The total cross section of the ${}^6$Li$(d,\alpha {)}^4$He reaction has been measured for deuteron energies between 50 and 180 keV. From a detailed distorted-wave Born approximation analysis of the angular distributions and the excitation function up to 1 MeV it was possible to determine the strength of a subthreshold resonance that dominates the cross section at sub-Coulomb energies and contributes significantly to the increase of the astrophysical $S$ factor at low energies. Consequently the electron screening energy we have determined for the ${}^6$Li(d,$\alpha {)}^4$He reaction is considerably smaller than the value given in previous works which overestimate the theoretical predictions. In addition the stellar reaction rate has been calculated up to a temperature of $T_9$=3.

For the determination of the ${}^{144}$Sm-$\alpha$ optical potential we measured the angular distribution of ${}^{144}$Sm$(\alpha$,$\alpha )$${}^{144}$Sm scattering at the energy $E_{\mathrm{lab}}=20\mathrm{}\mathrm{\hspace{0.5em}}\mathrm{MeV}$ with high accuracy. Using the known systematics of $\alpha$-nucleus optical potentials we are able to derive the ${}^{144}$Sm-$\alpha$ optical potential at the astrophysically relevant energy $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=9.5\mathrm{}$ MeV with very limited uncertainties.

It is quite likely that the site of the r process is the hot, neutron-rich “bubble” that expands off a protoneutron star during a core-collapse supernova. The $r$ process would then occur in an intense flux of neutrinos. In order to explore the consequences of the neutrino irradiation, we calculate the rates of charged-current and neutral-current neutrino reactions on neutron-rich heavy nuclei, and estimate the average number of neutrons emitted in the resulting spallation. Our results suggest, for a dynamic $r$ process occurring in an expanding bubble, that charged-current ${\nu }_e$ captures might help shorten the time scale for the $r$ process, bringing it into better accord with our expectations about the conditions in the hot bubble: neutrino reactions can be important in breaking through the waiting-point nuclei at $N=50\mathrm{}$ and 82, while still allowing the formation of abundance peaks. Furthermore, after the $r$ process freezes out, there appear to be distinctive neutral-current and charged-current postprocessing effects. These include a spreading of the abundance peaks and damping of the most pronounced features (e.g., peaks and valleys) in the unpostprocessed abundance distribution. Most importantly, a subtraction of the neutrino postprocessing effects from the observed solar $r$-process abundance distribution shows that two mass regions, $A=124\mathrm{}$–126 and 183–187, are inordinately sensitive to neutrino postprocessing effects. This imposes very stringent bounds on the freeze-out radii and dynamic time scales governing the $r$ process. Moreover, we find that the abundance patterns within these mass windows are entirely consistent with synthesis by neutrino interactions. This strongly argues that the $r$ process must occur in the intense neutrino flux provided by a core-collapse supernova. It also greatly restricts dynamic models for the supernova $r$-process nucleosynthesis.

The hyperfine structure of the radioactive ${\mathrm{isotope}}^{175}$Hf has been measured by means of laser spectroscopy. The magnetic dipole and electric quadrupole moments ${\mathrm{of}}^{175}$Hf are determined: ${\mathrm{\mu }}_{\mathrm{I}}$=-0.62(3)${\mathrm{\mu }}_{\mathrm{N}}$ and ${\mathrm{Q}}_{\mathrm{s}}$=+2.6(2) b; the sign of μ${}_{\mathrm{I}}$ has been shown to be negative. It has been shown ${\mathrm{that}}^{175}$Hf has almost the same nuclear charge radius ${\mathrm{as}}^{174}$Hf.

The ${}^{107}$Ag nucleus has been investigated with the ${}^{100}$Mo${(}^{11}$B,$4n\gamma )$ reaction at 39 MeV beam energy. Gamma-gamma coincidences and angular correlations were measured. The ground state band has been extended to higher spins and a three-quasiparticle rotational band has been established. The results were interpreted within the cranked shell model and total Routhian surface predictions.

Activation techniques have been used to measure the total cross section for the production of ${}^7$Be, ${}^{22}$Na, and ${}^{24}$Na in proton induced reactions on ${}^7$Li and ${}^{27}$Al targets at bombarding energies of 495 MeV and 795 MeV. The cross section for the ${}^7$Li${\mathrm{}(p,n)\mathrm{}}^7$Be(g.s.+0.43-MeV) reaction at 795 MeV is about 11–15 % larger than extrapolations based on previous data below 480 MeV.

The new neutron deficient isotope ${}^{212}$Pa has been produced in the ${}^{182}\mathrm{W}{(}^{35}\mathrm{Cl},5n)$ reaction at a beam energy of 182.5 MeV. Evaporation residues have been separated with the JAERI recoil mass separator and identified on the basis of time- and position-correlated $\alpha$-decay chains. The $\alpha$ decay from the ground state of ${}^{212}$Pa has been observed with an $\alpha$-particle energy of 8.270(30) MeV and a half-life of 5.1${}_{-1.9}^{+6.1\mathrm{}}$ ms.

Excited states have been identified in ${}^{111}$Te using the ${}^{56}$Fe${(}^{58}$Ni,$2pn)$ reaction at 240 MeV. Assignment of transitions to ${}^{111}$Te was made via measurements of $\gamma$ rays in coincidence with both evaporation neutrons and mass-analyzed recoils. The observed cascade of $\gamma$ rays is assumed to feed an isomeric state with $J^{\pi }{=11/2\mathrm{}}^{-}$, similar to the yrast structures observed in other odd-mass tellurium isotopes.

The high spin states of ${}^{82}$Zr have been studied through the ${}^{58}$Ni${(}^{27}$Al, ${p2n)}^{82}$Zr reaction using a 92 MeV ${}^{27}$Al beam up to an excitation energy $\sim 5.2$ MeV and a spin of $12ħ$. The electromagnetic transition probabilities were obtained from the lifetimes of nuclear states measured with recoil distance and line shape analysis methods. The measured lifetimes indicate a reduction in $Q_t$ values in going from $2^{+}$ to $4^{+}$ state.

The modified quark-meson coupling model, which features a density-dependent bag constant and bag radius in nuclear matter, is checked against the EMC effect within the framework of dynamical rescaling. Our emphasis is on the change in the average bag radius in nuclei, as evaluated in a local density approximation, and its implication for the rescaling parameter. We find that when the bag constant in nuclear matter is significantly reduced from its free-space value, the resulting rescaling parameter is in good agreement with that required to explain the observed depletion of the structure functions in the medium Bjorken $x$ region. Such a large reduction of the bag constant also implies large and canceling Lorentz scalar and vector potentials for the nucleon in nuclear matter which are comparable to those suggested by the relativistic nuclear phenomenology and finite-density QCD sum rules.

Two basic assumptions of the pseudosymplectic model are tested. These are the distribution of nucleons in normal and unique orbitals at a given deformation and the use of a scale factor to describe $\mathrm{BE}2\mathrm{}$ transitions. For the latter we compare calculations in the Nilsson model, which takes into account all nucleons, with the pseudo-Nilsson model, which only includes nucleons in normal orbitals. We find that both assumptions are well justified.

We address some properties of the quadrupole-quadrupole $\left(Q\cdot Q\right)$ interaction in nuclear studies. We here consider how to restore SU(3) symmetry even though we use only coordinate and not momentum terms. Using the Hamiltonian $H={\sum }_i{(p}^2/2m+m/2\mathrm{}{\omega }^2{r}_i^2\left)-\chi {\sum }_{i<j}Q\right(i\left)\mathrm{}\cdot Q\right(j\left)\mathrm{}-\right(\chi /2\left){\sum }_{i}Q\right(i\left)\mathrm{}\cdot Q\right(i)\mathrm{}$ with $Q_{\mu }{=r}^2{Y}_{2,\mu },$ we find that only 2/3 of the single-particle splitting $\left({\epsilon }_{0d}-{\epsilon }_{1s}\right)$ comes from the diagonal term of $Q\cdot Q$; the remaining 1/3 comes from the interaction of the valence nucleon with the core. The same is true in the $0f-1p$ shell.

The effects of higher order corrections of ring diagrams for the quark condensate are studied by using the bare vertex nuclear Schwinger-Dyson formalism based on σ-ω model. The correction of the ring diagrams affects the quark condensate when the σ meson “σ term” is large.

The nonrelativistic Ward-Takahashi identity, a consequence of local gauge invariance in quantum mechanics, shows the necessity of exchange current contributions in case of nonlocal and/or isospin-dependent potentials. It also implies Siegert’s hypothesis: in the nonrelativistic limit, two-body charge densities identically vanish. Neither current conservation, which follows from global gauge invariance, nor the constraints of (lowest order) relativity are sufficient to arrive at this result. Furthermore, a low-energy theorem for exchange contributions is established.

A temperature version of the shell-optical-model approach is given to describe the low-energy compound-to-compound transitions induced by external single-particle fields. The approach is applied to evaluate the mean intensity of the $P$-odd mixing of nuclear compound states. The unified description for the mixing and electromagnetic transitions allows one to evaluate the mean intensity without the use of free parameters. Calculation results are compared with available experimental data.

We present systematic calculations of the mass-radius (MR) relation of a neutron star (NS) using a large variety of modern equations of state (EOS) of dense matter. The role of strangeness on the EOS and on the MR relation is particularly emphasized. Theoretical results are then compared with the semiempirical MR relation recently extracted for the x-ray burst source 4U 1820-30. Based on this comparison, we propose that the compact object in 4U 1820-30 is a kaon-condensed nucleon star or a strange star.

A simple and model-independent method is described to derive neutron single-particle spectroscopic factors of bound $s$-wave states in ${}^{A+1\mathrm{}}Z$ = ${}^{A}Z\otimes n$ nuclei from neutron scattering lengths. Spectroscopic factors for the nuclei ${}^{13}$C, ${}^{14}$C, ${}^{16}$N, ${}^{17}$O, ${}^{19}$O, ${}^{23}$Ne, ${}^{37}$Ar, and ${}^{41}$Ar are compared to results derived from transfer experiments using the well-known disorted wave Born analysis and to shell model calculations. The scattering length of ${}^{14}$C is calculated from the ${}^{15}$C${}_{\mathrm{g}.\mathrm{s}.\mathrm{}}$ spectroscopic factor.

The spectra of high-energy $\gamma$ rays in coincidence with evaporation residues ${}^{155,154}$Er populated in the reaction of 241 MeV ${}^{64}$Ni on ${}^{92}$Zr have been compared with results from Monte Carlo statistical model calculations. The shape of the spectrum in coincidence with the ${}^{155}$Er nuclei is reproduced only by simulations in which the spin distribution is extended towards very high spin values.

The level density parameter has been calculated using the pairing plus quadrupole model in the mass region from A=132 up to A=210 at excitation energies of about 12, 20, 30, and 50 MeV. In view of the large number of nuclei, no quantal fluctuations have been considered in this work; therefore, the ground-state energies used to compute the excitation energy are the Hartree energies in the grand-canonical ensemble. It is not expected that this will change the systematic behavior of the level density parameter as a function of the mass number as the effect of the quantal fluctuations is small. The familiar mass dependence of the level density parameter at low excitation energy is qualitatively reproduced.

${}^3$He${(e,e}^{\prime }p)X$ cross sections were measured in parallel kinematics for recoil momenta around 260 MeV/$c$. A Rosenbluth decomposition of the cross section was made and transverse and longitudinal spectral functions were extracted. The longitudinal spectral function is strongly quenched relative to the transverse one, the ratio of the integral of the longitudinal to transverse spectral functions over the continuum channel being $0.175\pm 0.046\pm 0.049$. A model which takes into account final state interactions and meson exchange currents predicts a ratio of 0.43, it can therefore explain only part ot the quenching.