Indications for isospin impurity in the transition from the ground state to the first $2^{+}$ states of ${}^{30}\mathrm{S}$ and ${}^{30}\mathrm{Si}$ mirror nuclei are given, using electromagnetic and proton scattering probes. The ${}^{30}\mathrm{S}$ neutron and proton transition matrix elements are compared to the corresponding experimental mirror quantities in the ${}^{30}\mathrm{Si}$ nucleus, indicating a possible charge independence violation. The experimental ${}^{30}\mathrm{Si}$ neutron transition density deduced from previous $\left(p,p^{\prime }\right)$ scattering is found larger than the ${}^{30}\mathrm{S}$ proton transition density. Electromagnetic data on ${}^{30}\mathrm{P}$ are also incompatible with charge independence in the $T=1\left({}^{30}\mathrm{Si},{}^{30}\mathrm{P},{}^{30}\mathrm{S}\right)$ isobaric multiplet.

A wide variety of observables indicate that maximal fluctuations in the disassembly of hot nuclei with $A\sim 36$ occur at an excitation energy of $5.6\pm 0.5\text{MeV}∕\text{nucleon}$ and temperature of $8.3\pm 0.5\text{MeV}$. Associated with this point of maximal fluctuations are a number of quantitative indicators of apparent critical behavior. The associated caloric curve does not appear to show a flattening such as that seen for heavier systems. This suggests that, in contrast to similar signals seen for liquid-gas transitions in heavier nuclei, the observed behavior in these very light nuclei is associated with a transition much closer to the critical point.

As part of a measurement [E. Anciant et al., Phys. Rev. Lett. 85, 4682 (2000)] of the cross section of $\varphi$ meson photoproduction to high momentum transfer, we measured the polar angular decay distribution of the outgoing $K^{+}$ in the channel $\varphi \to K^{+}{K}^{-}$ in the $\varphi$ center-of-mass frame (the helicity frame). We find that $s$-channel helicity conservation (SCHC) holds in the kinematical range where $t$-channel exchange dominates (up to $-t\sim 2.5{\text{GeV}}^2$ for $E_{\gamma }=3.6\text{GeV}$). Above this momentum, $u$-channel production of a $\varphi$ meson dominates and induces a violation of SCHC. The deduced value of the $\varphi NN$ coupling constant lies in the upper range of previously reported values.

The reaction cross sections of ${}^{27,28}\mathrm{P}$ and the corresponding isotones on Si target were measured at intermediate energies. The measured reaction cross sections of the $N=12$ and 13 isotones show an abrupt increase at $Z=15$. The experimental results for the isotones with $Z⩽14$ as well as ${}^{28}\mathrm{P}$ can be well described by the modified Glauber theory of the optical limit approach. The enhancement of the reaction cross section for ${}^{28}\mathrm{P}$ could be explained in the modified Glauber theory with an enlarged core. Theoretical analysis with the modified Glauber theory of the optical limit and few-body approaches underpredicted the experimental data of ${}^{27}\mathrm{P}$. Our theoretical analysis shows that an enlarged core together with proton halo are probably the mechanism responsible for the enhancement of the cross sections for the reaction of ${}^{27}\mathrm{P}+{}^{28}\mathrm{Si}$.

We derive a set of relaxation equations describing the chemical equilibration of gluons, quarks, and $s$ quarks at finite baryon density based on Jüttner distribution of partons, and investigate strangeness production, chemical equilibration, and evolution. We find that strangeness production depends sensitively on initial values, furthermore, the increase of the quark phase lifetime with increasing initial quark chemical potential obviously heightens strangeness production. In addition, the obvious difference between the calculated strangeness and the one in the thermodynamic equilibrium system shows that the study of strangeness in the chemically equilibrating system is very significant.

A dispersion integral is derived that allows one to relate directly (spin-dependent) $\Lambda N$ invariant mass spectra, measured in a large-momentum transfer reaction such as $pp\to K^{+}p\Lambda$ or $\gamma d\to K^{+}n\Lambda$, to the scattering length for elastic $\Lambda N$ scattering. The involved systematic uncertainties are estimated and could be $0.3\text{fm}$ or even smaller. This estimate is confirmed by comparing results of the proposed formalism with those of microscopic model calculations. We also show, for the specific reaction $pp\to K^{+}\Lambda p$, how polarization observables can be used to separate the two spin states of the $\Lambda N$ system.

The wobbling motion excited on triaxial superdeformed nuclei is studied in terms of the cranked shell model plus random phase approximation. First, by calculating at a low rotational frequency the $\gamma$ dependence of the three moments of inertia associated with the wobbling motion, the mechanism of the appearance of the wobbling motion in positive-$\gamma$ nuclei is clarified theoretically—the rotational alignment of the $\pi i_{13∕2}$ quasiparticle(s) is the essential condition. This indicates that the wobbling motion is a collective motion that is sensitive to the single-particle alignment. Second, we prove that the observed unexpected rotational-frequency dependence of the wobbling frequency is an outcome of the rotational-frequency dependent dynamical moments of inertia.

Global equilibrium fragmentation inside a freeze-out constraining volume is a working hypothesis widely used in nuclear fragmentation statistical models. In the framework of classical Lennard-Jones molecular dynamics, we study how the relaxation of the fixed volume constraint affects the posterior evolution of microscopic correlations, and how a nonconfined fragmentation scenario is established. A study of the dynamical evolution of the relative kinetic energy fluctuations was also performed. We found that asymptotic measurements of such an observable can be related to the number of decaying channels available to the system at fragmentation time.

We calculate the magnetic moments of the pentaquark states from different models and compare our results with predictions of other groups.

The recent high statistics measurement of the $pp\to pp\eta$ reaction at an excess energy $Q=15.5\text{MeV}$ has been analyzed by means of partial wave decomposition of the cross section. Guided by the dominance of the final state ${}^{1}S_{0}pp$ interaction (FSI), we keep only terms involving the FSI enhancement factor. The measured $pp$ and $\eta p$ effective mass spectra can be well reproduced by lifting the standard Watson-Migdal approximation in the enhancement factor and by allowing for a linear energy dependence in the leading ${}^{3}P_0\to {}^{1}S_0,s$ partial wave amplitude. Higher partial waves seem to play only a marginal role.

Fission fragment mass distribution has been studied for the system ${}^{19}\mathrm{F}+{}^{232}\mathrm{Th}$ over an energy range of $105.4\text{MeV}$ to $84.2\text{MeV}$ in laboratory frame. For energies, above the Coulomb barrier, the variance of the mass distributions ${\sigma }_m^2$ varies linearly with temperature of the fused system, signifying statistical fusion-fission reaction. However, as energy decreases through the Coulomb barrier, a rapid increase in ${\sigma }_m^2$ is observed for the first time which may be a signal of onset of orientation dependent quasifission reaction.

High accuracy, absolute measurements of the neutron total cross section for ${}^3\mathrm{He}$ are reported for incident neutron energies $0.1–400\text{eV}$. The measurements were performed at the LANSCE short-pulse neutron spallation source. Using the previously determined cross section for neutron elastic scattering, $3.367\pm 0.019\mathrm{b}$, we extract a new value for the energy dependence of the ${}^3\mathrm{He}(n,p){}^3\mathrm{He}$ reaction cross section, ${\sigma }_{np}=(849.77\pm 0.14\pm 1.02)E^{-1∕2}-(1.253\pm 0.00{\pm }_{-0.049}^{+0.008})\mathrm{b}$, where the neutron energy is expressed in eV. The first uncertainty is statistical, the second systematic.

The limiting temperature $T_{\mathit{lim}}$ of a series of nuclei is calculated employing a set of microscopic nuclear equations of state (EOS’s). It is shown that the value of $T_{\mathit{lim}}$ is sensitive to the nuclear matter equation of state used. Comparison with the values extracted in recent phenomenological analysis appears to favor a definite selection of EOS’s. On the basis of this phenomenological analysis, it therefore seems possible to check the microscopic calculations of the nuclear EOS at finite temperature, which is hardly accessible through other experimental information.

We evaluate the hyperfine splitting of hydrogenlike ${}^{209}\mathrm{Bi}$ and ${}^{207}\mathrm{Pb}$ atoms based on a relativistic method for both the electron system and the nucleon system. The Bohr-Weisskopf (BW) effect is calculated with Lorentz covariant current. It is shown that the BW correction to the hyperfine splitting (HFS) is $0.58\%–0.67\%$ for ${}^{209}\mathrm{Bi}^{82+}$ and $3.79\%–4.00\%$ for ${}^{207}\mathrm{Pb}^{81+}$. It is also concluded that relativistic mean field theory reproduces the observed values of the HFS within the accuracy of $5\%$ in ${}^{209}\mathrm{Bi}^{82+}$ and $13\%$ in ${}^{207}\mathrm{Pb}^{81+}$.

A matrix coherent-state approach is applied to the interacting boson model (IBM) with configuration mixing to describe the evolving geometry of neutron-deficient Pb isotopes. It is found that for small mixing with parameters determined previously, the potential energy surface of ${}^{186}\mathrm{Pb}$ has three minima, which correspond to spherical, oblate, and prolate shapes, in agreement with recent measurements and mean-field calculations. Away from midshell, in the heavier Pb isotopes, no deformed minima occur. Our analysis suggests that the configuration-mixing IBM, used in conjunction with a matrix coherent-state method, may be a reliable tool for the study of geometric aspects of shape coexistence in nuclei.

Experimentally observed heaviest $N\approx Z$ nuclei, $\text{Ru}$ isotopes, are investigated by the shell model on a spherical basis with the extended $P+QQ$ Hamiltonian. The energy levels of all the $\text{Ru}$ isotopes can be explained by the shell model with a single set of force parameters. The calculations indicate an enhancement of quadrupole correlations in the $N=Z$ nucleus ${}^{88}\mathrm{Ru}$ as compared with the other Ru isotopes, but the observed moments of inertia seem to require much more enhancement of quadrupole correlations in ${}^{88}\mathrm{Ru}$. It is discussed that the particle alignment takes place at $8^{+}$ in ${}^{90}\mathrm{Ru}$ but is delayed in ${}^{88}\mathrm{Ru}$ till ${16}^{+}$ where the simultaneous alignments of proton and neutron pairs take place. The calculations present interesting predictions for ${}^{89}\mathrm{Ru}$ that the ground state is the $1∕2^{-}$ state and there are three $\Delta J=2$ bands with different particle alignments including the $T=0$ $p\text{−}n$ pair alignment.

The ground and first excited states in ${}^{15}\mathrm{F}$ were studied in resonant elastic scattering using the thick $\left({\text{CH}}_4\right)$ gas target method in inverse kinematics with a separated ${}^{14}\mathrm{O}$ beam. An analysis of the excitation functions of the elastic scattering was carried out with the potential model. The quantum numbers $1∕2^{+}$ (ground state) and $5∕2^{+}$ (first excited state) were assigned to the lowest two states in ${}^{15}\mathrm{F}$. Also, the widths and the proton decay energies of the unbound levels were obtained. The analysis of the data indicates that a large diffuseness is needed in the Woods-Saxon potential in order to describe single-particle features in drip-line nuclei.

The eigenfunctions and eigenenergies for a Dirac Hamiltonian with equal scalar and vector harmonic oscillator potentials are derived. Equal scalar and vector potentials may be applicable to the spectrum of an antinucleon embedded in a nucleus. Triaxial, axially deformed, and spherical oscillator potentials are considered. The spectrum has a spin symmetry for all cases and, for the spherical harmonic oscillator potential, a higher symmetry analogous to the SU(3) symmetry of the nonrelativistic harmonic oscillator is discussed.

New parameter sets for the Lagrangian density in the relativistic mean field (RMF) theory, PK1 with nonlinear $\sigma$- and $\omega$-meson self-coupling, PK1R with nonlinear $\sigma$-, $\omega$-, and $\rho$-meson self-coupling, and PKDD with the density-dependent meson-nucleon coupling are proposed. They are able to provide an excellent description not only for the properties of nuclear matter but also for the nuclei in and far from the valley of $\beta$ stability. For the first time in the parametrization of the RMF Lagrangian density, the center-of-mass correction is treated by a microscopic way, which is essential to unify the description of nuclei from light to heavy regions with one effective interaction.

The $g$ factor of the first excited $2^{+}$ state of ${}^{164}\mathrm{Yb}$ was measured by perturbed $\gamma \text{−}\gamma$ angular correlation in an external static magnetic field of $5.55\mathrm{T}$. The result, $g\left(2_1^{+}\right)=0.32\left(5\right)$, extends the systematics of $g\left(2_1^{+}\right)$ for Yb isotopes down to $N=94$. The behavior of the known experimental values of $g\left(2_1^{+}\right)$ vs neutron number $N$ for all isotopic chains from Ba to Pt is discussed. Several trends are observed: for some chains, especially in transitional regions, a rather strong $N$ dependence of the $g$ factors is observed; in regions of stable structure this dependence is much weaker, and for the Yb and Pt chains it is almost flat. While the different behaviors can be separately explained by valence or collective models, a unified interpretation of these systematic trends remains a challenge to microscopic theories.