The propagation of a $\Lambda$ hyperon in nuclear matter is studied within the Green’s function formalism. The probability density for adding a $\Lambda$ hyperon with momentum $k$ to the correlated nuclear matter ground state is obtained from the complete energy dependence of the real and imaginary parts of the $\Lambda$ self-energy. This self-energy incorporates the effects of short-range correlations induced by the hyperon-nucleon interaction and the strong coupling between $\Lambda N$ and $\Sigma N$ states which is known to be crucial for a correct determination of the $\Lambda$ binding energy. The calculated spectral functions and quasi-particle parameters for the $\Lambda$ are found to be qualitatively similar to corresponding results for correlated nucleons. In general, the $\Lambda$ is less strongly correlated with the nuclear matter environment at $k_F=1.36{\mathrm{fm}}^{-1}$ than a nucleon, in agreement with empirical information from finite nuclei.

The experimental landscape for the ${}^7\mathrm{B}\mathrm{e}+p$ radiative capture reaction is rapidly changing as new high precision data become available. We present an evaluation of existing data, detailing the treatment of systematic errors and discrepancies, and show how they constrain the astrophysical $S$ factor $\left(S_{17}\right)$, independent of any nuclear structure model. With theoretical models robustly determining the behavior of the subthreshold pole, the extrapolation error can be reduced and a constraint placed on the slope of $S_{17}$. Using only radiative capture data, we find $S_{17}\left(0\right)=20.7\pm 0.6\left(\mathrm{stat}\right)\pm 1.0\left(\mathrm{syst}\right)\mathrm{eV}$ $\mathrm{b}$ if data sets are completely independent, while if data sets are completely correlated we find $S_{17}\left(0\right)=21.4\pm 0.5\left(\mathrm{stat}\right)\pm 1.4\left(\mathrm{syst}\right)\mathrm{eV}$ $\mathrm{b}$. The truth likely lies somewhere in between these two limits. Although we employ a formalism capable of treating discrepant data, we note that the central value of the $S$ factor is dominated by the recent high precision data of Junghans et al. [Phys. Rev. C 68, 065803 (2003)], which imply a substantially higher value than other radiative capture and indirect measurements. Therefore we conclude that further progress will require new high precision data with a detailed error budget.

The absolute intensities of $\gamma$ rays produced in the decay of ${}^{182}\mathrm{Hf}$ were determined by measuring its $\gamma$-ray spectra with high-resolution $\mathrm{Ge}$ spectrometers. Because the sample was chemically purified more than 30 years ago, the daughter ${}^{182}\mathrm{Ta}\left(t_{1∕2}=114.43\mathrm{d}\right)$ was in secular equilibrium with ${}^{182}\mathrm{Hf}$ $\left(t_{1∕2}=8.90\times {10}^6\mathrm{yr}\right)$. The absolute intensities of ${}^{182}\mathrm{Hf}$ $\gamma$ rays were determined with respect to the intensities of ${}^{182}\mathrm{Ta}\gamma$ lines. In order to minimize summing losses from the peak areas, spectra were measured at low absolute efficiencies. The absolute intensity of the $270.4\text{−}\mathrm{keV}\text{−}\gamma$ ray was found to be $\left(79.0\pm 0.6\right)\%$ per ${}^{182}\mathrm{Hf}{\beta }^{-}$ decay.

We consider a simple model for the coordinate-space vacuum polarization function which is often parametrized in terms of a screening mass. We discuss the circumstances in which the value $m_{sc}=\pi T$ is obtained for the screening mass. In the model considered here, that result is obtained when the momenta in the relevant vacuum polarization integral are small with respect to the first Matsubara frequency.

The well deformed atomic nucleus ${}^{159}\mathrm{Gd}$ was investigated by means of radiative neutron capture and single neutron transfer reactions. Nearly 70 secondary $\gamma$ rays from the $(n,\gamma )$ reaction studied with high-resultion bent-crystal spectrometers at Grenoble are assigned to ${}^{159}\mathrm{Gd}$. About 200 levels with spin up to $\frac{11}{2}$ are observed in this nucleus below $2.3\mathrm{MeV}$ in $(d,p)$ and $(\mathbf{d},t)$ reactions investigated at the Tandem Van de Graaff accelerator in Garching using unpolarized $\left(18\mathrm{MeV}\right)$ and polarized $\left(22\mathrm{MeV}\right)$ deuteron beams, respectively. The proposed level scheme for this nucleus is arranged into 21 rotational bands. Experimentally observed levels are interpreted using predictions obtained within the quasiparticle-phonon model and the quasiparticle-rotor approach for a well deformed nucleus.

Solving the simplified model of the Hartree-Fock Bogoliubov equation in coordinate space with the correct asymptotic boundary conditions, the spin-orbit splitting, occupation probabilities, effective pair-gap, mean square radius, and spin-response function are studied for weakly bound $p$ neutrons. As the binding energy of $p_{3∕2}$ neutrons becomes small or approaches zero, the spin-orbit splitting $p_{3∕2}-p_{1∕2}$ in the one-body potential drastically decreases and, at the same time, the effective pair-gap for the $p$ neutrons becomes small, while the occupation probability of the $p_{3∕2}$ level decreases only slightly. Consequently, in that limit low-lying broader spin response with almost constant amount of total strength appears with the peak moving toward very low excitation energies.

The ${}^{11}\mathrm{B}({}^3\mathrm{He},t)$, and ${}^{11}\mathrm{B}(d,d^{\prime })$, and ${}^{11}\mathrm{B}(p,p^{\prime })$ reactions were measured at forward scattering angles including 0° to study the isovector and isoscalar spin-flip $M1$ strengths in ${}^{11}\mathrm{B}$. The measured ${}^{11}\mathrm{B}({}^3\mathrm{He},t)$ cross sections were compared with the results of the distorted-wave impulse-approximation (DWIA) calculation, and the Gamow-Teller (GT) strengths for low-lying states in ${}^{11}\mathrm{C}$ were determined. The GT strengths were converted to the isovector spin-flip $M1$ strengths using the isobaric analog relations under the assumption of the isospin symmetry. The isoscalar spin-flip $M1$ strengths were obtained from the $(d,d^{\prime })$ analysis by assuming that the shape of the collective transition form factor with the same $\Delta J^{\pi }$ is similar in the ${}^{11}\mathrm{B}(d,d^{\prime })$ and ${}^{12}\mathrm{C}(d,d^{\prime })$ reactions. The obtained isovector and isoscalar strengths were used in the DWIA calculations for the ${}^{11}\mathrm{B}(p,p^{\prime })$ reaction. The DWIA calculation reasonably well explains the present ${}^{11}\mathrm{B}(p,p^{\prime })$ result. However, the calculated cross section for the $8.92\text{−}\mathrm{MeV}$ $3∕2_2^{-}$ state was significantly smaller than the experimental values. The transition strengths obtained in the shell-model calculations were found to be 20–50 % larger than the experimental strengths. The transition strengths for the neutrino induced reactions were estimated by using the isovector and isoscalar spin-flip $M1$ strengths. The present results are quantitatively in agreement with the theoretical estimation discussing the axial isoscalar coupling in the neutrino scattering process, and are useful in the measurement of the stellar neutrinos using the neutral- and charged-current reactions on ${}^{11}\mathrm{B}$.

We study the mass dependence of various quantities (like the average and maximum density, collision rate, participant-spectator matter, and temperature, as well as time zones for higher density) by simulating different reactions at the energy of vanishing flow. This study is carried out within the framework of the quantum molecular dynamics model. Our findings clearly indicate the existence of a power law in all the above quantities calculated at the balance energy. A significant mass dependence exists for the temperature reached in the central sphere. All other quantities at the balance energy are either rather insensitive or depend weakly on the system size. The time zone for the higher density as well as the time of maximal density and collision rate follow a power law inverse to the energy of vanishing flow. The participant matter at the balance energy shows a remarkable lack of mass dependence that makes it a good candidate for studying the balance energy.

The ${}^{96}\mathrm{Mo}\left(p,d\right){}^{95}\mathrm{Mo}$ reaction has been studied with a $50\mathrm{MeV}$ polarized beam. Differential cross sections and analyzing powers have been measured for investigating the level structure in ${}^{95}\mathrm{Mo}$ up to the excitation energy of $5.8\mathrm{MeV}$. The standard distorted-wave Born approximation theory provides transfer angular momentum values and spectroscopic factors for the excited states. Furthermore, the theoretical analysis is extended also for the continuum region with a direct reaction model. Experimental double differential cross sections for continuum spectra are predicted well by adopting an asymmetric Lorentzian form for the response function in the distorted wave Born approximation based cross section calculations.

The resonance model is used to analyze the $\omega$- and $\varphi$-meson angular distributions in proton-proton collisions at $\sqrt{s}=2.83$ and $2.98\mathrm{GeV}$. The assumption of dominant contributions from $N^{*}\left(1720\right){\frac{3}{2}}^{+}$ and $N^{*}\left(1900\right){\frac{3}{2}}^{+}$ resonances which both have, according to the $\pi N$ scattering multichannel partial-wave analysis and∕or quark models predictions, dominant $p_{1∕2}$ $N\omega$ decay modes yields the right pattern of the $\omega$ angular distribution at $\sqrt{s}=2.83\mathrm{GeV}$. The angular distribution at $\sqrt{s}=2.98\mathrm{GeV}$ can be reproduced assuming the dominance of $N^{*}\left(2000\right){\frac{5}{2}}^{+}$ and $N^{*}\left(1900\right){\frac{3}{2}}^{+}$. The experimental $\varphi$-meson angular distributions do not show any asymmetry which requires the existence of a massive negative-parity spin-half resonance. This resonance could be identified with the $N^{*}\left(2090\right){\frac{1}{2}}^{-}$.

Recently, Davids and Typel recommended a “low” value of $S_{17}\left(0\right)$ based on fits to published direct and Coulomb dissociation data, in which they excluded the precise result of Junghans et al. We show that their statistical analysis is incorrect due to a substantial underestimate of the experimental uncertainties, and that there is no reason to exclude the Junghans et al. result based on statistical arguments.

We present data on $e^{+}{e}^{-}$ pair production accompanied by nuclear breakup in ultraperipheral gold-gold collisions at a center of mass energy of $200\mathrm{GeV}$ per nucleon pair. The nuclear breakup requirement selects events at small impact parameters, where higher-order diagrams for pair production should be enhanced. We compare the data with two calculations: one based on the equivalent photon approximation, and the other using lowest-order quantum electrodynamics (QED). The data distributions agree with both calculations, except that the pair transverse momentum spectrum disagrees with the equivalent photon approach. We set limits on higher-order contributions to the cross section.

The limitations for the use of the spectral function $S$ in the process ${}^3\mathrm{He}(e,e^{\prime }N)$ has been investigated in a kinematical regime constrained by the conditions that the three-nucleon $\left(3\mathrm{N}\right)$ center-of-mass energy $E_{3\mathrm{N}}^{\mathrm{c.m.}}⩽150\mathrm{MeV}$ and the magnitude of the three-momentum transfer, $\mid \vec{Q}\mid ⩽600\mathrm{MeV}∕c$. Results based on a full treatment of the final state interaction are compared to the spectral function approximation. In the case of proton knockout in the direction of the photon kinematical conditions have been identified where both response functions, $R_L$ and $R_T$, can be well approximated by $S$. These conditions occur for certain low missing momenta and missing energies but not in all cases. So care is required. In case of neutron knockout only $R_T$ is a candidate for an approximate treatment by $S$. In the case of $R_L$ the concept of using $S$ is not valid in the studied kinematical regime. This does not exclude the possibility that beyond that regime it might be useful. Possible applications using $S$ for the extraction of electromagnetic form factors of the nucleons are pointed out.

A suitable numerical approach based on Sturmian functions is employed to solve the pionium problem for both local and nonlocal potentials. The approach accounts for both the short-ranged strong interaction and the long-ranged Coulomb force and provides accurately the wave function and binding energy of pionium. It is found that the ground-state pionium wave function in realistic pion-pion strong interactions might be considerably different from the hydrogen-like one at a small distance.

The allowed and forbidden binary cluster configurations of the ground, superdeformed, and hyperdeformed states of some nuclei are determined, based on the (real or effective) $\mathrm{U}\left(3\right)$ selection rule. The stability of the cluster configurations from the viewpoint of the binding energy is also investigated.

The decays of the three isomers of ${}^{131}\mathrm{In}$ and the total decay energies of the two isomers of ${}^{131}\mathrm{Sn}$ have been studied in high sensitivity experiments at the OSIRIS mass separator. The main purpose of the investigation was to determine the position of the neutron hole $h_{11∕2}$ state, since a previous determination appeared to be in error. The present results support a small separation of the $d_{3∕2}$ and $h_{11∕2}$ neutron hole states. The new value obtained from measurements of decay energies is $69\pm 14\mathrm{keV}$. A more precise value of $65.1\mathrm{keV}$ may be deduced from the level scheme of ${}^{131}\mathrm{Sn}$ obtained currently, however without firm support from coincidence data. This relatively low excitation energy of the $h_{11∕2}$ state is in agreement with systematics and in disagreement with the previous determination. A re-evaluation of the $Q_{\beta }$ values and isomer spacings of ${}^{131}\mathrm{In}$ has been made.

Excited states in ${}^{124}\mathrm{Xe}$ were populated in the fusion-evaporation reaction ${}^{110}\mathrm{Pd}\left({}^{18}\mathrm{O,4}n\right){}^{124}\mathrm{Xe}$ at a beam energy of $80\mathrm{MeV}$. A recoil distance measurement using the Euroball spectrometer in Strasbourg and the Cologne plunger was performed. Altogether 19 lifetimes of excited states in six different bands were determined using gated spectra only, in order to avoid problems related to feeding. The measured $B\left(E2\right)$ values were used to derive the nuclear deformation of ${}^{124}\mathrm{Xe}$ and the interaction of the ground state band with two $s$ bands. Two $sd\text{−}\mathrm{IBM}\text{−}1$ calculations with two Hamiltonians of different complexities were performed, which show a good agreement with the measured $B\left(E2\right)$ values in the ground state band and the quasi-$\gamma$ band. The deduced $B\left(M1\right)$ values for the regular $M1$ band show the behavior expected for magnetic rotation. However, it is also shown that these experimental $B\left(M1\right)$ values can be described on the basis of a rotational band as well.

The low-energy levels of ${}^{120}\mathrm{Pd}_{74}$ were populated by $\beta$ decay of ${}^{120}\mathrm{Rh}_{75}$, which was produced via projectile fragmentation of a ${}^{136}\mathrm{Xe}_{82}$ beam at $120\mathrm{MeV}∕\text{nucleon}$. Delayed $\beta$-gated $\gamma$ rays with energies of 438 and $618\mathrm{keV}$ were observed in coincidence with ${}^{120}\mathrm{Rh}_{75}$ fragments and assigned to the $2_1^{+}\to 0^{+}$ and $4_1^{+}\to 2_1^{+}$ transitions, respectively, in ${}^{120}\mathrm{Pd}_{74}$. Isomeric $\gamma$-ray transitions are also reported for ${}^{120}\mathrm{Rh}_{75}$ and ${}^{126}\mathrm{Cd}_{78}$. The low-energy structure of ${}^{120}\mathrm{Pd}_{74}$ shows remarkable similarity to those of the isotopic ${}^{108}\mathrm{Pd}_{62}$ and isotonic ${}^{128}\mathrm{Xe}_{74}$ suggesting that these nuclides share the same $Z=50$ and $N=82$ closed shell structures with neutron-rich ${}^{120}\mathrm{Pd}_{74}$.

High-spin states in ${}^{123}\mathrm{Cs}$ were populated in the ${}^{64}\mathrm{Ni}\left({}^{64}\mathrm{Ni},p4n\right)$ reaction at a beam energy of $265\mathrm{MeV}$. Gamma-ray coincidences were measured using the Gammasphere spectrometer. Two additional bands have been placed in the level scheme and the four previously known bands have been extended to higher spin. At the highest spins, two of the bands show irregular level sequences. These structures of noncollective excitations, which compete with collective rotation, are interpreted as band-terminating states. The results are compared to cranked Nilsson-Strutinsky calculations, and configuration assignments to the bands and to the terminating states are discussed.