We study the structure of $\Lambda \mathrm{}\left(1405\right)\mathrm{}$ by means of a coupled-channel potential model and by fitting low-energy $\overline{K}N$ data, including the $K^{-}p$ scattering length obtained from the latest x-ray measurements of the kaonic hydrogen atom. From the best fit obtained, we find two possible interpretations of $\Lambda \mathrm{}\left(1405\right),$ either as (1) the ${70}^{-}$ three-quark state strongly coupled with $\overline{K}N$ and $\pi \Sigma$ or (2) a $\pi \Sigma$ resonance and/or an unstable $\overline{K}N$ bound state. In the latter case, the three-quark state that belongs to the ${70}^{-}$ multiplet is located slightly above the $\overline{K}N$ threshold and results in a sharp resonance peak in the $K^{-}p$ elastic cross section at laboratory momentum $170\hspace{0.5em}\mathrm{MeV}/c.\mathrm{}$ To explore these possibilities, measurements of the $\pi \Sigma$ invariant mass distribution and the $K^{-}p$ cross sections with finer resolution are required.

The nucleon effective mass, binding energy, and neutron star configuration in the relativistic mean-field (RMF) theory are considered. The calculations are motivated by the construction of the equation of state for a neutron star in the RMF theory. The equations of state for different parameter sets are calculated using the Feynman-Bogoliubov variational method for temperature different from zero. Various equations of state enable the construction of neutron star models.

The ${}^{138}\mathrm{La}\hspace{0.5em}{\beta }^{-}$ decay constant was determined geophysically. The isotopic growths of ${}^{138}{\mathrm{C}\mathrm{e}/}^{142}\mathrm{Ce}$ and ${}^{143}{\mathrm{N}\mathrm{d}/}^{144}\mathrm{Nd}$ were examined from ancient igneous crystalline rocks. For the Ce isotope measurement, a newly developed dynamic multicollector technique was applied. The crystallization age of the rocks was calculated to be $2037\pm 13$ Myr from the growth of ${}^{143}\mathrm{Nd}.$ From the age and the growth of ${}^{138}\mathrm{Ce},$ ${\lambda }_{\beta }$ of ${}^{138}\mathrm{La}$ was estimated to be $(2.37\mathrm{}\pm 0.10)\times {10}^{-12}\hspace{0.5em}{\mathrm{yr}}^{-1}.$ This value is consistent with those of the latest two $\gamma$-ray counting data of lanthanum compounds within the analytical error.

Mean lifetimes of 24 excited states in ${}^{128}\mathrm{Ba}$ populated via the ${}^{116}\mathrm{Cd}{(}^{16}\mathrm{O},4n)$ reaction at $E=76\mathrm{}\mathrm{MeV}$ were measured by means of the recoil-distance Doppler-shift method in coincidence mode. A new version of the differential decay-curve method which takes into account the velocity distribution of the recoils and the effect of the Doppler-shift attenuation in the stopper was applied for the lifetime determination. The $B\left(E2\mathrm{}\right)\mathrm{}$ values in the ground-state band indicate a reduction of the transition strengths which may be partly explained by the O(6) limiting case of the interacting boson model or alternatively, by rotationally induced changes in the single-particle level structure at spins higher than $I^{\pi }{=4\mathrm{}}^{+}.$ The general collective (or Frankfurt) model is found to describe well the intraband transition strengths in the quasi-γ band which also exhibit the features characteristic for a $K=2\mathrm{}ħ$ rotational band. However, none of the collective models applied can describe in a consistent way all observed properties of the low-lying collective states. The newly measured $B(E2,\overrightarrow{I}I-2)$ and $B(M1,\overrightarrow{I}I-1)$ transition strengths reconfirm the configuration $\pi h_{11/2}{d}_{5/2}$ of the negative-parity semidecoupled bands. The lowest levels of the higher-lying “dipole” band in ${}^{128}\mathrm{Ba},$ which is built on the high-K four-quasiparticle prolate configuration $\left(\pi h_{11/2}{d}_{5/2}\right)\otimes \left(\nu h_{11/2}{g}_{7/2}\right),$ are studied.

Results of fission fragment mass-energy distributions of the compound ${}^{226}\mathrm{Th}$ nucleus formed in the sub-barrier fusion reaction ${}^{18}\mathrm{O}{+}^{208}\mathrm{Pb}$ at an energy of ${}^{18}\mathrm{O}$ ions $E_{\mathrm{lab}}=78\mathrm{}$ MeV are reported. The reaction has been studied twice using two different accelerators, and both sets of experimental data agree quite well. Performed analysis of the experimental data with the use of a new multicomponent method has shown that alongside the well-known modes, i.e., the symmetric (S) and two asymmetric modes standard-one and standard-two, a high-energy mode standard-three has manifested itself. The last named mode appears due to the influence of the close-to-sphere neutron shell with $N\approx 50$ in the light fission fragment group. Theoretical calculations of the prescission shapes of the fissioning nuclei ${}^{224,226}\mathrm{Th}$ confirm this conclusion.

The ${}^{12}\mathrm{C}(\gamma ,np)$ and ${}^{12}\mathrm{C}(\gamma ,pp)$ reactions have been studied using the Glasgow photon tagging spectrometer at the Mainz MAMI electron microtron for $E_{\gamma }=150\mathrm{}–700$ MeV over a kinematic range which extends well beyond the approximately back-to-back detector arrangements of previous work. For ${}^{12}\mathrm{C}(\gamma ,np)$ the general trends of the missing energy distributions are reproduced over a wide range of kinematics and photon energies by the theory developed by the Valencia group. The corresponding ${}^{12}\mathrm{C}(\gamma ,pp)$ channel is overestimated by a factor of ∼3. Detailed comparisons of the experimental data with a Monte Carlo simulation of the direct $2N$ knockout process provide the first evidence above the $\Delta$ resonance for direct $2N$ knockout and show that this process dominates the ${}^{12}\mathrm{C}(\gamma ,np)$ reaction at low missing energies up to $E_{\gamma }\sim 700$ MeV. The ${}^{12}\mathrm{C}(\gamma ,pp)$ reaction is somewhat less well described by the Monte Carlo simulation. A possible explanation of the observed discrepancies within a direct $2N$ framework is presented. At high recoil momenta both $2N$ reaction channels exhibit an excess yield compared to the Monte Carlo prediction of direct $2N$ knockout. The excess yield in this region is compared with the predicted effects of short-range correlations and with the predicted contributions due to other reaction mechanisms.

The space-averaged phase-space density and entropy per particle are both fundamental observables which can be extracted from the two-particle correlation functions measured in heavy-ion collisions. Two techniques have been proposed to extract the densities from correlation data: either by using the radius parameters from Gaussian fits to meson correlations or by using source imaging, which may be applied to any like-pair correlation. We show that the imaging and Gaussian fits give the same result in the case of meson interferometry. We discuss the concept of an equivalent instantaneous source on which both techniques rely. We also discuss the phase-space occupancy and entropy per particle. Finally, we propose an improved formula for the phase-space occupancy that has a more controlled dependence on the uncertainty of the experimentally measured source functions.

The ${}^{176}\mathrm{Lu}$ properties as a cosmochronometer and a cosmothermometer are studied, combining Coulomb excitation with the recoil method. The results confirm that this isotope should be dismissed as a reliable cosmochronometer. On the other hand, this nucleus synthesis takes place, in all probability, at temperatures between ${2.35}_{10}$ and ${3.6}_2\times {10}^8\hspace{0.5em}\mathrm{K}.$ The assignment of the levels reached leads to some difficulties as to their reduced transition probabilities.

The giant dipole resonances (GDR) of ${}^{120}\mathrm{Sn}$ are calculated in linear response theory incorporating the thermal shape fluctuations within the static path approximation (SPA). This is the first application of such an approach to the GDR in a realistic nucleus at finite temperature and angular momentum using a model Hamiltonian with a quadrupole-quadrupole interaction. The results obtained show that thermal fluctuations of quadrupole shapes increase the GDR width only by about $15\%$ at $T=4\mathrm{}\hspace{0.5em}\mathrm{MeV}$ compared to its value at $T=0.\mathrm{}$ The effect of angular momentum on the damping of the hot GDR of this nucleus increases the GDR width by $\sim 22\%$ at $T=2\mathrm{}\hspace{0.5em}\mathrm{MeV}$ and $J\simeq 69ħ$ compared to its value at $T=2\mathrm{}\hspace{0.5em}\mathrm{MeV}$ and $J=0.\mathrm{}$ A combined effect of temperature and angular momentum leads to a GDR energy that is nearly independent of the excitation energy.

We evaluate thermodynamical quantities and transport coefficients of a dense and hot hadronic matter based on the event generator URASiMA (Ultra-Relativistic AA collision Simulator based on Multiple Scattering Algorithm). The statistical ensembles in equilibrium with fixed temperature and chemical potential are generated by imposing periodic boundary conditions to the simulation of the URASiMA, where energy density and baryon number density are conserved. Achievements of the thermal equilibrium and the chemical equilibrium are confirmed by the common value of the slope parameter in the energy distributions and the saturation of the numbers of contained particles, respectively. By using the generated ensembles, we investigate the temperature dependence and the chemical potential dependence of the baryon diffusion constant of a dense and hot hadronic matter.

Three mutually perpendicular symmetry axes of the second order, inversion, and time reversal can be used to construct a double point group denoted by $D_{2h}^{\mathrm{TD}}.$ Properties of this group are analyzed in relation to the symmetry and symmetry-breaking effects within the mean-field (Hartree-Fock) theories, both in even and odd fermion systems. We enumerate space symmetries of local one-body densities, and symmetries of electromagnetic moments, that appear when some or all of the $D_{2h}^{\mathrm{TD}}$ elements represent self-consistent mean-field symmetries.

We analyze breaking of symmetries that belong to the double point group $D_{2h}^{\mathrm{TD}}$ (three mutually perpendicular symmetry axes of the second order, inversion, and time reversal). Subgroup structure of the $D_{2h}^{\mathrm{TD}}$ group indicates that there can be as many as 28 physically different, broken-symmetry mean-field schemes — starting with solutions obeying all the symmetries of the $D_{2h}^{\mathrm{TD}}$ group, through 26 generic schemes in which only a nontrivial subgroup of $D_{2h}^{\mathrm{TD}}$ is conserved, down to solutions that break all of the $D_{2h}^{\mathrm{TD}}$ symmetries. Choices of single-particle bases and the corresponding structures of single-particle Hermitian operators are discussed for several subgroups of $D_{2h}^{\mathrm{TD}}.$

Complete dynamical investigation of the extremely neutron-rich ${}^5\mathrm{H}$ nucleus is performed in a three-body ${}^3\mathrm{H}+n+n$ continuum. A three-body resonance enhancement is found for the “ground state” $J^{\pi }{=1/2\mathrm{}}^{+}$ at about 2.5–3.0 MeV. The broad structures in the production cross sections correspond to wide ${3/2}^{+}$ and ${5/2}^{+}$ levels in the three-body continuum.

Rotational bands in ${}^{73}\mathrm{Br}$ have been investigated up to spins of $I=65/2\mathrm{}$ using the EUROBALL III spectrometer. One of the negative-parity bands displays the highest rotational frequency $ħ\omega =1.85\mathrm{}\mathrm{MeV}$ reported to date in nuclei with $A>~25.$ At high frequencies, the experimental ${\mathcal{J}}^{\mathrm{}\left(2\right)\mathrm{}}$ dynamic moment of inertia for all bands decreases to very low values, ${\mathcal{J}}^{\mathrm{}\left(2\right)\mathrm{}}<~10{ħ}^2{\mathrm{MeV}}^{-1}.$ The bands are described in the configuration-dependent cranked Nilsson–Strutinsky model. The calculations indicate that one of the negative-parity bands is observed up to its terminating single-particle state at spin 63/2. This result establishes the first band termination in the $A\approx 70$ mass region.

The degrees of the deformation of atomic nuclei at scission configurations of the mass-symmetric and mass-asymmetric fission modes are studied. The β shape elongation of the fissioning nucleus, associated with the asymmetric fission is found to be constant for $A_f=213\mathrm{}–260,$ while that associated with the symmetric fission is larger but also constant for a wide range of fissioning nuclei ${(A}_f=205\mathrm{}–260)$ except for the low-energy induced and spontaneous fission of heavy nuclei with $A_f=245\mathrm{}–262$ where a change of the nucleon number by one unit is found to cause a very rapid change in β. A systematic correlation between the scission deformation and the fission properties such as the mass-yield distribution and the TKE are found. The constancy of the β gives rise to new formulas of ${\mathrm{TKE}}_{\mathrm{sym}}=0.1173\mathrm{}\times {(Z}_f^2{/A}_f^{1/3})+7.5\mathrm{}\mathrm{MeV}$ for symmetric fission, and of ${\mathrm{TKE}}_{\mathrm{asym}}=0.1217\mathrm{}\times {(Z}_f^2{/A}_f^{1/3})+3.5\mathrm{}\mathrm{MeV}$ for asymmetric fission. The physical origin of the well-known simple linear function for the TKE released in the fission process is found to be the invariance of the degrees of the elongation of scissioning nuclei. The mass dispersion of fission products was found to have a direct correlation with the β value; as β becomes larger, the width of the mass yield distribution becomes wider. Our understanding of the spontaneous fission properties of heavy nuclides in the ${}^{258}\mathrm{Fm}$ region is presented. In this region, two different scission configurations, one giving $\beta \sim 1.53$ which is the characteristic value for the asymmetric deformation and the other giving $\beta \sim 1.33$ which is for the symmetric deformation, are found.

Quasielastic excitation functions for the ${}^{12,13}\mathrm{C}{+}^{105,106}\mathrm{Pd}$ systems were measured at near barrier energies. The representations of the fusion barrier distributions derived from the measured cross sections were analyzed by comparison with simplified coupled-channel calculations. The influence of transfer reaction channels can be distinguished from that due to the inelastic excitation. The influence of two-phonon state on the barrier distributions was evaluated.

We performed a nuclear matter G-matrix calculation removing the angle-average approximation from the treatment of the Pauli exclusion operator. Although the corrections to the standard angle-averaged matrix elements are very small, the dependence of the new G matrix on the projection quantum number M of the relative angular momentum J is significant on the scale of typical medium effects.

Charged particle multiplicities from high-multiplicity interactions of 158 GeV/nucleon Pb ions with Pb target nuclei have been measured using high-resolution nuclear emulsion chambers with sensitivity from the peak of the pseudorapidity distribution forward to $\eta >9.\mathrm{}$ The characteristics of these interactions have been compared to those of central interactions of 200 GeV/nucleon proton, O, and S beams on silver or bromine targets and to results from simulations using the FRITIOF 7.02 and VENUS 4.12 Monte Carlo event generators. Multiplicities scale with the number of wounded nucleons, although the multiplicities for Pb+Pb interactions in the central region are significantly lower than predicted by either Monte Carlo model. We examine the shape of the pseudorapidity distribution and its dependence on centrality in detail, because in this symmetric system the participant projectile target masses are independent of centrality, so any dependence of the shape on centrality must therefore be a dynamical effect. No dependence of the produced particle pseudorapidity distribution on multiplicity or centrality is seen. VENUS, the only one of the two models which attempts to incorporate reinteraction phenomena, predicts a narrowing of the pseudorapidity distributions for the highest multiplicity events, which we do not observe. In general, FRITIOF produces better fits to the all-charged-particle (primarily pion) data than does VENUS.

An additional term should be added to the thermopotential if the quark masses are density dependent. The strange quark matter is discussed in this self-consistent method. In addition to the ordinary density function of quark masses, another one is also assumed. There exists a region in which strange quark matter is stable at zero temperature.

Production of lepton pairs in the $\gamma \overrightarrow{p}{e}^{-}{e}^{+}p$ reaction is studied at photon energies up to 1 GeV. We show that even if lepton charge is not measured there are extensive kinematical regimes where the nuclear process dominates over the Bethe-Heitler contribution. The decomposition is performed of the unpolarized cross section for virtual Compton scattering in terms of response functions. These are expressed in terms of a polarization density matrix of the virtual photon and are shown to be sensitive to the properties of baryon resonances in the first and the second resonance regions. In the analysis a unitary K-matrix model is used, based on an effective Lagrangian including nucleon, mesons, and baryon resonances with masses up to 1.7 GeV. Results of the model are compared with data for real-photon Compton scattering and predictions are given for observables in photoproduction of lepton pairs.