Cross sections for the $\gamma p\to K^{+}\Lambda$ reaction were measured at backward angles using linearly polarized photons in the range 1.50 to 2.37 GeV. In addition, the beam asymmetry for this reaction was measured for the first time at backward angles. The Λ was detected at forward angles in the LEPS spectrometer via its decay to $p{\pi }^{-}$ and the $K^{+}$ was inferred using the technique of missing mass. These measurements, corresponding to kaons at far backward angles in the center-of-mass frame, complement similar CLAS data at other angles. Comparison with theoretical models shows that the reactions in these kinematics provide further opportunities to investigate the reaction mechanisms of hadron dynamics.

Using an effective potential that is based on the Skyrme-Hartree-Fock mean-field model, systematic α-decay properties of even-even heavy and superheavy nuclei have been investigated. Calculations do not raise any adjustable parameter. The obtained α-decay half-lives agree reasonably well with experimental data. The characteristics of the effective potential and the deformation effect on the α decay are discussed.

Excited states of the neutron-deficient ${}^{103}\mathrm{Cd}$ nucleus have been investigated via the ${}^{72}\mathrm{Ge}$(${}^{35}\mathrm{Cl}$, $p3n$) reaction at beam energy of 135 MeV by use of in-beam spectroscopic methods. Gamma rays depopulating the excited states were detected using the Gammasphere spectrometer with high-fold γ-ray coincidences. A quadrupole γ-ray coincidence analysis (${\gamma }^4$) has been used to extend the known level scheme. The positive-parity levels have been established up to $J=35/2\hslash$ and $E_x=7.071$ MeV. In addition to the observation of a highly fragmented level scheme belonging to the positive-parity sequences at $E_x~5$ MeV, the termination of a negative-parity sequence connected by $E2$ transitions has been established at $J=47/2\hslash$ and $E_x=11.877$ MeV. The experimental results corresponding to both the positive- and negative-parity sequences have been theoretically interpreted in the framework of the core particle coupling model. Evidence is presented for a shape change from collective prolate to noncollective oblate above the $J^{\pi }=39/2^{-}$ (8011-keV) level and for a smooth termination of the negative-parity band.

The “experimental barrier distribution” provides a parameter-free representation of experimental heavy-ion capture cross sections that highlights the effects of entrance-channel couplings. Its relation to the $s$-wave transmission is discussed, and in particular it is shown how the full capture cross section can be generated from an $l=0$ coupled-channels calculation. Furthermore, it is shown how this transmission can be simply exploited in calculations of quasifission and evaporation-residue cross sections. The system ${}^{48}\mathrm{Ca}+{}^{154}\mathrm{Sm}$ is studied in detail. A calculation of the compound-nucleus spin distribution reveals a possible energy dependence of barrier weights due to polarization arising from target and projectile quadrupole phonon states; this effect also gives rise to an entrance-channel “extra-push.”

The atomic masses of the neutron-deficient radioactive rubidium isotopes ${}^{74-77,79,80,83}\mathrm{Rb}$ have been measured with the Penning trap mass spectrometer ISOLTRAP. Using the time-of-flight cyclotron resonance technique, relative mass uncertainties ranging from $1.6\times {10}^{-8}$ to $5.6\times {10}^{-8}$ were achieved. In all cases, the mass precision was significantly improved as compared with the prior Atomic-Mass Evaluation; no significant deviations from the literature values were observed. The exotic nuclide ${}^{74}\mathrm{Rb}$, with a half-life of only 65 ms, is the shortest-lived nuclide on which a high-precision mass measurement in a Penning trap has been carried out. The significance of these measurements for a check of the conserved-vector-current hypothesis of the weak interaction and the unitarity of the Cabibbo-Kobayashi-Maskawa matrix is discussed.

Two particle azimuthal correlations are studied in $4.2A$ GeV C+Ta collisions observed with the 2-m propane bubble chamber exposed at JINR Dubna Synchrophasotron. The correlations are analyzed both for protons and negative pions, and their dependence on the collision centrality, rapidity and rapidity difference is investigated. It is found that protons show a weak back-to-back correlations, while a side-by-side correlations are observed for negative pions. Restricting both protons to the target or projectile fragmentation region, the side-by-side correlations are observed for protons also. Using the two particle correlation function, the flow analysis is performed and intensity of directed flow is determined without event-by event estimation of the reaction plane.

The decay of extremely neutron deficient ${}^{45}\mathrm{Fe}$ has been studied by means of a new type of a gaseous detector in which a technique of digital imaging was used to record tracks of charged particles. The ${\beta }^{+}$ decay channels accompanied by proton emission were clearly identified. In addition to β-delayed one-proton and β-delayed two-proton decays, β-delayed three-proton emission was recorded which represents the first direct and unambiguous observation of this decay channel. The branching ratio for the β decay of ${}^{45}\mathrm{Fe}$ and the corresponding partial half-life are found to be $0.30\pm 0.04$ and $T_{1/2}(\beta )=8.7\pm 1.3$ ms, respectively.

The ground and excited states of ${}^8\mathrm{He}$ were investigated with a method of antisymmetrized molecular dynamics (AMD). We adopted effective nuclear interactions that systematically reproduce the binding energies of ${}^4\mathrm{He}$, ${}^6\mathrm{He}$, and ${}^8\mathrm{He}$. The ground state of ${}^8\mathrm{He}$ has both the $j\text{−}j$ coupling feature ($p_{3/2}$ closure) and the $L\text{−}S$ coupling feature (${}^4\mathrm{He}$$+2n+2n$) with a slight tail of dineutron at the long distance region. The theoretical results give an indication of the $0_2^{+}$ state with a dineutron gaslike structure, where two dineutrons are moving in an $S$ wave around the α core with a dilute density. The dineutron structure (${}^4\mathrm{He}$$+2n+2n$) of this state is similar to the $3\alpha$-cluster structure of the ${}^{12}\mathrm{C}$($0_2^{+}$) state, which has been interpreted as an α condensate state. Because the ${}^8\mathrm{He}$($0_2^{+}$) state has a significant overlap with the dineutron condensate wave function, we suggest that this theoretically predicted $0_2^{+}$ state is a candidate for the dineutron condensate state.

The presence of isomeric levels with half-lives in the microsecond range has been identified in ${}^{125,126,127,128}\mathrm{Cd}$. Neutron-rich Cd isotopes were produced from the fragmentation of a 120 MeV/nucleon ${}^{136}\mathrm{Xe}$ beam and uniquely identified through their time-of-flight, energy loss, and total kinetic energy. γ rays from these isomeric levels were measured with an array of Ge detectors that were gated for 15 μs by a particle implantation trigger from a stack of Si detectors. The γ rays observed in the decay of ${}^{126,128}\mathrm{Cd}$ isomers populate low-energy levels previously identified in the β decay of ${}^{126,128}\mathrm{Ag}$. The γ rays found in the decay of ${}^{125,127}\mathrm{Cd}$ isomers are consistent with expected yrast structures observed in lighter, odd-mass Cd isotopes. The appearance of these isomers at the point where $N/Z$ exceeds 1.6 is interpreted as an indication of the onset of a weakened neutron-neutron interaction that has been proposed for ${}^{134}\mathrm{Sn}$, whose $N/Z$ also exceeds 1.6.

The binding energy differences of mirror nuclei with $A=15,17,27,39$, and 41 are calculated using a time-odd triaxial relativistic mean field approach with PK1. Compared with the axially deformed RMF calculations with PK1, NL3, and NLSH, the discrepancy between the calculated and experimental values, i.e., Okamoto-Nolen-Schiffer (ONS) anomaly, is systematically reduced by the appropriate treatment of the γ deformation degree of freedom, center-of-mass motion, and core polarization effect.

Aiming at a microscopic description of heavy ion collisions in the beam energy region of about $10A$ GeV, we extend the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) transport model by including a relativistic mean field, in-medium baryon-baryon cross sections, and three-body collisions. The model is then compared with experimental data for central Au+Au collisions at $2A\text{−}10A$ GeV and central Pb+Pb collisions at $30A$ and $40A$ GeV on the proton rapidity spectra, the midrapidity yields of ${\pi }^{+},K^{\pm },$ and $(\Lambda +{\Sigma }^0)$, and the transverse mass spectra of ${\pi }^{\pm }$ and $K^{\pm }$. The three-body collisions increase the inverse slope parameters of the hadron $m_{\perp }$ spectra to good agreement with the data.

With the experimental data from STAR and PHENIX on the centrality dependence of the $p_T$ spectra of protons and antiprotons produced at midrapidity in Au+Au collisions at 200 GeV, we show that for protons and antiprotons there exists a scaling distribution independent of the colliding centrality. The scaling functions can also describe data from BRAHMS for both proton and antiproton spectra at $y=2.2$ and 3.2. The scaling behaviors are shown to be incompatible with the usual string fragmentation scenario for particle production.

An experiment on testing the time-reversal symmetry in the emission of a mixed $E2\text{−}M1$ Mössbauer γ-transition in ${}^{171}\mathrm{Yb}$ has been carried out. The imaginary part of the ratio of a reduced multipole matrix element has been measured by observing the appearance of the additional linear polarization of γ-rays transmitted through the system of resonant filters. The application of this system has made it possible to exclude corrections for the spurious phase that emerges due to the interaction of a $\gamma$-ray with surrounding atomic electrons. In the experiment, the phase $\sin (\Delta \eta )=(6.3\pm 4.6)\times {10}^{-5}$ and the coefficient of self-compensation of the Faraday rotation $k=-(1.1\pm 1.0)\times {10}^{-4}$ have been observed. The limit $\Delta \eta$ has been found equal to $10.9\times {10}^{-5}$. This is the accuracy of determination of the $T$-invariance retention.

The $g$ factor of the $2_1^{+}$ state of ${}^{170}\mathrm{Hf}$ was measured by perturbed γ-γ angular correlation in a static external magnetic field. The result, $g(2_1^{+})=0.28$(5), extends the systematics of $g$ factors of even-even Hf isotopes to $N=98$ and enables a better test of theoretical models. The $g(2_1^{+})$ experimental values of these isotopes exhibit a remarkable constancy as a function of neutron number. This phenomenon, which was also observed for other isotopic chains in the Gd–W range, is explained in terms of a recently proposed empirical model.

New experimental information has been obtained on the μs isomeric cascade in the very neutron-rich ${}^{136}\mathrm{Sb}$ using γ-ray and conversion-electron spectroscopy at the Lohengrin mass spectrometer of the Institut Laue-Langevin. Two new transitions have been observed and their multipolarities determined, resolving the question of the origin of the isomerism. The new level scheme is in good agreement with predictions of a realistic shell-model calculation. The isomeric state is tentatively assigned a spin and parity of $6^{-}$ and a proposed $\pi g_{7/2}\nu (f_{7/2}){}^3$ dominant configuration.

A finite-range density and momentum-dependent effective interaction is used to calculate the density and temperature dependence of the symmetry energy coefficient $C_{\mathrm{sym}}(\rho ,T)$ of infinite nuclear matter. This symmetry energy is then used in the local density approximation to evaluate the excitation energy dependence of the symmetry energy coefficient of finite nuclei in a microcanonical formulation that accounts for thermal and expansion effects. The results are in good harmony with the recently reported experimental data from energetic nucleus-nucleus collisions.

A study of the charge and matter densities and the corresponding rms radii for even-even isotopes of Ni, Kr, and Sn has been performed in the framework of the deformed self-consistent mean-field Skyrme HF+BCS method. The resulting charge radii and neutron skin thicknesses of these nuclei are compared with available experimental data, as well as with other theoretical predictions. The formation of a neutron skin, which manifests itself in an excess of neutrons at distances greater than the radius of the proton distribution, is analyzed in terms of various definitions. Formation of a proton skin is shown to be unlikely. The effects of deformation on the neutron skins in even-even deformed nuclei far from the stability line are discussed.

The pre- and post-scission neutron multiplicities are measured for ${}^{16}\mathrm{O}+{}^{181}\mathrm{Ta}$ and ${}^{19}\mathrm{F}+{}^{178}\mathrm{Hf}$ systems where the same compound nucleus ${}^{197}\mathrm{Tl}$ is formed at the same excitation energies ($E^{*}=72,$ 76, and 81 MeV). The measured pre-scission neutron multiplicities are found to be different for the two reactions and this difference in neutron yield increases with the excitation energy of the compound nucleus. The experimental pre-scission neutron yield is compared with predictions from the statistical model of compound nuclear decay containing the strength of nuclear viscosity as a free parameter. The magnitude of nuclear viscosity required to fit the experimental yield is found to be different for the two reactions. Because the two systems under consideration lie on the two sides of the Businaro-Gallone point, this observation indicates that the entrance channel mass asymmetry plays an important role in determining the number of neutrons emitted prior to scission in fusion-fission reactions.

The lifetime variations of a nuclear level in a plasma environment at thermodynamic equilibrium are discussed. Nuclear excitation and decay processes, including radiative processes, nuclear excitation by electron capture and internal conversion, nuclear excitation by electron transition and bound internal conversion are taken into account. The model is able to deal with any number of nuclear level having an influence on the considered level lifetime. Lifetime variations of several orders of magnitude are observed for various levels on different nuclei. The importance of NEET process on the examples of the ${}^{201}\mathrm{Hg}$ (1.565 keV) and the ${}^{93}\mathrm{Mo}$ (2424.89 keV) isomer levels is especially pointed out.

The axial-vector Ward-Takahashi identity is used to derive mass formulas for neutral pseudoscalar mesons. Flavor symmetry breaking entails nonideal flavor content for these states. Adding that the ${\eta }^{\text{'}}$ is not a Goldstone mode, exact chiral-limit relations are developed from the identity. They connect the dressed-quark propagator to the topological susceptibility. It is confirmed that in the chiral limit the ${\eta }^{\text{'}}$ mass is proportional to the matrix element which connects this state to the vacuum via the topological susceptibility. The implications of the mass formulas are illustrated using an elementary dynamical model, which includes an Ansatz for that part of the Bethe-Salpeter kernel related to the non-Abelian anomaly. In addition to the current-quark masses, the model involves two parameters, one of which is a mass-scale. It is employed in an analysis of pseudoscalar- and vector-meson bound-states. While the effects of $\mathit{SU}(N_f=2)$ and $\mathit{SU}(N_f=3)$ flavor symmetry breaking are emphasized, the five-flavor spectra are described. Despite its simplicity, the model is elucidative and phenomenologically efficacious; e.g., it predicts $\eta \text{−}{\eta }^{\text{'}}$ mixing angles of $~-{15}^{°}$ and ${\pi }^0\text{−}\eta$ angles of $~1^{°}.$