In this paper states in ${}^{102}\mathrm{Pd}$ populated in the $\epsilon /{\beta }^{+}$ decay of ${}^{102}\mathrm{Ag},$ produced in the ${}^{89}\mathrm{Y}{(}^{16}\mathrm{O},3n)$ reaction, were studied with high efficiency Ge detectors. The level scheme of ${}^{102}\mathrm{Pd}$ is in good overall agreement with the predictions of the E(5) critical point symmetry, with the exception of the $0_2^{+}$ state, which may be of intruder character.

The masses of neutron-deficient nuclei close to the proton drip line are an important input for the rapid proton-capture process modeling above ${}^{56}\mathrm{Ni}.$ The measurement of the masses of proton-rich nuclei with $32<~Z<~35$ has been made using a direct time-of-flight technique. The masses of the nuclides ${}^{66}\mathrm{As}{,}^{68}\mathrm{Se},$ and ${}^{71}\mathrm{Br}$ are reported for the first time, with mass excesses of $-51500\left(680\right),$ $-53620\left(1000\right),$ and $-57060\left(570\right)\mathrm{}\hspace{0.5em}\mathrm{keV}$ being found. The masses agree well in most cases with the Audi-Wapstra systematics.

The role of the nucleon resonances in the double polarization observables of pion photoproduction is investigated by using the resonance parameters predicted by Capstick and Roberts. As an example, we show that the not-well-determined two-star resonance $N_{3/2}^{-}\mathrm{}\left(1960\right)\mathrm{}$ can be examined by performing experiments on beam-recoil polarization at large angles.

The ${}^{24}\mathrm{Mg}{(d,}^2\mathrm{He}{)}^{24}\mathrm{Na}$ and the ${}^{12}\mathrm{C}{(d,}^2\mathrm{He}{)}^{12}\mathrm{B}$ charge-exchange reactions have been studied at an incident energy of 170 MeV. The two protons in the ${}^1{S}_0\mathrm{}\left(\mathrm{pp}\right)\mathrm{}$ state (indicated as ${}^2\mathrm{He})$ were both momentum analyzed and detected by the same spectrometer and detector. Background-free ${}^2\mathrm{He}$ spectra with a resolution of about 150 keV (full width at half maximum) have been obtained allowing identification of many levels in the residual nucleus with high precision. It is found that the ${(d,}^2\mathrm{He})$ reaction at $0°$ is largely governed by the Gamow-Teller (GT) transition operator for the ${\beta }^{+}$ direction, which makes the reaction selective for isovector $1^{+}$ transitions. In the case of ${}^{24}\mathrm{Mg},$ the reaction is compared with $\mathrm{}(p,n)\mathrm{}$ reaction data in which the same levels in the analog nucleus ${}^{24}\mathrm{Al}$ are populated. Angular distributions of cross sections for the ${(d,}^2\mathrm{He})$ reaction are presented and compared with distorted-wave Born approximation calculations. GT matrix elements are deduced. A level-by-level comparison with shell-model calculations using the universal s-d interaction has been performed. Comparison with ${(p,p}^{\prime })$ data yields a level scheme for the $A=24\mathrm{}$ isospin triplet.

The phase transition in small $(A\approx {10}^2–{10}^3)$ asymmetric nuclear systems is studied in the framework of a mean-field model. The liquid-gas equilibrium point, calculated from Gibbs conditions, is found to depend strongly on the surface and Coulomb effects. The gas phase is more dense and symmetric than in infinite matter. The isospin of the gas phase is found to be very sensitive to global system parameters, like charge, density, or size.

Based on an approach recently proposed by us, simultaneous ${\chi }^2$ analyses are performed for elastic scattering, direct reaction (DR), and fusion cross section data for the ${}^6\mathrm{He}{+}^{209}\mathrm{Bi}$ system at near-Coulomb-barrier energies to determine the parameters of the polarization potential consisting of DR and fusion parts. We show that the data are well reproduced by the resultant potential, which satisfies the proper dispersion relation. A discussion is given of the nature of the threshold anomaly seen in the potential.

We discuss calculations of total reaction cross sections between complex nuclei, ${\sigma }_R,$ using optical limit and few-body Glauber models in which the free nucleon-nucleon cross sections ${\sigma }_{\mathrm{NN}}$ are replaced by their (reduced) values in the nuclear medium. This replacement lowers ${\sigma }_R$ by at most a few percent when ${\sigma }_{\mathrm{NN}}$ is determined from the local matter density in each overlapping volume element of the significant projectile-target trajectories. This relatively small effect contrasts with reductions of about 10% in ${\sigma }_R$ reported by Xiangzhou et al., who assume a global value for the matter density throughout the interaction region. For two-neutron halo nuclei, we investigate the significance of these in-medium effects for the neutron-removal cross sections, ${\sigma }_{-2n}.$ We show that use of an in-medium ${\sigma }_{\mathrm{NN}}$ raises ${\sigma }_{-2n}$ for ${}^6\mathrm{He}$ but lowers it for ${}^{11}\mathrm{Li},$ because of their different halo sizes.

A reanalysis of the (α,${\mathrm{\alpha }}^{\prime }$) data for extracting the reduced excitation probability ${B(E2;0\mathrm{}}_g^{+}\to I^{\pi }{K=2\mathrm{}}^{+}0)$ of the 1276.7 keV transition in ${}^{178}\mathrm{Hf}$ indicates an error in the earlier published value. The new value of $B\left(E2\mathrm{}\right)\mathrm{}$ from the (α,${\mathrm{\alpha }}^{\prime }$) data is 0.022(5) $e^2{\mathrm{b}}^2$ and is consistent with a recent measurement. The extracted total mean lifetime of the 1276.7 keV level is $\tau {=0.70\mathrm{}}_{-0.14}^{+0.22\mathrm{}}\hspace{0.5em}\mathrm{ps}.$

The possible existence of deeply bound nuclear $\overline{K}$ states is investigated theoretically for few-body systems. The nuclear ground states of a $K^{-}$ in ${}^3\mathrm{He},$ ${}^4\mathrm{He},$ and ${}^8\mathrm{Be}$ are predicted to be discrete states with binding energies of 108, 86, and 113 MeV and widths of 20, 34, and 38 MeV, respectively. The smallness of the widths arises from their energy-level locations below the $\Sigma \pi$ emission threshold. It is found that a substantial contraction of the surrounding nucleus is induced due to the strong attraction of the $I=0\mathrm{}$ $\overline{K}N$ pair, thus forming an unusually dense nuclear medium. Formation of the $T=0\mathrm{}{K}^{-}{\otimes }^3\mathrm{He}+K^0{\otimes }^3\mathrm{H}$ state in the ${}^4\mathrm{He}$ (stopped $K^{-},$ $n)$ reaction is proposed, with a calculated branching ratio of about 2%.

A new approach to the production and detection of bound neutron clusters is presented. The technique is based on the breakup of beams of very neutron-rich nuclei and the subsequent detection of the recoiling proton in a liquid scintillator. The method has been tested in the breakup of intermediate energy (30–50 MeV/nucleon) ${}^{11}\mathrm{Li},$ ${}^{14}\mathrm{Be},$ and ${}^{15}\mathrm{B}$ beams. Some six events were observed that exhibit the characteristics of a multineutron cluster liberated in the breakup of ${}^{14}\mathrm{Be},$ most probably in the channel ${}^{10}\mathrm{Be}{+}^{4}n.\mathrm{}$ The various backgrounds that may mimic such a signal are discussed in detail.

An analysis of incoherent photoproduction of η mesons off the deuteron for photon energies from threshold to 800 MeV is presented. The dominant contribution, the $\gamma N$-$\eta N$ amplitude, is described within an isobar model. Effects of the final state interactions in the nucleon-nucleon as well as $\eta N$ systems are included, employing models derived within the meson-exchange approach. It is found that their consideration is important. Specifically, due to an interference effect, the influence of the $\eta N$ final state interaction is enhanced in the reaction $\gamma \overrightarrow{d}\mathrm{np}\eta$ close to threshold.

The nickel isotopes exist over a wide range of neutron numbers, extending from proton-rich to very neutron-rich nuclei. Here we report a consistent study of the odd-mass $Z=28\mathrm{}$ nuclei in the full ${pf+g}_{9/2}$ shell using the generalized-seniority shell model. We include up to three unpaired nucleons in the odd sector, and up to two in the even sector. We also report related results for the odd-mass ${}^{69}\mathrm{Cu}$ and odd-odd ${}^{66}\mathrm{Co}$ nuclei. Our calculations make use of a realistic shell-model interaction, whose monopole part has been renormalized to fit the properties of nuclei near closed shells. The calculated results are in good global agreement with experimental data, and contain some evidence of the persistence of the $N=40\mathrm{}$ subshell closure around ${}^{68}\mathrm{Ni}.$ The results demonstrate the importance of keeping the entire ${pf+g}_{9/2}$ space as active, both for neutrons and protons.

The neutron-unstable odd-$N$ isotopes ${}^5\mathrm{He},$ ${}^7\mathrm{He},$ and ${}^8\mathrm{Li}$ (in its excited state of $E^{*}=2.26\mathrm{}\hspace{0.5em}\mathrm{MeV})$ were measured to show up as short-lived $\left(\tau \simeq {10}^{-21}-{10}^{-20}\hspace{0.5em}\mathrm{s}\right)$ intermediate light charged particles (LCPs) in ternary fission of ${}^{252}\mathrm{Cf}.$ For the study a high-efficiency angular correlation measurement between neutrons, LCPs, and main fission fragments has been performed. The evidence for the ternary ${}^5\mathrm{He}$ and ${}^7\mathrm{He}$ particles (lifetimes: $1\times {10}^{-21}\hspace{0.5em}\mathrm{s},$ and $4\times {10}^{-21}\hspace{0.5em}\mathrm{s},$ respectively) was disclosed from the measured angular distributions of their decay neutrons focused by the emission in flight towards the direction of motion of ${}^4\mathrm{He}$ and ${}^6\mathrm{He}$ ternary particles. Similarly, neutrons observed to be peaked around Li-particle motion could be attributed to the decay of the second excited state at $E^{*}=2.26\mathrm{}\hspace{0.5em}\mathrm{MeV}$ (lifetime: $2\times {10}^{-20}\hspace{0.5em}\mathrm{s})$ of ${}^8\mathrm{Li}.$ The fractional yields of the intermediate ${}^5\mathrm{He}$ and ${}^7\mathrm{He}$ ternary fission modes relative to the “true” ternary ${}^4\mathrm{He}$ and ${}^6\mathrm{He}$ modes, respectively, were determined to be 0.21(5) for both cases. The mean energy of the ${}^4\mathrm{He}$ residues resulting from the ${}^5\mathrm{He}$ decay was determined to be 12.4(3) MeV, compared to 15.7(2) MeV for all ternary α particles registered, and to 16.4(3) MeV for the true ternary α particles. The mean energy of the ${}^6\mathrm{He}$ residues from the ${}^7\mathrm{He}$ decay is 11.0(15) MeV, compared to 12.3(5) MeV for all ternary ${}^6\mathrm{He}$ particles. The population of ${}^8{\mathrm{Li}}^{*}$ was deduced to be 0.06(2) relative to Li ternary fission, and 0.33(20) relative to the yield of particle stable ${}^8\mathrm{Li}.$ The perspective of using the observed intermediate LCPs for probing the ternary scission configuration in ${}^{252}\mathrm{Cf}$ fission with the aid of trajectory calculations is briefly discussed.

Connections between charge balance functions, charge fluctuations, and correlations are presented. It is shown that charge fluctuations can be directly expressed in terms of balance functions under certain assumptions. The distortion of charge balance functions due to experimental acceptance is discussed and the effects of identical boson interference is illustrated with a simple model.

We analyze the radiative capture of the negative muon in hydrogen using amplitudes derived within the chiral Lagrangian approach. Besides the leading and next to leading order terms, given by the well-known Rood-Tolhoek Hamiltonian, we extract from these amplitudes the corrections of the next order in $1/M$ $(M$ is the nucleon mass). In addition, we estimate within the same formalism also the $\Delta \mathrm{}\left(1232\right)\mathrm{}$ isobar excitation effects and processes described by an anomalous Lagrangian. The model we consider allows us to put the Δ isobar off-shell. Our calculations show sensitivity of capture rates and photon spectra to Z, one of the off-shell parameters, related to the $\pi N\Delta$ vertex. We have found that the model can provide the photon spectra, which are in the interval $60\hspace{0.5em}\mathrm{MeV}<~k<~k_{\max }$ $(k$ is the photon momentum) close to the experimental one.

The nuclear reaction ${}^7\mathrm{Li}{(}^3\mathrm{He}{,p}_0{)}^9\mathrm{Be}$ was measured at effective center-of-mass energies of $E=106.3\mathrm{}$ and $E=112.8\mathrm{}\mathrm{keV}$ with the 180-kV Cockcroft-Walton accelerator at the Colorado School of Mines. As this reaction is a possible contributor to inhomogeneous big bang nucleosynthesis, all published data were compiled and used, together with our measurement, in a calculation of the thermonuclear reaction rate for temperatures up to ${10}^9\mathrm{K}.$

The study of intruder and multiphonon configurations is of great interest in nuclear structure physics because it is related to single-particle and collective motion. The rarest of the stable cadmium isotopes was investigated with the powerful combination of two complementary experimental techniques: $\gamma \gamma$ spectroscopy following the $\beta$ decay of ${}^{108}\mathrm{In},$ and population of excited states using the nonselective $(\alpha ,n)$ fusion-evaporation reaction. The intruder band in ${}^{108}\mathrm{Cd}$ up to its $4^{+}$ member is established on the measurement of branching ratios of in-band and intraband decays supported by upper limits for the lifetimes using Doppler shift attenuation method. The heavily suppressed absolute $E2\mathrm{}$ transition strength out of the proposed intruder band indicates this band structure to be fairly pure. These findings are compared to neighboring Cd isotopes and related six quasiproton structures. An analysis of the multiphonon structures observed in ${}^{108}\mathrm{Cd}$ and heavier Cd isotopes shows that the even mass cadmium chain forms a transitional path between the vibrational U(5) and the gamma-unstable O(6) limit with ${}^{108}\mathrm{Cd}$ closer to the O(6) description.

In a first experiment with accelerated beams at TRIUMF-ISAC, the scattering of radioactive ${}^{21}\mathrm{Na}$ ${(T}_{1/2}=22.49\mathrm{}\hspace{0.5em}\mathrm{s})$ on protons has been investigated. ${}^{21}\mathrm{Na}$ beams of typically $5\times {10}^7$ particles/s were employed while center-of-mass energies from 0.45 to 1.4 MeV were scanned and spectra with high statistics were collected. The experiment was carried out using large area silicon detectors at the TUDA facility. Three strong resonances corresponding to states in ${}^{22}\mathrm{Mg}$ have been identified at energies of 830 keV, 1115 keV, and 1311 keV, respectively. Using these data, aspects of the $T=1,$ $A=22\mathrm{}$ mirror system and the s-wave component of the astrophysically important ${}^{21}\mathrm{Na}(p,\gamma {)}^{22}\mathrm{Mg}$ reaction are discussed.

We apply a particle-particle random phase approximation (RPA) model to study the properties of the two-neutron valence wave function in nuclei ${}^{14}\mathrm{C},$ ${}^{12}\mathrm{Be},$ ${}^{11}\mathrm{Li},$ and ${}^{14}\mathrm{Be}.$ The RPA model takes account of two-body correlations in the cores so that it gives a better description of energies and amplitudes than models that assume a neutron closed shell (or subshell) core. With a Gogny neutron-neutron effective interaction or with the equivalent density dependent delta force we are able to reproduce the two-neutron separation energies in these nuclei and in the corresponding cores, except for ${}^9\mathrm{Li}.$ These calculations suggest the same $2s-{1p}_{1/2}$ shell inversion in ${}^{12}\mathrm{Be}{-}^{13}\mathrm{Be}$ than in ${}^{11}\mathrm{Be}.$

We investigate the role of the tensor force in the description of doubly odd deformed nuclei within the framework of the particle-rotor model. We study the rare-earth nuclei ${}^{174}\mathrm{Lu},$ ${}^{180}\mathrm{Ta},$ ${}^{182}\mathrm{Ta},$ and ${}^{188}\mathrm{Re}$ using a finite-range interaction, with and without tensor terms. Attention is focused on the lowest $K=0\mathrm{}$ and $K=1\mathrm{}$ bands, where the effects of the residual neutron-proton interaction are particularly evident. Comparison of the calculated results with experimental data evidences the importance of the tensor-force effects.