We present results from stopped beam rare isotope spectroscopic investigations at the GSI (RISING) experiment based on the detection of $\gamma$-ray transitions following the $\beta$ decay of ${}^{94}$Pd. A comparison between the measured low-lying level scheme of ${}^{94}$Rh and the prediction from shell-model calculations reveals the important roles of the $g_{7/2}$ and $g_{9/2}$ orbitals in explaining the structural features. The low values of the Gamow-Teller strengths $B\left(GT\right)$ can be attributed to the influence of the neutron-proton interaction, which gives rise to an increased seniority mixing for the nuclear states, thereby leading to a fragmentation of the strength to several daughter levels. These results provide further strong indications that ${}^{94}$Pd resides in the middle of a structural transition region in the Pd isotopes as the $N=Z$ line is approached.

The activation technique was used to measure the cross section for the reaction ${}^{40}\mathrm{Ar}(n,p){}^{40}\mathrm{Cl}$ in 0.5 MeV energy steps in the neutron energy range between 9 and 15 MeV. These data are important for estimating background contributions in neutrinoless double-beta decay and dark matter searches, as well as in argon-based large neutrino detectors. The data are compared to evaluations and theoretical predictions.

The Q values of double-electron capture in ${}^{124}$Xe, ${}^{130}$Ba, and ${}^{136}$Ce and double-beta decay of ${}^{124}$Sn and ${}^{130}$Te have been determined with the Penning-trap mass spectrometer SHIPTRAP with a few hundred eV uncertainty. These nuclides are members of three isobaric triplets with common daughter nuclides. The main goal of this work was to investigate the existence of the resonant enhancement of the neutrinoless double-electron-capture rates in ${}^{124}$Xe and ${}^{130}$Ba in order to assess their suitability for the search for neutrinoless double-electron capture. Based on our results, in neither of these cases is the resonance condition fulfilled.

The level structure of ${}^{10}$C below 7 MeV is discussed. We suggest the spin-parity assignments for the unbound states in ${}^{10}$C. The assignments are based on the observed widths, Coulomb displacement energies, the reported decay modes, the potential model prediction, and the shell-model calculations.

With the improved scission-point model mass distributions are calculated for induced fission of different Hg isotopes with even mass numbers $A=180,$ 184, 188, 192, 196, and 198. The calculated mass distribution and mean total kinetic energy of fission fragments are in good agreement with the existing experimental data. The asymmetric mass distribution of fission fragments of ${}^{180}$Hg observed in the recent experiment is explained. The change in the shape of the mass distribution from asymmetric to more symmetric is revealed with increasing $A$ of the fissioning ${}^A$Hg nucleus, and reactions are proposed to verify this prediction experimentally.

The systematic study of doubly closed shell ${}^{208}\mathrm{Pb}$-daughter cluster radioactivity using different versions of proximity potentials within the preformed cluster-decay model is extended to daughter nuclei other than ${}^{208}\mathrm{Pb}$. The nuclear proximity potentials used in the calculation of total interaction potential cover a wide range of barrier characteristics. The decay half-life of the cluster changes significantly with the use of these different potentials because of the corresponding change in the preformation probability ($P_0$) and penetration probability ($P$) of the cluster. The cluster radioactivity is worked out at touching as well as at an elongated neck configuration by taking the neck-length parameter $\Delta R=0.5$ fm. In order to observe the effect of deformation, the spherical fragmentation of clusters is also taken into account and the standard root-mean-square (rms) deviation is also compared for the various nuclear proximity potentials. It is observed that Prox 1977 reproduces the experimental half-lives very well at $\Delta R=0.5$ fm and further improves upon the value obtained in previous work. Thus Prox 1977 turns out to be a better option for studying the cluster decay of radioactive nuclei; however, the calculated half-lives of ${}^{14}\mathrm{C}$ clusters are still poor. With the use of mod-Prox 1988, having stronger isospin and asymmetry dependence, the comparison for ${}^{14}\mathrm{C}$ clusters improves significantly and the standard rms deviation from experimental half-lives comes out to be 1.01 and 1.46 for spherical and deformed choices of fragmentation, respectively. The standard rms deviation reported for various proximity potentials can be further improved if the precise experimental half-lives of 15, out of the 45 clusters used in present study, are made available. Till now only lower limits are available for these clusters. The barrier characteristics of various interaction potentials obtained using different nuclear proximity potentials are also explored in the context of ground-state cluster radioactivity. The new cases of ${}^{34}\mathrm{Si}$ decay of ${}^{238}\mathrm{U}$ and ${}^{14}\mathrm{C}$ and ${}^{15}\mathrm{N}$ decays of ${}^{223}\mathrm{Ac}$ are also included in the present study of 45 clusters. Predictions of half-lives of possible cluster decays in the trans-lead region are also made using Prox 1977. The deformation effect is included with optimum cold orientations.

Parity-violating (PV) effects in neutron-deuteron radiative capture are studied using Desplanques, Donoghue, and Holstein (DDH) and effective field theory weak potentials. The values of PV effects are calculated using wave functions, obtained by solving three-body Faddeev equations in configuration space for realistic strong potentials. The relations between physical observables and low-energy constants are presented, and dependencies of the calculated PV effects on strong and weak potentials are discussed. The presented analysis shows the possible reason for the existing discrepancy in PV nuclear data analysis using the DDH approach and reveals a new opportunity to study short-range interactions in nuclei.

A nonlocal energy-dependent two-body quasipotential (E2Q) is defined within the framework of the three-body Faddeev formalism. The Fourier transform of this E2Q generates an energy-dependent Yukawa-type local potential. After an appropriate average of the potential with respect to the energy, a variety of local potentials with different ranges are obtained. These include a Yukawa potential, a Van der Waals potential, and a $1/r^2$ potential. An interesting potential appears in the $\pi$$\mathrm{NN}$ system, which gives rise to the one-pion-exchange $\mathrm{NN}$ interaction. It is also found that the Yukawa potential is automatically accompanied by an additional longer-range interaction. This potential could give rise to an infinite number of bound states near the threshold above the deuteron bound state with a more interesting physics than the Efimov effect.

A scheme that elucidates the nature of critical-point symmetries in intermediately deformed odd-$A$ nuclei by linking them to critical-point symmetries of neighboring even-even nuclei is introduced. Specifically, a symmetry called DX(3) is proposed, which shows primary characteristics in the decoupling limit for odd-$A$ systems. Some experimental indications about the symmetry in some intermediately deformed odd-$A$ nuclei are discussed.

Reaction products from the system ${}^{136}\mathrm{Xe}+{}^{208}$Pb at ${}^{136}$Xe ions laboratory energies of 700, 870, and 1020 MeV were studied by two-body kinematics and by a catcher-foil activity analysis to explore the theoretically proposed suitability of such reaction as a means to produce neutron-rich nuclei in the neutron shell closure $N=126$. Cross sections for products heavier than ${}^{208}$Pb were measured and were found sensibly larger than new theoretical predictions. Transfers of up to 16 nucleons from Xe to Pb were observed.

We calculate the magnetic form factor of the deuteron up to $O\left(e{P}^4\right)$ in the chiral effective field theory expansion of the electromagnetic current operator. The two low-energy constants which enter the two-body part of the isoscalar NN three-current operator are fit to experimental data, and the resulting values are of natural size. The $O\left(e{P}^4\right)$ description of $G_M$ agrees with data for momentum transfers $Q^2<0.35$ GeV${}^2$.

The assumption of an exact isospin symmetry would imply equal strengths for mirror $E1$ transitions (at least, in the long-wavelength limit). Actually, large violations of this symmetry rule have been indicated by a number of experimental results, the last of which is the ${}^{67}$As-${}^{67}$Se doublet investigated at GAMMASPHERE. Here, we examine in detail various possible origins of the observed asymmetry. The coherent effect of Coulomb-induced mixing with the high-lying giant isovector monopole resonance is proposed as the most probable process to produce a large asymmetry in the $E1$ transitions, with comparatively small effect on the other properties of the parent and daughter levels.

The shape, deformation, and orientation dependence as well as in-medium effects are investigated for the reaction cross sections of ${}^{16,19}\text{C}+\text{C}$ systems within the optical Glauber theory, which is currently used to deduce information about the structure of exotic nuclei. A density- and energy-dependent effective nucleon-nucleon reaction cross section is used locally to study in-medium effects. The projectile deformation is treated by a deformed Fermi shape with quadrupole and hexadecapole deformations, where the deformation parameters of ${}^{16}\text{C}$ and ${}^{19}\text{C}$ are calculated from the Lagrangian density of the relativistic mean-field (RMF) model. A strong prolate deformation is predicted for ${}^{16}\text{C}$ while a more stronger oblate shape is predicted for ${}^{19}\text{C}$. Medium effects are found to be important for extracting reliable information about the nuclear densities and radii. The deformations and orientations strongly affected the reaction cross section. The difference in the reaction cross section calculated at orientation angle $\pi /2$ and at zero degree is of the order of 400 mb. The integrated reaction cross section over all orientation angles (angle average), including in-medium effects, predicted the experimental reaction cross section of ${}^{19}\text{C}+{}^{12}\text{C}$. For ${}^{16}\text{C}+{}^{12}\text{C}$ the rms radius of ${}^{16}\text{C}$ is increased to about $7\%$ than that predicted by the RMF model in order to predict the experimental data. This greater increase in the rms radius of ${}^{16}\text{C}$, to about 3 fm, indicates a neutron halo structure for this nucleus. The deduced spherical Fermi distributions which fit the experimental data of ${}^{16,19}\text{C}+{}^{12}\text{C}$ systems are in fact a prediction of the angle average cross sections.

For deuteron scattering from ${}^{58}$Ni at laboratory energies of 56, 79, and 120 MeV, we study the dynamic polarization potentials (DPPs) induced by $S$-wave and $D$-wave breakup (BU), separately and together, in order to gain insight into the nature of the DPP as well as a counterintuitive property: the existence of $L$ values for which the BU coupling increases $|S_L|$, a ‘wrong-way’ effect. The effect is associated with the existence of emissive regions in the imaginary DPP, suggesting a connection with the nonlocal nature of the DPP. The same relationship was previously found for ${}^6$Li scattering, indicating a generic effect bearing on the dynamics of nuclear reactions.

The formalism of the linear response for the Skyrme energy density functional including tensor terms derived in Refs. [1,2] for nuclear matter is applied here to the case of pure neutron matter. As in Ref. [2] we present analytical results for the response function in all channels, the Landau parameters, and the odd-power sum rules. Special emphasis is given to the inverse energy weighted sum rule because it can be used to detect nonphysical instabilities. Typical examples are discussed and numerical results shown. Moreover, as a direct application, neutrino propagation in neutron matter is investigated through its neutrino mean-free path at zero temperature. This quantity turns out to be very sensitive to the tensor terms of the Skyrme energy density functional.

The Gamow-Teller (GT) strength distribution has been investigated in a high-resolution (${}^3$He,$t$) charge-exchange experiment on the double-beta ($\beta \beta$) decaying nucleus ${}^{100}$Mo. The experiment was carried out at the Osaka University Research Center for Nuclear Physics (RCNP) with a 420 MeV incident ${}^3$He beam and the Grand Raiden magnetic spectrometer. A final-state energy resolution of 33 keV was achieved. It was found that nearly the entire low-energy (up to $\approx 4$ MeV) ${\mathrm{GT}}^{-}$ strength is concentrated in the ground-state transition to ${}^{100}$Tc, which is interpreted as a result of the particular neutron and proton sub-shell occupancies. The impact on the matrix elements for the two-neutrino double-beta ($2\nu \beta \beta$) decay and the use of ${}^{100}$Mo as a neutrino detection material is discussed.

Decays from isomeric states in the neutron-deficient $N=73$ nuclei ${}^{132}$Pr and ${}^{130}$La have been observed for the first time. Half-lives of 486(70) ns and 2.46(4) $\mu$s were measured for two isomeric states in ${}^{132}$Pr. The decay from the 486 ns $\left(8^{-}\right)$ isomer has been interpreted as a hindered $E1$ transition from the bandhead state of the excited $\pi h_{11/2}\otimes \nu g_{7/2}$ configuration. The decay from the 2.5 $\mu$s $\left(8^{+}\right)$ isomer is consistent with the Weisskopf estimate for a low-energy $E2$ transition. An analogous 0.74(3) $\mu$s decay from an $\left(8^{+}\right)$ isomer in the neighboring isotone ${}^{130}$La has also been observed which similarly can be explained if the transition has $E2$ character. The Weisskopf interpretation for the isomer hindrance is strengthened by the lack of evidence for shape or $K$ isomerism due to the $\gamma$-soft shapes predicted by configuration-constrained potential-energy-surface calculations.

Elastic-scattering angular distributions for the ${}^{6,7}$Li $+$ ${}^{80}$Se systems were measured at center-of-mass energies from below to above the Coulomb barrier, 13 $⩽$ $E$${}_{c.m.}⩽$ 24 MeV. The experimental elastic-scattering cross sections were analyzed within the framework of the optical model to study the energy dependence of the real and imaginary parts of the nuclear-interaction potential. The main objective was to investigate the threshold anomaly in those weakly bound systems. The behavior of the calculated potentials as a function of energy indicates that our results are qualitatively consistent with the dispersion relation. The threshold anomaly was observed in the ${}^7$Li $+$ ${}^{80}$Se system and for the ${}^6$Li $+$ ${}^{80}$Se system a breakup threshold anomaly is apparent. An analysis of the absorptive processes, involved in the discussion of the experimental results, was performed using the phenomenological optical potentials that best fit the experimental data.

The cross section for radiative capture of neutron on carbon-14 is calculated using the model-independent formalism of halo effective field theory. The dominant contribution from $E1$ transition is considered, and the cross section is expressed in terms of elastic-scattering parameters of the effective-range expansion. Contributions from both resonant and nonresonant interaction are calculated. Significant interference between these leads to a capture contribution that deviates from a simple Breit-Wigner resonance form.