Excited states have been identified in the isotones ${}_{74}^{159}$W and ${}_{75}^{160}$Re, which were produced in fusion-evaporation reactions of a beam of 310-MeV ${}^{58}$Ni ions with an isotopically enriched ${}^{106}$Cd target. The strongest $\gamma$-ray transitions in ${}^{159}$W and ${}^{160}$Re are interpreted as continuing the regular sequence of states identified in lighter $N=$ 85 isotones that are built upon 9/2${}^{-}$ and 10${}^{+}$ states, respectively. The half-life of ${}^{155}$Hf, the $\beta$-decaying daughter of the $\alpha$ decay of ${}^{159}$W, was measured with improved precision to be 840 $\pm$ 30 ms.

The structure of low-energy collective states in proton-deficient $N=28$ isotones is analyzed using structure models based on the relativistic energy density functional DD-PC1. The relativistic Hartree-Bogoliubov model for triaxial nuclei is used to calculate binding energy maps in the $\beta$-$\gamma$ plane. The evolution of neutron and proton single-particle levels with quadrupole deformation, and the occurrence of gaps around the Fermi surface, provide a simple microscopic interpretation of the onset of deformation and shape coexistence. Starting from self-consistent constrained energy surfaces calculated with the functional DD-PC1, a collective Hamiltonian for quadrupole vibrations and rotations is employed in the analysis of excitation spectra and transition rates of ${}^{46}$Ar, ${}^{44}$S, and ${}^{42}$Si. The results are compared to available data, and previous studies based either on the mean-field approach or large-scale shell-model calculations. The present study is particularly focused on ${}^{44}$S, for which data have recently been reported that indicate pronounced shape coexistence.

Several quantities that can be observed in surrogate ratio methods (SRM) are investigated for nuclei of uranium region to see if they can be used to infer the spin-and-parity distributions that are crucially important to the validity of SRM. The evaporation neutron spectra and cascading $\gamma$-ray spectra are calculated by the Hauser-Feshbach theory, while fission fragment mass distributions are calculated by the fluctuation-dissipation theorem. It was found that the energy spectrum of cascading $\gamma$ rays and those of evaporated neutrons become softer as the spin of the decaying nuclei increases. The multiplicity of emitted $\gamma$ rays increases drastically as the spin increases. Both these effects are brought about by the fact that transition from high-spin states to low-lying levels are hindered. The mass distribution of fission fragments also shows a clear spin dependence, namely, the mass-symmetric fission is enhanced when the spin of the decaying system is large. This can be interpreted as an enhancement of mass division controlled by the liquid-drop energy relative to the shell correction part. The present results indicate that there are possibilities to use these observables to infer populated spin distributions in the surrogate reactions.

The symmetry energy in the nuclear equation of state affects many aspects of nuclear astrophysics, nuclear structure, and nuclear reactions. Recent constraints from heavy-ion collisions, including isospin diffusion observables, have started to put constraints on the symmetry energy below nuclear saturation density, but these constraints depend on the employed transport model and input physics other than the symmetry energy. To understand these dependencies, we study the influence of the symmetry energy, isoscalar mean-field compressibility and momentum dependence, in-medium nucleon-nucleon cross sections, and light cluster production on isospin diffusion within the pBUU transport code. In addition to the symmetry energy, several uncertain issues strongly affect isospin diffusion, most notably the cross sections and cluster production. In addition, there is a difference in the calculated isospin transport ratios, depending on whether they are computed using the isospin asymmetry either of the residue or of all forward-moving fragments. Measurements that compare the isospin transport ratios of these two quantities would help place constraints on the input physics, such as the density dependence of the symmetry energy.

The proton radioactivity lifetimes of proton emitters from the ground and the isomeric states are calculated using the microscopic M3Y $+$ Ex and R3Y $+$ Ex (proposed) nucleon-nucleus interaction potentials. These interaction potentials are obtained by single folding the densities of the daughter nuclei supplemented by a zero-range pseudopotential. The quantum-mechanical-tunneling probability is calculated within the WKB approximation. The calculated results are found to be in good agreement with the experimental data for both the M3Y and R3Y interactions.

The flow of charm is calculated in 2 $+$ 1 ideal hydrodynamics by introducing the charge of $c\overline{c}$ pair assuming that the number of $c\overline{c}$ pairs is conserved in relativistic heavy ion collisions. It is found that the mean radial flow velocity of charm quarks is smaller than that of bulk matter by 10 $\sim$ 15% and the measured $v_2$ of heavy-flavor electrons is reproduced up to $p_T^e=$ 1.5 GeV/$c$ in Au $+$ Au collisions at Relativistic Heavy Ion Collider (RHIC). The same flow is applied to regenerated $J/\psi$ and its $v_2$ is discussed.

We perform three-body model calculations for soft dipole excitations of the proton-rich Borromean nucleus ${}^{17}$Ne. To this end, we assume that ${}^{17}$Ne takes the ${}^{15}\mathrm{O}+p+p$ structure, in which the two valence protons are excited from the $0^{+}$ ground state configuration to $1^{-}$ continuum states. We employ a density-dependent contact force for the nuclear part of the pairing interaction, and discretize the continuum states with the box boundary condition. We show by explicitly including the Coulomb interaction between the valence protons that the Coulomb repulsion does not significantly alter the $E1$ strength distribution. We point out that the effect of the Coulomb repulsion in fact can be well simulated by renormalizing the nuclear pairing interaction.

The differential cross sections of the inelastic scattering leading to the excitation of short-lived states in the stable ${}^{13}$C and ${}^9$Be nuclei as well as the radioactive ${}^{11}$Be nucleus have been analyzed. Signatures of neutron halos in the excited states located close to the neutron emission thresholds have been investigated by applying a recently developed modified diffraction model. The abnormally large rms radius was identified for the 3.089-MeV $1/2^{+}$ state of ${}^{13}$C. Significantly enlarged diffraction radii were found for the 1.68-MeV $1/2^{+}$ and the 3.05-MeV $5/2^{+}$ states of ${}^9$Be. The analysis of the diffraction radii of the weakly bound radioactive ${}^{11}$Be nuclei have shown that the 1.78-MeV $5/2^{+}$ and 3.41-MeV $3/2^{+}$ states in ${}^{11}$Be have the same diffraction radii as the $1/2^{+}$ ground state, which is known as the best example of a state with one-neutron halo.

We study the possibility of determining the quark content of the scalar mesons $a^0\left(980\right)$ and $f^0\left(980\right)$ through their hydrodynamical flow signature in relativistic heavy ion collisions. Utilizing the constituent quark scaling of hydrodynamic flow, we find that the tetraquark $a^0\left(980\right)$ or $f^0\left(980\right)$ mesons will have a $v_2$ of 0.38 at a transverse momentum of 6 GeV$/c$ in 20–60$\%$ central Au + Au collisions at $\sqrt{s_{NN}}=$ 200 GeV. The feasibility of measuring $a^0\left(980\right)\to {\pi }^0\eta$ and $f^0\left(980\right)\to {\pi }^{+}{\pi }^{-}$ with the PHENIX and STAR detectors at the Relativistic Heavy Ion Collider is also discussed. Even though the mid-rapidity cross sections for these mesons at high $p_T$ are non-negligible, their broad mass range will make them difficult to detect in both $p+p$ and $\mathrm{Au}+\mathrm{Au}$ collisions.

A relativistic interacting quark-diquark model of baryons with direct and exchange interaction has been used to calculate the nucleon electromagnetic form factors. The results have been compared with experimental data.

Strong chromofields developed at early stages of relativistic heavy-ion collisions give rise to the collective deceleration of net baryons from colliding nuclei. We have solved classical equations of motion for baryonic slabs under the action of a time-dependent chromofield. We have studied the sensitivity of the slab trajectories and their final rapidities to the initial strength and decay pattern of the chromofield as well as to the back-reaction of produced plasma. This mechanism can naturally explain significant baryon stopping observed at Relativistic Heavy Ion Collider corresponding to an average rapidity loss $\langle \delta y\rangle \approx 2$. Using a Bjorken-like hydrodynamical model with a particle production source term, we also study the evolution of partonic plasma produced as the result of chromofield decay. Due to the delayed formation and expansion of plasma, its maximum energy density is much lower than the initial energy density of the chromofield. Predictions of baryon stopping for $\text{Pb}\text{+}\text{Pb}$ collisions at Large Hadron Collider energies were made.

We derive the short-range contributions and the leading relativistic corrections to the three-nucleon force at next-to-next-to-next-to-leading order in the chiral expansion.

Two-neutron densities obtained from microscopic wave functions of ${}^6$He and ${}^8$He are investigated to reveal dineutron correlations. In particular, the comparison of the two-neutron density with the product of one-neutron densities is useful for a quantitative discussion of dineutron correlations. The calculations show that the $S=0$ spatial two-neutron correlation increases at the surface of ${}^6$He$\left(0_1^{+}\right)$ and ${}^8$He$\left(0_2^{+}\right)$. The enhancement is remarkable in the ${}^6$He$\left(0_1^{+}\right)$ ground state but not as prominent in the ${}^8$He$\left(0_1^{+}\right)$ ground state. Configuration mixing of many Slater determinants is essential to describe the dineutron correlations. Two-neutron densities in ${}^{12}$C wave functions with $\alpha$-cluster structures are also studied.

We present a computational methodology for a theory of the lowest axially symmetric octupole excitations applicable to all even-even nuclei beyond the lightest. The theory is the well-known generator-coordinate extension (GCM) of the Hartree-Fock-Bogoliubov (HFB) self-consistent mean field theory. We use the discrete-basis Hill-Wheeler (HW) method to compute the wave functions with an interaction from the Gogny family of Hamiltonians. Comparing to the compiled experimental data on octupole excitations, we find that the performance of the theory depends on the deformation characteristics of the nucleus. For nondeformed nuclei, the theory reproduces the energies to about $\pm 20$% apart from an overall scale factor of $\approx 1.6$. The performance is somewhat poorer for (quadrupole) deformed nuclei, and for both together the dispersion of the scaled energies about the experimental values is about $\pm 25$%. This compares favorably with the performance of similar theories of the quadrupole excitations. Nuclei having static octupole deformations in HFB theory form a special category. These nuclei have the smallest measured octupole excitation energies as well as the smallest predicted energies. However, in these cases the energies are seriously underpredicted by the theory. We find that a simple two-configuration approximation, the minimization after projection (MAP) method, is almost as accurate as the full HW treatment, provided that the octupole-deformed nuclei are omitted from the comparison. This article is accompanied by a tabulation of the predicted octupole excitations for 818 nuclei extending from drip-line to drip-line, computed with several variants of the Gogny interaction.

Event-by-event fluctuations are central to the current understanding of ultrarelativistic heavy-ion collisions. In particular, fluctuations in the geometry of the early-time collision system are responsible for new phenomena such as triangular flow, which have solved important puzzles in existing data. We propose a simple model where initial fluctuations stem from independent flux tubes randomly distributed in the transverse plane. We calculate analytically the moments of the initial anisotropies (dipole asymmetry, eccentricity, triangularity), which are the sources of anisotropic flow, and their mutual correlations. Our analytic results are in good agreement with calculations from commonly used Monte Carlo codes, providing a simple understanding of the fluctuations contained in these models. Any deviation from these results in future experimental data would thus indicate the presence of nontrivial correlations between the initial flux tubes and/or extra sources of fluctuations that are not present in current models.

The lifetime of the first excited $2^{+}$ state in the neutron deficient nuclide ${}^{108}$Te has been measured for the first time, using a combined recoil decay tagging and recoil distance Doppler shift technique. The deduced reduced transition probability is $B(E2;0_{\mathrm{g}.\mathrm{s}.}^{+}\to 2^{+})=0.{39}_{-0.04}^{+0.05}{e}^2{\mathrm{b}}^2$. Compared to previous experimental data on neutron deficient tellurium isotopes, the new data point constitutes a large step (six neutrons) toward the $N=50$ shell closure. In contrast to what has earlier been reported for the light tin isotopes, our result for tellurium does not show any enhanced transition probability with respect to the theoretical predictions and the tellurium systematics including the new data is successfully reproduced by state-of-the-art shell model calculations.

We studied the properties of even-even actinide nuclei using the binary cluster model. Band-mixing calculation of the $K^{\pi }=0^{-}$ negative parity bands arising from the core nucleus having two different states and with the core and cluster having different effective charges enabled a simultaneous interpretation of the electromagnetic transitions.

The ${}^{48}\mathrm{Ca}(\gamma ,n)$ cross section was measured by using $\gamma$-ray beams of energies between 9.5 and 15.3 MeV generated at the Triangle Universities Nuclear Laboratory high-intensity $\gamma$-ray source. Prior to this experiment, no direct measurements had been made with $\gamma$-ray beams of sufficiently low energy spread to observe a structure in this energy range. The cross sections were measured at 34 different $\gamma$-ray energies with an enriched ${}^{48}\mathrm{Ca}$ target. Neutron emission is the dominant decay mechanism in the measured energy range that spans from the threshold, across the previously identified $M1$ strength, and up the low-energy edge of the $E1$ giant dipole resonance. This paper found $B\left(M1\right)=6.8\pm 0.5{\mu }_N^2$ for the 10.23-MeV resonance, a value greater than previously measured. Structures in the cross section have been observed whose magnitudes are in agreement with existing data and that are commensurate with extended random-phase approximation calculations.