatter of the
3H binding energy and the doublet scattering length values around an averaged
straight line (Phillips line). This allows to use doublet scattering length and
the 3H binding energy as independent low energy observables.


title: Probing additional dimensions in the universe with neutron experiments

abstract:
  We carry out a simple analysis of (n+3)-dimensional gravity in the context of
recent work on 'large' supplementary dimensions and deduce a formula for the
expected compactification radius for the n additional dimensions in the
universe, as a function of the Planck and the electro-weak scales. We argue
that the correspondingly modified gravitational force gives rise to effects
that might be within the detection range of dedicated neutron experiments. A
scattering analysis of the corresponding modified gravitational forces suggests
that slow neutron scattering off atomic nuclei with null spin may provide an
experimental test for these ideas.


title: The Quark-Gluon Plasma in Equilibrium

abstract:
  Our current knowledge of the quark-gluon plasma in thermodynamical
equilibrium is reviewed. The phase diagram of strongly interacting matter is
discussed, with emphasis on the quark-hadron phase transition and the
color-superconducting phases of quark matter. Lattice QCD results on the order
of the phase transition, the thermodynamical functions, the heavy quark free
energy, mesonic spectral functions, and recent results for nonzero quark
chemical potential are presented. Analytic attempts to compute the
thermodynamical properties of strongly interacting matter, such as perturbation
theory, quasiparticle models, ``hard-thermal-loop''(HTL)-resummed perturbation
theory, the Polyakov-loop model, as well as linear sigma models are discussed.
Finally, color-superconducting quark matter is considered in the limit of weak
coupling. The gap equation and the excitation spectrum are derived. The
solution of the gap equation, gap parameters in various color-superconducting
phases, and critical temperatures for the transition to normal-conducting quark
matter are presented. A summary of gluon and photon properties in color
superconductors is given.


title: Configuration-Space-Faddeev Born Approximations

abstract:
  Alternative definitions of the Born approximation and the distorted-wave Born
approximation within the framework of the configuration-space Faddeev equations
are explored. The most natural definition does not correspond to the Born
approximation derived from the Schroedinger equation, even though the exact
T-matrices for both formalisms are equivalent. The Schroedinger form is
optimal, although it is shown that the differences are numerically unimportant.
The DWBA corresponding to the Faddeev equations is not channel symmetric,
although numerically this is unimportant for the p-d (Coulomb) case.
Convergence of the Born approximation partial-wave series is briefly
investigated for p-d and n-d scattering below breakup threshold.


title:
Goldstone Bosons in the 3P2 Superfluid Phase of Neutron Matter and
  Neutrino Emission

abstract:
  At the high densities present in the interior of neutron stars, the neutrons
are condensed into the 3P2 superfluid phase. While this condensation has little
impact on the equation of state, it can have an important role in determining
the low-temperature energy-momentum transport properties. The spontaneous
breaking of baryon number by the condensate gives rise to the familiar
Goldstone boson, but in addition, the spontaneous breaking of rotational
invariance by the condensate gives rise to three Goldstone bosons, in general,
one for each broken generator of rotations. These Goldstone bosons, which
couple to the Z0, provide a new mechanism for neutrino emission. Using a
low-energy effective field theory to describe the dynamics of these Goldstone
bosons we estimate the neutrino emissivity of dense neutron matter and show
that their annihilation is the dominant energy-loss mechanism over a range of
temperatures.


title: Cluster-decay of hot $^{56}$Ni$^*$ formed in $^{32}$S+$^{24}$Mg reaction

abstract:
  The decay of $^{56}Ni^*$, formed in $^{32}S+^{24}Mg$ reaction at the incident
energies $E_{cm}$=51.6 and 60.5 MeV, is calculated as a cluster decay process
within the Preformed Cluster-decay Model (PCM) of Gupta et al. re-formulated
for hot compound systems. The observed deformed shapes of the exit channel
fragments are simulated by introducing the neck-length parameter at the
scission configuration, which nearly coincides the $^{56}Ni$ saddle
configuration. This is the only parameter of the model, which though is also
defined in terms of the binding energy of the hot compound system and the
ground-state binding energies of the various emitted fragments. The calculated
s-wave cross sections for nuclear shapes with outgoing fragments separated
within nuclear proximity limit (here $\sim$0.3 fm) can be compared with the
experimental data, and the TKEs are found to be in reasonably good agreement
with experiments for the angular momentum effects added in the sticking limit
for the moment of inertia. Also, some light particle production (other than the
statistical evaporation residue, not treated here) is predicted at these
energies and, interestingly, $^4He$, which belongs to evaporation residue, is
found missing as a dynamical cluster-decay fragment.


title: Structure of positive energy states in a deformed mean-field potential

abstract:
  We investigate the properties of single-particle resonances in a
non-spherical potential by solving the coupled-channels equations for the
radial wave functions. We first generalize the box discretization method for
positive energy states to a deformed system. As in the spherical case, we find
that the discretized energy is stabilized against the box size when a resonance
condition is met. Using the wave functions thus obtained, we then discuss the
energy and the radial dependences of scattering wave functions in the vicinity
of an isolated resonance. In the eigenchannel basis, where the $S$-matrix is
diagonal, we propose a generalized expression for the factorization formula for
the multi-channel wave function. We find that the factorized wave function
agrees well with the exact solution inside the centrifugal barrier when the
energy distance from the resonance is less than the resonance width.


title:
Model-independent low momentum nucleon interaction from phase shift
  equivalence

abstract:
  We present detailed results for the model-independent low momentum
nucleon-nucleon interaction V_{low k}. By introducing a cutoff in momentum
space, we separate the Hilbert space into a low momentum and a high momentum
part. The renormalization group is used to construct the effective interaction
V_{low k} in the low momentum space, starting from various high precision
potential models commonly used in nuclear many-body calculations. With a cutoff
in the range of $\Lambda ~ 2.1 fm^{-1}$, the new potential V_{low k} is
independent of the input model, and reproduces the experimental phase shift
data for corresponding laboratory energies below $E_{lab} ~ 350 MeV$, as well
as the deuteron binding energy with similar accuracy as the realistic input
potentials. The model independence of V_{low k} demonstrates that the physics
of nucleons interacting at low momenta does not depend on details of the high
momentum dynamics assumed in conventional potential models. V_{low k} does not
have momentum components larger than the cutoff, and as a consequence is
considerably softer than the high precision potentials. Therefore, when V_{low
k} is used as microscopic input in the many-body problem, the high momentum
effects in the particle-particle channel do not have to be addressed by
performing a Brueckner ladder resummation or short-range correlation methods.
By varying the cutoff, we study how the model independence of V_{low k} is
reached in different partial waves. This provides numerical evidence for the
separation of scales in the nuclear problem, and physical insight into the
nature of the low momentum interaction.


title:
Isospin effects on two-nucleon correlation functions in heavy-ion
  collisions at intermediate energies

abstract:
  Using an isospin-dependent transport model, we study isospin effects on
two-nucleon correlation functions in heavy-ion collisions induced by
neutron-rich nuclei at intermediate energies. We find that these correlation
functions are sensitive to the density dependence of nuclear symmetry energy,
but not to the incompressibility of symmetric nuclear matter and the medium
dependence of nucleon-nucleon cross sections. This sensitivity is mainly due to
effects of nuclear symmetry energy on the emission times of neutrons and
protons as well as their relative emission sequence. We also study the
variations of the symmetry energy effects on nucleon-nucleon correlations with
respect to the impact parameter, incident energy, and mass number of heavy ion
collisions.


title: Nuclear Supersymmetry: New Tests and Extensions

abstract:
  Extensions of nuclear supersymmetry are discussed, together with a proposal
for new, more stringent and precise tests that probe the susy classification
and specific two-particle correlations among supersymmetric partners. The
combination of these theoretical and experimental studies may play a unifying
role in nuclear phenomena.


title: Isospin fractionation and isoscaling in dynamical nuclear collisions

abstract:
  Isoscaling is found to hold for fragment yields in the antisymmetrized
molecular dynamics (AMD) simulations for collisions of calcium isotopes at 35
MeV/nucleon. This suggests the applicability of statistical considerations to
the dynamical fragment emission. The observed linear relationship between the
isoscaling parameters and the isospin asymmetry of fragments supports the above
suggestion. The slope of this linear function yields information about the
symmetry energy in low density region where multifragmentation occurs.


title: Models for photo- and electro-production of K^+ in view of new data

abstract:
  Predictions of isobaric and Regge models are compared with the latest
experimental data (Bonn,JLab) to select among the models those providing a
satisfactory description of the data. Only the Saclay-Lyon and MAID models are
in a reasonable agreement with both photo- and electro-production data ranging
up to about 2.5 GeV.


title: Weak Interactions in Atoms and Nuclei: The Standard Model and Beyond

abstract:
  Studies in nuclear and atomic physics have played an important role in
developing our understanding of the Standard Model of electroweak interactions.
We review the basic ingredients of the Standard Model, and discuss some key
nuclear and atomic physics experiments used in testing these ideas. We also
summarize the conceptual issues of the Standard Model that motivate the search
for new physics.


title:
Light scalar mesons in $J / psi ->$NN$meson meson$ decays in a chiral
  unitary approach

abstract:
  We study the four-body decays $J/\psi\to N {\bar N}$ {\it meson meson} using
a chiral unitary approach to account for the meson meson final state
interaction (FSI). The calculation of the $J/\psi\to N \bar N \pi^+ \pi^-$
process properly reproduces the experimental data after taking the FSI of
mesons and the contribution of intermediate $\rho$ meson into account. The
isoscalar resonances $\sigma$, $f_0(980)$ and the isovector resonance
$a_0(980)$ are generated through the FSI of the mesons in the channels
$J/\psi\to N \bar N \pi^0 \pi^0$ and $J/\psi\to N \bar N \pi^0 \eta$,
respectively. We also calculate the two mesons invariant mass distribution and
the partial decay width of $J/\psi\to N \bar N K^+ K^-$ and $J/\psi\to N \bar N
K^0 {\bar K}^0$, on which there is still no experimental data available.


title: Analytically solvable potentials for $\gamma$-unstable nuclei

abstract:
  An analytical solution of the collective Bohr equation with a Coulomb-like
and a Kratzer-like $\gamma-$unstable potential in quadrupole deformation space
is presented. Eigenvalues and eigenfunctions are given in closed form and
transition rates are calculated for the two cases. The corresponding
SO(2,1)$\times$SO(5) algebraic structure is discussed.


title:
Model-independent effects of Delta excitation in nucleon
  polarizabilities

abstract:
  Model-independent effects of $\Delta$(1232) excitation on nucleon
polarizabilities are computed in a Lorentz-invariant fashion. We find a large
effect of relative order $(M_\Delta - M)/M$ in some of the spin
polarizabilities, with the backward spin polarizability receiving the largest
contribution. Similar subleading effects are found to be important in the
fourth-order spin-independent polarizabilities $\alpha_{E\nu}$, $\al_{E2}$,
$\be_{M\nu}$, and $\be_{M 2}$. Combining our results with those for the
model-independent effects of pion loops we obtain predictions for spin and
fourth-order polarizabilities which compare favorably with the results of a
recent dispersion-relation analysis of data.


title:
Total Reaction Cross Section in an Isospin-Dependent Quantum Molecular
  Dynamics (IDQMD) Model

abstract:
  The isospin-dependent quantum molecular dynamics (IDQMD) model is used to
study the total reaction cross section $\sigma_R$. The energy-dependent Pauli
volumes of neutrons and protons have been discussed and introduced into the
IDQMD calculation to replace the widely used energy-independent Pauli volumes.
The modified IDQMD calculation can reproduce the experimental $\sigma_R$ well
for both stable and exotic nuclei induced reactions. Comparisons of the
calculated $\sigma_R$ induced by $^{11}Li$ with different initial density
distributions have been performed. It is shown that the calculation by using
the experimentally deduced density distribution with a long tail can fit the
experimental excitation function better than that by using the
Skyrme-Hartree-Fock calculated density without long tails. It is also found
that $\sigma_R$ at high energy is sensitive to the long tail of density
distribution.


title:
The calculation of total reaction cross sections induced by intermediate
  energy $\alpha$-particles with BUU Model

abstract:
  The Boltzmann-Uehling-Uhlenbeck (BUU) Model, which includes the Fermi motion,
the mean field, individual nucleon-nucleon (N-N) interactions and the Pauli
blocking effect etc., is used to calculate the total reaction cross section
$\sigma_R$ induced by $\alpha$-particles on different targets in the incident
energy range from 17.4 to 48.1 MeV/u. The calculation result can reproduce the
experimental data well. The nucleus-nucleus interaction radius parameter $r_0$
was extracted from experimental $\sigma_R$. It is found that $r_0$ becomes
constant with increasing the mass number of target.


title: Inhomogeneous Shadowing Effects on J/\psi Production in dA Collisions

abstract:
  We study the effect of spatially homogeneous and inhomogeneous shadowing on
$J/\psi$ production in deuterium-nucleus collisions. We discuss how the
shadowing and its spatial dependence may be measured by comparing central and
peripheral $dA$ collisions. These event classes may be selected by using gray
protons from heavy ion breakup and events where the proton or neutron in the
deuterium does not interact. We find that inhomogenous shadowing has a
significant effect on central $dA$ collisions, larger than is observed in
central $AA$ collisions. The inhomogeneity may be measured by comparing the
rapidity dependence of $J/\psi$ production in central and peripheral
collisions. Results are presented for $d$Au collisions at $\sqrt{s_{NN}} = 200$
GeV and $d$Pb collisions at $\sqrt{s_{NN}} = 6.2$ TeV.


title:
The chemical equilibration volume: measuring the degree of
  thermalization

abstract:
  We address the issue of the degree of equilibrium achieved in a high energy
heavy-ion collision. Specifically, we explore the consequences of incomplete
strangeness chemical equilibrium. This is achieved over a volume V of the order
of the strangeness correlation length and is assumed to be smaller than the
freeze-out volume. Probability distributions of strange hadrons emanating from
the system are computed for varying sizes of V and simple experimental
observables based on these are proposed. Measurements of such observables may
be used to estimate V and as a result the degree of strangeness chemical
equilibration achieved. This sets a lower bound on the degree of kinetic
equilibrium. We also point out that a determination of two-body correlations or
second moments of the distributions are not sufficient for this estimation.


title:
Comparative Analysis of the Mechanisms of Fast Light Particle Formation
  in Nucleus-Nucleus Collisions at Low and Intermediate Energies

abstract:
  The dynamics and the mechanisms of preequilibrium-light-particle formation in
nucleus-nucleus collisions at low and intermediate energies are studied on the
basis of a classical four-body model. The angular and energy distributions of
light particles from such processes are calculated. It is found that, at
energies below 50 MeV per nucleon, the hardest section of the energy spectrum
is formed owing to the acceleration of light particles from the target by the
mean field of the projectile nucleus. Good agreement with available
experimental data is obtained.


title: Meson and baryon elliptic flow at high pT from parton coalescence

abstract:
  The large and saturating differential elliptic flow v2(pT) observed in Au+Au
reactions at RHIC so far could only be explained assuming an order of magnitude
denser initial parton system than estimated from perturbative QCD.
Hadronization via parton coalescence can resolve this ``opacity puzzle''
because it enhances hadron elliptic flow at large pT relative to that of
partons at the same transverse momentum. An experimentally testable consequence
of the coalescence scenario is that v2(pT) saturates at about 50% higher values
for baryons than for mesons. In addition, if strange quarks have weaker flow
than light quarks, hadron v2 at high pT decreases with relative strangeness
content.


title:
Nuclear liquid-gas phase transition studied with antisymmetrized
  molecular dynamics

abstract:
  The nuclear liquid-gas phase transition of the system in ideal thermal
equilibrium is studied with antisymmetrized molecular dynamics. The time
evolution of a many-nucleon system confined in a container is solved for a long
time to get a microcanonical ensemble of a given energy and volume. The
temperature and the pressure are extracted from this ensemble and the caloric
curves are constructed. The present work is the first time that a microscopic
dynamical model which describes nuclear multifragmentation reactions well is
directly applied to get the nuclear caloric curve. The obtained constant
pressure caloric curves clearly show the characteristic feature of the
liquid-gas phase transition, namely negative heat capacity (backbending), which
is expected for the phase transition in finite systems.


title:
Remarkable long-range-systematic in the binding energies of alpha-nuclei
  II

abstract:
  In this letter I present further data that show the remarkable evidence for
the existence of an alpha-cluster stucture in the ground states of even-even
N=Z nuclei. Such a remarkable systematic was observed 20 years ago for these
nuclei at A<= 72 and is extended here up to A=100.


title: Flow Equations for Hamiltonians from Continuous Unitary Transformations

abstract:
  This thesis presents an overview of the flow equations recently introduced by
Wegner. The little known mathematical framework of the flow in the manifold of
unitarily equivalent matrices, as discovered in the mathematical literature
before Wegner's paper, is established in the initial chapter and used as a
background for the entire presentation. The application of flow equations to
the Foldy-Wouthuysen transformation and to the elimination of the
electron-phonon coupling in a solid is reviewed. Recent flow equations
approaches to the Lipkin model are examined thoroughly, paying special
attention to their utility near the phase change boundary. We present more
robust schemes by requiring that expectation values be flow dependent; either
through a variational or self-consistent calculation. The similarity
renormalization group equations recently developed by Glazek and Wilson are
also reviewed. Their relationship to Wegner's flow equations is investigated
through the aid of an instructive model.


title: Spin-dependent effective interactions for halo nuclei

abstract:
  We discuss the spin-dependence of the effective two-body interactions
appropriate for three-body computations. The only reasonable choice seems to be
the fine and hyperfine interactions known for atomic electrons interacting with
the nucleus. One exception is the nucleon-nucleon interaction imposing a
different type of symmetry. We use the two-neutron halo nucleus 11Li as
illustration. We demonstrate that models with the wrong spin-dependence are
basically without predictive power. The Pauli forbidden core and valence states
must be consistently treated.


title: Study of $^{44}$Ti in a Mixed--Symmetry Basis

abstract:
  The structure of $^{44}$Ti is studied in an oblique-basis that includes
spherical and SU(3) shell-model basis states. The results show that the
oblique-basis concept is applicable, even though the strong spin-orbit
interaction, which breaks the SU(3) symmetry, generates significant splitting
of the single-particle levels. Specifically, a model space that includes a few
SU(3) irreducible representations (irreps), namely, the leading (12,0) and next
to the leading (10,1) irreps -- including spin S=0 and 1 configurations of the
latter, plus spherical shell-model configurations (SSMC) that have at least two
valence nucleons confined to the $f_{7/2}$ orbit -- the SM(2) case, yield
results that are comparable to SSMC with at least one valence nucleon confined
to the $f_{7/2}$ orbit -- the SM(3) case.


title: Double Charge Exchange And Configuration Mixing

abstract:
  The energy dependence of forward pion double charge exchange reactions on
light nuclei is studied for both the Ground State transition and the
Double-Isobaric-Analog-State transitions. A common characteristic of these
double reactions is a resonance-like peak around 50 MeV pion lab energy. This
peak arises naturally in a two-step process in the conventional pion-nucleon
system with proper handling of nuclear structure and pion distortion. A
comparison among the results of different nuclear structure models demonstrates
the effects of configuration mixing. The angular distribution is used to fix
the single particle wave function.


title:
Influence of a momentum dependent interaction on the isospin dependence
  of fragmentation and dissipation in intermediate energy heavy ion collisions

abstract:
  We studied the influence of a momentum dependent interaction in the context
of isopspin effects on fragmentation and dissipation in intermediate energy
heavy ion collisions by using an isospin dependent quantum molecular dynamics
model. It is shown that the nuclear stopping, the number of nucleons emitted
,and the multiplicity of intermediate mass fragments are larger with a momentum
dependent interaction than without. In particular, the differences for these
observables, when using an isospin dependent in-medium nucleon nucleon cross
section versus an isospin independent one, are also larger at high energies for
a momentum dependent interaction than without one. Therefore,momentum
dependence enhances the sensitivities of those observables to the isospin
effect of the in-medium nucleon nucleon cross section towards high beam
energies


title: Quantum states of indefinite spins: From baryons to massive gravitino

abstract:
  I review theory and phenomenology of
  (K/2,K/2)*[(1/2,0)+(0,1/2)] states.
  First I make the case that the observed nucleon and Delta (1232) excitations
(up to Delta(1600)) are exhausted by unconstrained (K/2,K/2)*[(1/2,0)+(0,1/2)]
states with K=1,3, and 5, which originate from rotational and vibrational
excitations of an underlying quark--diquark configuration.
  Second, I consider the simplest case of K=1 and show that the
  \gamma^\mu\psi_\mu =0 constraint of the Rarita-Schwinger framework is a
short-hand of:
  - 1/3 (1/m^2 W^2 +3/4)\psi_\mu = \psi_\mu, the covariant definition of the
unique invariant subspace of the squared Pauli-Lubanski vector, W^2, that is a
parity singlet and of highest spin-3/2 at rest.
  I suggest to work in the 16 dimensional vector spinor space
  \Psi= A *\psi rather than keeping Lorentz and spinor indices separated and
show that the above second order equation guarantees the covariant description
of a has-been spin-3/2 states at rest without invoking further supplementary
conditions.
  In gauging the latter equation minimally and, in calculating the determinant,
one obtains a pathology-free energy-momentum dispersion relation, thus avoiding
the classical Velo-Zwanziger problem of imaginary energies in the presence of
an external electromagnetic field.


title: Scalar susceptibility and chiral symmetry restoration in nuclei

abstract:
  We study the nuclear modification of the scalar QCD susceptibility,
calculated as the derivative of the quark condensate with respect to the quark
mass. We show that it has two origins. One is the low lying nuclear
excitations. At normal nuclear density this part is constrained by the nuclear
incompressibility. The other part arises from the individual nucleon response
and it is dominated by the pion cloud contribution. Numerically the first
contribution dominates. The resulting increase in magnitude of the scalar
susceptibility at normal density is such that it becomes close to the
pseudoscalar susceptibility, while it is quite different in the vacuum. We
interpret it as a consequence of chiral symmetry restoration in nuclei.


title:
Simple solutions of relativistic hydrodynamics for longitudinally and
  cylindrically expanding systems

abstract:
  Simple, self-similar, analytic solutions of 1 + 1 dimensional relativistic
hydrodynamics are presented, generalizing the Hwa - Bjorken boost-invariant
solution to inhomogeneous rapidity distributions. These solutions are
generalized also to 1 + 3 dimensional, cylindrically symmetric firetubes,
corresponding to central collisions of heavy ions at relativistic bombarding
energies.


title: Low-momentum Pion Enhancement Induced by Chiral Symmetry Restoration

abstract:
  The thermal and nonthermal pion production by sigma decay and its relation
with chiral symmetry restoration in a hot and dense matter are investigated.
The nonthermal decay into pions of sigma mesons which are popularly produced in
chiral symmetric phase leads to a low-momentum pion enhancement as a possible
signature of chiral phase transition at finite temperature and density.


title:
Ground-state properties of closed-shell nuclei with low-momentum
  realistic interactions

abstract:
  Ground-state properties of 16O and 40Ca are calculated with a low-momentum
nucleon-nucleon potential, V-low-k, derived from the chiral N3LO interaction
recently constructed by Entem and Machleidt. The smooth V-low-k is used
directly in a Hartree-Fock approach, avoiding the difficulties of the
Brueckner-Hartree-Fock procedure. Corrections up to third order in the
Goldstone expansion are evaluated, leading to results that are in very good
agreement with experiment. Convergence properties of the expansion are
examined.


title: The Ter-Mikayelian Effect on QCD Radiative Energy Loss

abstract:
  The color dielectric modification of the gluon dispersion relation in a dense
QCD medium suppresses both the soft and collinear gluon radiation associated
with jet production. We compute both the longitudinal and transverse plasmon
contributions to the zeroth order in opacity radiative energy loss. This QCD
analog of the Ter-Mikayelian effect in QED leads to $\sim 30%$ reduction of the
energy loss of high transverse momentum charm quarks produced in a QCD plasma
with a characteristic Debye mass $\mu\sim 0.5$ GeV.


title: Some applications of renormalized RPA in bosonic field theories

abstract:
  We present some applications of the renormalized RPA in bosonic field
theories. We first present some developments for the explicit calculation of
the total energy in Phi^4 theory and discuss its phase structure in 1+1
dimensions. We also demonstrate that the Goldstone theorem is satisfied in the
O(N) model within the renormalized RPA.