The neutron capture cross sections of ${}^{142}\mathrm{Nd}$ and ${}^{144}\mathrm{Nd}$ which were determined recently with the Karlsruhe $4\pi {\mathrm{BaF}}_2$ detector have been reanalyzed at low energies. The parameters of 52 resonances in ${}^{142}\mathrm{Nd}$ and of 78 resonances in ${}^{144}\mathrm{Nd}$ were extracted by means of a shape analysis program, yielding a more reliable determination of the averaged cross sections below 20 keV. This study confirms the previously reported stellar cross sections, so that the $s$-process study based on these data remains unchanged.

Low-lying dipole strength in the neutron-hole nucleus ${}^{207}\mathrm{Pb}$ has been investigated in nuclear resonance fluorescence (NRF) measurements performed with bremsstrahlung beams with an end-point energy of 4.1 MeV. Known excitations at 898 ${(3/2\mathrm{}}^{-}),$ 3303 ${(1/2\mathrm{}}^{+}),$ and 3927 ${(3/2\mathrm{}}^{-})\mathrm{keV}$ were observed and their absolute total strengths were determined with improved precision. While excellent sensitivity was obtained in this study, no other dipole excitations could be detected in the energy region from 1 to 4 MeV.

Quasielastic (QE) excitation function measurements have been carried out for the ${}^{12}\mathrm{C}{+}^{232}\mathrm{Th}$ fissile system at ${\theta }_{\mathrm{lab}}=170\mathrm{}°$ in the energy range of $E_{\mathrm{lab}}$ = 51–79 MeV. The data has been analyzed to obtain a representation of the fusion barrier distribution, which has been compared with that obtained from fusion-fission excitation function measurements available from literature. The QE data have also been analyzed in the framework of generalized elastic scattering model to obtain the mean-square average compound nuclear spin $\left(〈l^2〉\right)$ values, which has been compared with the prediction of standard fusion model (CCDEF) calculations and also with that obtained from fission fragment angular anisotropy measurements. The results show that the barrier distributions obtained from QE and fission excitation function measurement are consistent with each other. The $〈l^2〉$ values are also consistent with prediction of CCDEF calculations, but are in disagreement with the experimental $〈l^2〉$ values obtained from fission fragment anisotropy measurements.

Yrast states up to spin $16ħ$ in ${}^{166}\mathrm{Dy}$ were observed, for the first time, using a quasielastic neutron-transfer reaction in the bombardment of ${}^{118}\mathrm{Sn}$ with ${}^{164}\mathrm{Dy}$ at $E_{\mathrm{lab}}=790\mathrm{}$ MeV. The ratio of the ${}^{166}\mathrm{Dy}$ production cross section relative to the inelastic cross section, integrated over the c.m. scattering angle range $110°$ to $140°$, is $\approx 0.0027$. This experiment demonstrates that the improved sensitivity, provided by the new generation of highly segmented $4\pi$ $\gamma$-ray arrays coupled to a $4\pi$ heavy-ion detector array, makes subbarrier heavy-ion-induced nucleon-transfer reactions a powerful probe of the structure of neutron-rich nuclei at moderately high spin. A comparison with the production of ${}^{164}\mathrm{Dy}$ in the reaction between ${}^{118}\mathrm{Sn}$ and ${}^{162}\mathrm{Dy}$ is made.

We calculate the sea quark distribution of the nucleon in a meson cloud model. The novel feature of our calculation is the implementation of a special $\pi \mathrm{NN}$ form factor recently obtained by Holzwarth and Machleidt. This form factor is hard for small and soft for large momentum transfers. We show that this feature leads to a substantial improvement.

The validity of a model treating the short-range correlations up to the first order is studied by calculating the charge response of an infinite system and comparing the obtained results with those of a Fermi Hypernetted Chain calculation.

The transitions between complex configurations, to which the giant dipole resonance (GDR) and the double giant dipole resonance (DGDR) doorway states are coupled, are taken into account in second order perturbation theory for the reaction amplitude. It is proved that only transitions between GDR and DGDR doorway states play an essential role in the Coulomb excitation of the DGDR.

Initially energetically forbidden internal conversion processes induced by a high intensity radiation field of appropriate frequency are discussed in the case of ${}^{99m}\mathrm{Tc}$ and ${}^{105m}\mathrm{Ag}$. Hindering effects of saturation and power broadening are taken into consideration as well. Results of a recent paper are also disputed.

The properties of hot matter are studied in the frame of the relativistic Brueckner-Hartee-Fock theory. The equations are solved self-consistently in the full Dirac space. For the interaction we used the potentials given by Brockmann and Machleidt. The obtained critical temperatures are smaller than in most of the nonrelativistic investigations. We also calculated the thermodynamic properties of hot matter in the relativistic Hartree-Fock approximation, where the force parameters were adjusted to the outcome of the relativistic Brueckner-Hartree-Fock calculations at zero temperature. Here, one obtains higher critical temperatures, which are comparable with other relativistic calculations in the Hartree scheme.

To study the nuclear symmetry energy, we extend the Dirac-Brueckner approach with a Bonn one-boson-exchange nucleon-nucleon interaction to the general case of asymmetric nuclear matter. We extract the symmetry energy coefficient at the saturation to be about 31 MeV, which is in good agreement with the empirical value of $30\pm 4\mathrm{MeV}.$ The symmetry energy is found to increase almost linearly with the density, which differs considerably from the results of nonrelativistic approaches. This finding also supports the linear parametrization of Prakash, Ainsworth, and Lattimer. We find, furthermore, that the higher-order dependence of the nuclear equation of state on the asymmetry parameter is unimportant.

The amplitudes at a series of discrete energies obtained from a previous analysis of $\overline{p}\overrightarrow{p}\pi \pi$ have been used as input to a global energy-dependent analysis of data in the momentum range 360–1550 MeV/$c$. The results confirm the previous analysis and yield refined values for meson resonance parameters in this energy region.

In-medium nucleon-nucleon cross sections are calculated from reaction matrices of the nonrelativistic Brueckner approach. Calculated cross sections are parametrized as a function of the incident energy and the nuclear density. The nonrelativistic cross sections are found to be reduced from free ones as observed in relativistic Brueckner calculations. This reduction of the in-medium cross sections is ascribed to the flux renormalization represented by an effective mass. It is pointed out that we should be careful to avoid double counting the effective mass effects when in-medium cross sections calculated are applied in various models of dynamical nuclear processes.

The ${}^{154}\mathrm{Sm}(\overrightarrow{d},t)$ reaction at high energy resolution $(n,\gamma ),$ average resonance capture (ARC), and coincidence measurements were performed to study the deformed nucleus ${}^{153}\mathrm{Sm}.$ Strength distributions from $(\overrightarrow{d},t)$ and completeness for $I^{\pi }={\frac{1}{2}}^{-}$ and ${\frac{3}{2}}^{-}$ states up to 1500 keV from ARC provide one of the first detailed tests of the interacting boson fermion model (IBFM) in a deformed nucleus in a multiorbit environment. For negative parity states the model accounts for the large number of low spin (${\frac{1}{2}}^{-}$, ${\frac{3}{2}}^{-}$) states much better than the Nilsson model since the even-even core in the IBFM calculations automatically includes excited vibrational states. The IBFM calculations also predict $\mathrm{}(d,t)\mathrm{}$ spectroscopic factors better than the Nilsson model with pairing and Coriolis mixing. Neither the IBFM nor the Nilsson approach can explain the low lying positive parity states. The IBFM calculations show that for certain combinations of parameters, the monopole term in the boson-fermion Hamiltonian has more than a scaling effect: it can attenuate the Coriolis mixing (energy staggering). Finally suggested improvements in the treatment of pairing in the IBFM are made.

Small-angle relative velocity correlations have been measured for the emission of soft intermediate mass fragments $(0.7\mathrm{}<~E/A<~3.0\mathrm{MeV})$ in high-deposition-energy events produced in the 4.8 GeV ${}^3{\mathrm{H}\mathrm{e}+}^{197}\mathrm{Au}$ reaction. The experimental correlations are compared with an $N$-body Coulomb-trajectory simulation that accounts for the fragment spectra, multiplicity, and charge distributions. In order to reproduce the data, a small residue $(Z\sim 10–20)$ that is located randomly in the breakup volume is required. This analysis indicates breakup time scales of order $\tau =20\mathrm{}–50\mathrm{fm}/c.\mathrm{}$

We have remeasured the ground state $g$ factor of ${}^9\mathrm{C}$ using the technique of nuclear magnetic resonance on beta-emitting nuclei (β-NMR) on spin-polarized ${}^9\mathrm{C}$ nuclei produced by the fragmentation of a ${}^{20}\mathrm{Ne}$ beam at 80 MeV/nucleon in a Nb target. Our new value of 1.396(3)${\mu }_N$ is consistent with the previously measured value of the ground state magnetic moment of this nuclide. The results of shell model calculations employing isospin-nonconserving (INC) terms in the nuclear Hamiltonian are shown to better reproduce the quenched magnetic dipole moment of ${}^9\mathrm{C}$ and the previously described anomalous isoscalar spin expectation value 〈σ〉 for the ${}^9{\mathrm{L}\mathrm{i}-}^9\mathrm{C}$ mirror system.

The internal pair conversion (IPC) of transitions in Pb nuclei has been studied. Recent calculations of IPC for transitions with energies up to 2 MeV predict large differences in the shapes of the angular correlations according to their magnetic or electric character. We have measured absolute pair-conversion coefficients for $E1\mathrm{}$ transitions in ${}^{206}\mathrm{Pb}$ and an $M1\mathrm{}$ transition in ${}^{207}\mathrm{Pb}$ with uncertainties three to five times smaller than previous measurements. The measured positron-electron angular correlations are in good agreement with the predictions of the recent calculations and display the predicted differences between the electric and magnetic cases.

Discrete γ-ray spectra have been measured as a function of incident neutron energy for nuclei produced in the ${}^{196}\mathrm{Pt}(n,xn\gamma )$ reactions. Spectroscopy was done using the large-scale Compton suppressed Ge γ-ray spectrometer GEANIE. The “white” source neutron beam was produced at the Los Alamos Neutron Science WNR facility. Reaction neutron energy was determined using the time-of-flight technique. Reaction-channel yields were inferred from the measured intensity sum of the $2_1^{+}\to 0_1^{+}$ and the $2_2^{+}\to 0_1^{+}$ transitions for the ${}^{196}\mathrm{Pt}\mathrm{}(n,xn)\mathrm{}$ reactions for $x<~15.$ Weisskopf-Ewing calculations (including precompound) done with the HMS-ALICE code correctly predict the bulk of the $\mathrm{}(n,xn)\mathrm{}$ reaction products for low multiplicity. However, they do not accurately predict yield ratios of the different $\mathrm{}(n,xn)\mathrm{}$ reactions for $x>~9.$ In addition, there is no consistent experimental indication of charged-particle reaction channels $\mathrm{}(n,pxn)\mathrm{}$ for incident neutron energies above 60 MeV where they are predicted to account for approximately $1/3$ of the total reaction cross section. Several possible causes are discussed for these discrepancies. Finally, the region of $E-J$ phase space populated in this reaction is probed for several of the strongest reaction channels through the observation of relative yields for different yrast and off-yrast states.

A new isomeric state in ${}^{217}\mathrm{Pa}$ has been observed with an α-decay of $E_{\alpha }=9.540\mathrm{}\pm 0.050\mathrm{MeV}$ and $T_{1/2}{=1.5\mathrm{}}_{-0.4}^{+0.9\mathrm{}}\mathrm{ms}.$ The isotope ${}^{217}\mathrm{Pa}$ was produced in the reaction ${}^{28}{\mathrm{S}\mathrm{i}+}^{194}\mathrm{Pt}$ at a beam energy of 163 MeV. Measured α-decay half-life was reproduced by the cluster model calculation with a transferred angular momentum of $l=7\mathrm{}ħ.$

We present an analytical estimate for the upper limit of the shell correction $\delta K_A$ to the compressibility coefficient $K_A$ of finite nuclei. A simple model with a spherical harmonic oscillator potential was adopted and the self-consistency condition was taken into account. We find that the magnitude of the shell correction term $\delta K_A$ is comparable to that associated with the current experimental uncertainties in determining the energy of the isoscalar giant monopole resonance.