The equations of relativistic hydrodynamics are transformed so that steps forward in time preserve local simultaneity. In these variables, the space-time coordinates of neighboring points on the mesh are simultaneous according to comoving observers. Aside from the time step varying as a function of the location on the mesh, the local velocity gradient and the local density then evolve according to nonrelativistic equations of motion. Analytic solutions are found for two one-dimensional cases with constant speed of sound. One solution has a Gaussian density profile when mapped onto the new coordinates. That solution is analyzed for the effects of longitudinal acceleration in relativistic heavy ion collisions at the Relativistic Heavy Ion Collider, especially in regards to two-particle correlation measurements of the longitudinal size.

In the small $Q^2$ region, the sum rule for the polarized structure function $g_2$ corresponding to the moment at $n=0$ is derived. This sum rule shows that there is a tight connection among the resonances, the elastic and the continuum in the $g_2$. Further, the Born term contribution in this sum rule is proportional to $Q^2$ and very small compared with that in the corresponding sum rule for the polarized structure function $g_1$. However, the Born term contribution divided by $Q^2/2$ which also appears in the Schwinger sum rule for the $g_2$ corresponding to the moment at $n=1$ has a very similar behavior with that in the sum rule for the $g_1$ corresponding to the moment at $n=0$.

We apply a three-body model consisting of two valence neutrons and the core nucleus ${}^{14}\mathrm{C}$ in order to investigate the ground state properties and electric quadrupole transition of the ${}^{16}\mathrm{C}$ nucleus. The discretized continuum spectrum within a large box is taken into account by using a single-particle basis obtained from a Woods-Saxon potential. The calculated $B(E2)$ value from the first $2^{+}$ state to the ground state shows good agreement with the observed data with the core polarization charge which reproduces the experimental $B(E2)$ value for ${}^{15}\mathrm{C}$. We also show that the present calculation accounts well for the longitudinal momentum distribution of the ${}^{15}\mathrm{C}$ fragment from the breakup of the ${}^{16}\mathrm{C}$ nucleus. We point out that the dominant ($d_{5/2}){}^2$ configuration in the ground state of ${}^{16}\mathrm{C}$ plays a crucial role in these agreements.

We present an intranuclear cascade (INC) model which includes the dynamics of the cascade particles and uses in-medium $\mathit{NN}$ elastic cross sections. Our model is still based on the impulse approximation and does not have the complexity of other sophisticated nuclear models. Nevertheless, its results of angle-energy distributions of emitted nucleons in continuum are in good agreement with experimental data for nucleon induced reactions from low intermediate energy to high energy, between 14 MeV and 1.6 GeV, and for light to heavy target nuclei. Comparisons with results of Bertini's INC model and of a previous version of our INC model show the clear contribution of the combined effects of better dynamics and the in-medium $\mathit{NN}$ cross sections. From our results, we conclude that our INC model effectively includes the preequilibrium emission.

It has been shown that a final state interaction model, used to describe $J/\psi$ suppression, can also describe the fixed $p_T$ suppression of the ${\pi }^0$ (and charged pion) yield at all values of $p_T$, with a final state interaction cross section σ close to one milibarn. We propose an extension of the model to the pion motion in the transverse plane, which introduces a dependence of the suppression on the azimuthal angle ${\theta }_R$. Using the same value of σ, we obtain values of the elliptic flow $v_2$ close to the experimental ones, for all values of $p_T$, including the soft-$p_T$ region.

This paper summarizes the yields and the emission patterns of $K^{+}$ and of $K^{-}$ mesons measured in inclusive C+C, Ni+Ni, and Au+Au collisions at incident energies from $0.6A$ to $2.0A$ GeV using the Kaon Spectrometer KaoS at GSI. For Ni+Ni collisions at $1.5A$ and at $1.93A$ GeV as well as for Au+Au at $1.5A$ GeV, detailed results are presented of the multiplicities, of the inverse slope parameters, and of the anisotropies in the angular emission patterns as a function of the collision centrality. When comparing transport-model calculations to the measured $K^{+}$ production yields, an agreement is only obtained for a soft nuclear equation of state (compression modulus $K_{\mathrm{N}}\approx 200$ MeV). The production of $K^{-}$ mesons at energies around $1A$ to $2A$ GeV is dominated by the strangeness-exchange reaction $K^{-}N\rightleftharpoons \pi Y$ ($Y=\Lambda ,\Sigma$) which leads to a coupling between the $K^{-}$ and $K^{+}$ yields. However, both particle species show distinct differences in their emission patterns suggesting different freeze-out conditions for $K^{+}$ and $K^{-}$ mesons.

The Cornell-Norton and Nachtmann moments of nucleon spin structure functions are discussed with a nonvanishing nucleon mass. Target-mass corrections to the truncated moments of the structure functions are calculated. Moreover, the corrections to the Bloom-Gilman quark-hadron dualities of $g_1^p$ and $g_2^p$ in both the inelastic resonance production region and the elastic one are analyzed.

The problem of the microscopic description of excited states of the even-even open-shell atomic nuclei is considered. A model is formulated which allows one to go beyond the quasiparticle random phase approximation. The physical content of the model is determined by the quasiparticle time blocking approximation (QTBA) which enables one to include contributions of the two-quasiparticle and the two-phonon configurations, while excluding (blocking) more complicated intermediate states. In addition, the QTBA ensures consistent treatment of ground state correlations in the Fermi systems with pairing. The model is based on the generalized Green function formalism (GGFF) in which the normal and the anomalous Green functions are treated in a unified way in terms of the components of generalized Green functions in a space that is double the size of the usual single-particle space. Modification of the GGFF is considered in the case when the many-body nuclear Hamiltonian contains two-, three-, and other many-particle effective forces.

Based on the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous ${\chi }^2$ analyses are performed for elastic scattering and fusion cross section data for the ${}^6\mathrm{Li}+{}^{208}\mathrm{Pb}$ system at near-Coulomb-barrier energies. A folding potential is used as the bare potential. It is found that the real part of the resultant DR part of the polarization potential is repulsive, which is consistent with the results from the continuum discretized coupled channel (CDCC) calculations and the normalization factors needed for the folding potentials. Further, it is found that both DR and fusion parts of the polarization potential satisfy separately the dispersion relation.

We calculate the nucleon form factors $G_A$ and $G_P$ of the isovector axial-vector current and the pion-nucleon form factor $G_{\pi N}$ in manifestly Lorentz-invariant baryon chiral perturbation theory up to and including order $\mathcal{O}(p^4)$. In addition to the standard treatment including the nucleon and pions, we also consider the axial-vector meson $a_1$ as an explicit degree of freedom. This is achieved by using the reformulated infrared renormalization scheme. We find that the inclusion of the axial-vector meson effectively results in one additional low-energy coupling constant that we determine by a fit to the data for $G_A$. The inclusion of the axial-vector meson results in an improved description of the experimental data for $G_A$, while the contribution to $G_P$ is small.

Fission fragment angular distributions were measured in ${}^{11}\mathrm{B}+{}^{243}\mathrm{Am}$ reaction in the beam energy ($E_{\mathrm{lab}}$) range of 60–72 MeV. Experimental anisotropies in ${}^{11}\mathrm{B}+{}^{243}\mathrm{Am}$ reaction were found to be higher than the values calculated using the statistical theory indicating contribution from noncompound nucleus fission. For ${}^{11}\mathrm{B}+{}^{243}\mathrm{Am}$ reaction, entrance channel mass asymmetry is higher than the Businaro-Gallone critical mass asymmetry. Observation of anomalous fission fragment angular distribution in ${}^{11}\mathrm{B}+{}^{243}\mathrm{Am}$ reaction possibly indicates that the target deformation plays an important role in deciding the contribution from noncompound nucleus fission.

The relativistic proton-neutron quasiparticle random phase approximation (PN-RQRPA) is applied in the calculation of β-decay half-lives of neutron-rich nuclei in the $Z\approx 28$ and $Z\approx 50$ regions. The study is based on the relativistic Hartree-Bogoliubov calculation of nuclear ground states, using effective Lagrangians with density-dependent meson-nucleon couplings, and also extended by the inclusion of couplings between the isoscalar meson fields and the derivatives of the nucleon fields. This leads to a linear momentum dependence of the scalar and vector nucleon self-energies. The residual QRPA interaction in the particle-hole channel includes the $\pi +\rho$ exchange plus a Landau-Migdal term. The finite-range Gogny interaction is employed in the $T=1$ pairing channel, and the model also includes a proton-neutron particle-particle interaction. The results are compared with available data, and it is shown that an extension of the standard relativistic mean-field framework to include momentum-dependent nucleon self-energies naturally leads to an enhancement of the effective (Landau) nucleon mass, and thus to an improved PN-QRPA description of ${\beta }^{-}$-decay rates.

The nuclear states in ${}^{23}\mathrm{F}$ have been investigated following the β decay of ${}^{23}\mathrm{O}$. The measurement of ${}^{23}\mathrm{O}$ was carried out at the National Superconducting Cyclotron Laboratory using fragments from the reaction of a ${}^{48}\mathrm{Ca}$ beam in a Be target. The half-life and total neutron emission probability were determined to be 97(8) ms and 7(2)%, respectively, for ${}^{23}\mathrm{O}$ β decay. Ten γ-ray decays in ${}^{23}\mathrm{F}$ and a single γ-ray in ${}^{22}\mathrm{F}$ were observed to establish the β decay scheme for ${}^{23}\mathrm{O}$. Shell model calculations are in reasonable agreement with the measured β branching and $B$(GT) values for the lowest energy state. The excitation energies of the first $1/2^{+}$ and $3/2^{+}$ states have been determined to be 2243(8) and 4066(16) keV, respectively, indicating a widening of the $5/2^{+}$–$1/2^{+}$ state gap in ${}^{23}\mathrm{F}$. The decay scheme of the largest contaminant ${}^{26}\mathrm{Ne}$ in the experiment was established.

The elastic scattering of the halo nucleus ${}^6\mathrm{He}$ from a proton target at 717 MeV/nucleon is investigated within three different multiple-scattering formulations of the total transition amplitude. The factorized impulse approximation (FIA) and the fixed scatterer approximation (FSA) of the multiple-scattering expansion are used to evaluate accurately the single-scattering terms and to test the validity of a few-body Glauber approach. The latter also includes terms beyond single scattering and the importance of these terms is investigated. The differential cross section is calculated for proton scattering from ${}^6\mathrm{He}$ at 717 MeV in inverse kinematics and compared with recent data.

We studied the influence of dispersive self-energy effects, three-body forces, and polarization contributions to the interaction kernel on the ${}^1{S}_0$ proton pairing in neutron star matter. We found that a strong suppression of the gap by self-energy effects and three-body forces is at low density compensated by the attractive polarization interaction, shifting the domain of pairing to below ${\rho }_B\approx 0.3{\mathrm{fm}}^{-3}$.

An excitation function for resonance elastic scattering of $p+$${}^{12}\mathrm{N}$ was measured in the center of mass energy range of 0.8–2.7 MeV. Measurements were performed using inverse kinematics and the thick-target techniques. The data were analyzed in the framework of the R-matrix formalism. A definitive spin and parity assignment was possible for the first excited state of ${}^{13}\mathrm{O}$ at an excitation energy of 2.69 MeV as ${\mathrm{J}}^{\pi }={\frac{1}{2}}^{+}$. An indication of the presence of a new level in ${}^{13}\mathrm{O}$ at an excitation energy of 3.29 MeV with tentative spin-parity assignment ${\mathrm{J}}^{\pi }={\frac{1}{2}}^{-}$ or ${\frac{3}{2}}^{-}$ was obtained. We evaluate the impact of this measurement on the reaction rate of ${}^{12}\mathrm{N}$($p$,γ)${}^{13}\mathrm{O}$ for nucleosynthesis in low-metallicity stars.

By using a new boundary condition model, we calculate Coulomb phase shifts in “momentum space.” The $K$-matrix equation for the auxiliary potential is introduced by a Lemma under the boundary condition. The equation permits one to avoid many prohibited rules for the long-range property. Our numerical phase shift shows good agreement with the analytical phase shift. The usual renormalized phase shifts are also presented for comparison.

We compare recent experimental results for the spectroscopic properties of ${}^{23}\mathrm{F}$ with theoretical results based on the new Hamiltonians USDA and USDB for the $\mathit{sd}$-shell model space. The implications for the proton single-particle energies in ${}^{23}\mathrm{F}$ are discussed. Conclusions are drawn about the level scheme of ${}^{23}\mathrm{F}$ and the accuracy of the new Hamiltonians from these comparisons.

The width of charge balance function in high energy hadron-hadron and relativistic heavy-ion collisions are studied using the Monte Carlo generators PYTHIA and AMPT, respectively. The narrowing of balance function as the increase of multiplicity is found in both cases. The mean parton-freeze-out time of a heavy-ion collision event is used as the characteristic hadronization time for the event. It turns out that for a fixed multiplicity interval the width of balance function is consistent with being independent of hadronization time.