The stochastic dynamical approach to fission is employed to investigate the influence of initial excitation energy ($E^{*}$) of Hg compound nuclei (CNs) on its excitation energy at scission ($E_{\mathrm{sc}}^{*}$) as a function of nuclear friction strength ($\beta$). It is demonstrated that raising $E^{*}$ can increase the sensitivity of $E_{\mathrm{sc}}^{*}$ to $\beta$ significantly. Moreover, we compare the sensitivity under two contrasting conditions for formed Hg CNs: (i) high $E^{*}$ but low angular momentum ${\ell }_c$ (populated in proton-induced spallation reactions at GeV energies) and (ii) low $E^{*}$ but high angular momentum ${\ell }_c$ (produced through heavy-ion fusion mechanisms). We find that $E_{\mathrm{sc}}^{*}$ is more sensitive to $\beta$ under the conditions of case (i). Our findings suggest that, in experiments, when using $E_{\mathrm{sc}}^{*}$ to probe nuclear friction, it may be useful to choose the spallation reaction avenue induced by energetic (GeV) protons as a possible way to yield highly excited nuclei.

The azimuthal anisotropies of the collective transverse flow of hadrons are investigated in a large range of heavy-ion collision energy within the parton-hadron-string dynamics (PHSD) microscopic transport approach which incorporates explicit partonic degrees of freedom in terms of strongly interacting quasiparticles (quarks and gluons) in line with an equation-of-state from lattice QCD as well as dynamical hadronization and hadronic dynamics in the final reaction phase. The experimentally observed increase of the elliptic flow $v_2$ with bombarding energy is successfully described in terms of the PHSD approach in contrast to a variety of other kinetic models based on hadronic interactions. The analysis of higher-order harmonics $v_3$ and $v_4$ shows a similar tendency of growing deviations between partonic and purely hadronic models with increasing bombarding energy. This signals that the excitation functions of azimuthal anisotropies provide a sensitive probe for the underling degrees of freedom excited in heavy-ion collisions.

The dipole strength function and the nuclear level density of the compound nucleus ${}^{78}$Se were studied in a combined analysis of a cold neutron capture experiment on ${}^{77}$Se performed at the research reactor in Budapest and a photon-scattering experiment on ${}^{78}$Se performed at the electron linear accelerator ELBE with bremsstrahlung produced at a kinetic electron energy of $11.5\mathrm{M}\mathrm{e}\mathrm{V}$. In the combined analysis we developed the extreme statistical code $\gamma$dex for the simulation of radiative cascade deexcitations occurring in neutron capture and photon scattering. Comparisons of experimental and simulated neutron capture spectra allow us to estimate a temperature of $T=900\mathrm{k}\mathrm{e}\mathrm{V}$ for the level density according to the constant-temperature model for ${}^{78}$Se. Using $\gamma$dex, we were also able to estimate ground-state branching ratios and intensities of inelastic transitions for states in ${}^{78}$Se excited via photon scattering. In this way, we derived the photoabsorption cross section from $4\mathrm{M}\mathrm{e}\mathrm{V}$ up to the neutron separation energy from the measured photon-scattering data. The results obtained match the photoabsorption cross section derived from ($\gamma ,n$) measurements and show an enhancement of dipole strength around $9\mathrm{M}\mathrm{e}\mathrm{V}$.

An experiment to search for the $\alpha$ decay of ${}^{112}$Cs has been performed at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. The $\alpha$ decay of ${}^{112}$Cs was not observed, thus setting the upper limit of the $\alpha$ branching ratio at 0.26$\%$. The half-life of ${}^{112}$Cs was measured as $506\pm 55\mu$s. In the same measurement the decay properties of its proton decay daughter ${}^{111}$Xe were also reinvestigated. The newly measured $\alpha$ branching ratio for ${}^{111}$Xe is $10.4\pm 1.9\%$. The experimental proton separation energies $S_p$ for odd-$Z$ nuclei above ${}^{100}$Sn were compared to shell model calculations. The calculated proton separation energies for ${}^{103}$Sb and ${}^{102}$Sb point to half-lives of the order of 10 ps and 1 ns, respectively.

An equation of motion method for solving the nuclear eigenvalue problem in a basis of microscopic multiphonon states is reformulated consistently in terms of Tamm-Dancoff phonons. The potential and limits of the method are illustrated through the calculation of the nuclear response to dipole and quadrupole external fields in ${}^{16}$O. The calculation is performed using either a Nilsson or a Hartree-Fock basis. The role of the multiphonon states is shown to depend strongly on the choice of the basis. The effect of the truncation of the three-phonon subspace is also discussed.

The fusion cross section for ${}^{12}$C+${}^{13}$C has been measured down to $E_{\mathrm{c}.\mathrm{m}.}=2.6$ MeV, at which the cross section is of the order of 20 nb. By comparing the cross sections for the three carbon isotope systems, ${}^{12}$C+${}^{12}$C, ${}^{12}$C+${}^{13}$C, and ${}^{13}$C+${}^{13}$C, it is found that the cross sections for ${}^{12}$C+${}^{13}$C and ${}^{13}$C+${}^{13}$C provide an upper limit for the fusion cross section of ${}^{12}$C+${}^{12}$C over a wide energy range. After calibrating the effective nuclear potential for ${}^{12}$C+${}^{12}$C using the ${}^{12}$C+${}^{13}$C and ${}^{13}$C+${}^{13}$C fusion cross sections, it is found that a coupled-channels calculation with the ingoing wave boundary condition (IWBC) is capable of predicting the major peak cross sections in ${}^{12}$C+${}^{12}$C. A qualitative explanation for this upper limit is provided by the Nogami-Imanishi model and by level density differences among the compound nuclei. It is found that the strong resonance found at 2.14 MeV in ${}^{12}$C+${}^{12}$C exceeds this upper limit by a factor of more than 20. The preliminary result from the most recent measurement shows a much smaller cross section at this energy, which agrees with our predicted upper limit.

Background. In the “cold” fusion reactions based on the use of lead and bismuth targets, the proton-rich isotopes of superheavy (SH) elements up to $Z=113$ have been produced. More neutron-rich isotopes of SH elements (up to $Z=118$) have been synthesized in “hotter” fusion reactions of ${}^{48}$Ca with actinide targets. $\alpha$-decay half-lives of different isotopes of the same SH elements (for example, 112) were found to vary by several orders of magnitude. This indicates strong shell effects in this area of the nuclear map. The understanding of these effects and other properties of SH nuclei is strongly impeded by the absence of experimental data on decay properties of the not-yet-synthesized isotopes of SH elements located between those produced in the “cold” fusion reactions and those produced in the “hot” fusion reactions and also by the yet missing neutron-enriched isotopes of these elements.

Purpose. In this paper we search for the optimal fusion reactions which may be used to fill this gap of the nuclear map and significantly extend the area of known SH nuclei.

Method. For the calculation of the cross sections we use the same approach which was employed earlier for successful predictions of all ${}^{48}$Ca induced fusion reactions.

Results. Several fusion reactions of the stable projectiles ${}^{40}$Ar, ${}^{44}$Ca, and ${}^{48}$Ca with different isotopes of actinides (lighter and heavier than those that have been already utilized in the Dubna experiments) could be used for synthesis of new SH nuclei. Predicted cross sections for the production of new isotopes of SH nuclei were found to be quite large, and the corresponding experiments can be easily performed at existing facilities. For the first time a “narrow pathway” to the middle of the island of stability was found owing to possible ${\beta }^{+}$ decay of SH nuclei ${}^{291}$115 and ${}^{291}$114 which could be formed in ordinary fusion reactions.

Production of ${\Delta }^0$(1232) resonances in $d$ + ${}^{12}$C collisions at 4.2$A$ GeV/$c$ was investigated with $4\pi$ acceptance, for the first time. The mass distribution of ${\Delta }^0$(1232) resonances produced in $d$ + ${}^{12}$C collisions was reconstructed and their mass and width were extracted. The kinematical distributions of ${\Delta }^0$(1232) were reconstructed in the laboratory frame and the corresponding mean kinematical characteristics were estimated. The fraction of charged π${}^{-}$ mesons coming from ${\Delta }^0$(1232) decay as well as the relative number of nucleons excited to ${\Delta }^0$(1232) in freeze-out conditions were estimated. The freeze-out temperature of ${\Delta }^0$(1232) was estimated and compared to results of other experiments with different sets of colliding nuclei and various incident energies.

A new equation of state for a hot and dense hadron gas (HG) is obtained where the finite hard-core size of baryons has been incorporated into a thermodynamically consistent formulation of excluded volume correction. Our model differs from other existing approaches on the following points. We assign a hard-core volume only to each baryon and mesons, which, although they possess a small volume, can fuse and interpenetrate into one another. Use of the full quantum statistics is made to obtain the grand canonical partition function, where excluded-volume correction has been incorporated by explicitly integrating over volume. We thus find that the new model works even for cases of extreme temperatures and/or densities where most other approaches fail. The numerical calculation indicates that the causality is respected by our prescription even at extreme densities. The temperature and density dependences of various thermodynamical quantities, e.g., pressure, baryon density, entropy and energy density, compare well with the results of other microscopic HG models. After suitable parametrization of the center-of-mass energy in terms of temperature and baryon chemical potential, we explore some new freeze-out criteria which exhibit full independence of the collision energy and of the structures of the colliding nuclei. We further demonstrate the suitability of our model for explaining the various experimental results of the multiplicity ratios of various particles and their antiparticles. Finally, we use our excluded-volume model to obtain the transport behavior of a hot and/or dense HG, such as shear viscosity- to-entropy ratio and speed of sound, and compare the results with earlier calculations.

Low-density neutron matter has been studied extensively for many decades, with a view to better understanding the properties of neutron-star crusts and neutron-rich nuclei. Neutron matter is beyond experimental control, but in the past decade it has become possible to create systems of fermionic ultracold atomic gases in a regime close to low-density neutron matter. In both these contexts pairing is significant, making simple perturbative approaches impossible to apply and necessitating ab initio microscopic simulations. Atomic experiments have also probed polarized matter. In this work, we study population-imbalanced neutron matter (possibly relevant to magnetars and to density functionals of nuclei) arriving at the lowest-energy configuration to date. For small-to-intermediate relative fractions, the system turns out to be fully normal, while beyond a critical polarization we find phase coexistence between a partially polarized normal neutron gas and a balanced superfluid gas. As in cold atoms, a homogeneous polarized superfluid is close to stability but not stable with respect to phase separation. We also study the dependence of the critical polarization on the density.

The role of prolate and oblate deformations of colliding nuclei in the sub-barrier capture process is studied within the quantum-diffusion approach. A comparison of the calculated and measured capture cross sections in the reactions ${}^{16}\mathrm{O},{}^{48}\mathrm{Ca}+{}^{154}\mathrm{Sm}$ and ${}^{74}\mathrm{Ge}+{}^{74}\mathrm{Ge}$ show that transitions during the capture process occur from the potential minimum with an oblate deformation of the ground state to the minimum with a prolate deformation of the nuclei ${}^{154}\mathrm{Sm}$ and ${}^{74}\mathrm{Ge}$. These transitions crucially influence the sub-barrier capture. The capture cross sections and mean-angular momenta are predicted for the reactions of ${}^{36}\mathrm{S}+{}^{170}\mathrm{Er},{}^{174}\mathrm{Yb}$.

Bound-state-like wave functions are used to determine the scattering matrix corresponding to low-energy $n$-$d$ and $p$-${}^3$He collisions. To this end, the coupled-channel form of the integral relations derived from the Kohn variational principle is used. The construction of degenerate bound-state-like wave functions belonging to the continuum spectrum of the Hamiltonian is discussed. Examples are shown using realistic nucleon-nucleon forces.

High-spin states in ${}^{120}$Te were populated in the reaction ${}^{80}$Se(${}^{48}$Ca, $\alpha 4n$)${}^{120}$Te at a beam energy of 207 MeV and $\gamma$-ray coincidences were measured using the Gammasphere spectrometer. The previously known level scheme is extended to higher spin and new interband transitions and side-feeding branches are established. Five highly deformed rotational bands, extending up to almost $I=50$, are observed for the first time. The bands are compared with similar structures found recently in neighboring nuclei. The experimental results are interpreted within the framework of the cranked Nilsson-Strutinsky model. Configuration assignments to several terminating states and to the high-spin bands are discussed.

We deal with a novel approach to formulation of the relativistic dissipative hydrodynamics by extending the so-called matching conditions widely used in the literature. The form of the nonequilibrium entropy current can be determined by requiring thermodynamical stability of the entropy current under extended matching conditions. We derive equations of motion for the relativistic dissipative fluid based on the Eckart theory and show that linearized equations obtained from them are stable against small perturbations. It is also shown that the required fluid stability conditions are related to the causality of the model.

${}^{25}\text{Al}+\mathit{\text{p}}$ elastic scattering in inverse kinematics was measured to explore the level structure of ${}^{26}\mathrm{Si}$ above its proton threshold. The ${}^2\text{H}{(}^{24}\text{Mg},n){}^{25}\text{Al}$ reaction was used to produce a 3.4 MeV/nucleon ${}^{25}\text{Al}$ radioactive beam with intensities of about 10${}^6$ ions per second on target. By using a thick target of ${\left({\text{CH}}_2\right)}_n$, a center-of-mass energy range of 3 MeV was scanned, reaching up to about 8.5 MeV in excitation energy in ${}^{26}\mathrm{Si}$. This energy range covered the region of importance for the ${}^{25}\text{Al}(p,\gamma ){}^{26}\mathrm{Si}$ at temperatures characteristic of explosive nucleosynthesis. Level parameters of six strong $s$-wave ${}^{25}\text{Al}+p$ resonances in ${}^{26}\mathrm{Si}$ were extracted from fits to the measured excitation functions using the $R$-matrix formalism. Two new levels have been discovered, while for two others, our spin-parity assignments disagree with the results of some previous studies. Lastly, our resonance parameters for the remaining two levels are in good agreement with past experimental work, and with recent shell-model calculations.

The nucleus ${}^{205}$Fr has been studied through $\gamma$-ray and electron spectroscopy using the recoil-decay tagging technique. The resulting level scheme presents a spherical structure built on the 9/2${}^{-}$ ground state and a rotational structure on top of a short-lived isomer. The isomer, with a spin and parity of 13/2${}^{+}$ and a half-life of 80(20) ns, de-excites by an $M2$ transition directly to the 9/2${}^{-}$ ground state. Another, longer-lived, isomer, with a half-life of 1.15(4) ms, has also been found and assigned a spin and parity of 1/2${}^{+}$. Transitions populating and de-exciting this isomer have been observed as well.

The angular dependence of proton-proton correlation functions is studied in central ${}^{\text{40}}\text{Ca}+{}^{\text{40}}\text{Ca}$ and ${}^{\text{48}}\text{Ca}+{}^{\text{48}}\text{Ca}$ nuclear reactions at $E/A=80$ MeV. Measurements were performed with the High Resolution Array (HiRA) complemented by the 4$\pi$ Array at the National Superconducting Cyclotron Laboratory. A striking angular dependence in the laboratory frame is found within proton-proton correlation functions for both systems that greatly exceeds the measured and expected isospin dependent difference between the neutron-rich and neutron-deficient systems. Sources measured at backward angles reflect the participant zone of the reaction, while much larger sources observed at forward angles reflect the expanding, fragmenting, and evaporating projectile remnants. The decrease of the size of the source with increasing momentum is observed at backward angles while a weaker trend in the opposite direction is observed at forward angles. The results are compared to the theoretical calculations using the Boltzmann-Uehling-Uhlenbeck (BUU) transport model.

The ${}^{41}$Ca($n$,α)${}^{38}$Ar reaction cross section was studied at the linear accelerator GELINA of the Institute for Reference Materials and Measurements in Geel (Belgium) and was determined up to a neutron energy of about 80 keV using the time-of-flight technique. In this energy region, 15 resonances were observed, whereas none were identified before. For some of them, resonance parameters such as resonance energy, total width, area, and spin could be determined. From the obtained cross-section data, Maxwellian averaged cross sections have been calculated at various stellar temperatures for further use in stellar models.

We discuss the role of higher order couplings in conjunction with kaon condensation using recent versions of relativistic mean field models. We focus on an interaction (G2) in which all the parameters are obtained by fitting the finite nuclear data and successfully applied to reproduce a variety of nuclear properties. Our results show that the higher order couplings play a significant role at higher densities where kaons dominate the behavior of the equation of state. We compare our results with other interactions (NLl, NL3, G1, and FSUGold) and show that the new couplings bring down the mass of a neutron star (NS), which is further reduced in the presence of kaons to yield results consistent with the present observational constraints. We show that the composition of the NS varies with the parameter sets.

The potential energy surfaces of actinide nuclei in the $({\beta }_{20},{\beta }_{22},{\beta }_{30})$ deformation space are obtained from a multidimensional constrained covariant density functional theory. With this newly developed theory, we are able to explore the importance of the triaxial and octupole shapes simultaneously along the whole fission path. It is found that aside from the octupole deformation, the triaxiality also plays an important role upon the second fission barriers. Both the outer and the inner barriers are lowered by the triaxial deformation compared with axially symmetric results. This lowering effect for the reflection-asymmetric outer barrier is 0.5$\sim$1 MeV, accounting for $10\%\sim 20\%$ of the barrier height. With the inclusion of the triaxial deformation, a good agreement with the data for the outer barriers of actinide nuclei is achieved.