Excitation functions of reaction residues produced in the ${}^{14}\mathrm{N}+{}^{169}\mathrm{Tm}$ system have been measured to high precision at energies above the fusion barrier, ranging from $1.04V_B$ to $1.30V_B$, and analyzed in the framework of the statistical model code pace4. Analysis of $\alpha$-emitting channels points toward the onset of incomplete fusion even at slightly above-barrier energies where complete fusion is supposed to be one of the dominant processes. The onset and strength of incomplete fusion have been deduced and studied in terms of various entrance channel parameters. Present results together with the reanalysis of existing data for various projectile-target combinations conclusively suggest strong influence of projectile structure on the onset of incomplete fusion. Also, a strong dependence on the Coulomb effect $\left(Z_P{Z}_T\right)$ has been observed for the present system along with different projectile-target combinations available in the literature. It is concluded that the fraction of incomplete fusion linearly increases with $Z_P{Z}_T$ and is found to be more for larger $Z_P{Z}_T$ values, indicating significantly important linear systematics.

We investigate the effect of large magnetic fields on the ($2+1$)-dimensional reduced-magnetohydrodynamical expansion of hot and dense nuclear matter produced in $\sqrt{s_{\mathrm{NN}}}=200$ GeV Au+Au collisions. For the sake of simplicity, we consider the case where the magnetic field points in the direction perpendicular to the reaction plane. We also consider this field to be external, with energy density parametrized as a two-dimensional Gaussian. The width of the Gaussian along the directions orthogonal to the beam axis varies with the centrality of the collision. The dependence of the magnetic field on proper time ($\tau$) for the case of zero electrical conductivity of the QGP is parametrized following Deng et al. [Phys. Rev. C 85, 044907 (2012)], and for finite electrical conductivity following Tuchin [Phys. Rev. C 88, 024911 (2013)]. We solve the equations of motion of ideal hydrodynamics for such an external magnetic field. For collisions with nonzero impact parameter we observe considerable changes in the evolution of the momentum eccentricities of the fireball when comparing the case when the magnetic field decays in a conducting QGP medium and when no magnetic field is present. The elliptic-flow coefficient $v_2$ of ${\pi }^{-}$ is shown to increase in the presence of an external magnetic field and the increment in $v_2$ is found to depend on the evolution and the initial magnitude of the magnetic field.

Recently, a variety of studies have shown the importance of including nonlocality in the description of reactions. The goal of this work is to revisit the phenomenological approach to determining nonlocal optical potentials from elastic scattering. We perform a ${\chi }^2$ analysis of neutron elastic scattering data off ${}^{40}\mathrm{Ca}, {}^{90}\mathrm{Zr}$, and ${}^{208}\mathrm{Pb}$ at energies $E\approx 5–40$ MeV, assuming a Perey and Buck [Nucl. Phys. 32, 353 (1962)] or Tian et al. [Int. J. Mod. Phys. E 24, 1550006 (2015)] nonlocal form for the optical potential. We introduce energy and asymmetry dependencies in the imaginary part of the potential and refit the data to obtain a global parametrization. Independently of the starting point in the minimization procedure, an energy dependence in the imaginary depth is required for a good description of the data across the included energy range. We present two parametrizations, both of which represent an improvement over the original potentials for the fitted nuclei as well as for other nuclei not included in our fit. Our results show that, even when including the standard Gaussian nonlocality in optical potentials, a significant energy dependence is required to describe elastic-scattering data.

The change of proton and neutron skin thicknesses is investigated in nuclei after α decay. The skin thicknesses are self-consistently calculated. The observed α decays lead to relatively large decrease of the proton skin in the daughter nuclei. A large increase of the neutron skin in the daughter nucleus reflects the hindered α decay. This hindrance is related to the decrease of both the $Q_{\alpha }$ value and the preformation probability in the parent nucleus. For each isotopic chain, the observed half-lives consistently correlate with the change of the proton (neutron) skin thickness, from parent to daughter nuclei.

For the $1^{+}$ first-excited state of ${}^{26}\mathrm{P}$, the lifetime and the upper limit on the proton width have been combined with shell-model spectroscopic factors to place an upper limit on the proton single-particle (sp) width. With a potential model, this limit on sp width allows an upper limit on the $1^{+}$ resonance energy of $E_{\mathrm{r}}<124\mathrm{keV}$. Combining with the known $1^{+}$ excitation energy provides a limit on the proton separation energy of ${}^{26}\mathrm{P}\left(\mathrm{g}.\mathrm{s}.\right)$ of $S_{\mathrm{p}}>40\mathrm{keV}$, considerably better than a recent result of $S_{\mathrm{p}}>-135\mathrm{keV}$ from a similar procedure that used $R$-matrix sp widths.

Isoscalar giant resonances in ${}^{44}\mathrm{Ca}$ have been studied with inelastic scattering of 240 MeV α particles at small angles including $0^{\circ }$. A majority of the energy weighted sum rule was identified for $E0$ and $E2$ ($\approx 70\%$), and nearly half was identified for $E1$. The strength distributions are compared with the predictions from Hartree-Fock based random phase approximation calculations with the KDE0v1 Skyrme-type interaction. The giant monopole resonance energy moments for ${}^{40,44,48}\mathrm{Ca}$ increase with mass, contrary to what would be expected with a negative symmetry energy, $K_{\tau }$.

The in-gas laser ionization and spectroscopy (IGLIS) technique was applied on the ${}^{212–215}\mathrm{Ac}$ isotopes, produced at the Leuven Isotope Separator On-Line (LISOL) facility by using the in-gas-cell and the in-gas-jet methods. The first application under on-line conditions of the in-gas-jet laser spectroscopy method showed a superior performance in terms of selectivity, spectral resolution, and efficiency in comparison with the in-gas-cell method. Following the analysis of both experiments, the magnetic-dipole moments for the ${}^{212–215}\mathrm{Ac}$ isotopes, electric-quadrupole moments and nuclear spins for the ${}^{214,215}\mathrm{Ac}$ isotopes are presented and discussed. A good agreement is obtained with large-scale nuclear shell-model calculations by using a ${}^{208}\mathrm{Pb}$ core.

The time differential perturbed angular distribution technique with ${\mathrm{LaBr}}_3$ detectors has been applied to the $I^{\pi }={\frac{11}{2}}^{-}$ isomeric state ($E_x=846$ keV, $\tau =107$ ns) in ${}^{107}\mathrm{Cd}$, which was populated and recoil-implanted into a gadolinium host following the ${}^{98}\mathrm{Mo}$(${}^{12}\mathrm{C}$, $3n$)${}^{107}\mathrm{Cd}$ reaction. The static hyperfine field strength of Cd recoil implanted into gadolinium was thus measured, together with the fraction of nuclei implanted into field-free sites, under similar conditions as pertained for a previous implantation perturbed angular distribution $g$-factor measurement on the $I^{\pi }={10}^{+}$ state in ${}^{110}\mathrm{Cd}$. The ${}^{110}\mathrm{Cd}g\left({10}^{+}\right)$ value was thereby reevaluated, bringing it into agreement with the value expected for a seniority-two $\nu h_{11/2}$ configuration.

The cold ternary fission of ${}^{250}\mathrm{Cm}$ accompanied with ${}^4\mathrm{He}$, ${}^{10}\mathrm{Be}$, ${}^{14}\mathrm{C}$, and ${}^{16}\mathrm{O}$ light charged particles in the equatorial three-cluster model configuration is studied. Driving potential and fission yield for each accompanied light charged particles for individual fragmentation are calculated. The obtained results reveal that even-mass-number components are more favored than odd-mass-number components. Furthermore, upon increasing the mass of light fixed fragment in ternary fission, the probability of crossing over the potential barrier (driving potential) is decreased considerably due to the height of the potential barrier. The comparison between relative yields for a variety of fragmentation in each group indicates that the presence of doubly or near doubly magic closed-shell fragments are more favored in the cold ternary fission of the ${}^{250}\mathrm{Cm}$ superheavy isotope.

Transfer-induced fission fragment angular distribution measurements have been carried out in ${}^6\mathrm{Li}+{}^{238}\mathrm{U}$ reaction at beam energies of 36 and 40 MeV in coincidence with projectile-like fragments. The fission fragment anisotropies for $\alpha$- and deuteron-transfer-induced fission reactions are obtained with respect to the recoil direction. The anisotropy values for transfer-induced fissions are observed to be either similar or lower than the inclusive measurement. In order to quantitatively understand the present experimental data on transfer-induced fission, anisotropy values have been compared with the preequilibrium fission model considering ground-state spin of the projectile and/or target. It is found that the model predicts the inclusive and exclusive anisotropy data reasonably well.

A detailed $\alpha$-decay spectroscopy study of ${}^{180}\mathrm{Tl}$ has been performed at ISOLDE (CERN). $Z$-selective ionization by the Resonance Ionization Laser Ion Source (RILIS) coupled to mass separation provided a high-purity beam of ${}^{180}\mathrm{Tl}$. Fine-structure $\alpha$ decays to excited levels in the daughter ${}^{176}\mathrm{Au}$ were identified and an $\alpha$-decay scheme of ${}^{180}\mathrm{Tl}$ was constructed based on an analysis of $\alpha -\gamma$ and $\alpha -\gamma -\gamma$ coincidences. Multipolarities of several $\gamma$-ray transitions deexciting levels in ${}^{176}\mathrm{Au}$ were determined. Based on the analysis of reduced $\alpha$-decay widths, it was found that all $\alpha$ decays are hindered, which signifies a change of configuration between the parent and all daughter states.

Accounting for viscous damping within Fokker-Planck equations led to various improvements in the understanding and analysis of nuclear fission of heavy nuclei. Analytical expressions for the fission time are typically provided by Kramers' theory, which improves on the Bohr-Wheeler estimate by including the time scale related to many-particle dissipative processes along the deformation coordinate. However, Kramers' formula breaks down for sufficiently high excitation energies where Kramers' assumption of a large barrier no longer holds. Focusing on the overdamped regime for energies $T>1$ MeV, Kramers' theory should be replaced by a new analytical theory derived from the Ornstein-Uhlenbeck first-passage time method that is proposed here. The theory is applied to fission time data from fusion-fission experiments on ${}^{16}\mathrm{O}+{}^{208}\mathrm{Pb}\to {}^{224}\mathrm{Th}$. The proposed model provides an internally consistent one-parameter fitting of fission data with a constant nuclear friction as the fitting parameter, whereas Kramers' fitting requires a value of friction which falls out of the allowed range. The theory provides also an analytical formula that in future work can be easily implemented in numerical codes such as cascade or joanne4.

We evaluate the corrections of the two-photon exchange (TPE) process on the ${\gamma }^{*}N\mathrm{\Delta }$ transition form factors. The contributions of the TPE process to $eN\to e\mathrm{\Delta }\left(1232\right)\to eN\pi$ are calculated in a hadronic model with the inclusion of only the elastic nucleon intermediate states, to estimate its effects on the multipoles $M_{1^{+}}^{(3/2)},E_{1^{+}}^{(3/2)},S_{1^{+}}^{(3/2)}$ at the $\mathrm{\Delta }$ peak. We find that TPE effects on $G_M^{*}$ are very small. $G_E^{*},$ and $G_C^{*}$ are also little affected at small $Q^2$. For $G_E^{*}$, the TPE effects reach about $3–8\%$ near $Q^2\sim 4{\mathrm{GeV}}^2$, depending on the model, MAID or SAID, used to emulate the data. For $G_C^{*}$, the TPE effects decrease rapidly with increasing $\epsilon$ while growing with increasing $Q^2$ to reach $\sim 6–15\%$ with $Q^2\sim 4{\mathrm{GeV}}^2$ at $\epsilon =0.2$. Sizeable TPE corrections to $G_E^{*}$ and $G_C^{*}$ found here point to the need to include TPE effects in the multipole analysis in the region of high $Q^2$ and small $\epsilon$. The TPE corrections to $R_{EM}$ and $R_{SM}$ obtained in our hadronic calculation are compared with those obtained in a partonic calculation for moderate momentum transfer of $2<Q^2<4{\mathrm{GeV}}^2$.

The evolution of collectivity with spin along the yrast line in the neutron-deficient nucleus ${}^{112}\mathrm{Te}$ has been studied by measuring the reduced transition probability of excited states in the yrast band. In particular, the lifetimes of the $4^{+}$ and $6^{+}$ excited states have been determined by using the recoil distance Doppler-shift method. The results are discussed using both large-scale shell-model and total Routhian surface calculations.

The $\delta$-shell representation of the nuclear force allows a simplified treatment of nuclear correlations. We show how this applies to the Bethe–Goldstone equation as an integral equation in coordinate space with a few mesh points, which is solved by inversion of a five-dimensional square matrix in the single channel cases and a $10\times 10$ matrix for the tensor-coupled channels. This allows us to readily obtain the high-momentum distribution, for all partial waves, of a back-to-back correlated nucleon pair in nuclear matter. We find that the probability of finding a high-momentum correlated neutron–proton pair is about 18 times that of a proton–proton one, as a result of the strong tensor force, thus confirming in an independent way previous results and measurements.

Rapid shape changes are observed for neutron-rich nuclei with A around 100. In particular, a sudden onset of ground-state deformation is observed in the Zr and Sr isotopic chains at N = 60: Low-lying states in $N\le 58$ nuclei are nearly spherical, while those with $N\ge 60$ have a rotational character. Nuclear lifetimes as short as a few picoseconds can be measured using fast-timing techniques with ${\mathrm{LaBr}}_3$(Ce) scintillators, yielding a key ingredient in the systematic study of the shape evolution in this region. We used neutron-induced fission of ${}^{241}\mathrm{Pu}$ and ${}^{235}\mathrm{U}$ to study lifetimes of excited states in fission fragments in the $A\sim 100$ region with the EXILL-FATIMA array located at the PF1B cold neutron beam line at the Institut Laue-Langevin. In particular, we applied the generalized centroid difference method to deduce lifetimes of low-lying states for the nuclei ${}^{98}\mathrm{Zr}$ (N = 58), ${}^{100}\mathrm{Zr}$, and ${}^{102}\mathrm{Zr}$ ($N\ge 60$). The results are discussed in the context of the presumed phase transition in the Zr chain by comparing the experimental transition strengths with the theoretical calculations using the interacting boson model and the Monte Carlo shell model.

A separable form of the Gogny pairing force is implemented in tilted axis cranking covariant density functional theory for the description of rotational bands in open shell nuclei. The developed method is used to investigate the yrast sequence of ${}^{109}\mathrm{Ag}$ for an example. The experimental energy spectrum, angular momenta, and electromagnetic transition probabilities are well reproduced by taking into account pairing correlations with the separable pairing force. An abrupt transition of the rotational axis from the long-intermediate plane to the long-short one is obtained and discussed in detail.

The rearrangements of protons and neutrons amongst the valence single-particle orbitals during double-$\beta$ decay of ${}^{100}\mathrm{Mo}$ have been determined by measuring cross sections in ($d,p$), ($p,d$), (${}^3\mathrm{He},\alpha$), and (${}^3\mathrm{He},d$) reactions on ${}^{98,100}\mathrm{Mo}$ and ${}^{100,102}\mathrm{Ru}$ targets. The deduced nucleon occupancies reveal significant discrepancies when compared with theoretical calculations; the same calculations have previously been used to determine the nuclear matrix element associated with the decay probability of double-$\beta$ decay of the ${}^{100}\mathrm{Mo}$ system.