title: Long-wavelength spin- and spin-isospin correlations in nucleon matter

abstract:
  We analyse the long-wavelength response of a normal Fermi liquid using Landau
theory. We consider contributions from intermediate states containing one
additional quasiparticle-quasihole pair as well as those from states containing
two or more additional quasiparticle-quasihole pairs. For the response of an
operator corresponding to a conserved quantity, we show that the behavior of
matrix elements to states with more than one additional quasiparticle-quasihole
pair at low excitation energies $\omega$ varies as $1/\omega$. It is shown how
rates of processes involving transitions to two quasiparticle-quasihole states
may be calculated in terms of the collision integral in the Landau transport
equation for quasiparticles.


title: Multi-level and two-level models of the decay out of superdeformed bands

abstract:
  We compare a multi-level statistical model with a two-level model for the
decay out of superdeformed rotational bands in atomic nuclei. We conclude that
while the models depend on different dimensionless combinations of the input
parameters and differ in certain limits, they essentially agree in the cases
where experimental data is currently available. The implications of this
conclusion are discussed.


title: Hadron attenuation at HERMES and JLab

abstract:
  We investigate the attenuation of hadrons in deep inelastic lepton-nucleus
scattering in the kinematical regime of the HERMES and Jefferson Lab
experiments. The calculation is carried out in the framework of a BUU transport
model. Our results indicate a strong influence of (pre)hadronic final state
interactions on the observed multiplicity ratios.


title:
In-Medium properties of the omega meson in photon induced nuclear
  reactions

abstract:
  We discuss the possibility to study the in-medium changes of the properties
of the omega meson in reactions on ordinary nuclei with elementary
electromagnetic probes. We present a tree-level calculation of the elementary
gamma p -> omega p process which is extended to describe also the
photoproduction of medium-modified omega mesons in nuclear matter. Using a
semi-classical transport approach we obtain results for e+e- and pi0 gamma
photoproduction off heavy nuclei in the invariant mass range of the rho and
omega mesons. Both reactions are also studied experimentally and are presently
being analyzed at accelerator facilities in Bonn and at Jefferson Lab. We show
that the in-medium signals expected can be as large as those obtained in
heavy-ion reactions.


title:
On isospin-breaking corrections to the energy level displacement of the
  ground state of kaonic hydrogen

abstract:
  In the model of low-energy bar-K N interactions near threshold (EPJA 21, 11
(2004); 25, 79 (2005)) we calculate isospin-breaking corrections to the energy
level displacement of the ground state of kaonic hydrogen, investigated by
Meissner, Raha and Rusetsky (EPJC 35, 349 (2004)) within the non-relativistic
effective Lagrangian approach based on ChPT by Gasser and Leutwyler. Our
results agree well with those by Mei\ss ner et al.. In addition we calculate
the dispersive corrections, caused by the transition K^-p -> bar-K^0n ->K^-p
with the bar-K^0n pair on-mass shell. We show also how hypothesis on the
dominant role of the bar-K^0n-cusp for the S-wave amplitude of low-energy K^-p
scattering near threshold, used by Meissner et al., can be realized in our
approach. The result agrees fully with that by Meissner et al..


title:
Low-energy pions in nuclear matter and pi pi photoproduction within a
  BUU transport model

abstract:
  In the present paper we investigate a method to describe low-energy
scattering events of pions and nuclei within a Boltzmann-Uehling-Uhlenbeck
(BUU) transport model. Implementing different scenarios of medium
modifications, we studied the mean free path of pions in nuclear matter at low
momenta and compared pion absorption simulations to data. Pursuing these
studies we have shown, that also in a regime of a long pionic wave length the
semi-classical BUU model still generates reasonable results. We present results
on pi-induced events in the regime of 10 MeV < Tkin < 130 MeV and photo-induced
pi pi production at incident beam energies of 400-460 MeV.


title:
Hyperfine anomaly in Be isotopes in the cluster model and the neutron
  spatial distribution

abstract:
  The study of the hyperfine anomaly of neutron rich nuclei, in particular,
neutron halo nuclei, can give a very specific and unique way to measure their
neutron distribution and confirm a halo structure. The hyperfine structure
anomaly in Be+ ions is calculated with a realistic electronic wave function,
obtained as a solution of the Dirac equation. In the calculations, the Coulomb
potential modified by the charge distribution of the clustered nucleus and
three electrons in the 1s^2 2s configuration is used. The nuclear wave function
is obtained in the core+nucleon model of 9,11Be. The aim of this study is to
test whether the hyperfine structure anomaly reflects a halo structure in 11Be.


title: "Naked" Cronin effect in A+A collisions from SPS to RHIC

abstract:
  Baseline computations of the Cronin effect in nuclear collisions at energies
spanning the SPS and the RHIC accelerators are performed in the Glauber-Eikonal
model, which ascribes the effect to initial-state incoherent multiple parton
scatterings. The model accounts very well for the mid-rapidity Cronin effect in
hadron-nucleus collisions in the 27-200 GeV center of mass energy range, and
will be extended to nucleus-nucleus collisions. The computations are performed
under the assumption that the partons do not interact with the medium produced
in the collision. Therefore, medium effects such as energy loss in a
Quark-Gluon Plasma may be detected and measured as deviations from the
presented baseline computation of the "naked" Cronin effect.


title: Possibility to study a two-proton halo in $^{17}$Ne

abstract:
  The nuclide $^{17}$Ne is studied theoretically in a three-body
$^{15}$O+$p$+$p$ model. We demonstrate that the experimental condition for
existence of a proton halo in $^{17}$Ne can be reasonably quantified in terms
of $s/d$ configuration mixing. We discuss experimental evidences for a proton
halo in $^{17}$Ne. We define which kind of experimental data could elucidate
this issue.


title: Three-body resonant radiative capture reactions in astrophysics

abstract:
  We develop the formalism based on the S-matrix for $3 \to 3$ scattering to
derive the direct three-body resonant radiative capture reaction rate. Within
this formalism the states, which decay only/predominantly directly into
three-body continuum, should also be included in the capture rate calculations.
%The results obtained indicate that some theoretical calculations are
%incomplete. Basing on the derivation, as well as on the modern experimental
data and theoretical calculations concerning $^{17}$Ne nucleus, we
significantly update the reaction rate for $^{15}$O($2p$,$\gamma$)$^{17}$Ne
process in explosive environment. We also discuss possible implementations for
the $^{18}$Ne($2p$,$\gamma$)$^{20}$Mg, $^{38}$Ca($2p$,$\gamma$)$^{40}$Ti, and
$^4$He($n\alpha$,$\gamma$)$^{9}$Be reactions.


title:
The nuclear scissors mode within two approaches (Wigner function moments
  versus RPA)

abstract:
  Two complementary methods to describe the collective motion, RPA and Wigner
function moments method, are compared on an example of a simple model -
harmonic oscillator with quadrupole-quadrupole residual interaction. It is
shown that they give identical formulae for eigenfrequencies and transition
probabilities of all collective excitations of the model including the scissors
mode, which here is the subject of our special attention. The exact relation
between the variables of the two methods and the respective dynamical equations
is established. The normalization factor of the "synthetic" scissors state and
its overlap with physical states are calculated analytically. The orthogonality
of the spurious state to all physical states is proved rigorously.


title: Three-neutron resonance trajectories for realistic interaction models

abstract:
  Three-neutron resonances are investigated using realistic nucleon-nucleon
interaction models. The resonance pole trajectories are explored by first
adding an additional interaction to artificially bind the three-neutron system
and then gradually removing it. The pole positions for the three-neutron states
up to J=5/2 are localized in the third energy quadrant-Im (E)<=0, Re
(E)<=0-well before the additional interaction is removed. Our study shows that
realistic nucleon-nucleon interaction models exclude any possible experimental
signature of three-neutron resonances.


title: Nuclear masses set bounds on quantum chaos

abstract:
  It has been suggested that chaotic motion inside the nucleus may
significantly limit the accuracy with which nuclear masses can be calculated.
Using a power spectrum analysis we show that the inclusion of additional
physical contributions in mass calculations, through many-body interactions or
local information, removes the chaotic signal in the discrepancies between
calculated and measured masses. Furthermore, a systematic application of global
mass formulas and of a set of relationships among neighboring nuclei to more
than 2000 nuclear masses allows to set an unambiguous upper bound for the
average errors in calculated masses which turn out to be almost an order of
magnitude smaller than estimated chaotic components.


title: Naive Dimensional Analysis for Three-Body Forces Without Pions

abstract:
  For systems of three identical particles in which short-range forces produce
shallow two-particle bound states, and in particular for the ``pion-less''
Effective Field Theory of Nuclear Physics, I extend and systematise the
power-counting of three-body forces to all partial-waves and orders, including
external currents. With low-energy observables independent of the details of
short-distance dynamics, the typical strength of a three-body force is
determined from the superficial degree of divergence of the three-body diagrams
which contain only two-body forces. This na\"ive dimensional analysis must be
amended as the asymptotic solution to the leading-order Faddeev equation
depends for large off-shell momenta crucially on the partial wave and
spin-combination of the system. It is shown by analytic construction to be
weaker in most channels with angular momentum smaller than 3 than expected.
This demotes many three-nucleon forces to high orders. Observables like the
quartet-S-scattering length are less sensitive to three-nucleon forces than
guessed. I also comment on the Efimov effect and limit-cycle for non-zero
angular momentum.

categories: nucl-th cond-mat.other hep-ph physics.atm-clus


title: Nuclear pasta structures in neutron stars and the charge screening

abstract:
  Non-uniform structures of the nucleon matter are expected at subnuclear
densities and above the nuclear density: they are called nuclear pastas and
kaon pastas, respectively. We numerically study these phases by means of the
density functional theory with relativistic mean-fields and the electric field;
the electric field is properly taken into account. Our results demonstrate a
particular role of the charge screening effects on these non-uniform
structures.


title:
Description of the two-nucleon system on the basis of the Bargmann
  representation of the S matrix

abstract:
  For the effective-range function $k\cot \delta $, a pole approximation that
involves a small number of parameters is derived on the basis of the Bargmann
representation of the $S$ matrix. The parameters of this representation, which
have a clear physical meaning, are related to the parameters of the Bargmann
$S$ matrix by simple equations. By using a polynomial least-squares fit to the
function $k\cot \delta $ at low energies, the triplet low-energy parameters of
neutron-proton scattering are obtained for the latest experimental data of
Arndt et al. on phase shifts. The results are $a_{t}=5.4030 $fm, $r_{t}=1.7494
$fm, and $v_{2}=0.163 $fm$^{3}$. With allowance for the values found for the
low-energy scattering parameters and for the pole parameter, the pole
approximation of the function $k\cot \delta $ provides an excellent description
of the triplet phase shift for neutron-proton scattering over a wide energy
range ($T_{\text{lab}}\lesssim 1000 $MeV), substantially improving the
description at low energies as well. For the experimental phase shifts of Arndt
et al., the triplet shape parameters $v_{n}$ of the effective-range expansion
are obtained by using the pole approximation. The description of the phase
shift by means of the effective-range expansion featuring values found for the
low-energy scattering parameters proves to be fairly accurate over a broad
energy region extending to energy values approximately equal to the energy at
which this phase shift changes sign, this being indicative of a high accuracy
and a considerable value of the effective-range expansion in describing
experimental data on nucleon-nucleon scattering. The properties of the deuteron
that were calculated by using various approximations of the effective-range
function comply well with their experimental values.


title: Trajectory analysis for fusion path in superheavy-mass region

abstract:
  We propose an effective method for the precise investigation of the
fusion-fission mechanism in the superheavy-mass region, using the
fluctuation-dissipation model. The trajectory calculation with friction is
performed in the nuclear deformation space using the Langevin equation. In the
reaction $^{48}$Ca+$^{244}$Pu, the trajectories are classified into the
fusion-fission process, the quasi-fission process and the deep quasi-fission
process. By analyzing the time evolution of each trajectory, the mechanism of
each process is clearly revealed, i.e., it is explained why a trajectory takes
a characteristic path in this model. We discuss, in particular, the condition
under which the fusion path is followed, which is crucial in the discussion of
the possibility of synthesizing superheavy elements.


title: Quantum Statistical Effects on Fusion Dynamics of Heavy-Ions

abstract:
  In order to describe the fusion of two very heavy nuclei at near barrier
energies, a generalized Langevin approach is proposed, which incorporates the
quantum statistical fluctuations in accordance with the fluctuation and
dissipation theorem. It is illustrated that the quantum statistical effects
introduce an enhancement of the formation of compound nucleus, though the
quantum enhancement is somewhat less pronounced as indicated in the previous
calculations.


title:
Deformed Woods-Saxon Potential in the Frame of Supersymmetric Quantum
  Mechanics for Any l-State

abstract:
  A novel analytically solvable deformed Woods-Saxon potential is investigated
by means of the Supersymmetric Quantum Mechanics. Hamiltonian hierarchy method
and the shape invariance property are used in the calculations. The energy
levels are obtained for any l-state. The interrelations for some nuclear
scattering processes are also discussed


title:
On the Interpretation of the Processes 3He(e,e'p)2H and 3He(e,e'p)(pn)
  at High Missing Momenta

abstract:
  It is shown that the effects of the Final State Interaction (FSI) in the
exclusive processes 3He(e,e'p)2H and 3He(e,e'p)(pn), can be successfully
treated in terms of a Generalized Eikonal Approximation (GEA), based upon the
direct calculation of the Feynman diagrams describing the rescattering of the
struck nucleon. As a matter of fact, using realistic three-body wave functions
corresponding to the AV18 interaction, the results of our parameter free
calculation exhibits a very satisfactory agreement with recent experimental
data from Jlab covering the region of missing momentum and energy with p_m <
1.0 GeV/c and E_m < 100 MeV. It is demonstrated that the missing momentum
dependence of the experimental cross section of the process 3He(e,e'p)2H is
mainly governed at p_m < 0.2 GeV/c by the Plane Wave Impulse Approximation
(PWIA), at 0.2 < p_m < 0.6 GeV/c by the single rescattering FSI, and at 0.6
GeV/c < p_m by the double rescattering FSI.


title: Baryons on the lattice

abstract:
  I comment on progress of lattice QCD techniques and calculations. Recent
results on pentaquark masses as well as of the spectrum of excited baryons are
summarizned and interpreted. The present state of calculations of quantities
related to the nucleon structure and of electromagnetic transition form factors
is surveyed.


title: Information entropy and nucleon correlations in nuclei

abstract:
  The information entropies in coordinate and momentum spaces and their sum
($S_r$, $S_k$, $S$) are evaluated for many nuclei using "experimental"
densities or/and momentum distributions. The results are compared with the
harmonic oscillator model and with the short-range correlated distributions. It
is found that $S_r$ depends strongly on $\ln A$ and does not depend very much
on the model. The behaviour of $S_k$ is opposite. The various cases we consider
can be classified according to either the quantity of the experimental data we
use or by the values of $S$, i.e., the increase of the quality of the density
and of the momentum distributions leads to an increase of the values of $S$. In
all cases, apart from the linear relation $S=a+b\ln A$, the linear relation
$S=a_V+b_V \ln V$ also holds. V is the mean volume of the nucleus. If $S$ is
considered as an ensemble entropy, a relation between $A$ or $V$ and the
ensemble volume can be found. Finally, comparing different electron scattering
experiments for the same nucleus, it is found that the larger the momentum
transfer ranges, the larger the information entropy is. It is concluded that
$S$ could be used to compare different experiments for the same nucleus and to
choose the most reliable one.


title:
Electromagnetic structure of A=2 and 3 nuclei and the nuclear current
  operator

abstract:
  Different models for conserved two- and three-body electromagnetic currents
are constructed from two- and three-nucleon interactions, using either
meson-exchange mechanisms or minimal substitution in the momentum dependence of
these interactions. The connection between these two different schemes is
elucidated. A number of low-energy electronuclear observables, including (i)
$np$ radiative capture at thermal neutron energies and deuteron
photodisintegration at low energies, (ii) $nd$ and $pd$ radiative capture
reactions, and (iii) isoscalar and isovector magnetic form factors of $^3$H and
$^3$He, are calculated in order to make a comparative study of these models for
the current operator. The realistic Argonne $v_{18}$ two-nucleon and Urbana IX
or Tucson-Melbourne three-nucleon interactions are taken as a case study. For
$A$=3 processes, the bound and continuum wave functions, both below and above
deuteron breakup threshold, are obtained with the correlated
hyperspherical-harmonics method. Three-body currents give small but significant
contributions to some of the polarization observables in the
$^2$H($p,\gamma$)$^3$He process and the $^2$H($n,\gamma$)$^3$H cross section at
thermal neutron energies. It is shown that the use of a current which did not
exactly satisfy current conservation with the two- and three-nucleon
interactions in the Hamiltonian was responsible for some of the discrepancies
reported in previous studies between the experimental and theoretical
polarization observables in $pd$ radiative capture.


title: Finite temperature effects in antiferromagnetism of nuclear matter

abstract:
  The influence of the finite temperature on the antiferromagnetic (AFM) spin
ordering in symmetric nuclear matter with the effective Gogny interaction is
studied within the framework of a Fermi liquid formalism. It is shown that the
AFM spin polarization parameter of partially polarized nuclear matter for low
enough temperatures increases with temperature. The entropy of the AFM spin
state for some temperature range is larger than the entropy of the normal
state. Nerveless, the free energy of the AFM spin state is always less than the
free energy of the normal state and, hence, the AFM spin polarized state is
preferable for all temperatures below the critical temperature.


title: Space- and time-like electromagnetic form factors of the nucleon

abstract:
  Recent experimental data on space- and time-like form factors of the nucleon
are analyzed in terms of a two-component model with a quark-like intrinsics
structure and a meson cloud. A good overall agreement is found for all
electromagnetic form factors with the exception of the neutron magnetic form
factor in the time-like region.


title: Inhomogeneous freeze-out in heavy-ion collisions

abstract:
  Relative hadron abundances from high-energy heavy-ion collisions reveal
substantial inhomogeneities of temperature and baryon-chemical potential within
the decoupling volume. The freeze-out volume is not perfectly "stirred", i.e.
the concentrations of pions, kaons, (anti-) nucleons etc are inhomogeneous.
Such inhomogeneities in the late stages of the hydrodynamic expansion might be
traces of a first-order phase transition.


title:
Isospin-violating nucleon-nucleon forces using the method of unitary
  transformation

abstract:
  Recently, we have derived the leading and subleading isospin-breaking
three-nucleon forces using the method of unitary transformation. In the present
work we extend this analysis and consider the corresponding two-nucleon forces
using the same approach. Certain contributions to the isospin-violating one-
and two-pion-exchange potential have already been discussed by various groups
within the effective field theory framework. Our findings agree with the
previously obtained results. In addition, we present the expressions for the
subleading charge-symmetry-breaking two-pion exchange potential which were not
considered before. These corrections turn out to be numerically important.
Together with the three-nucleon force results presented in our previous work,
the results of the present study specify completely isospin-violating nuclear
forces up to the order $q^5/\Lambda^5$, where $q$ ($\Lambda$) denotes the soft
(hard) scale.


title: Dynamical baryon resonances from chiral unitarity

abstract:
  We report on the latests developments in the field of baryonic resonances
generated from the meson-baryon interaction in coupled channels using a chiral
unitary approach. The collection of resonances found in different strangeness
and isospin sectors can be classified into SU(3) multiplets. The Lambda(1405)
emerges as containing the effect of two poles of the scattering amplitude and
various reactions that might preferentially select one or the other pole are
discussed.


title: In-matter three-body problem

abstract:
  We formulate three-dimensional equations for the finite temperature in-matter
three-body problem. Our approach takes into account the full infinite series
for the effective pair-interaction kernel, so that all possible two-body
sub-processes allowed by the underlying Hamiltonian are retained.


title:
Sum Rule Approach to the Isoscalar Giant Monopole Resonance in Drip Line
  Nuclei

abstract:
  Using the density-dependent Hartree-Fock approximation and Skyrme forces
together with the scaling method and constrained Hartree-Fock calculations, we
obtain the average energies of the isoscalar giant monopole resonance. The
calculations are done along several isotopic chains from the proton to the
neutron drip lines. It is found that while approaching the neutron drip line,
the scaled and the constrained energies decrease and the resonance width
increases. Similar but smaller effects arise near the proton drip line,
although only for the lighter isotopic chains. A qualitatively good agreement
is found between our sum rule description and the presently existing random
phase approximation results. The ability of the semiclassical approximations of
the Thomas-Fermi type, which properly describe the average energy of the
isoscalar giant monopole resonance for stable nuclei, to predict average
properties for nuclei near the drip lines is also analyzed. We show that when
hbar corrections are included, the semiclassical estimates reproduce, on
average, the quantal excitation energies of the giant monopole resonance for
nuclei with extreme isospin values.


title: Charm elliptic flow at RHIC

abstract:
  Charm elliptic flow in heavy ion collisions at the Relativistic Heavy Ion
Collider (RHIC) is studied in a multiphase transport model. Assuming that the
cross section for charm quark scattering with other light quarks is the same as
that between light quarks, we find that both charm and light quark elliptic
flows are sensitive to the value of the cross section. Compared to that of
light quarks, the elliptic flow of charm quarks is smaller at low transverse
momentum but approaches comparable values at high transverse momentum. Similar
features are seen in the elliptic flow of charmed mesons as well as that of the
electrons from their semileptonic decays when the charmed mesons are produced
from quark coalescence during hadronization of the partonic matter. To describe
the large electron elliptic flow observed in available experimental data
requires a charm quark scattering cross section that is much larger than that
given by the perturbative QCD.


title:
The Cranked Nilsson-Strutinsky versus the Spherical Shell Model: A
  Comparative Study of pf-Shell Nuclei

abstract:
  A comparative study is performed of a deformed mean field theory, represented
by the cranked Nilsson-Strutinsky (CNS) model, and the spherical shell model.
Energy spectra, occupation numbers, B(E2)-values, and spectroscopic quadrupole
moments in the light pf shell nuclei are calculated in the two models and
compared. The result is also compared to available experimental data which are
generally well described by the shell model. Although the Nilsson-Strutinsky
calculation does not include pairing, both the subshell occupation numbers and
quadrupole properties are found to be rather similar in the two models. It is
also shown that ``unpaired'' shell model calculations produce very similar
energies as the CNS at all spins. The role of the pairing energy in the
description of backbending and signature splitting in odd-mass nuclei is also
discussed.


title:
Mean-Field Effects on Collective Flows in High-Energy Heavy-Ion
  Collisions at 2-158A GeV energies

abstract:
  Collective flows in heavy-ion collisions from AGS ($(2-11)A$ GeV) to SPS
($(40,158)A$ GeV) energies are investigated in a nonequilibrium transport model
with nuclear mean-field (MF). Sideward $<p_x>$, directed $v_1$, and elliptic
flows $v_2$ are systematically studied with different assumptions on the
nuclear equation of state (EOS). We find that momentum dependence in the
nuclear MF is important for the understanding of the proton collective flows at
AGS and SPS energies. Calculated results with momentum dependent MF
qualitatively reproduce the experimental data of proton sideward, directed, and
elliptic flows in a incident energy range of $(2-158)A$ GeV.


title: Isospin dependence of 6He+p optical potential and the symmetry energy

abstract:
  A consistent folding analysis of the elastic p(6He,6He)p scattering and
charge exchange p(6He,6Li*)n reaction data measured at Elab=41.6A MeV has been
performed within the coupled channels formalism. We have used the isovector
coupling to link the isospin dependence of 6He+p optical potential to the cross
section of p(6He,6Li*)n reaction exciting the 0+ isobaric analog state (IAS) at
3.563 MeV in 6Li. Based on these results and the Hartree-Fock calculation of
asymmetric nuclear matter using the same isospin-dependent effective
nucleon-nucleon interaction, we were able to confirm that the most realistic
value of the symmetry energy Esym is around 31 MeV. Our analysis has also shown
that the measured charge exchange p(6He,6Li*)n data are quite sensitive to the
halo tail of the 6He density used in the folding calculation and the IAS of 6Li
is likely to have a halo structure similar to that established for the ground
state of 6He.


title: Properties of quark matter produced in heavy ion collision

abstract:
  We describe the hadronization of quark matter assuming that quarks creating
hadrons coalesce from a continuous mass distribution. The pion and antiproton
spectrum as well as the momentum dependence of the antiproton to pion ratio are
calculated. This model reproduces fairly well the experimental data at RHIC
energies.


title: Spin-dependent neutrino-induced nucleon knockout

abstract:
  We study neutrino-induced nucleon knockout off atomic nuclei and examine the
polarization properties of the ejectile. A detailed study of the spin
dependence of the outgoing nucleon is presented. The numerical results are
derived within a non-relativistic plane-wave impulse-approximation approach.
Our calculations reveal large polarization asymmetries, and clear
dissimilarities between neutrino- and antineutrino-induced reactions. They
reflect the fact that neutrino-induced nucleon knockout is dominated by the
transverse axial current and gains its major contributions from forward nucleon
emission and backward lepton scattering.


title: Alternate Derivation of Ginocchio-Haxton relation [(2j+3)/6]

abstract:
  We address the problem, previously considered by Ginocchio and Haxton (G-H),
of the number of states for three identical particles in a single j-shell with
angular momentum J=j. G-H solved this problem in the context of the quantum
Hall effect. We address it in a more direct way. We also consider the case
J=j+1 to show that our method is more general, and we show how to take care of
added complications for a system of five identical particles.


title:
Coordinate Space HFB Calculations for the Zirconium Isotope Chain up to
  the Two-Neutron Dripline

abstract:
  We solve the Hartree-Fock-Bogoliubov (HFB) equations for deformed, axially
symmetric even-even nuclei in coordinate space on a 2-D lattice utilizing the
Basis-Spline expansion method. Results are presented for the neutron-rich
zirconium isotopes up to the two-neutron dripline. In particular, we calculate
binding energies, two-neutron separation energies, normal densities and pairing
densities, mean square radii, quadrupole moments, and pairing gaps. Very large
prolate quadrupole deformations (beta2=0.42,0.43,0.47) are found for the
(102,104,112)Zr isotopes, in agreement with recent experimental data. We
compare 2-D Basis-Spline lattice results with the results from a 2-D HFB code
which uses a transformed harmonic oscillator basis.


title: Effective Nucleon Masses in Symmetric and Asymmetric Nuclear Matter

abstract:
  The momentum and isospin dependence of the in-medium nucleon mass are
studied. Two definitions of the effective mass, i.e. the Dirac mass $m^*_D$ and
the nonrelativistic mass $m^*_{NR}$ which parameterizes the energy spectrum,
are compared. Both masses are determined from relativistic
Dirac-Brueckner-Hartree-Fock calculations. The nonrelativistic mass shows a
distinct peak around the Fermi momentum. The proton-neutron mass splitting in
isospin asymmetric matter is $m^*_{D,n} <m^*_{D,p}$ and opposite for the
nonrelativistic mass, i.e. $m^*_{NR,n} >m^*_{NR,p}$, which is consistent with
nonrelativistic approaches.


title: Probing Matter Radii of Neutron-Rich Nuclei by Antiproton Scattering

abstract:
  We propose to use antiprotons to investigate the sizes of stable and
neutron-rich exotic nuclei by measurements of the $\pbar A$ absorption cross
section along isotopic chains in inverse kinematics. The expected effects are
studied theoretically in a microscopic model. The $\pbar U$ optical potentials
are obtained by folding free space $\pbar N$ scattering amplitudes with HFB
ground state densities and solving the scattering equations by direct
integration. The mass dependence of absorption cross sections is found to
follow closely the nuclear root-mean-square radii. The total absorption cross
section is shown to be a superposition of cross sections describing partial
absorption on neutrons and protons, respectively. Thus measuring the
differential cross sections for absorption on neutrons and protons will give
information on their respective distributions. In neutron-rich nuclei the outer
neutron layer shields the absorption on the protons giving access to
investigations of antiproton-neutron interactions in matter.


title: Dilepton production at SIS energies

abstract:
  In this short review the results of detailed studies for dilepton production
from $p+A$ and $A+A$ reactions at SIS energies are presented. The calculations
are based on a semi-classical BUU transport model that includes the off-shell
propagation of vector mesons and evaluates the width of the vector mesons
dynamically. Different scenarios of in-medium modifications of vector mesons,
such as collisional broadening and dropping vector meson masses, are
investigated and the possibilities for an experimental observation of in-medium
effects in $p+A$ reactions at 1--4 GeV are discussed for a variety of nuclear
targets.


title: Constrained Molecular Dynamics II: a N-body approach to nuclear systems

abstract:
  In this work we illustrate the basic development of the constrained molecular
dynamics applied to the N-body problem in nuclear physics. The heavy
computational taskes related to quantum effects, to the presence of the "hard
core" repulsive interaction have been worked out by defining a set of
transformations based on the concept of impulsive forces. In particular in the
implemented version II of the Constrained Molecular Dynamics model the problem
related to the non conservation of the total angular momentum has been solved.
This problem can affect others semiclassical microscopic approaches as due to
the "hard core" repulsive interaction or to the use of stochastic forces. The
effect of the restored conservation law on the fusion cross section for
40Ca+40Ca system is also briefly discussed.


title:
A Shell Model Description of the Decay Out of the Super-Deformed Band of
  36Ar

abstract:
  Large scale shell model calculations in two major oscillator shells (sd and
pf) describe simultaneously the super-deformed excited band of 36Ar and its
low-lying states of dominant sd character. In addition, several two particle
two hole states and a side band of negative parity are also well reproduced. We
explain the appearance of the super-deformed band at such low excitation energy
as a consequence of the very large correlation energy of the configurations
with many particles and many holes (np-nh) relative to the normal filling of
the spherical mean field orbits (0p-0h). We study the mechanism of mixing
between these different configurations, to understand why the super-deformed
band survives and how it finally decays into the low-lying sd-dominated states
via the indirect mixing of the 0p-0h and 4p-4h configurations.


title: Multifragmentation, Clustering, and Coalescence in Nuclear Collisions

abstract:
  Nuclear collisions at intermediate, relativistic, and ultra-relativistic
energies offer unique opportunities to study in detail manifold fragmentation
and clustering phenomena in dense nuclear matter. At intermediate energies, the
well known processes of nuclear multifragmentation -- the disintegration of
bulk nuclear matter in clusters of a wide range of sizes and masses -- allow
the study of the critical point of the equation of state of nuclear matter. At
very high energies, ultra-relativistic heavy-ion collisions offer a glimpse at
the substructure of hadronic matter by crossing the phase boundary to the
quark-gluon plasma. The hadronization of the quark-gluon plasma created in the
fireball of a ultra-relativistic heavy-ion collision can be considered, again,
as a clustering process. We will present two models which allow the simulation
of nuclear multifragmentation and the hadronization via the formation of
clusters in an interacting gas of quarks, and will discuss the importance of
clustering to our understanding of hadronization in ultra-relativistic
heavy-ion collisions.


title: Microscopic models for exotic nuclei

abstract:
  Starting from successful self-consistent mean-field models, this paper
discusses why and how to go beyond the mean field approximation. To include
long-range correlations from fluctuations in collective degrees of freedom, one
has to consider symmetry restoration and configuration mixing, which give
access to ground-state correlations and spectroscopy.


title:
Target mass number dependence of subthreshold antiproton production in
  proton-, deuteron- and alpha-particle-induced reactions

abstract:
  Data from KEK on subthreshold $\bar{\mrm{p}}$ as well as on $\pi^\pm$ and
$\mrm{K}^\pm$ production in proton-, deuteron- and $\alpha$-induced reactions
at energies between 2.0 and 12.0 A GeV for C, Cu and Pb targets are described
within a unified approach. We use a model which considers a nuclear reaction as
an incoherent sum over collisions of varying numbers of projectile and target
nucleons. It samples complete events and thus allows for the simultaneous
consideration of all final particles including the decay products of the
nuclear residues. The enormous enhancement of the $\bar{\mrm{p}}$ cross
section, as well as the moderate increase of meson production in deuteron and
$\alpha$ induced compared to proton-induced reactions, is well reproduced for
all target nuclei. In our approach, the observed enhancement near the
production threshold is mainly due to the contributions from the interactions
of few-nucleon clusters by simultaneously considering fragmentation processes
of the nuclear residues. The ability of the model to reproduce the target mass
dependence may be considered as a further proof of the validity of the cluster
concept.


title:
Asymptotic normalization coefficients for mirror virtual nucleon decays
  in a microscopic cluster model

abstract:
  It has been suggested recently (Phys. Rev. Lett. 91, 232501 (2003)) that
charge symmetry of nucleon-nucleon interactions relates the Asymptotic
Normalization Coefficients (ANCs) of proton and neutron virtual decays of
mirror nuclei. This relation is given by a simple analytical formula which
involves proton and neutron separation energies, charges of residual nuclei and
the range of their strong interaction with the last nucleon. Relation between
mirror ANCs, if understood properly, can be used to predict astrophysically
relevant direct proton capture cross sections using neutron ANCs measured with
stable beams. In this work, we calculate one-nucleon ANCs for several light
mirror pairs, using microscopic two-, three- and four-cluster models, and
compare the ratio of mirror ANCs to the predictions of the simple analytic
formula. We also investigate mirror symmetry between other characteristics of
mirror one-nucleon overlap integrals, namely, spectroscopic factors and
single-particle ANCs.


title:
Unified approach to photo and electro-production of mesons with
  arbitrary spins

abstract:
  A new approach to identify the independent amplitudes along with their
partial wave multipole expansions, for photo and electro-production is
suggested,which is generally applicable to mesons with arbitrary spin-parity.
These amplitudes facilitate direct identification of different resonance
contributions.


title:
Coulomb distortion of relativistic electrons in the nuclear
  electrostatic field

abstract:
  Continuum states of the Dirac equation are calculated numerically for the
electrostatic field generated by the charge distribution of an atomic nucleus.
The behavior of the wave functions of an incoming electron with a given
asymptotic momentum in the nuclear region is discussed in detail and the
results are compared to different approximations used in the data analysis for
quasielastic electron scattering off medium and highly charged nuclei. It is
found that most of the approximations provide an accurate description of the
electron wave functions in the range of electron energies above 100 MeV
typically used in experiments for quasielastic electron scattering off nuclei
only near the center of the nucleus. It is therefore necessary that the
properties of exact wave functions are investigated in detail in order to
obtain reliable results in the data analysis of quasielastic (e,e'p) knockout
reactions or inclusive quasielastic (e,e') scattering. Detailed arguments are
given that the effective momentum approximation with a fitted potential
parameter is a viable method for a simplified treatment of Coulomb corrections
for certain kinematical regions used in experiments. Numerical calculations
performed within the framework of the single particle shell model for nucleons
lead to the conclusion that our results are incompatible with calculations
performed about a decade ago, where exact electron wave functions were used in
order to calculate Coulomb corrections in distorted wave Born approximation. A
discussion of the exact solutions of the Dirac equation for free electrons in a
Coulomb field generated by a point-like charge and some details relevant for
the numerical calculations are given in the appendix.


title: Phase structure of a two-fluid bosonic system

abstract:
  The phase diagram of a two-fluid bosonic system is investigated. The
proton-neutron interacting boson model (IBM-2) possesses a rich phase structure
involving three control parameters and multiple order parameters. The surfaces
of quantum phase transition between spherical, axially-symmetric deformed, and
SU*(3) triaxial phases are determined, and the evolution of classical
equilibrium properties across these transitions is investigated. Spectroscopic
observables are considered in relation to the phase diagram.


title:
Pairing Matrix Elements and Pairing Gaps with Bare, Effective and
  Induced Interactions

abstract:
  The dependence on the single-particle states of the pairing matrix elements
of the Gogny force and of the bare low-momentum nucleon-nucleon potential
$v_{low-k}$ is studied in the semiclassical approximation for the case of a
typical finite, superfluid nucleus ($^{120}$Sn). It is found that the matrix
elements of $v_{low-k}$ follow closely those of $v_{Gogny}$ on a wide range of
energy values around the Fermi energy $e_F$, those associated with $v_{low-k}$
being less attractive. This result explains the fact that around $e_F$ the
pairing gap $\Delta_{Gogny}$ associated with the Gogny interaction (and with a
density of single-particle levels corresponding to an effective $k$-mass
$m_k\approx 0.7 m$) is a factor of about 2 larger than $\Delta_{low-k}$,being
in agreement with $\Delta_{exp}$= 1.4 MeV. The exchange of low-lying collective
surface vibrations among pairs of nucleons moving in time-reversal states gives
rise to an induced pairing interaction $v_{ind}$ peaked at $e_F$. The
interaction $(v_{low-k}+ v_{ind})Z_{\omega}$ arising from the renormalization
of the bare nucleon-nucleon potential and of the single-particle motion
($\omega-$mass and quasiparticle strength $Z_{\omega}$) due to the
particle-vibration coupling leads to a value of the pairing gap at the Fermi
energy $\Delta_{ren}$ which accounts for the experimental value.


title:
Attractive and repulsive contributions of medium fluctuations to nuclear
  superfluidity

abstract:
  Oscillations of mainly surface character (S=0 modes) give rise, in atomic
nuclei, to an attractive (induced) pairing interaction, while spin (S=1) modes
of mainly volume character generate a repulsive interaction, the net effect
being an attraction which accounts for a sizeable fraction of the experimental
pairing gap. Suppressing the particle-vibration coupling mediated by the proton
degrees of freedom, i.e., mimicking neutron matter, the total surface plus
spin-induced pairing interaction becomes repulsive.


title: Properties of mesons and nucleons in chiral topological models of QCD

abstract:
  The problem under consideration in this thesis has, actually, two aspects.
The first one concerns the case when a nucleon is in free space that is in
vacuum, while the second one studies a nucleon embedded into a nuclear
environment. Both of these two aspects have been considered in the framework of
chiral topological models of QCD. The whole content of the thesis may be
divided into two main parts. In the first part the original Skyrme model with
finite pion mass has been extended by inclusion of the light scalar - isoscalar
sigma - meson. The Lagrangian has been further extended by explicit inclusion
of sigma, rho and omega - mesons as well. In order to get a more complete
picture of NN potential the appropriate meson - nucleon vertex form - factors
are obtained. The second part of the thesis considers a nucleon immersed into a
nuclear medium. For this purpose a medium modified Skyrme Lagrangian has been
proposed. The Lagrangian describes well such well known medium effects as
decreasing of nucleon mass and increasing of its size (swelling). We studied
also a system with finite temperature also. The temperature effects are taken
into account by using the method of termofield dynamics (TFD). The
corresponding critical temperatures for each meson - nucleon system are
calculated .


title:
Kaon Condensation and Lambda-Nucleon Loop in the Relativistic Mean-Field
  Approach

abstract:
  The possibility of kaon condensation in high-density symmetric nuclear matter
is investigated including both s- and p-wave kaon-baryon interactions within
the relativistic mean-field (RMF) theory. Above a certain density, we have a
collective ${\bar K}_s$ state carrying the same quantum numbers as the
antikaon. The appearance of the ${\bar K}_s$ state is caused by the time
component of the axial-vector interaction between kaons and baryons. It is
shown that the system becomes unstable with respect to condensation of
$K$-${\bar K}_s$ pairs. We consider how the effective baryon masses affect the
kaon self-energy coming from the time component of the axial-vector
interaction. Also, the role of the spatial component of the axial-vector
interaction on the possible existence of the collective kaonic states is
discussed in connection with $\Lambda$-mixing effects in the ground state of
high-density matter. Implications of $K{\bar K}_s$ condensation for high-energy
heavy-ion collisions are briefly mentioned.


title: Universality in few-body systems with large scattering length

abstract:
  Effective Field Theory (EFT) provides a powerful framework that exploits a
separation of scales in physical systems to perform systematically improvable,
model-independent calculations. Particularly interesting are few-body systems
with short-range interactions and large two-body scattering length. Such
systems display remarkable universal features. In systems with more than two
particles, a three-body force with limit cycle behavior is required for
consistent renormalization already at leading order. We will review this EFT
and some of its applications in the physics of cold atoms and nuclear physics.
In particular, we will discuss the possibility of an infrared limit cycle in
QCD. Recent extensions of the EFT approach to the four-body system and N-boson
droplets in two spatial dimensions will also be addressed.


title: On Parametric Resonance in Quantum Many-Body System

abstract:
  The dynamics governed by a requantized collective Hamiltonian in the coupled
Lipkin model is investigated in the time-dependent variational approach with
squeezed state. It is pointed out that there is a possibility of the parametric
resonance mechanism which leads to amplifying the amplitude of quantum
fluctuation around the collective mode in this model.


title:
The role of the pion pair term in the theory of the weak axial meson
  exchange currents

abstract:
  The structure of the weak axial pion exchange current is discussed in various
models. It is shown how the interplay of the chiral invariance and the double
counting problem restricts uniquely the form of the pion potential term, in the
case when the nuclear dynamics is described by the Schroedinger equation with
the static nucleon-nucleon potential.


title: Bounds on the presence of quantum chaos in nuclear masses

abstract:
  Differences between measured nuclear masses and those calculated using the
Finite Range Droplet Model are analyzed. It is shown that they have a well
defined, clearly correlated oscillatory component as a function of the proton
and neutron numbers. At the same time, they exhibit in their power spectrum the
presence of chaos. Comparison with other mass calculations strongly suggest
that this chaotic component arises from many body effects not included in the
mass formula, and that they do not impose limits in the precision of mass
calculations.


title: Three-body problem at finite temperature and density

abstract:
  We derive practical three-body equations for the equal-time three-body Green
function in matter. Our equations describe both bosons and fermions at finite
density and temperature, and take into account all possible two-body
sub-processes allowed by the underlying Hamiltonian.


title: Ground States Rotational Band in Deformed e-e Nuclei

abstract:
  In the frame work of the hydrodynamical model, a new model of the ground
state rotational bands of deformed e-e nuclei is developed by introducing the
variable moment of inertia, and the effect of beta- and gamma- vibrational
bands. The model is applied to calculate the energies of the ground state band
of 158Dy. The results of our calculations are in close agreement with data
compared with other existing models.


title:
Isospin mixing and Fermi transitions: Selfconsistent deformed mean field
  calculations and beyond

abstract:
  We study Fermi transitions and isospin mixing in an isotopic chain 70-78 Kr
considering various approximations that use the same Skyrme-Hartree-Fock single
particle basis. We study Coulomb effects as well as the effect of BCS and
quasiparticle random phase approximation (QRPA) correlations. A measure of
isospin mixing in the approximate ground state is defined by means of the
expectation value of the isospin operator squared in N=Z nuclei (which is
generalized to N different from Z nuclei). Starting from strict Hartree-Fock
approach without Coulomb, it is shown that the isospin breaking is negligible,
on the order of a few per thousand for (N-Z)=6, increasing to a few percent
with Coulomb. Pairing correlations induce rather large isospin mixing and Fermi
transitions of the forbidden type (beta- for N<Z, and beta+ for N>Z). The
enhancement produced by BCS correlations is compensated to a large extent by
QRPA correlations induced by isospin conserving residual interactions that tend
to restore isospin symmetry.


title: Formal and Physical R-matrix parameters

abstract:
  Notes from 11 October 2004 lecture presented at the Joint Institute for
Nuclear Astrophysics R-Matrix School at Notre Dame University.


title:
Nucleon electromagnetic form factors and polarization observables in
  space-like and time-like regions

abstract:
  We perform a global analysis of the experimental data of the electromagnetic
nucleon form factors, in space-like and time-like regions. We give the
expressions of the observables in annihilation processes, such as $p+\bar{p}\to
\ell^+ +\ell^- $, $\ell=e$ or $\mu$, in terms of form factors. We discuss some
of the phenomenological models proposed in the literature for the space-like
region, and consider their analytical continuation to the time-like region.
After determining the parameters through a fit on the available data, we give
predictions for the observables which will be experimentally accessible with
large statistics, polarized annihilation reactions.


title:
The sigma - nucleon form factor in a chiral topological model with
  anomalous dimension

abstract:
  The chiral soliton model including pi, rho, omega mesons is extended for the
case when the scalar - isoscalar sigma meson has an anomalous dimension - d.
The form factor of the sigma - nucleon interaction calculated and to be found
not highly sensitive to the value of d.


title: Thermal Recombination: Beyond the Valence Quark Approximation

abstract:
  Quark counting rules derived from recombination models agree well with data
on hadron production at intermediate transverse momenta in relativistic
heavy-ion collisions. They convey a simple picture of hadrons consisting only
of valence quarks. We discuss the inclusion of higher Fock states that add sea
quarks and gluons to the hadron structure. We show that, when recombination
occurs from a thermal medium, hadron spectra remain unaffected by the inclusion
of higher Fock states. However, the quark number scaling for elliptic flow is
somewhat affected. We discuss the implications for our understanding of data
from the Relativistic Heavy Ion Collider.


title: Hadron Masses in Medium and Neutron Star Properties

abstract:
  We investigate the properties of the neutron star with relativistic mean
field models. We incorporate in the quantum hadrodynamics and in the
quark-meson coupling models a possible reduction of meson masses in nuclear
matter. The equation of state for neutron star matter is obtained and is
employed in Oppenheimer-Volkov equation to extract the maximum mass of the
stable neutron star. We find that the equation of state, the composition and
the properties of the neutron stars are sensitive to the values of the meson
masses in medium.


title:
Kinetic energy spectra for fragments and break-up density in
  multifragmentation

abstract:
  We investigate the possibility, in nuclear fragmentation, to extract
information on nuclear density at break-up from fragment kinetic energy spectra
using a simultaneous scenario for fragment emission. The conclusions we derive
are different from the recently published results of Viola et al. [Phys. Rev.
Lett. 93, (2004), 132701] assuming a sequential fragment emission and claiming
that the experimentally observed decrease of peak centroids for kinetic energy
spectra of fragments with increasing bombarding energy is due to a monotonic
decrease of the break-up density.


title:
An alternative understanding of mass formulas in terms of nuclear
  structure

abstract:
  A typical form of mass formula is re-explained in terms of nuclear structure.
  For $ N \approx Z $ nuclei, we propose to start with the shell model picture
and to consider the T=0 $2n-2p$ ($\alpha$-like) correlations as the fundamental
concept, instead of the symmetry energy.
  Subsequently, the symmetry energy is described on the basis of the
$\alpha$-like superfluidity caused by the T=0 $2n-2p$ correlations, in parallel
with the pairing energy described on the basis of the pairing superfluidity.
This re-explanation gives useful insight for understanding the nuclear mass
formula. The origin of the Wigner energy is also explained in an interacting
boson model for the Cooper pairs in the $\alpha$-like superfluid vacuum. Adding
a correction term due to the T=0 $2n-2p$ correlations, which determines the T=0
base level for nuclear masses, can improve the mass formulas in practice.


title:
Folding model analysis of proton radioactivity of spherical proton
  emitters

abstract:
  Half lives of the decays of spherical nuclei away from proton drip line by
proton emissions are estimated theoretically. The quantum mechanical tunneling
probability is calculated within the WKB approximation. Microscopic
proton-nucleus interaction potentials are obtained by single folding the
densities of the daughter nuclei with M3Y effective interaction supplemented by
a zero-range pseudo-potential for exchange along with the density dependence.
Strengths of the M3Y interaction are extracted by fitting its matrix elements
in an oscillator basis to those elements of the G-matrix obtained with the
Reid-Elliott soft-core nucleon-nucleon interaction. Parameters of the density
dependence are obtained from the nuclear matter calculations. Spherical charge
distributions are used for calculating the Coulomb interaction potentials.
These calculations provide reasonable estimates for the observed proton
radioactivity lifetimes of proton rich nuclei for proton emissions from 26
ground and isomeric states of spherical proton emitters.


title: Screening of nuclear pairing in nuclear and neutron matter

abstract:
  The screening potential in the $^1S_0$ and $^3S_1$ pairing channels in
neutron and nuclear matter in different approximations is discussed. It is
found that the vertex corrections to the potential are much stronger in nuclear
matter than in neutron matter.


title:
Obtaining the Specific Heat of Hadronic Matter from CERN/RHIC
  Experiments

abstract:
  The specific heat of hot hadronic matter is related to particle production
yields from experiments done at CERN/RHIC. The mass fluctuation of excited
hadrons plays an important role. Connections of the specific heat, mean
hadronic mass excited and its fluctuation with properties of baryon and
electric chemical potentials (value, slope and curvature) are also developed. A
possible divergence of the specific heat as 1/(To-T)^2 is discussed. Some
connections with net charge fluctuations are noted.


title: Classification of States in O(8) Proton-Neutron Pairing Model

abstract:
  Isoscalar (T=0) plus isovector (T=1) pairing hamiltonian in LS-coupling,
which is important for heavy N=Z nuclei, is solvable in terms of a O(8) algebra
for some special values of the mixing parameter that measures the competition
between T=0 and T=1 pairing. The O(8) algebra is generated, amongst others, by
the $S=1,T=0$ and $S=0,T=1$ pair creation and annihilation operators . Shell
model algebras, with only number conserving operators, that are complementary
to the $O(8) \supset O_{ST}(6) \supset O_S(3) \otimes O_T(3)$, $O(8) \supset [
O_S(5) \supset O_S(3) ] \otimes O_T(3)$ and $O(8) \supset [ O_T(5) \supset
O_T(3)] \otimes O_S(3)$ sub-algebras are identified. The problem of
classification of states for a given number of nucleons (called `plethysm'
problem in group theory), for these group chains is solved explicitly for
states with O(8) seniority $v=0, 1, 2, 3$ and 4. Using them, band structures in
isospin space are identified for states with $v=0, 1, 2$ and 3.


title: From Nuclear To Sub-Hadronic Physics : A Global View Of Indian Efforts

abstract:
  A panoramic view seeks to trace the principal ideas governing the phenomenal
growth of Nuclear Physics from a modest beginning in the Thirties, to an
all-embracing field now protruding to the subhadronic on the one hand, and to
high temperature QGP physics on the other. In this narrative, which makes no
claims to completeness, Indian efforts have been highlighted vis-a-vis other
similar efforts, within a common standard of global recognition.


title:
Momentum-space treatment of Coulomb interaction in three-nucleon
  reactions with two protons

abstract:
  The Coulomb interaction between the two protons is included in the
calculation of proton-deuteron elastic scattering, radiative proton-deuteron
capture and two-body electromagnetic disintegration of ${}^3\mathrm{He}$. The
hadron dynamics is based on the purely nucleonic charge-dependent (CD) Bonn
potential and its realistic extension CD Bonn + $\Delta$ to a coupled-channel
two-baryon potential, allowing for single virtual $\Delta$-isobar excitation.
Calculations are done using integral equations in momentum space. The screening
and renormalization approach is employed for including the Coulomb interaction.
Convergence of the procedure is found already at moderate screening radii. The
reliability of the method is demonstrated. The Coulomb effect on observables is
seen at low energies for the whole kinematic regime. In proton-deuteron elastic
scattering at higher energies the Coulomb effect is confined to forward
scattering angles; the $\Delta$-isobar effect found previously remains
unchanged by Coulomb. In electromagnetic reactions Coulomb competes with other
effects in a complicated way.


title: K-Lambda and K-Sigma photoproduction in a coupled channels framework

abstract:
  A coupled channels analysis, based on the K-matrix approach, is presented for
photo-induced kaon production. It is shown that channel coupling effects are
large and should not be ignored. The importance of contact terms in the
analysis, associated with short range correlations, is pointed out. The
extracted parameters are compared with SU(3)-model predictions.


title:
Evaluation of the $\pi\pi$ scattering amplitude in the $\sigma$-channel
  at finite density

abstract:
  The $\pi\pi$ scattering amplitude in the $\sigma$-channel is studied at
finite baryonic density in the framework of a chiral unitary approach which
successfully reproduces the meson meson phase shifts and generates the $f_0$
and $\sigma$ resonances in vacuum. We address here a new variety of mechanisms
recently suggested to modify the $\pi\pi$ interaction in the medium, as well as
the role of the $s-$wave selfenergy, in addition to the $p-$wave, in the
dressing of the pion propagators.


title:
Benchmark calculation for proton-deuteron elastic scattering observables
  including Coulomb

abstract:
  Two independent calculations of proton-deuteron elastic scattering
observables including Coulomb repulsion between the two protons are compared in
the proton lab energy region between 3 MeV and 65 MeV. The hadron dynamics is
based on the purely nucleonic charge-dependent AV18 potential. Calculations are
done both in coordinate space and momentum space. The coordinate-space
calculations are based on a variational solution of the three-body
Schr\"odinger equation using a correlated hyperspherical expansion for the wave
function. The momentum-space calculations proceed via the solution of the
Alt-Grassberger-Sandhas equation using the screened Coulomb potential and the
renormalization approach. Both methods agree within 1% on all observables,
showing the reliability of both numerical techniques in that energy domain. At
energies below three-body breakup threshold the coordinate-space method remains
favored whereas at energies higher than 65 MeV the momentum-space approach
seems to be more efficient.


title:
Including beta- and gamma- Vibrations in Evaluating the Ground State
  Rotational Band of Deformed Even-Even Nuclei

abstract:
  From the semi-empirical formalisms of Bohr-Mottelson, a new model, based on
the effect of beta- and gamma- head energies and the variable moment of
inertia, was developed to calculate the ground state rotational band of almost
all deformed e-e nuclei. The model can be tuned for nuclei with experimentally
available beta- and gamma-vibrational energies as well as for those with
unmeasured beta- and gamma-vibrations.


title: Overdamping Phenomena near the Critical Point in O($N$) Model

abstract:
  We consider the dynamic critical behavior of the propagating mode for the
order parameter fluctuation of the O($N$) Ginzburg-Landau theory, involving the
canonical momentum as a degree of freedom. We reexamine the renormalization
group analysis of the Langevin equation for the propagating mode. We find the
fixed point for the propagating mode as well as that for the diffusive one, the
former of which is unstable to the latter. This indicates that the propagating
mode becomes overdamped near the critical point. We thus can have a sufficient
understanding of the phonon mode in the structural phase transition of solids.
We also discuss the implication for the chiral phase transition.


title: Isospin fluctuations in spinodal decomposition

abstract:
  We study the isospin dynamics in fragment formation within the framework of
an analytical model based on the spinodal decomposition scenario. We calculate
the probability to obtain fragments with given charge and neutron number,
focussing on the derivation of the width of the isotopic distributions. Within
our approach this is determined by the dispersion of N/Z among the leading
unstable modes, due to the competition between Coulomb and symmetry energy
effects, and by isovector-like fluctuations present in the matter that
undergoes the spinodal decomposition. Hence the widths exhibit a clear
dependence on the properties of the Equation of State. By comparing two systems
with different values of the charge asymmetry we find that the isotopic
distributions reproduce an isoscaling relationship.


title: Dihadron fragmentation: in vacuum and in matter

abstract:
  Two particle correlations within a single jet produced in deeply inelastic
scattering (DIS) off a large nucleus as well as in heavy-ion collisions are
explored. This is performed within the framework of the medium modified
dihadron fragmentation functions. The modification occurs due to gluon
bremsstrahlung induced by multiple scattering. The modified fragmentation
functions for dihadrons are found to follow closely that of single hadrons
leading to a weak nuclear suppression of their ratios as measured by HERMES in
DIS experiments. Meanwhile, a moderate medium enhancement of the near-side
correlation of two high $p_T$ hadrons is found in central heavy-ion collisions,
partially due to trigger bias caused by the competition between parton energy
loss and the initial Cronin effect.


title:
Comment on "Constraints on proton structure from precision atomic
  physics measurements"

abstract:
  We strongly disagree with the procedure used in a recent paper to extract the
Zemach moment for hydrogen.


title: Backbending Effect in Deformed e-e Nuclei

abstract:
  An extension of the previously proposed Variable Moment of Inertia with
Softness model VMIS has been applied to describe successfully the effect of
backbending in some deformed e-e nuclei. The model shows good results in the
rare earth and actinide regions.


title: Two-scale scalar mesons in nuclei

abstract:
  We generalize the linear sigma model in order to develop a chiral-invariant
model of nuclear structure. The model is natural, and contains not only the
usual sigma meson which is the chiral partner of the pion but also a new
chiral-singlet that is responsible for the medium-range nucleon-nucleon
attraction. This approach provides significant advantages in terms of its
description of nuclear matter and finite nuclei in comparison with conventional
models based on the linear sigma model.


title: Inclusive Quasi-Elastic Neutrino Reactions

abstract:
  The Quasi-Elastic contribution of the nuclear inclusive electron scattering
model developed in Nucl. Phys. A 627 (1997) 543 is extended to the study of
electroweak Charged Current induced nuclear reactions, at intermediate energies
of interest for future neutrino oscillation experiments. The model accounts for
long range nuclear (RPA) correlations, Final State Interaction and Coulomb
corrections. RPA correlations are shown to play a crucial role in the whole
range of neutrino energies, up to 500 MeV, studied in this work. Predictions
for inclusive muon capture for different nuclei, and for the reactions
$^{12}$C$(\nu_\mu,\mu^-)X$ and $^{12}$C$(\nu_e,e^-)X$ near threshold are also
given.


title: Transfer to the continuum and Breakup reactions

abstract:
  Reaction theory is an essential ingredient when performing studies of nuclei
far from stability. One approach for the calculation of breakup reactions of
exotic nuclei into two fragments is to consider inelastic excitations into the
single particle continuum of the projectile. Alternatively one can also
consider the transfer to the continuum of a system composed of the light
fragment and the target. In this work we make a comparative study of the two
approaches, underline the different inputs, and identify the advantages and
disadvantages of each approach. Our test cases consist of the breakup of
$^{11}$Be on a proton target at intermediate energies, and the breakup of $^8$B
on $^{58}$Ni at energies around the Coulomb barrier. We find that, in practice
the results obtained in both schemes are in semiquantitative agreement. We
suggest a simple condition that can select between the two approaches.


title:
Towards a consistent approach to nuclear structure: EFT of two- and
  many-body forces

abstract:
  We review the nuclear forces currently in use, i.e., the high-precision NN
potentials of the 1990's and the nuclear two- and many-body forces based upon
chiral effective field theory (EFT). We argue that the EFT approach is superior
to any of the older schemes. Since accurate chiral forces are available now,
the stage is set for microscopic nuclear structure to move into a new exciting
era.


title: Particle yield fluctuations and chemical non-equilibrium at RHIC

abstract:
  We study charge fluctuations within the statistical hadronization model.
Considering both the particle yield ratios and the charge fluctuations we show
that it is possible to differentiate between chemical equilibrium and
non-equilibrium freeze-out conditions. As an example of the procedure we show
quantitatively how the relative yield ratio $\Lambda/K^-$ together with the
normalized net charge fluctuation $v(Q)=\ave{\Delta Q^2}/\ave{\Nch}$ constrain
the chemical conditions at freeze-out. We also discuss the influence of the
limited detector acceptance on fluctuation measurements, and show how this can
be accounted for within a quantitative analysis.


title: Nuclear pasta structures and the charge screening effect

abstract:
  Non uniform structures of the nucleon matter at subnuclear densities are
numerically studied by means of the density functional theory with relativistic
mean-fields coupled with the electric field. A particular role of the charge
screening effects is demonstrated.


title:
Effects of jet quenching on the hydrodynamical evolution of quark-gluon
  plasma

abstract:
  We study the effects of jet quenching on the hydrodynamical evolution of the
quark-gluon plasma (QGP) fluid created in a heavy-ion collision. In jet
quenching, a hard QCD parton, before fragmenting into a jet of hadrons,
deposits a fraction of its energy in the medium, leading to suppressed
production of high-pT hadrons. Assuming that the deposited energy quickly
thermalizes, we simulate the subsequent hydrodynamic evolution of the QGP
fluid. For partons moving at supersonic speed, v_p > c_s, and sufficiently
large energy loss, a shock wave forms leading to conical flow [1]. The PHENIX
Collaboration recently suggested that observed structures in the azimuthal
angle distribution [2] might be caused by conical flow. We show here that
conical flow produces different angular structures than predicted in [1] and
that, for phenomenologically acceptable values of parton energy loss, conical
flow effects are too weak to explain the structures seen by PHENIX [2].


title: Study on the One-Proton Halo Structure in $^{23}$Al

abstract:
  The Glauber theory has been used to investigate the reaction cross section of
proton-rich nucleus $^{23}$Al. A core plus a proton structure is assumed for
$^{23}$Al. HO-type density distribution is used for the core while the density
distribution for the valence proton is calculated by solving the eigenvalue
problem of Woods-Saxon potential. The transparency function in an analytical
expression is obtained adopting multi-Gaussian expansion for the density
distribution. Coulomb correction and finite-range interaction are introduced.
This modified Glauber model is apt for halo nuclei. A dominate s-wave is
suggested for the last proton in $^{23}$Al from our analysis which is possible
in the RMF calculation.


title: Semileptonic Decays of Heavy Lambda Baryons in a Quark Model

abstract:
  The semileptonic decays of Lambda_c and Lambda_b are treated in the framework
of a constituent quark model. Both nonrelativistic and semirelativistic
Hamiltonians are used to obtain the baryon wave functions from a fit to the
spectra, and the wave functions are expanded in both the harmonic oscillator
and Sturmian bases. The latter basis leads to form factors in which the
kinematic dependence on q^2 is in the form of multipoles, and the resulting
form factors fall faster as a function of q^2 in the available kinematic
ranges. As a result, decay rates obtained in the two models using the Sturmian
basis are significantly smaller than those obtained using the harmonic
oscillator basis. In the case of the Lambda_c, decay rates calculated using the
Sturmian basis are closer to the experimentally reported rates. However, we
find a semileptonic branching fraction for the Lambda_c to decay to excited
Lambda* states of 11% to 19%, in contradiction with what is assumed in
available experimental analyses. Our prediction for the Lambda_b semileptonic
decays is that decays to the ground state Lambda_c provide a little less than
70% of the total semileptonic decay rate. For the decays Lambda_b to Lambda_c,
the analytic form factors we obtain satisfy the relations expected from
heavy-quark effective theory at the non-recoil point, at leading and
next-to-leading orders in the heavy-quark expansion. In addition, some features
of the heavy-quark limit are shown to naturally persist as the mass of the
heavy quark in the daughter baryon is decreased.


title:
Regularities with random interactions in energy centroids defined by
  group symmetries

abstract:
  Regular structures generated by random interactions in energy centroids
defined over irreducible representations (irreps) of some of the group
symmetries of the interacting boson models $sd$IBM, $sdg$IBM, $sd$IBM-$T$ and
$sd$IBM-$ST$ are studied by deriving trace propagations equations for the
centroids. It is found that, with random interactions, the lowest and highest
group irreps in general carry most of the probability for the corresponding
centroids to be lowest in energy. This generalizes the result known earlier,
via numerical diagonalization, for the more complicated fixed spin ($J$)
centroids where simple trace propagation is not possible.


title:
Thermalization of neutrons at ultracold nanoparticles to the energy
  range of ultracold neutrons

abstract:
  Two hypothesizes concerning interaction of neutrons with nanoparticles and
having applications in the physics of ultracold neutron (UCN) were recently
considered in ref. [Physics of Atomic Nuclei 65(3): 400 (2002)]; they were
motivated by the experimental observation of small changes in energy of UCN
upon their collisions with surface. The first hypothesis explaines the nature
of the observed phenomenon by inelastic coherent scattering of UCN on
nanoparticles weakly attached at surface, in a state of permanent thermal
motion. It got experimental confirmed in ref. [Physics of Atomic Nuclei 65(11):
1996 (2002)]. The second hypothesis inverts the problem of neutron interaction
with nanoparticles in the following sence. In all experiments with UCN, the
trap-wall temperature was much higher than a temperature of about 1 mK, which
corresponds to the UCN energy. Therefore, UCN preferentially increased their
energy. The surface density of weakly attached nanoparticles was low. If,
however, the nanoparticles temperature is lower than the neutron temperature
and if the nanoparticles density is high, the problem of interaction of
neutrons with nanoparticles is inverted. In this case, the neutrons can cool
down, under certain conditions, owing tot heir scattering on
ultracold-heavy-water, deuterium, and oxigen nanoparticles to their temperature
of about 1 mK, with result that the UCN density increases by many orders of
magnitude. In the present article we repeat the argumentation given in the
first mentioned article and formulate in a very general way the research
program in order to verify validity of this hypothesis. Both the theoretical
and the experimental investigation of the problem are going to intensify in the
near future.


title: New inversion methods for the Lorentz Integral Transform

abstract:
  The Lorentz Integral Transform approach allows microscopic calculations of
electromagnetic reaction cross sections without explicit knowledge of final
state wave functions. The necessary inversion of the transform has to be
treated with great care, since it constitutes a so-called ill-posed problem. In
this work new inversion techniques for the Lorentz Integral Transform are
introduced. It is shown that they all contain a regularization scheme, which is
necessary to overcome the ill-posed problem. In addition it is illustrated that
the new techniques have a much broader range of application than the present
standard inversion method of the Lorentz Integral Transform.


title:
$J/\psi$ Gluonic Dissociation Revisited : II. Hydrodynamic Expansion
  Effects

abstract:
  We explicitly take into account the effect of hydrodynamic expansion profile
on the gluonic breakup of $J/\psi$'s produced in an equilibrating parton
plasma. Attention is paid to the space-time inhomogeneities as well as Lorentz
frames while deriving new expressions for the gluon number density $n_g$,
average dissociation rate $<\tilde{\Gamma}>$, and $\psi$ survival probability
$S$. A novel type of partial wave {\em interference} mechanism is found to
operate in the formula of $<\tilde{\Gamma}>$. Nonrelativistic longitudinal
expansion fro small length of the initial cylinder is found to push the
$S(p_T)$ graph above the no flow case considered by us earlier \cite{rev1}.
However, relativistic flow corresponding to large length of the initial
cylinder pushes the curve of $S(p_T)$ downwards at LHC but upwards at RHIC.
This mutually different effect on $S(p_T)$ may be attributed to the different
initial temperatures generated at LHC and RHIC.


title:
Neutron-neutron correlation in the halo dissociation of light exotic
  nuclei

abstract:
  We present model results for the two-halo-neutron correlation functions,
$C_{nn}$, for the dissociation process of light exotic nuclei modelled as two
neutrons and a core. A minimum is predicted for $C_{nn}$ as a function of the
relative momentum of the two neutrons, $p_{nn}$, due to the coherence of the
neutrons in the halo and final state interaction. Studying the systems
$^{14}$Be, $^{11}$Li and $^{6}$He within this model, we show that the numerical
asymptotic limit, $C_{nn}\to 1$, occurs only for $p_{nn}\gtrsim$ 400 MeV$/c$,
while such limit is reached for much lower values of $p_{nn}$ in an independent
particle model as the one used in the analysis of recent experimental data. Our
model is consistent with data once the experimental correlation function is
appropriately normalized.


title:
Continuum effects on the pairing in neutron drip-line nuclei studied
  with the canonical-basis HFB method

abstract:
  The canonical-basis HFB method provides an efficient way to describe pairing
correlations involving the continuum part of the single-particle spectrum in
coordinate-space representations. It can be applied to super-conducting
deformed drip-line nuclei as easily as to stable or spherical nuclei. This
method is applied to a simulation of the approach to the neutron drip line. It
turns out that the HFB solution has a stronger pairing and a smaller
deformation as the Fermi level is raised. However, such changes are smooth and
finite. No divergences or discontinuities of the radius or other quantities are
found in the limit of zero Fermi energy. The nuclear density continues to be
localized even a little beyond the drip line.


title: Asymmetry parameter for nonmesonic hypernuclear decay

abstract:
  We derive general explicit expressions for a shell-model calculation of the
intrinsic asymmetry parameter, $a_\Lambda$, in nonmesonic weak hypernuclear
decay. They include the effects of three-body kinematics in the final states of
the decay and correctly treat the contribution of transitions originating from
single-proton states beyond the s-shell. The expressions are particularized to
the cases of $^5_\Lambda$He and $^{12}_\Lambda$C and used for the calculation
of $a_\Lambda$ in several one-meson-exchange models. Besides the strictly local
approximation usually adopted for the transition potential, we also consider
the addition of the first-order nonlocality terms. We find values for
$a_\Lambda$ ranging from -0.62 to -0.24, in qualitative agreement with other
theoretical estimates but in contradiction with some recent experimental
determinations.


title:
Probing the isospin dependence of the in-medium nucleon-nucleon cross
  sections with radioactive beams

abstract:
  Within a transport model we search for potential probes of the isospin
dependence of the in-medium nucleon-nucleon (NN) cross sections. Traditional
measures of the nuclear stopping power are found sensitive to the magnitude but
they are ambiguous for determining the isospin dependence of the in-medium NN
cross sections. It is shown that isospin tracers, such as the neutron/proton
ratio of free nucleons, at backward rapidities/angles in nuclear reactions
induced by radioactive beams in inverse kinematics is a sensitive probe of the
isospin dependence of the in-medium NN cross sections. At forward
rapidities/angles, on the other hand, they are more sensitive to the density
dependence of the symmetry energy. Measurements of the rapidity/angular
dependence of the isospin transport in nuclear reactions will enable a better
understanding of the isospin dependence of in-medium nuclear effective
interactions.


title:
Formation of Kaonic Atoms and Kaonic Nuclei by In-flight ($K^-,p$)
  reactions

abstract:
  We study the kaonic atom and kaonic nucleus formation by the in-flight ($K^-,
p$) reactions for C, O, Si and Ca target cases theoretically. Deeply bound
kaonic atoms were predicted to exist as quasi-stable states and were expected
to be observed in some proper experimental methods. Kaonic nuclear states are
also expected to exist with large decay widths. We evaluate the formation cross
sections of the kaonic atoms and kaonic nuclei using an effective number
approach. We show that the indications of the kaonic bound states can be
observed in the outgoing proton energy spectra.


title: Relativistic corrections to the nuclear Schiff moment

abstract:
  Parity and time invariance violating ($P,T$-odd) atomic electric dipole
moments (EDM) are induced by interaction between atomic electrons and nuclear
$P,T$-odd moments which are produced by $P,T$-odd nuclear forces. The nuclear
EDM is screened by atomic electrons. The EDM of a non-relativistic atom with
closed electron subshells is induced by the nuclear Schiff moment. For heavy
relativistic atoms EDM is induced by the nuclear local dipole moments which
differ by 10-50% from the Schiff moments calculated previously.
  We calculate the local dipole moments for ${^{199}{\rm Hg}}$ and ${^{205}{\rm
Tl}}$ where the most accurate atomic and molecular EDM measurements have been
performed.


title: New features of some proton-neutron collective states

abstract:
  Using a schematic solvable many-body Hamiltonian, one studies a new type of
proton-neutron excitations within a time dependent variational approach.
Classical equations of motion are linearized and subsequently solved
analytically. The harmonic state energy is compared with the energy of the
first excited state provided by diagonalization as well as with the energies
obtained by a renormalized RPA and a boson expansion procedure. The new
collective mode describes a wobbling motion, in the space of isospin, and
collapses for a particle-particle interaction strength which is much larger
than the physical value. A suggestion for the description of the system in the
second nuclear phase is made. We identified the transition operators which
might excite the new mode from the ground state.


title: Double pion photoproduction on nucleon and deuteron

abstract:
  Photoproduction of two pions on nucleon and deuteron is studied for photon
energies from threshold up to $E_\gamma = 1.5$ GeV. For the elementary operator
an effective Lagrangean approach is used with resonance and Born contributions.
The model parameters are fixed by resonance decay widths and multipole analyses
of single pion photoproduction. A satisfactory description of total cross
sections of two-pion production on the proton for various charge channels is
achieved, except for $\pi^0\pi^0$ production for which a significant
underestimation is found near threshold. The operator then serves for the
evaluation of this reaction on the deuteron in the impulse approximation. In
addition, $NN$ rescattering in the final state is taken into account, but $\pi
N$ and $\pi\pi$ rescatterings are neglected. Results are presented for total
cross sections and target asymmetries.


title:
Electromagnetic properties of ground and excited state pseudoscalar
  mesons

abstract:
  The axial-vector Ward-Takahashi identity places constraints on particular
properties of every pseudoscalar meson. For example, in the chiral limit all
pseudoscalar mesons, except the Goldstone mode, decouple from the axial-vector
current. Nevertheless, all neutral pseudoscalar mesons couple to two photons.
The strength of the \pi_n^0 \gamma \gamma coupling, where n=0 denotes the
Goldstone mode, is affected by the Abelian anomaly's continuum contribution.
The effect is material for n \neq 0. The \gamma* \pi_n \gamma* transition form
factor, T_{\pi_n}(Q^2), is nonzero for all n, and T_{\pi_n}(Q^2) \approx
(4\pi^2/3) (f_{\pi_n}/Q^2) at large Q^2. For all pseudoscalars but the
Goldstone mode, this leading contribution vanishes in the chiral limit. In this
instance the ultraviolet power-law behaviour is 1/Q^4 for n \neq 0, and we find
numerically T_{\pi_1}(Q^2) \simeq (4\pi^2/3) (-<\bar q q>/Q^4). This subleading
power-law behaviour is always present. In general its coefficient is not simply
related to f_{\pi_n}. The properties of n \neq 0 pseudoscalar mesons are
sensitive to the pointwise behaviour of the long-range piece of the interaction
between light-quarks.


title: Chiral perturbation theory for electroweak reactions on deuterium

abstract:
  I summarize two recent applications of chiral perturbation theory to
electromagnetic reactions on deuterium: elastic electron-deuteron scattering,
and Compton scattering on deuterium. Both calculations have now been carried
out to three orders in the chiral expansion. The expansion shows good
convergence and is able to reproduce data for q < 600 MeV in e-d and for
omega=55-95 MeV in gamma-d. These results demonstrate that ChiPT can be used to
reliably compute operators and wave functions for low-momentum-transfer
reactions in light nuclear systems.


title: Deuteron Dipole Polarizabilities and Sum Rules

abstract:
  The scalar, vector, and tensor components of the (generalized) deuteron
electric polarizability are calculated, as well as their logarithmic
modifications. Several of these quantities arise in the treatment of the
nuclear corrections to the deuterium Lamb shift and the deuterium hyperfine
structure. A variety of second-generation potential models are used and a
(subjective) error is assigned to the calculations. The zero-range
approximation is used to analyze a subset of the results, and a simple
relativistic version of this approximation is developed.


title: Dibaryon model for nuclear force and the properties of the $3N$ system

abstract:
  The dibaryon model for $NN$ interaction, which implies the formation of an
intermediate six-quark bag dressed by a $\sigma$-field, is applied to the $3N$
system, where it results in a new three-body force of scalar nature between the
six-quark bag and a third nucleon. A new multicomponent formalism is developed
to describe three-body systems with nonstatic pairwise interactions and
non-nucleonic degrees of freedom. Precise variational calculations of $3N$
bound states are carried out in the dressed-bag model including the new scalar
three-body force. The unified coupling constants and form factors for $2N$ and
$3N$ force operators are used in the present approach, in a sharp contrast to
conventional meson-exchange models. It is shown that this three-body force
gives at least half the $3N$ total binding energy, while the weight of
non-nucleonic components in the $^3$H and $^3$He wavefunctions can exceed 10%.
The new force model provides a very good description of $3N$ bound states with
a reasonable magnitude of the $\sigma NN$ coupling constant. A new Coulomb $3N$
force between the third nucleon and dibaryon is found to be very important for
a correct description of the Coulomb energy and r.m.s. charge radius in $^3$He.
In view of the new results for Coulomb displacement energy obtained here for
A=3 nuclei, an explanation for the long-term Nolen--Schiffer paradox in nuclear
physics is suggested. The role of the charge-symmetry-breaking effects in the
nuclear force is discussed.


title:
Covariant description of kinetic freeze out through a finite space-like
  layer

abstract:
  The problem of Freeze Out (FO) in relativistic heavy ion reactions is
addressed. We develop and analyze an idealized one-dimensional model of FO in a
finite layer, based on the covariant FO probability. The resulting post FO
phase-space distributions are discussed for different FO probabilities and
layer thicknesses.


title:
Covariant description of kinetic freeze out through a finite time-like
  layer

abstract:
  The Freeze Out (FO) problem is addressed for a covariant FO probability and a
finite FO layer with a time-like normal vector continuing the line of studies
introduced in Ref. [1]. The resulting post FO momentum distribution functions
are presented and discussed. We show that in general the post FO distributions
are non-thermal and asymmetric distributions even for time-like FO situations.


title: Complex Scaled Spectrum Completeness for Coupled Channels

abstract:
  The Complex Scaling Method (CSM) provides scattering wave functions which
regularize resonances and suggest a resolution of the identity in terms of such
resonances, completed by the bound states and a smoothed continuum. But, in the
case of inelastic scattering with many channels, the existence of such a
resolution under complex scaling is still debated. Taking advantage of results
obtained earlier for the two channel case, this paper proposes a representation
in which the convergence of a resolution of the identity can be more easily
tested. The representation is valid for any finite number of coupled channels
for inelastic scattering without rearrangement.


title: Light Nuclei within Nuclear Matter

abstract:
  We investigate the properties of 3He, 4He, 6He, 7Li and 16O nuclei in nuclear
matter of finite temperature and density. A Dyson expansion of the many-body
Green function leads to few-body equations that are solved using the
ntegro-Differential Equation Approach (IDEA) and the Antisymmetrized Molecular
Dynamics (AMD) methods. The use of the latter method allows us to trace the
individual movement of the wave packet for each nucleon and the formation and
disintegration of quasi-nuclei in a changing thermodynamical nuclear matter
environment.


title:
Novel mechanism of high-$p_T$ production from an opaque quark-gluon
  plasma

abstract:
  We find that in an opaque quark-gluon plasma, significant particle production
at high transverse momenta can occur via acceleration of (initially)
lower-momentum partons. This new mechanism, which is the opposite of parton
energy loss (jet quenching), has important implications for observables, such
as elliptic flow, in heavy-ion collisions at RHIC energies and above.


title: Parton and Hadron Correlations in Jets

abstract:
  Correlation between shower partons is first studied in high $p_T$ jets. Then
in the framework of parton recombination the correlation between pions in
heavy-ion collisions is investigated. Since thermal partons play very different
roles in central and peripheral collisions, it is found that the correlation
functions of the produced hadrons behave very differently at different
centralities, especially at intermediate $p_T$. The correlation function that
can best exhibit the distinctive features is suggested. There is not a great
deal of overlap between what we can calculate and what has been measured.
Nevertheless, some aspects of our results compare favorably with experimental
data.


title: Electron scattering on halo nuclei

abstract:
  The inelastic scattering of electrons on weakly-bound nuclei is studied with
a simple model based on the long range behavior of the bound state wavefunction
and on the effective-range expansion for the continuum wavefunctions. Three
mechanisms have been considered: (a) dissociation of halo nuclei by high energy
electrons, (b) dissociation by electrons present in a fixed target, and (c)
Coulomb dissociation. It is shown that the properties of halo nuclei can be
studied in electron-radioactive beam colliders using the electro-disintegration
process. A comparison with fixed-target experiments is also performed.


title:
Probing the QCD equation of state with thermal photons in
  nucleus-nucleus collisions at RHIC

abstract:
  Thermal photon production at mid-rapidity in Au+Au reactions at
$\sqrt{s_{NN}}$ = 200 GeV is studied in the framework of a 2D+1 hydrodynamical
model that describes efficiently the bulk identified hadron spectra at RHIC.
The combined thermal plus NLO pQCD photon spectrum is in good agreement with
the yields measured by the PHENIX experiment for all Au+Au centralities. Within
our model, we demonstrate that the correlation of the thermal photon slopes
with the charged hadron multiplicity in each centrality bin provides direct
empirical information on the underlying degrees of freedom and on the equation
of state, $s(T)/T^3$, of the strongly interacting matter.


title: An Approach To Potential Scattering

abstract:
  Recently developed time-independent bound-state perturbation theory is
extended to treat the scattering domain. The changes in the partial wave phase
shifts are derived explicitly and the results are compared with those of other
methods.


title: Thermodynamical consistent CJT calculation in studying nuclear matter

abstract:
  We have attempted to apply the CJT formalism to study the nuclear matter. The
thermodynamic potential is calculated in Hartree-Fock approximation in the CJT
formalism. After neglecting the medium effects to the mesons, the numerical
results are found very consistent with those obtained from the mean field
calculation. In our calculation the thermodynamical consistency is also
preserved.


title: Nuclear time-reversal violation and the Schiff moment of 225Ra

abstract:
  We present a comprehensive mean-field calculation of the Schiff moment of the
nucleus 225Ra, the quantity which determines the static electric dipole moment
of the corresponding atom if time-reversal (T) invariance is violated in the
nucleus. The calculation breaks all possible intrinsic symmetries of the
nuclear mean field and includes, in particular, both exchange and direct terms
from the full finite-range T-violating nucleon-nucleon interaction, and the
effects of short-range correlations. The resulting Schiff moment, which depends
on three unknown T-violating pion-nucleon coupling constants, is much larger
than in 199Hg, the isotope with the best current experimental limit on its
atomic electric-dipole moment.


title:
Signals in Single-Event Pion Interferometry for Granular Sources of
  Quark-Gluon Plasma Droplets

abstract:
  We investigate two-pion Bose-Einstein correlations of quark-gluon plasma
droplet sources in single-event measurements. We find that the distribution of
the fluctuation between correlation functions of the single- and mixed-events
provide useful signals to detect the granular structure of the source.


title:
Spherical Hartree-Fock calculations with linear momentum projection
  before the variation.Part I: Energies, form factors, charge densities and
  mathematical sum rules

abstract:
  Spherical Hartree--Fock calculations with projection onto zero total linear
momentum before the variation are performed for the nuclei 4He, 12C, 16O, 28Si,
32S and 40Ca using a density--independent effective nucleon--nucleon
interaction. The results are compared to those of usual spherical Hartree--Fock
calculations subtracting the kinetic energy of the center of mass motion either
before or after the variation and to the results obtained analytically with
oscillator occupations. Total energies, hole--energies, elastic charge form
factors and charge densities and the mathematical Coulomb sum rules are
discussed.


title:
Associated Particle Distributions in Jets Produced in Heavy-Ion
  Collisions

abstract:
  We study the pion distributions in jets produced in heavy-ion collisions in
association with trigger particles restricted to definite momentum ranges. We
determine the centrality dependence of the associated particle distributions
for both d+Au and Au+Au collisions in the recombination model. The
central-to-peripheral ratios show significant dependence on centrality for
Au+Au collisions, but negligible dependence for d+Au collisions. The results
are in agreement with the qualitative features of the data.


title:
Extension of the CEM2k and LAQGSM Codes to Describe Photo-Nuclear
  Reactions

abstract:
  The improved Cascade-Exciton Model (CEM) code CEM2k+GEM2 and the Los Alamos
version of the Quark-Gluon String Model code LAQGSM are extended to describe
photonuclear reactions. First, we incorporate into CEM2k+GEM2 new evaluations
of elementary cross sections based on the latest experimental data and also
make several improvements in the description of the de-excitation of nuclei
remaining after the cascade stage of reactions induced by arbitrary
projectiles. Next, for photonuclear reactions we include in CEM2k+GEM2 a
normalization to evaluated experimental absorption cross sections based on the
recent systematics by Kossov. Then, we extend our high-energy code LAQGSM by
adding the photonuclear mode which was ignored in all its previous versions,
and add to it the photonuclear part from our improved CEM2k+GEM2. In this work
we present a short description of the photonuclear mode as incorporated into
our codes, show several illustrative results, and point out some unresolved
problems.


title:
Semi-relativistic description of quasielastic neutrino reactions and
  superscaling in a continuum shell model

abstract:
  The so-called semi-relativistic expansion of the weak charged current in
powers of the initial nucleon momentum is performed to describe
charge-changing, quasielastic neutrino reactions $(\nu_\mu,\mu^-)$ at
intermediate energies. The quality of the expansion is tested by comparing with
the relativistic Fermi gas model using several choices of kinematics of
interest for ongoing neutrino oscillation experiments. The new current is then
implemented in a continuum shell model together with relativistic kinematics to
investigate the scaling properties of $(e,e')$ and $(\nu_\mu,\mu^-)$ cross
sections.