Using the statistical and quantum diffusion approaches, we study the population of ground-state rotational bands of superheavy nuclei produced in the fusion-evaporation reactions ${}^{208}$Pb(${}^{48}$Ca,2$n$)${}^{254}$No, ${}^{206}$Pb(${}^{48}$Ca,2$n$)${}^{252}$No, and ${}^{204}$Hg(${}^{48}$Ca,2$n$)${}^{250}$Fm. By describing the relative intensities of $E2$ transitions between the rotational states, the entry spin distributions of residual nuclei, and the excitation functions for these reactions, the dependence of fission barriers of shell-stabilized nuclei on angular momentum is investigated.

Excited-state energies and $E2$ transition probabilities have been calculated for the four well-deformed nuclei considered in the recent work of R. V. Jolos and P. von Brentano, using the three mass parameters proposed in their work, while also taking into account the interplay of rotational and vibrational modes. The Davidson potential is used as a potential of the $\beta$ vibration. The same approach is applied to the odd ${}^{173}\mathrm{Yb}$ nucleus.

In this work we analyze the tensor-force component of effective interactions appropriate for nuclear shell-model studies, with particular emphasis on the monopole term of the interactions. Standard nucleon-nucleon ($NN$) interactions such as AV8' and $\chi$N${}^3$LO are tailored to shell-model studies by employing $V_{\mathrm{low}k}$ techniques to handle the short-range repulsion of the $NN$ interactions and by applying many-body perturbation theory to incorporate in-medium effects. We show, via numerical studies of effective interactions for the $sd$ and the $pf$ shells, that the tensor-force contribution to the monopole term of the effective interaction is barely changed by these renormalization procedures, resulting in almost the same monopole term as the one of the bare $NN$ interactions. We propose to call this feature renormalization persistency of the tensor force, as it is a remarkable property of the renormalization and should have many interesting consequences in nuclear systems. For higher multipole terms, this feature is maintained to a somewhat smaller extent. We present general intuitive explanations for the renormalization persistency of the tensor force as well as analyses of core-polarization terms in perturbation theory. The central force does not exhibit a similar renormalization persistency.

The mechanism of backbending is semiphenomenologically investigated based on the hybridization of two rotational bands. These bands are defined by treating a model Hamiltonian describing two interacting subsystems: a set of particles moving in a deformed mean field and interacting among themselves through an effective pairing force and a phenomenological deformed core whose intrinsic ground state is an axially symmetric coherent boson state. The two components interact with each other by a quadrupole-quadrupole and a spin-spin interaction. The total Hamiltonian is considered in the space of states with good angular momentum, projected from a quadrupole deformed product function. The single-particle factor function defines the nature of the rotational bands, one corresponding to the ground band in which all particles are paired and another one built upon a $i_{13/2}$ neutron broken pair. The formalism is applied to six deformed even-even nuclei, known as being good backbenders. Agreement between theory and experiment is fairly good.

The structure of neutron-rich nuclei with a few nucleons beyond ${}^{132}$Sn is investigated by means of large-scale shell-model calculations. For a considerably large model space, including neutron core excitations, a new effective interaction is determined by employing the extended pairing-plus-quadrupole model with monopole corrections. The model provides a systematical description for energy levels of $A=133$–135 nuclei up to high spins and reproduces available data of electromagnetic transitions. The structure of these nuclei is analyzed in detail, with emphasis of effects associated with core excitations. The results show evidence of hexadecupole correlation in addition to octupole correlation in this mass region. The suggested feature of magnetic rotation in ${}^{135}$Te occurs in the present shell-model calculation.

The absence of certain $LS$ states in atoms leads to the vanishing of several 6-$j$ symbols. One of these vanishing 6-$j$'s explains the absence of a certain $jj$ coupling state in a nucleus, while the other explains the vanishing of a certain state for a system of three bosons. This is part of a continuing study of “companion problems.” It is noted that the vanishing 6-$j$'s play an important role for establishing partial dynamical symmetries. Whenever possible we offer alternate explanations that do not involve 6-$j$ symbols. Extensions to vanishing 9-$j$ symbols are also shown. Regge symmetries help to make connections between different topics.

The nucleus ${}^{102}$Ru was studied with the GRID lifetime technique and an upper limit on the $B(E2:2_3^{+}\to 0_2^{+}$) of 21.6 W.u. was obtained. This nucleus is pivotal in the $A\sim 100$ region as it marks the boundary, in $Z$, between nuclei that do, and do not, become deformed with increasing neutron number, and, in $N$, between those that exhibit characteristics of a phase transition mediated by changes in subshell structure and those that do not. The measurements are discussed primarily in terms of vibrational structure.

The neutron capture process is considered as an alternative method for production of superheavy (SH) nuclei. Strong neutron fluxes might be provided by nuclear reactors and nuclear explosions in the laboratory frame and by supernova explosions in nature. All these cases are discussed in the paper. There are two gaps of short-lived nuclei (one is the well-known fermium gap and the other one is located in the region of $Z=106$–108 and $N\sim 170)$ which impede the formation of SH nuclei by rather weak neutron fluxes realized at available nuclear reactors. We find that in the course of multiple (rather “soft”) nuclear explosions these gaps may be easily bypassed, and thus, a measurable amount of the neutron-rich long-living SH nuclei located at the island of stability may be synthesized. Existing pulsed reactors do not allow one to bypass these gaps. We formulate requirements for the pulsed reactors of the next generation that could be used for production of long-living SH nuclei. Natural formation of SH nuclei (in supernova explosions) is also discussed. The yield of SH nuclei relative to lead is estimated to be about ${10}^{-12}$, which is not beyond the experimental sensitivity for a search of SH elements in cosmic rays.

With the HIJING/B$¯B$ v2.0 heavy ion event generator, we explore the phenomenological consequences of several high parton density dynamical effects predicted in central Pb+Pb collisions at the Large Hadron Collider (LHC) energies. These include (1) jet quenching due to parton energy loss ($dE/dx$), (2) strangeness and hyperon enhancement due to strong longitudinal color field (SCF), and (3) enhancement of baryon-to-meson ratios due to baryon-antibaryon junction (J$¯J$) loops and SCF effects. The saturation/minijet cutoff scale $p_0(s,A)$ and effective string tension $\kappa (s,A)$ are constrained by our previous analysis of LHC $p+p$ data and recent data on the charged multiplicity for Pb+Pb collisions reported by the ALICE collaboration. We predict the hadron flavor dependence (mesons and baryons) of the nuclear modification factor $R_{AA}\left(p_T\right)$ and emphasize the possibility that the baryon anomaly could persist at the LHC up to $p_T\sim 10$ GeV, well beyond the range observed in central Au+Au collisions at RHIC energies.

We calculate the nuclear modification factor ($R_{AA}$) of light hadrons by taking into account the initial state momentum anisotropy of the quark-gluon plasma (QGP) expected to be formed in relativistic heavy ion collisions. Such an anisotropy can result from the initial rapid longitudinal expansion of the matter. A phenomenological model for the space-time evolution of the anisotropic QGP is used to obtain the time dependence of the anisotropy parameter $\xi$ and the hard momentum scale, $p_{\mathrm{hard}}$. The result is then compared with the PHENIX experimental data to constrain the isotropization time scale, ${\tau }_{\mathrm{iso}}$ for fixed initial conditions (FIC). It is shown that the extracted value of ${\tau }_{\mathrm{iso}}$ lies in the range $0.5⩽{\tau }_{\mathrm{iso}}⩽1.5$. However, using a fixed final multiplicity (FFM) condition does not lead to any firm conclusion about the extraction of the isotropization time. The present calculation is also extended to contrast with the recent measurement of nuclear modification factor by the ALICE collaboration at $\sqrt{s}=2.76$ TeV. It is argued that in the present approach, the extraction of ${\tau }_{\mathrm{iso}}$ at this energy is uncertain and, therefore, refinement of the model is necessary. The sensitivity of the results on the initial conditions has been discussed. We also present the nuclear modification factor at Large Hadron Collider (LHC) energies with $\sqrt{s}=5.5$ TeV.

We present an efficient method for calculating strength functions using the finite-amplitude method (FAM) for deformed superfluid heavy nuclei within the framework of the nuclear density functional theory. We demonstrate that FAM reproduces strength functions obtained with the fully self-consistent quasiparticle random-phase approximation (QRPA) at a fraction of the computational cost. As a demonstration, we compute the isoscalar and isovector monopole strengths for strongly deformed configurations in ${}^{100}$Zr and ${}^{240}$Pu by considering huge quasiparticle QRPA spaces. Our approach to FAM, based on Broyden's iterative procedure, opens the possibility for large-scale calculations of strength distributions in well-deformed superfluid nuclei across the nuclear landscape.

We explain a form for the rainbow-ladder kernel whose momentum dependence is consonant with modern DSE- and lattice-QCD results, and assess its capability as a tool in hadron physics. In every respect tested, this form produces results for observables that are at least equal to the best otherwise obtained in a comparable approach. Moreover, it enables the natural extraction of a monotonic running-coupling and gluon mass.

The effects of short-range correlations on the nucleon self-energy in ${}^{40}$Ca are investigated using the charge-dependent Bonn (CDBonn) interaction. Comparisons are made with recent results for the self-energy of ${}^{40}$Ca derived from the dispersive optical-model (DOM). Particular emphasis is placed on the nonlocality of the imaginary part of the microscopic self-energy which suggests that future DOM analyses should include this feature. In particular, data below the Fermi energy appear sensitive to the implied orbital angular-momentum dependence of the self-energy. Quasiparticle properties obtained for the CDBonn interaction are substantially more mean-field-like than the corresponding DOM results with spectroscopic factors larger by about 0.2. Reaction cross sections obtained from the microscopic self-energy for scattering energies up to 100 MeV indicate that an adequate description of volume absorption is obtained while a considerable fraction of surface absorption is missing. The analysis of the nonlocality of the imaginary part of the microscopic self-energy suggests that a simple Gaussian provides an adequate description, albeit with rather large values for $\beta$, the nonlocality parameter.

Using the quantum molecular dynamics model, we study the role of mass asymmetry of colliding nuclei on the fragmentation at the corresponding balance energies and on their mass dependence. The study is done by keeping the total mass of the system fixed as 40, 80, 160, and 240 and by varying the mass asymmetry (defined as $\eta =\frac{A_T-A_P}{A_T+A_P}$; where $A_T$ and $A_P$ are the masses of the target and projectile, respectively) of the reaction from 0.1 to 0.7. Our results clearly indicate a sizeable effect of mass asymmetry on the multiplicity of various fragments. The mass asymmetry dependence of various fragments is found to increase with increase in total system mass (except for heavy mass fragments). Similarly to symmetric reactions, a systematic power-law mass dependence of various fragment multiplicities is also found to exist for large asymmetries.

Production cross sections of evaporation residues, ${}^{149}$Tb, ${}^{150}$Tb, ${}^{151}$Tb, and ${}^{149}$Gd, are measured using the stacked foil technique followed by off-line $\gamma$-spectrometry in ${}^{12}$C-induced reactions on naturally abundant mononuclidic praseodymium target in the 44- to 79-MeV incident energy range. Measured data are interpreted by comparison with previous measurements and theoretical predictions of the nuclear reaction model code PACE4. About 5$\%$ and 14$\%$ of the theoretical cross sections have been measured for ${}^{149}$Tb and ${}^{150}$Tb, respectively. The new cross sections of ${}^{149}$Tb complement those measured earlier by $\alpha$ spectrometry. Cross sections of ${}^{151}$Tb are comparable to the theory. Cumulative cross sections of ${}^{149}$Gd shed light on the nuclear reaction mechanism. In addition, the discussion shows the feasibility of producing ${}^{149}$Tb in $p$- and $\alpha$-induced reactions on gadolinium isotopes.

There are two main reasons for the absence of a practical theory of stripping to resonance states that could be used by experimental groups: The numerical problem of the convergence of the distorted-wave Born approximation (DWBA) matrix element when the full transition operator is included and the ambiguity over what spectroscopic information can be extracted from the analysis of transfer reactions populating the resonance states. The purpose of this paper is to address both questions. The theory of the deuteron stripping is developed, which is based on the post continuum discretized coupled channels (CDCCs) formalism going beyond of the DWBA and surface integral formulation of the reaction theory [A. S. Kadyrov et al., Ann. Phys. 324, 1516 (2009)]. First, the formalism is developed for the DWBA and then it is extended to the CDCC formalism, which is the ultimate goal of this work. The CDCC wave function takes into account not only the initial elastic $d+A$ channel but also its coupling to the deuteron breakup channel $p+n+A$ missing in the DWBA. Stripping to both bound states and resonances is included. The convergence problem for stripping to resonance states is solved in the post CDCC formalism. The reaction amplitude is parametrized in terms of the reduced width amplitudes (asymptotic normalization coefficients), inverse level matrix, boundary condition, and channel radius, which are the same parameters used in the conventional $R$-matrix method. For stripping to resonance states, many-level and one- and two-channel cases are considered. The theory provides a consistent tool to analyze both binary resonant reactions and deuteron stripping in terms of the same parameters.

In this Brief Report, we propose general expressions for six-$j$ and nine-$j$ coefficients arising in the study of the $J$-pairing interaction of identical fermions in a single-$j$ shell. In the literature such coefficients are available only for a number of given angular momenta.

Isospin mixing in the hot compound nucleus ${}^{80}$Zr was studied by measuring and comparing the $\gamma$-ray emission from the fusion reactions ${}^{40}\text{Ca}+{}^{40}\text{Ca}$ at $E_{\text{beam}}=200$ MeV and ${}^{37}\text{Cl}+{}^{44}\text{Ca}$ at $E_{\text{beam}}=153$ MeV. The $\gamma$ yield associated with the giant dipole resonance is found to be different in the two reactions because, in self-conjugate nuclei, the E1 selection rules forbid the decay between states with isospin $I=0$. The degree of mixing is deduced from statistical-model analysis of the $\gamma$-ray spectrum emitted by the compound nucleus ${}^{80}$Zr with the standard parameters deduced from the $\gamma$ decay of the nucleus ${}^{81}$Rb. The results are used to deduce the zero-temperature value, which is then compared with the latest predictions. The Coulomb spreading width is found to be independent of temperature.

A shell-model study of proton-neutron pairing in $2p1f$ shell nuclei using a parametrized Hamiltonian that includes deformation and spin-orbit effects as well as isoscalar and isovector pairing is reported. By working in a shell-model framework we are able to assess the role of the various modes of proton-neutron pairing in the presence of nuclear deformation without violating symmetries. Results are presented for ${}^{44}$Ti, ${}^{45}$Ti, ${}^{46}$Ti, ${}^{46}$V, and ${}^{48}$Cr to assess how proton-neutron pair correlations emerge under different scenarios. We also study how the presence of a one-body spin-obit interaction affects the contribution of the various pairing modes.