We performed in-gas-cell laser ionization spectroscopy of ${}^{194,196}\mathrm{Os}$, which were produced by multinucleon transfer reactions at the KEK Isotope Separation System (KISS). The nuclei of interest were identified through $\beta$-decay spectroscopy and a newly applied multireflection time-of-flight mass spectrograph (MRTOF-MS). From the study of laser resonance spectra, isotope shifts (ISs) of the transition ${\lambda }_1=247.758$ nm for ${}^{194}\mathrm{Os}$ and ${}^{196}\mathrm{Os}$ were measured for the first time. The change in the mean-square charge radius $\delta {\langle r^2\rangle }^{192,A}$ and the quadrupole deformation parameter ${\langle {\beta }_2^2\rangle }^{1/2}$ were deduced from the IS measurements. The results were compared with the theoretical calculations and the predicted shape transition at ${}^{194}\mathrm{Os}$ is discussed.

The two-fermion two-time correlation function in the pairing channel is discussed within the equation of motion framework. Starting from the bare two-fermion interaction, we derive the equation of motion for the two-fermion pair propagator in a strongly correlated medium. The resulting equation is of the Dyson type with the kernel having static and one-frequency dependent components and, thus, can be regarded as a Dyson Bethe-Salpeter equation (Dyson-BSE). The many-body hierarchy generated by the dynamical interaction kernel is truncated on the level of two-body correlation functions, thus neglecting the explicit three-body and higher-rank correlations. The truncation is performed via a cluster expansion of the intermediate three-particle-one-hole correlation function irreducible in the particle-particle channel, that leads to the coupling between single fermions and emergent bosonic quasibound states (phonons). The latter couplings are, thus, derived in terms of the exact mapping of the in-medium two-fermion correlation functions onto the domain of phonons without introducing new parameters. The approach is applied to calculations of the pairing gaps in medium-mass nuclear systems, that include calcium, nickel and tin isotopic chains.

Two-quasiparticle excitations of medium mass nuclei with well-defined axial deformation are studied within the covariant density functional framework. The evolution of high-$K$ isomers is analyzed in a self-consistent axially symmetric relativistic Hartree-Bogoliubov calculation using the blocking approximation. The occurrence of the $6^{+}$ and $8^{-}$ low-energy high-$K$ isomers in the region from Er to Pb ($68\le Z\le 82,98\le N\le 112$) is evaluated and compared to available data. The importance of the quasiparticle spectrum in the energy evolution of the high-$K$ states is discussed in detail.

We address the connection between the saturating behavior of infinite nuclear matter and the description of finite nuclei based on state-of-the-art chiral two- and three-nucleon forces. We observe that chiral two- and three-nucleon interactions (at ${\mathrm{N}}^2\mathrm{L}\mathrm{O}$ and at ${\mathrm{N}}^3\mathrm{L}\mathrm{O}$), which have been found to predict realistic binding energies and radii for a wide range of finite nuclei (from $p$-shell nuclei up to nickel isotopes) are unable to saturate infinite nuclear matter. On the other hand, it has been shown that, when the fits of the $c_D$ and $c_E$ couplings of the chiral three-nucleon interactions include the constraint of nuclear matter saturation in addition to, as is typically the case, the triton binding energy, medium-mass nuclei are underbound and their radii are systematically too large. We discuss this apparent inconsistency and perform test calculations for various scenarios to shed light on the issue.

A new measurement of the neutron-induced fission cross section of ${}^{236}\mathrm{U}$ relative to the standard ${}^{235}\mathrm{U}\left(n,f\right)$ cross section from 0.4–40 MeV was carried out by the time-of-flight method and a multicell fast fission ionization chamber at the China Spallation Neutron Source-Back-n white neutron source. The measured resonance peaks and the distribution of fission event-energy spectrum from the ${}^{235}\mathrm{U}\left(n,f\right)$ reaction are in good agreement with that of the ENDF/B-VIII.0 evaluation, which confirms the reliability of the experimental setup. The measured ${}^{236}\mathrm{U}{/}^{235}\mathrm{U}$ fission cross section ratios in 0.4–40 MeV neutron energy region are compared to previous measurements. The ${}^{236}\mathrm{U}$ fission cross section with the relative experimental uncertainty of 11.2%–2.9% in 0.4–1 MeV and 2.9%–2.8% in 1–40 MeV is determined and compared to calculation, previous measurements, and main evaluations. The present theoretical result with calculation program UNF reproduces the experimental data and the LANSCE data better than ENDF/B-VIII.0 evaluation does in the secondary fission region. The result confirms current evaluations from 0.4–40 MeV in most energy points and provides the experimental data for evaluating the discrepancies in the relevant energy region.

We reexamine Moravcsik's theorem on the unique extraction of amplitudes from polarization observables, which has been originally published in 1985. The proof is (re-)written in a more formal and detailed way and the theorem is corrected for the special case of an odd number of amplitudes (this case was treated incorrectly in the original publication). Moravcsik's theorem, in the modified form, can be applied in principle to the extraction of an arbitrary number of $N$ helicity amplitudes. The uniqueness theorem is then applied to hadronic reactions involving particles with spin. The most basic example is pion-nucleon scattering ($N=2$), the first nontrivial example is pseudoscalar meson photoproduction ($N=4$), and the most technically involved case treated here is given by pseudoscalar meson electroproduction ($N=6$). The application of Moravcsik's theorem to electroproduction yields new results, which for the first time provide insights into the structure and content of complete sets for this particular process. The uniqueness statements for the various reactions are compared and an attempt is made to recognize general patterns, which emerge under the application of the theorem.

Background: Calculating microscopic effective interactions (optical potentials) for elastic nucleon-nucleus scattering has already led to a large body of work. For leading-order calculations a nucleon-nucleon (NN) interaction and a one-body density of the nucleus were taken as input to rigorous calculations of microscopic full-folding calculations.

Purpose: Based on the spectator expansion of the multiple scattering series, we employ a chiral next-to-next-to-leading order (NNLO) nucleon-nucleon interaction on the same footing in the structure as well as in the reaction calculation to obtain an effective potential for nucleon-nucleus elastic scattering, consistent in leading-order, which includes the spin of the struck target nucleon.

Methods: The leading order effective folding potential is computed by first deriving a nonlocal scalar density as well as a spin-projected momentum distribution. Those are then integrated with the off-shell Wolfenstein amplitudes $A$, $C$, and $M$. The resulting nonlocal potential serves as input to a momentum-space Lippmann-Schwinger equation, whose solutions are summed to obtain the nucleon-nucleus scattering observables.

Results: We calculate elastic scattering observables for ${}^4\mathrm{He}$, ${}^6\mathrm{He}$, ${}^8\mathrm{He}$, ${}^{12}\mathrm{C}$, and ${}^{16}\mathrm{O}$ in the energy regime between 100 and 200 MeV projectile kinetic energy, and compare to available data. We also explore the extension down to about 70 MeV, and study the effect of ignoring the spin of the struck nucleon in the nucleus.

Conclusions: In our calculations we contrast elastic scattering off closed-shell and open-shell nuclei. We find that for closed-shell nuclei the approximation of ignoring the spin of the struck target nucleon is excellent. We only see effects of the spin of the struck target nucleon when considering ${}^6\mathrm{He}$ and ${}^8\mathrm{He}$, which are nuclei with an $N/Z$ ratio larger than 1.

The fusion evaporation residue cross sections ${\sigma }_{xn}$ for the decay of the compound nucleus (CN) ${}^{274}\mathrm{Hs}^{*}$ via $3n$- to $5n$-decay channels, synthesized in ${}^{248}\mathrm{Cm}+{}^{26}\mathrm{Mg}, {}^{238}\mathrm{U}+{}^{36}\mathrm{S}$, and ${}^{226}\mathrm{Ra}+{}^{48}\mathrm{Ca}$ reactions, are studied including deformations ${\beta }_{2i}$ for compact hot orientations ${\theta }_i$ at various excitation energies of $E^{*}=40$ to 51 MeV, which support symmetric fission, in agreement with experiments. For the nuclear interaction potentials, we use the Skyrme energy density functional based on the semiclassical extended Thomas-Fermi approach, which means an extension of our earlier study of excitation functions of ${}^{248}\mathrm{Cm}+{}^{26}\mathrm{Mg}, {}^{238}\mathrm{U}+{}^{36}\mathrm{S}$, and ${}^{226}\mathrm{Ra}+{}^{48}\mathrm{Ca}$ reactions, based on the dynamical cluster-decay model (DCM). In the present work the above reactions have been investigated by using a hot compact configuration. The Skyrme forces used here are the conventional SIII and the newer GSkI and KDE0(v1) given for both normal and isospin-rich nuclei, with densities added in the frozen density approximation. Interestingly, with the inclusion of both conventional and new Skyrme forces, the DCM gives an excellent fit within one parameter fitting of $\mathrm{\Delta }R$ to the measured data on the fusion evaporation residue for all three incoming channels at the energy range $E^{*}=40$ to 51 MeV, independent of the entrance channel and the Skyrme force used. The possible fusion-fission and quasifission mass-regions of fragments on the DCM are also predicted. The DCM with Skyrme forces is further used to look for all the possible target-projectile combinations forming the “cold” CN ${}^{274}\mathrm{Hs}^{*}$ at the CN excitation energy of $E^{*}$ for “hot compact” configurations. The role of magic shells is shown in enhancing the evaporation residue cross sections, not only for the entrance channel ${}^{226}\mathrm{Ra}+{}^{48}\mathrm{Ca}$ but also for the residue ${}^{270}\mathrm{Hs}$, compared to its neighboring isotopes ${}^{269-271}\mathrm{Hs}$. The fusion evaporation residue cross sections for the proposed new reactions in synthesizing the CN ${}^{274}\mathrm{Hs}^{*}$ are also estimated for future experiments.

Elastic scattering of a series of doubly closed-shell nuclei at low energy has been described in the framework of optical potential model generated from the particle-vibration coupling approach on top of the collective excited states obtained from the random-phase approximation. We focus on the effects of the spin-orbit and velocity-dependent interaction on the angular distributions and analyzing powers by comparing these observables with experimental data. It has been found that the contribution of the two-body velocity-dependent and two-body spin-orbit terms are important to improve results for ${}^{16}\mathrm{O},{}^{40}\mathrm{Ca},{}^{48}\mathrm{Ca}$, and ${}^{208}\mathrm{Pb}$. The velocity-dependent interactions strongly reduce the absorption on the surface while the spin-orbit interactions sightly increase the absorption in the interior.

We study the diffractive jet production in electron-ion collisions in the kinematic region where the mass $M_X$ of the diffractive final state is larger than $Q^2$. Based on parton saturation framework, predictions are done for the kinematics of future or possible $eA$ machines as the EIC, LHeC, HE-LHeC, and FCC-eA. We analyze the differential cross section as a function of jet (gluon) transverse momentum and from the experimental point of view this observable could be used to extract the saturation scale as a function of $x_{IP}$.

We propose a new way to experimentally determine the subleading low-energy structure constant of doubly virtual Compton scattering on a proton. Such empirical determination will reduce the theoretical model error in estimates of the hadronic correction to the muonic hydrogen Lamb shift. We demonstrate that the dilepton forward-backward asymmetry in the $e^{-}p\to e^{-}p{e}^{-}{e}^{+}$ process, which can be accessed at electron scattering facilities, yields a large sensitivity to this so far unknown low-energy constant.

The role of repulsive interactions in statistical systems of Bose particles is investigated. Three different phenomenological frameworks are considered: a mean-field model, an excluded volume model, and a model with a medium-dependent effective mass. All three models are tuned to yield similar equations of state, with only minor deviations from the ideal Bose gas at small chemical potentials. Our analysis indicates, however, that these models lead to qualitatively different results for the Bose-Einstein condensation phenomenon. We discuss the different aspects of this phenomenon, namely, an onset of the Bose-Einstein condensation, particle number fluctuations, and a behavior of the Bose condensate. The obtained results can be helpful for interpreting the lattice QCD data at small temperature and large isospin chemical potential and the data on multiple pion production in high-energy nuclear collisions.

The event rates for WIMP-nucleus and neutrino-nucleus scattering processes, expected to be detected in ton-scale rare-event detectors, are investigated. We focus on nuclear isotopes that correspond to the target nuclei of current and future experiments looking for WIMP- and neutrino-nucleus events. The nuclear structure calculations, performed in the context of the deformed shell model, are based on Hartree-Fock intrinsic states with angular momentum projection and band mixing for both the elastic and the inelastic channels. Our predictions in the high-recoil-energy tail show that detectable distortions of the measured/expected signal may be interpreted through the inclusion of the nonnegligible incoherent channels.

Background: Globular clusters are known to exhibit anomalous abundance trends such as the sodium-oxygen anticorrelation. This trend is thought to arise via pollution of the cluster interstellar medium from a previous generation of stars. Intermediate-mass asymptotic giant branch stars undergoing hot bottom burning (HBB) are a prime candidate for producing sodium-rich oxygen-poor material, and then expelling this material via strong stellar winds. The amount of ${}^{23}\mathrm{Na}$ produced in this environment has been shown to be sensitive to uncertainties in the ${}^{22}\mathrm{Ne}(p,\gamma ){}^{23}\mathrm{Na}$ reaction rate. The ${}^{22}\mathrm{Ne}(p,\gamma ){}^{23}\mathrm{Na}$ reaction is also activated in classical nova nucleosynthesis, strongly influencing predicted isotopic abundance ratios in the Na-Al region. Therefore, improved nuclear physics uncertainties for this reaction rate are of critical importance for the identification and classification of pre-solar grains produced by classical novae.

Purpose: At temperatures relevant for both HBB in AGB stars and classical nova nucleosynthesis, the ${}^{22}\mathrm{Ne}(p,\gamma ){}^{23}\mathrm{Na}$ reaction rate is dominated by narrow resonances, with additional contribution from direct capture. This study presents new strength values for seven resonances, as well as a study of direct capture.

Method: The experiment was performed in inverse kinematics by impinging an intense isotopically pure beam of ${}^{22}\mathrm{Ne}$ onto a windowless ${\mathrm{H}}_2$ gas target. The ${}^{23}\mathrm{Na}$ recoils and prompt $\gamma$ rays were detected in coincidence using a recoil mass separator coupled to a $4\pi$ bismuth-germanate scintillator array surrounding the target.

Results: For the low-energy resonances, located at center of mass energies of 149, 181, and 248 keV, we recover stength values of $\omega {\gamma }_{149}=0.{17}_{-0.04}^{+0.05}, \omega {\gamma }_{181}=2.2\pm 0.4$, and $\omega {\gamma }_{248}=8.2\pm 0.7 \mu \text{eV}$, respectively. These results are in broad agreement with recent studies performed by the LUNA and TUNL groups. However, for the important reference resonance at 458 keV we obtain a strength value of $\omega {\gamma }_{458}=0.44\pm 0.02$ eV, which is significantly lower than recently reported values. This is the first time that this resonance has been studied completely independently from other resonance strengths. For the 632-keV resonance we recover a strength value of $\omega {\gamma }_{632}=0.48\pm 0.02$ eV, which is an order of magnitude higher than a recent study. For reference resonances at 610- and 1222-keV, our strength values are in agreement with the literature. In the case of direct capture, we recover an $S$ factor of 60 keV b, consistent with prior forward kinematics experiments.

Conclusions: In summary, we have performed the first direct measurement of ${}^{22}\mathrm{Ne}(p,\gamma ){}^{23}\mathrm{Na}$ in inverse kinematics. Our results are in broad agreement with the literature, with the notable exception of the 458-keV resonance, for which we obtain a lower strength value. We assessed the impact of the present reaction rate in reference to a variety of astrophysical environments, including AGB stars and classical novae. Production of ${}^{23}\mathrm{Na}$ in AGB stars is minimally influenced by the factor of 4 increase in the present rate compared to the STARLIB-2013 compilation. The present rate does however impact upon the production of nuclei in the Ne-Al region for classical novae, with dramatically improved uncertainties in the predicted isotopic abundances present in the novae ejecta.

Neutrinos play an important role in compact star astrophysics: neutrino heating is one of the main ingredients in core-collapse supernovae, neutrino-matter interactions determine the composition of matter in binary neutron star mergers and have among others a strong impact on conditions for heavy element nucleosynthesis, and neutron star cooling is dominated by neutrino emission except for very old stars. Many works in the last decades have shown that in dense matter medium effects considerably change the neutrino-matter interaction rates, whereas many astrophysical simulations use analytic approximations which are often far from reproducing more complete calculations. In this work we present a scheme which allows to incorporate improved rates for charged current interactions into simulations and show as an example some results for core-collapse supernovae, where a noticeable difference is found in the location of the neutrinospheres of the low-energy neutrinos in the early post-bounce phase.

$\mathrm{\Lambda }$-deuteron two-particle momentum correlation functions, to be measured in high-energy heavy-ion collisions, are investigated. In particular, the question is addressed whether such correlations can serve as an additional and alternative source of information on the elementary $\mathrm{\Lambda }N$ interaction. The study is performed within the Lednicky-Lyuboshits formalism, utilizing an effective range expansion for the two relevant $S$-wave $\mathrm{\Lambda }d$ amplitudes with parameters taken from the literature. It is found that in collisions characterized by a large emitting source the $\mathrm{\Lambda }d$ correlation function is predominantly sensitive to the quartet state (${}^{4}S_{3/2}$). In contrast, for small source sizes the contribution from the doublet partial wave (${}^{2}S_{1/2}$) could be significant. Though the latter is constrained by the hypertriton binding energy, its present experimental uncertainty impedes an accurate determination of the doublet amplitude and, in turn, complicates conclusions on the quartet state.

The positive-parity doublet bands with configuration $\pi h_{11/2}\otimes \nu h_{11/2}$ and negative-parity bands with $\pi h_{11/2}\otimes \nu \left(g_{7/2}{d}_{5/2}\right)$ observed in ${}^{124}\mathrm{Cs}$, and the possibility of multiple chiral doublets ($\mathrm{M}\chi \mathrm{D}$) with octupole correlations are investigated using the reflection-asymmetric triaxial particle rotor model. The calculated excitation energies, energy staggering parameters, and the electromagnetic transitional probabilities are in good agreement with the data available and satisfy the expected features of chiral doublet bands. The angular momentum geometry and its evolution with spin are studied with the angular momentum components and the azimuthal plot. In comparison with a typical chiral vibration pattern for the positive-parity doublet bands, a transient static chirality around $I=12\hslash$ is shown for the calculated negative-parity doublet bands.

In the latest version of the quark-meson coupling (QMC) model, $\mathrm{QMC}\pi$-III-T, the density functional is improved to include the tensor component quadratic in the spin current and a pairing interaction derived in the QMC framework. Traditional pairing strengths are expressed in terms of the QMC parameters and the parameters of the model optimized. A variety of nuclear observables are calculated with the final set of parameters. The inclusion of the tensor component improves the predictions for ground-state bulk properties, while it has a small effect on the single-particle spectra. Further, its effect on the deformation of selected nuclei is found to improve the energies of doubly magic nuclei at sphericity. Changes in the energy curves along the Zr chain with increasing deformation are investigated in detail. The new pairing functional is also applied to the study of neutron shell gaps, where it leads to improved predictions for subshell closures in the superheavy region.

Employing the recoil ion transport unit (RITU) and a fusion-evaporation reaction, the $\alpha$ decay of ${}^{211}\mathrm{Pa}$ has been identified via the implantation-decay correlation technique through observation of chains up to four consecutive decays. An $\alpha$-particle energy and half-life of 8320(40) keV and $3.8_{-1.4}^{+4.6}$ ms, respectively, were measured, corresponding to favored $\alpha$ decay. In addition, more precise $\alpha$-decay properties of ${}^{212}\mathrm{Pa}$ and ${}^{213}\mathrm{Pa}$ were obtained due to accumulated statistics. The present data were compared to those predicted by selected atomic mass models and it was used to estimate the possibility of observing proton emission from these isotopes.

Background: The isotope ${}^{99}\mathrm{Mo}$, the generator of ${}^{99m}\mathrm{Tc}$ used for diagnostic imaging, is supplied by extraction from fission fragments of highly enriched uranium in reactors. However, a reactor-free production method of ${}^{99}\mathrm{Mo}$ is sought worldwide due to concerns about nuclear proliferation.

Purpose: Production methods using accelerators have attracted attention. Recently, ${}^{99}\mathrm{Mo}$ production through a muon capture reaction was proposed and it was found that about $50\%$ of ${}^{100}\mathrm{Mo}$ turned into ${}^{99}\mathrm{Mo}$ through the ${}^{100}\mathrm{Mo}\left({\mu }^{-},n\right)$ reaction [I. Hashim et al., Nucl. Instrum. Methods Phys. Res., Sect. A 963, 163749 (2020)]. However, the detailed physical process of the muon capture reaction is not completely understood. We therefore study the muon capture reaction on ${}^{100}\mathrm{Mo}$ by a theoretical approach.

Methods: We use the proton-neutron quasiparticle random phase approximation to calculate the muon capture rate. The muon wave function is calculated with consideration of the electronic distribution of the atom and the nuclear charge distribution. The particle evaporation process from the daughter nucleus, ${}^{100}\mathrm{Nb}$, is calculated by the Hauser-Feshbach statistical model.

Results: From the model calculation, about $38\%$ of ${}^{100}\mathrm{Mo}$ is converted to ${}^{99}\mathrm{Mo}$ through the muon capture reaction, which is in reasonable agreement with the experimental data. It is revealed that negative parity states, especially the $1^{-}$ state, play an important role in ${}^{100}\mathrm{Mo}\left({\mu }^{-},n\right){}^{99}\mathrm{Nb}$. Charged particle emission is hindered due to its large separation energy and the Coulomb barrier.

Conclusions: Isotope production by the muon capture reaction strongly depends on the nuclear structure. To understand the mechanism, excitation energy functions have to be known microscopically.