Elliptic flow holds much promise for studying the early-time thermalization attained in ultrarelativistic nuclear collisions. Flow measurements also provide a means of distinguishing between hydrodynamic models and calculations which approach the low density (dilute gas) limit. Among the effects that can complicate the interpretation of elliptic flow measurements are azimuthal correlations that are unrelated to the reaction plane (nonflow correlations). Using data for Au + Au collisions at $\sqrt{s_{\mathrm{NN}}}=130\mathrm{}\mathrm{GeV}\mathrm{}$ from the STAR time projection chamber, it is found that four-particle correlation analyses can reliably separate flow and nonflow correlation signals. The latter account for on average about 15% of the observed second-harmonic azimuthal correlation, with the largest relative contribution for the most peripheral and the most central collisions. The results are also corrected for the effect of flow variations within centrality bins. This effect is negligible for all but the most central bin, where the correction to the elliptic flow is about a factor of 2. A simple new method for two-particle flow analysis based on scalar products is described. An analysis based on the distribution of the magnitude of the flow vector is also described.

It has been recently shown that metastable domain walls exist in high-density QCD $\left(\mu \ne 0\right)$ as well as in QCD with large number of colors ${(N}_c\to \infty ),$ with the lifetime being exponentially long in both cases. Such metastable domain walls may exist in our world as well, especially in hot hadronic matter with temperature close to critical. In this paper we discuss what happens if a bubble made of such wall is created in heavy ion collisions, in the mixed phase between QGP and hadronic matter. We show it will further be expanded to larger volume $\sim 20{\mathrm{fm}}^3$ by the pion pressure, before it disappears, either by puncture or contraction. Both scenarios leave distinctive experimental signatures of such events, negatively affecting the interference correlations between the outgoing pions.

The electromagnetic elastic form factors of pseudoscalar and vector mesons are analyzed for spacelike momentum transfers in terms of relativistic quark models based on the Hamiltonian light-front formalism elaborated in different reference frames ${(q}^{+}=0\mathrm{}$ and $q^{+}\ne 0).$ As far as the one-body approximation for the electromagnetic current operator is concerned, it is shown that the predictions of the light-front approach at $q^{+}=0\mathrm{}$ should be preferred, particularly in case of light hadrons, because of (i) the relevant role played by the Z graph at $q^{+}\ne 0,$ and (ii) the appropriate elimination of spurious effects, related to the orientation of the null hyperplane where the light-front wave function is defined.

A study of $\gamma \overrightarrow{p}K\Sigma$ processes in an isobar model at tree level is reported. By comparing model calculations to the published SAPHIR data, we explore the possible role of different isospin $I=\frac{1}{2}$ ${(N}^{*})$ and $I=\frac{3}{2}$ (${\mathrm{\Delta }}^{\mathrm{*}}$) resonances in the reaction dynamics. In our analysis, the inclusion of the “missing” $D_{13}\mathrm{}\left(1895\right)\mathrm{}$ resonance does only slightly improve the global description of the Σ photoproduction data. More convincing signals for the presence of such a “missing” resonance emerged in the analysis of the isospin related $\gamma \overrightarrow{p}{K}^{+}\Lambda$ reaction. Various implementations of the nonresonant part of the Σ photoproduction amplitude are presented. The sensitivity of the computed observables and extracted resonance parameters to the uncertainties inherent to the treatment of the nonresonant (background) diagrams are discussed.

The measured $\mathrm{ft}$ values for superallowed $0^{+}\to 0^{+}$ nuclear $\beta$ decay can be used to obtain the value of the vector coupling constant and thus to test the unitarity of the Cabibbo-Kobayashi-Maskawa matrix. An essential requirement for this test is accurate calculations for the radiative and isospin symmetry-breaking corrections that must be applied to the experimental data. We present a new and consistent set of calculations for the nuclear-structure-dependent components of these corrections. These new results do not alter the current status of the unitarity test—it still fails by more than two standard deviations—but they provide calculated corrections for eleven new superallowed transitions that are likely to become accessible to precise measurements in the future. The reliability of all calculated corrections is explored and an experimental method indicated by which the structure-dependent corrections can be tested and, if necessary, improved.

The possible occurrence of highly deformed configurations in the ${}^{40}\mathrm{Ca}$ dinuclear system formed in the ${}^{28}\mathrm{Si}{+}^{12}\mathrm{C}$ reaction is investigated by analyzing the spectra of emitted light charged particles. Both inclusive and exclusive measurements of the heavy fragments $(A>~10)$ and their associated light charged particles (protons and $\alpha$ particles) have been made at the IReS Strasbourg VIVITRON Tandem facility at bombarding energies of $E_{\mathrm{lab}}{(}^{28}\mathrm{Si})=112\mathrm{}\mathrm{MeV}$ and 180 MeV by using the ICARE charged particle multidetector array. The energy spectra, velocity distributions, and both in-plane and out-of-plane angular correlations of light charged particles are compared to statistical-model calculations using a consistent set of parameters with spin-dependent level densities. The analysis suggests the onset of large nuclear deformation in ${}^{40}\mathrm{Ca}$ at high spin.

The Kelvin circulation, which is the Casimir invariant of the general collective motion gcm(3) Lie algebra, is determined for a rapidly rotating triaxial nucleus in the classical domain. The potential energy is approximated by the sum of Coulomb repulsion and attractive surface energy terms, and the kinetic energy is adopted from the Riemann ellipsoidal model. An accurate approximation valid for both small and large deformations is reported for the potential energy. The Riemann ellipsoid theory allows for collective rotation in the continuum from rigid body motion to irrotational flow; the rigidity parametrizes this kinematical continuum. Analytic formulas are derived for the circulation, angular momentum, and energy as functions of the axis lengths, fissility, and rigidity. In particular, the bifurcation point to Jacobi triaxial shapes from noncollective oblate spheroids is given by a simple analytic formula. For a given fissility, the bifurcation point depends sensitive- ly on the rigidity. The Kelvin circulation remains approximately constant for triaxial ellipsoids as the angular momentum increases. This implies that gcm(3) is an approximate partial dynamical symmetry for rapidly rotating triaxial nuclei.

Reaction and elastic differential cross sections are calculated for light nuclei in the framework of the Glauber theory. The optical phase-shift function is evaluated by Monte Carlo integration. This enables us to use the most accurate wave functions and calculate the phase-shift functions without approximation. Examples of proton-nucleus (e.g., ${p-}^6\mathrm{He},$ ${p-}^6\mathrm{Li})$ and nucleus-nucleus ${(\mathrm{e}.\mathrm{g}.,}^6\mathrm{He}{-}^{12}\mathrm{C})$ scatterings illustrate the effectiveness of the method. This approach gives us a possibility of a more stringent analysis of the high-energy reactions of halo nuclei.

Due to large $\pi \overrightarrow{N}\Delta$ cross section a pion acquires a large width in nuclear matter. Therefore, a $\Delta$ resonance decaying in the nuclear medium can produce far off-shell pions, which will gradually lose their virtuality while propagating to the vacuum. To describe such off-shell dynamics, we implemented a pion spectral function for finite nuclear matter density—calculated on the basis of the $\Delta$-hole model—in the Boltzmann-Uehling-Uhlenbeck transport approach. The pion off-shell dynamics leads to an enhancement of the low-$p_t$ pion yields in the collisions of Au+Au at $1A\mathrm{GeV}.$

The ${}^8\mathrm{B}$ solar neutrino flux inferred from a global analysis of solar neutrino experiments is within 11% $\left(1\mathrm{}\sigma \right)$ of the predicted standard solar model value if only active neutrinos exist, but could be as large as 1.7 times the standard prediction if sterile neutrinos exist. We show that the total ${}^8\mathrm{B}$ neutrino flux (active plus sterile neutrinos) can be determined experimentally to about 10% $\left(1\mathrm{}\sigma \right)$ by combining charged current measurements made with the KamLAND reactor experiment and with the SNO CC solar neutrino experiment, provided the LMA neutrino oscillation solution is correct and the simulated performance of KamLAND is valid. Including also SNO NC data, the sterile component of the ${}^8\mathrm{B}$ neutrino flux can be measured by this method to an accuracy of about 12% $\left(1\mathrm{}\sigma \right)$ of the standard solar model flux. Combining Super-Kamiokande and KamLAND measurements and assuming the oscillations occur only among active neutrinos, the ${}^8\mathrm{B}$ neutrino flux can be measured to 6% $\left(1\mathrm{}\sigma \right);$ the total flux can be measured to an accuracy of about 9%. The total ${}^7\mathrm{Be}$ solar neutrino flux can be determined to an accuracy of about 28% $\left(1\mathrm{}\sigma \right)$ by combining measurements made with the KamLAND, SNO, and gallium neutrino experiments. One can determine the total ${}^7\mathrm{Be}$ neutrino flux to a $1\sigma$ accuracy of about 11% or better by comparing data from the KamLAND experiment and the BOREXINO solar neutrino experiment provided both detectors work as expected. The $\mathrm{pp}$ neutrino flux can be determined to about 15% using data from the gallium, KamLAND, BOREXINO, and SNO experiments.

We determine the influence of the three-body force and the medium modification of meson masses on pairing in nuclear and neutron matter. A reduction of the pairing gap is found and increases with density.

To study the effect of the weak binding energy on the interaction potential between a light exotic nucleus and a target, elastic scattering of ${}^6\mathrm{He}$ at 38.3 MeV/nucleon on a ${}^{12}\mathrm{C}$ target was measured at Grand Accélérateur National d’Ions Lourds (GANIL). The ${}^6\mathrm{He}$ beam was produced by fragmentation. The detection of the scattered particles was performed by the GANIL spectrometer. The energy resolution was good enough to separate elastic from inelastic scattering contributions. The measured elastic data have been analyzed within the optical model, with the real part of the optical potential calculated in the double-folding model using a realistic density-dependent nucleon-nucleon interaction and the imaginary part taken in the conventional Woods-Saxon (WS) form. A failure of the “bare” real folded potential to reproduce the measured angular distribution over the whole angular range suggests quite a strong coupling of the higher-order breakup channels to the elastic channel. To estimate the strength of the breakup effects, a complex surface potential with a repulsive real part (designed to simulate the polarization effects caused by the projectile breakup) was added to the real folded and imaginary WS potentials. A realistic estimate of the polarization potential caused by the breakup of the weakly bound ${}^6\mathrm{He}$ was made based on a parallel study of ${}^6\mathrm{He}{+}^{12}\mathrm{C}$ and ${}^6\mathrm{Li}{+}^{12}\mathrm{C}$ optical potentials at about the same energies.

A precursor of a possible isospin separation instability in dense neutron-rich matter is predicted to appear as a local minimum in the excitation function of nuclear collective flow above the pion production threshold within an isospin-dependent hadronic transport model. The qualitative nature of this novel signal, unlike other quantitative observables, makes it a very useful probe of the isospin dependence of the nuclear equation of state using heavy rare isotopes at intermediate, rare-isotope accelerator energies.

We analyze the role of meson exchange currents (MECs) in photon- and electron-induced one nucleon emission reactions in a fully relativistic model. The relativistic mean-field theory is used for the bound state and the Pauli reduction for the scattering state. Direct one-body and exchange two-body terms in the nuclear current are considered. Results for the ${}^{12}\mathrm{C}(\gamma ,p)$ and ${}^{16}\mathrm{O}(\gamma ,p)$ differential cross sections and photon asymmetries are displayed in an energy range between 60 and 196 MeV. The two-body seagull current affects the cross section less than in nonrelativistic analyses. In the case of the ${}^{16}\mathrm{O}(\gamma ,n)$ differential cross section, MEC effects are large but not sufficient to reproduce the data. MECs have a small effect on ${(e,e}^{\prime }p)$ calculations.

We propose a procedure based on phase equivalent chains of Darboux transformations to generate local potentials satisfying the radial Schrödinger equation and sharing the same scattering data. For potentials related by a chain of transformations, an analytic expression is derived for the Jost function. It is shown how the same system of S-matrix poles can be differently distributed between poles and zeros of a Jost function that corresponds to different potentials with equal phase shifts. The concept of shallow and deep phase equivalent potentials is analyzed in connection with distinct distributions of poles. It is shown that phase equivalent chains do not violate the Levinson theorem. The method is applied to derive a shallow and a family of deep phase equivalent potentials describing the ${}^1{S}_0$ partial wave of the nucleon-nucleon scattering.

A fusion-evaporation reaction has been employed to search for isomeric states in the $N=77\mathrm{}$ isotope ${}_{63}^{140}\mathrm{Eu}$ near the proton-drip line. The recoiling nuclei were implanted into a silicon detector, at the focal plane of a gas-filled separator, where prompt and delayed $\gamma$-ray transitions were correlated across isomeric states using recoil-isomer tagging. The feeding and decay of a new 299(3) ns isomeric state was established. This measurement represents the first observation of excited high-spin states in ${}^{140}\mathrm{Eu}.$ The behavior of the new states above the isomer is discussed in terms of theoretical calculations based upon the cranked-shell model and upon the experimental systematics of other $N=77\mathrm{}$ isotones. Within this framework, the isomer is interpreted to be built upon a $\pi h_{11/2}\otimes \nu h_{11/2}$ two-quasiparticle configuration.

Fusion excitation functions have been measured to high precision for the reactions ${}^{32}\mathrm{S}{+}^{89}\mathrm{Y}$ and ${}^{34}\mathrm{S}{+}^{89}\mathrm{Y}.$ The sub-barrier fusion cross sections for ${}^{32}\mathrm{S}{+}^{89}\mathrm{Y}$ are found to be more enhanced over single-barrier penetration calculations than those for ${}^{34}\mathrm{S}{+}^{89}\mathrm{Y},$ and the shapes of the two experimental barrier distributions are significantly different. The effects of proton transfer and double phonon excitations have been examined using exact coupled channels calculations. These suggest that the difference between the two systems lies mainly in the collectivity of the projectiles, whilst proton transfer has only a minor effect.

We have used existing data on the one-proton-removal cross section of ${}^9\mathrm{C}$ at 285 MeV/nucleon and Glauber model calculations to extract the asymptotic normalization coefficient for the wave function of the last proton in the ground state of ${}^9\mathrm{C}.$ The calculations are done first using folded potentials starting from two different effective nucleon-nucleon interactions and second in the optical limit using three nucleon-nucleon interactions, and the results are found to be consistent, with no new parameters adjusted. We find $C^2{(p}_{3/2}{)+C}^2{(p}_{1/2})=1.22\mathrm{}\pm 0.13{\mathrm{fm}}^{-1}.$ From this result we obtain the astrophysical factor for the proton radiative capture reaction ${}^8\mathrm{B}(p,\gamma {)}^9\mathrm{C}$ as $S_{18}\mathrm{}\left(0\right)=46\mathrm{}\pm 6\mathrm{eV}\mathrm{b}.$ The calculated energy dependence of the astrophysical S factor for the energy region $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=0\mathrm{}-0.8\mathrm{MeV}$ and the reaction rates for $T_9=0\mathrm{}-1$ are included.