The ${}^7\mathrm{Li}+{}^{28}\mathrm{Si}$ elastic scattering was studied at near-barrier energies, namely, 8, 8.5, 9, 10, 11, 13, 15, and $16\text{MeV}$, with the aim to map the real and imaginary part of the optical potential and therefore probe the threshold anomaly. Angular distributions were measured over a wide angular range of (${\theta }_{\mathrm{lab}}=25°$ to $150°$) for the lower energies and of (${\theta }_{\mathrm{lab}}=10°$ to $100°$) for the higher energies. The present data, together with previous ones on heavier targets (${}^{138}\mathrm{Ba}$ and ${}^{208}\mathrm{Pb}$) at near barrier energies, were analyzed by using optical potentials obtained in a double-folding framework. The results were compared with previous measurements of ${}^6\mathrm{Li}$ on the same targets. It was found that a striking difference occurs between the imaginary potentials of ${}^6\mathrm{Li}$ and ${}^7\mathrm{Li}$, which, respectively, present an increasing and decreasing behavior approaching the barrier from higher to lower energies. On the other hand, this energy variation is not fully reflected to the real part of the potential, as it is described by dispersion relations. The strength of the real potential remains almost constant with a weak declining and uprising trend for the ${}^6\mathrm{Li}$ and ${}^7\mathrm{Li}$, respectively. For a better understanding of our results, continuum-discretized-coupled-channel calculations were also performed and are discussed.

We investigate the hyperon-nucleon interactions in the QCD sum rule starting from the nucleon matrix element of the hyperon correlation function. Through the dispersion relation, the correlation function in the operator product expansion (OPE) is related with its integral over the physical energy region. The dispersion integral around the hyperon-nucleon $\left(YN\right)$ threshold is identified as a measure of the interaction strength in the $YN$ channel. The Wilson coefficients of the OPE for the hyperon correlation function are calculated. The obtained sum rules relate $YN$ interaction strengths to the nucleon matrix elements of the quark-gluon composite operators, which include strange quark operators as well as up and down quark operators. It is found that the $YN$ interaction strengths are smaller than the $NN$ interaction strength since the nucleon matrix elements of strange quark operators are smaller than those of up and down quark operators. Among $YN$ channels $\Lambda N$ channel has stronger interaction than $\Sigma N$ and $\Xi N$ channels. It is also found that the interaction strength is greater in the ${\Sigma }^{+}p\left({\Xi }^{0}p\right)$ channel than in the ${\Sigma }^{-}p\left({\Xi }^{-}p\right)$ channel since the nucleon matrix elements of up quark operators are greater than those of down quark operators. The spin-dependent part is much smaller than the spin-independent part in the $YN$ and $NN$ channels. The results of the sum rules are compared with those of the phenomenological meson-exchange models.

The experimental results of dependence of black fragment azimuth $\left(\varphi \right)$ and projected angle $\left(\psi \right)$ distributions on polar angle $\theta$ in silicon-emulsion collisions at $4.5A\text{GeV}∕c$ (the Dubna momentum) are reported. There are two regions of enhancement around $\varphi =\pm 90°$ for different $\theta$ ranges. These enhancements are due to directed $\left(v_1\right)$ and elliptic $\left(v_2\right)$ flows. The $v_1$ and $v_2$ dependence of values on $\theta$ shows that the directed flow is weak and the elliptic flow is strong in these collisions. A multisource ideal gas model is used to describe the experimental results of dependence. The Monte Carlo calculated results are approximately in agreement with the experimental data.

Calculating single-particle (Nilsson) levels in axially symmetric quadrupole-deformed potentials in coordinate space, the structure of weakly bound neutron orbits is studied in the absence of pair correlation. It is shown that in the wave functions of ${\Omega }^{\pi }=1∕2^{+}$ orbits, where $\Omega$ expresses the projection of the particle angular momentum along the symmetry axis, the $\ell =0\left(s_{1∕2}\right)$ component becomes overwhelmingly dominant as the binding energy of the orbits approaches zero, irrespective of the size of the deformation and the kind of Nilsson orbits. Consequently, all ${\Omega }^{\pi }=1∕2^{+}$ levels become practically unavailable for both deformation and many-body pair correlation, when the levels approach continuum or lie in the continuum.

In a recent paper [M. Horoi, J. Kaiser, and V. Zelevinsky, Phys. Rev. C 67, 054309 (2003)] proposed a method of calculating $J$-, $T$-, and parity-dependent shell model nuclear level densities using centroids and widths for configurations with fixed spin, isospin and parity quantum numbers, and the energies of the yrast states calculated with the exponential convergence method [M. Horoi, A. Volya, and V. Zelevinsky, Phys. Rev. Lett. 82, 2064 (1999); M. Horoi, B. A. Brown, and V. Zelevinsky, Phys. Rev. C 65, 027303 (2002); M. Horoi, B. A. Brown, and V. Zelevinsky, Phys. Rev. C 67, 034303 (2003)]. When used in many major shell model spaces the results are affected by contributions of the spurious center-of-mass states. Attempts to eliminate these contributions would require knowledge of fixed-$J$ centroids and widths for restricted shell model configurations, such as the $N\hslash \omega$ excitations. We derive explicit expressions for matrix elements that can be used to calculate the fixed-$J$ configuration widths and use them to reduce the contribution of the spurious center-of-mass states to the nuclear level density for excitation energies $<20\text{MeV}$. This approach could be also applied to other many-fermion systems, such as atomic clusters.

Reaction $K^{-}p\to {\pi }^0{\pi }^0\Lambda$ was measured at eight incident $K^{-}$ momenta between 514 and $750\text{MeV}∕c$ using the Crystal Ball multiphoton spectrometer. The reaction dynamics are displayed in total cross sections, Dalitz plots, invariant-mass spectra, production angular distributions, and the $\Lambda$ polarization. The ${\pi }^0{\pi }^0\Lambda$ production is dominated by the ${\pi }^0{\Sigma }^0\left(1385\right)$ intermediate state; no trace of other light ${\Sigma }^{\ast }$ states is observed, and the role of the $f_0\left(600\right)$ meson appears to be insignificant. A striking similarity is seen between $K^{-}p\to {\pi }^0{\pi }^0\Lambda$ and ${\pi }^{-}p\to {\pi }^0{\pi }^{0}n$; this can be understood as a consequence of dynamical flavor symmetry.

We construct a scaling function $f\left({\psi }^{\prime }\right)$ for inclusive electron scattering from nuclei within the coherent density fluctuation model (CDFM). The latter is a natural extension to finite nuclei of the relativistic Fermi gas model within which the scaling variable ${\psi }^{\prime }$ was introduced by Donnelly and collaborators. The calculations show that the high-momentum components of the nucleon momentum distribution in the CDFM and their similarity for different nuclei lead to quantitative description of the superscaling in nuclei. The results are in good agreement with the experimental data for different transfer momenta showing superscaling for negative values of ${\psi }^{\prime }$, including those smaller than $-1$.

The cross sections for production of the pentaquark baryon ${\Xi }_5^{+}$ from the reaction $\gamma p\to K^0{K}^0{\Xi }_5^{+}$ and of ${\Xi }_5^{--}$ from the reaction $\gamma n\to K^{+}{K}^{+}{\Xi }_5^{--}$ are evaluated in a hadronic model that includes their couplings to both $\Sigma \overline{K}$ and $\Sigma {\overline{K}}^{*}$. Values for these coupling constants are determined from the empirical $\pi NN\left(1710\right)$ and $\rho NN\left(1710\right)$ coupling constants by assuming that ${\Xi }_5^{+}$, ${\Xi }_5^{--}$, and $N\left(1710\right)$ belong to the same antidecuplet of spin 1∕2 and positive parity as the pentaquark ${\Theta }^{+}$. Introducing empirical form factors at strong interaction vertices, we obtain a cross section of about $0.03–0.6\text{nb}$ for the reaction $\gamma p\to K^0{K}^0{\Xi }_5^{+}$ and about $0.1–0.6\text{nb}$ for the reaction $\gamma n\to K^{+}{K}^{+}{\Xi }_5^{--}$ at photon energy $E_{\gamma }=4.5\text{GeV}$, depending on the value of the coupling constant $g_{K^{*}\Sigma {\Xi }_5}$.

Some general features of the Bethe-Weizsäcker mass formula recently extended to light nuclei have been explored. Though this formula improves fits to the overall binding energy versus neutron number curves of all elements from Li to Bi and it does seem to work well in delineating the positions of all old and new magic numbers through comparison with the experimental data, yet it is not well tuned for predicting finer details like the macroscopic-microscopic calculations. The mass predictions have also been found to be less accurate compared to those by the macroscopic-microscopic calculations. Few cases for light nuclei have been discussed.

Some properties of the modified Bethe-Weizsäcker mass formula (BWM) are discussed. As BWM has no shell effect included, the extra stability or, magicity in nuclei clearly stands out when experimental mass data are compared with BWM predictions. If the shell effect quenches, the BWM predictions come closer to the experimental data.

A new theoretical framework is presented that uses a localized triaxially deformed Gaussian as the single-particle wave packet. The model space enables us to adequately describe both the deformed mean-field structure and the cluster structure within the same framework. The improvement over the original version of antisymmetrized molecular dynamics which uses the spherical Gaussian is verified by its application to the ${}^{20}\mathrm{Ne}$ nucleus. The coexistence and interplay of the cluster structure and the deformed mean-field structure in the low-excited states of ${}^{20}\mathrm{Ne}$ is studied. In particular, the intraband $E2$ transition probabilities in $K^{\pi }=0_1^{+}$ and $2^{-}$ bands are reproduced without any effective charge.

The level scheme of ${}^{190}\mathrm{Au}$ was extended up to high spin using $\gamma$ spectroscopy with the Eurogam-II array and internal conversion measurements with the electron-$\gamma$ spectrometer of Orsay. Several sets of rotation-aligned bands were found and associated with high-$j$, low-$K$ configurations. According to the total Routhian surface and cranked shell model calculations these bands are caused by the nonaxiality of the nuclear deformation $\left(\gamma ⩽-70°\right)$. Furthermore, very good agreement was obtained between the experimental data and the theoretical predictions for the properties of these bands, such as alignments, band-crossing frequencies, and signature inversion, thus supporting the suggested nonaxial shapes.

We show that an unambiguous way of determining the universal limiting fragmentation region is to consider the derivative $\left(d^{2}n∕d{\eta }^2\right)$ of the pseudorapidity distribution per participant pair. In addition, we find that the transition region between the fragmentation and the central plateau regions exhibits a second kind of universal behavior that is only apparent in $d^{2}n∕d{\eta }^2$. The $\sqrt{s}$ dependence of the height of the central plateau ${(dn∕d\eta )}_{\eta =0}$ and the total charged particle multiplicity $n_{\text{total}}$ critically depend on the behavior of this universal transition curve. Analyzing available Relativistic Heavy-Ion Collider (RHIC) data, we show that ${(dn∕d\eta )}_{\eta =0}$ can be bounded by ${\ln }^{2}s$ and $n_{\text{total}}$ can be bounded by ${\ln }^{3}s$. We also show that the deuteron-gold data from RHIC has exactly the same features as the gold-gold data indicating that these universal behaviors are a feature of the initial state parton-nucleus interactions and not a consequence of final state interactions. Predictions for LHC energy are also given.

Exclusive electroproduction of ${\pi }^0$ mesons on protons in the backward hemisphere has been studied at $Q^2=1.0{\text{GeV}}^2$ by detecting protons in the forward direction in coincidence with scattered electrons from the $4\text{GeV}$ electron beam in Jefferson Lab’s Hall A. The data span the range of the total $\left(\gamma *p\right)$ center-of-mass energy $W$ from the pion production threshold to $W=2.0\text{GeV}$. The differential cross sections ${\sigma }_{\mathrm{T}}+ϵ{\sigma }_{\mathrm{L}}$, ${\sigma }_{\text{TL}}$, and ${\sigma }_{\text{TT}}$ were separated from the azimuthal distribution and are presented together with the MAID and SAID parametrizations.

The density dependencies of various effective interaction strengths in the relativistic mean field are studied and carefully compared for nuclear matter and neutron stars. The influences of different density dependencies are presented and discussed on mean field potentials, saturation properties for nuclear matter, equations of state, maximum masses, and corresponding radii for neutron stars. Though the interaction strengths and the potentials given by various interactions are quite different in nuclear matter, the differences of saturation properties are subtle, except for NL2 and TM2, which are mainly used for light nuclei, while the properties by various interactions for pure neutron matter are quite different. To get an equation of state for neutron matter without any ambiguity, it is necessary to constrain the effective interactions either by microscopic many-body calculations for the neutron matter data or the data of nuclei with extreme isospin. For neutron stars, the interaction with large interaction strengths give strong potentials and large Oppenheimer-Volkoff (OV) mass limits. The density-dependent interactions DD-ME1 and TW-99 favor a large neutron population due to their weak $\rho$-meson field at high densities. The OV mass limits calculated from different equations of state are $2.02–2.81M_{☉}$, and the corresponding radii are $10.78–13.27\text{km}$. After the inclusion of the hyperons, the corresponding values become $1.52–2.06M_{☉}$ and $10.24–11.38\text{km}$.

The paper does not take into account previous work where the effect the authors discuss is explored in detail. It is known from this previous work that the approach is incomplete.

A comparison is made between a Brueckner-Hartree-Fock study of spin polarized nuclear matter allowing for deformation of the Fermi spheres and studies of such systems in terms of the Landau parametrization of the effective interaction.

It is proved that the potentials of the form ${\beta }^{2n}$ (with $n$ being integer) provide a “bridge” between the U(5) symmetry of the Bohr Hamiltonian with a harmonic oscillator potential (occurring for $n=1$) and the E(5) model of Iachello (Bohr Hamiltonian with an infinite well potential, materialized for $n\to \infty$). Parameter-free (up to overall scale factors) predictions for spectra and $B\left(E2\right)$ transition rates are given for the potentials ${\beta }^4$, ${\beta }^6$, and ${\beta }^8$, corresponding to $R_4=\mathrm{E}\left(4\right)∕\mathrm{E}\left(2\right)$ ratios of 2.093, 2.135, and 2.157, respectively, compared to the $R_4$ ratios 2.000 of U(5) and 2.199 of E(5). Hints about nuclei showing this behavior, as well as about potentials bridging the E(5) symmetry with O(6) are briefly discussed. A note about the appearance of Bessel functions in the framework of $\mathrm{E}\left(n\right)$ symmetries is given as a by-product.

The high spin level structure of ${}^{104}\text{Ag}$ has been extended to $I^{\pi }={20}^{+}$ and excitation energy of $7.159\text{MeV}$ through the discrete line $\gamma$-ray spectroscopy. The negative parity ground state band has been confirmed and extended to $I^{\pi }={18}^{-}$. Two new nonyrast dipole bands, one with positive and the other with negative parity, have been observed. The parities of the two bands have been established through polarization directional correlation measurement of the feed-out transitions from these bands. The level lifetimes have been measured in the ground state band and the positive parity dipole band. The measured total angular momenta and the $B\left(M1\right)$ rates have been compared with the predictions of hybrid version of the tilted axis cranking. The $B\left(M1\right)$ rates have also been compared with the values obtained from Dönau’s geometric formula. The tilted axis calculations give good overall agreement which suggests that all the three bands of ${}^{104}\text{Ag}$ exhibits magnetic rotation.

We analyze the $\alpha$ decay between ground states along $N-Z$ chains in deformed heavy and superheavy nuclei, by using the pairing approach. We show that the derivative of the preformation amplitude is practically a constant along any $\alpha$ chain, while that of the outgoing wave function changes exponentially upon the Coulomb parameter. This leads to the breakdown of the continuity equation and therefore to wrong decay widths. The behavior cannot be explained within the standard shell model. We significantly correct this deficiency by considering an $\alpha$-cluster factor in the preformation amplitude, depending exponentially upon the Coulomb parameter. Thus, four-body correlations, connected with the radial shape of the preformation factor, are directly evidenced by the $\alpha$-decay systematics. Moreover, this procedure, in principle, fully determines the $Q$ value and is an important development in the $\alpha$-decay theory. It also allows us to analyze the relative $\alpha$-clustering structure of the emitter. It turns out that the isotopes close to the region $N>126$ and superheavy nuclei have a stronger clustering behavior. For superheavy region an additional dependence upon the number of interacting $\alpha$ particles is necessary.