In the investigation of exploring the “island of stability” and its superheavy elements, scientists have regularly synthesized new elements to the periodic table. This article is a consistent and systematical study performed for the synthesis of $Z=126$ via two incoming channels, i.e., ${}^{60}\mathrm{Fe}+{}^{250}\mathrm{Fm}$ and ${}^{64}\mathrm{Ni}+{}^{249}\mathrm{Cf}$. This work establishes a test bench to check the compatibility for the synthesis of $Z=126$ via two incoming channels within the framework of the dynamical cluster-decay model (DCM). Element 126, also known as unbihexium, is a hypothetical chemical element. This element is thought to be a possible member of the island of stability, where some nuclei are predicted to have increased stability. It is proposed to be stable for its size, possibly due to the island-of-stability effect. This article is the extension of the previous study of $Z=120$ [S. Chopra and P. O. Hess, Phys. Rev. C 110, 014615 (2024)]. The focal point of this work is to compare the cross sections of both reactions in order to understand their compatibility. In the process of compound nucleus formation, two heavy nuclei touch and engage in strong competition with the fission and quasifission processes. This study is absolutely contingent on the ideas taken from the previously studied superheavy elements using the dynamical cluster-decay model. In this study, we include the deformation effects up to hexadecupole (${\beta }_{4i}$) and with compact orientations ${\theta }_i$ for non-coplanar degrees of freedom. The only parameter of the model is the neck-length parameter, which varies smoothly with the temperature of the compound nucleus, and its value remains within the range of validity ($\sim 2\mathrm{fm}$) of the proximity potential. We extend the DCM calculations to three energies, i.e., $E^{*}=37$, 40, and 43 MeV. Two different sets of $\mathrm{\Delta }R\text{'}\mathrm{s}$ are adjusted to the observed data for ${\sigma }_{\mathrm{ER}}$ and ${\sigma }_{\mathrm{ff}}$ for Ni- and Fe-induced reactions.

Using the recombination model extended to the heavy flavor scenario, we investigate the production of charmed mesons, i.e., $D^0, D_s^{+}$, and $J/\psi$, in $\mathrm{Pb}+\mathrm{Pb}$ collisions at $\sqrt{s_{NN}}=2.76$ and 5.02 TeV at the CERN Large Hadron Collider including the heavy flavor energy loss inside the hot and dense medium. Soft, semihard, and hard partons all play important roles in our model and are uniformly treated for all mesons produced. The resulting transverse momentum spectra and the second azimuthal harmonic $v_2$ for these mesons are presented and compared with the available experimental data. The good agreement provides strong support again that the quark recombination mechanism is an effective model for hadronization in relativistic heavy-ion collisions.

I numerically estimate the spacetime profile of the electromagnetic fields produced in intermediate-energy heavy-ion collisions at $\sqrt{s_{NN}}=2.4\text{–}7.7\mathrm{GeV}$ for a wide range of impact parameters $b=0\text{–}9\mathrm{fm}$, using a hadronic cascade model, jam (Jet AA Microscopic transport model). I demonstrate that (1) the produced electromagnetic fields are as strong as $eE,eB=O({\left(50\mathrm{MeV}\right)}^2)$; (2) that the produced fields extend in spacetime about $V_4=O({\left(10\mathrm{fm}\right)}^4)$; (3) that the magnetic field dominates around the collision point, while the other broad regions of spacetime are dominated by the electric field; and (4) that a topological electromagnetic-field configuration such that $\mathit{E}·\mathit{B}\ne 0$ is realized.

Correlations between event-by-event fluctuations of anisotropic flow harmonics are measured in Pb-Pb collisions at a center-of-mass energy per nucleon pair of 5.02 TeV, as recorded by the ALICE detector at the LHC. This study presents correlations up to the hexagonal flow harmonic $v_6$, which was measured for the first time. The magnitudes of these higher-order correlations are found to vary as a function of collision centrality and harmonic order. These measurements are compared to viscous hydrodynamic model calculations with EKRT initial conditions and to the iEBE-VISHNU model with ${\mathrm{T}}_{\mathrm{R}}\mathrm{ENTo}$ initial conditions. The observed discrepancies between the data and the model calculations vary depending on the harmonic combinations. Due to the sensitivity of model parameters estimated with Bayesian analyses to these higher-order observables, the results presented in this work provide new and independent constraints on the initial conditions and transport properties in theoretical models used to describe the system created in heavy-ion collisions.

Direct observation of proton emission for very small Q values is often unfeasible due to the long partial half-lives of the proton emission channel associated with tunneling through the Coulomb barrier. Therefore, proton emitters with very small decay energies may require the masses of both parent and daughter nuclei in order to establish them as proton unbound. Nuclear mass models have been used to predict the proton dripline of the thulium (Tm) isotopic chain $(Z=69)$, but until now the proton separation energy has not been experimentally tested. Mass measurements were performed using a multiple reflection time-of-flight mass spectrometer (MR-TOF-MS) at TRIUMF's TITAN facility to conclusively map the limit of proton-bound Tm. The masses of neutron-deficient ${}^{149}\mathrm{Tm}$ and ${}^{150}\mathrm{Tm}$, combined with measurements of ${}^{149m,g}\mathrm{Er}$ (which were found to deviate from literature by $\approx 150\mathrm{keV}$), provide the first experimental confirmation that ${}^{149}\mathrm{Tm}$ is the first proton-unbound nuclide in the Tm chain. Our measurements also enable determination of the strength of the $N=82$ neutron shell gap at the Tm proton drip line, providing evidence supporting its continued existence.

The effects of the spin-orbit coupling strength and pairing correlation on the $\alpha$ decay of ${}^{210}\mathrm{Po}$ are explored in the framework of the spherical Skyrme-Hartree-Fock Bogoliubov theory and mean-field cluster potential approach with the SLy4 interaction. It is shown that the localization of the $\alpha$ cluster is enhanced by the increasing spin-obit coupling strength. However, the localization of the $\alpha$ cluster is getting weaker and weaker with the growing pairing field. Therefore, the roles of the spin-orbit coupling strength and pairing correlation in the $\alpha$-cluster preformation are competitive. Besides, it is found that the effect on the half-life from the $\alpha$-decay energy is much stronger than that from the $\alpha$-cluster localization although they all are influenced by the spin-obit coupling strength and pairing field.

Background: High-energy neutron cross sections are important for fusion devices, accelerator driven subcritical reactors, nuclear waste transmutation, astrophysics, etc.

Purpose: Neutron cross sections were measured using quasimonoenergetic neutrons produced via ${}^7\mathrm{Li}(p,n)X$ reaction in the high-energy region where available data are scarce or have large uncertainties. Significant discrepancies are also present in theoretical predictions and evaluated nuclear data libraries.

Methods: Natural Nd and Sr samples were irradiated with neutrons produced through ${}^7\mathrm{Li}(p,n)X$ reactions. Neutron flux was measured using the Aluminium and Gold foils neutron activation technique. A correction procedure was applied for the low-energy tail of the dominant neutron peak. The proton flux was recorded by monitoring the beam current. Offline $\gamma$-ray spectroscopy measurements were performed using the HPGe detector for irradiated samples and monitor foils. The neutron-induced cross sections for the ${}^{150}\mathrm{Nd}(n,2n){}^{149}\mathrm{Nd}$ and ${}^{86}\mathrm{Sr}(n,2n){}^{85m}\mathrm{Sr}$ reactions were measured with a detailed study of uncertainty propagation using covariance analysis. Theoretical calculations of the cross sections for the reaction channel were performed using the TALYS-1.96, EMPIRE-3.2.3, and YAHFC-v3.66 codes, and the results were compared with the present experimental data. The contributions of different reaction processes, including direct, pre-equilibrium, and compound reactions, were estimated using TALYS. The experimental data were also compared with the results from evaluated nuclear data libraries, i.e., TENDL-2021, JENDL-5.0, ENDF/B-VIII.0, and EAF-2010.

Results: The ($n$, $2n$) reaction cross sections for ${}^{150}\mathrm{Nd}$ and ${}^{86}\mathrm{Sr}$ were measured and compared with the theoretical estimates. The theoretical estimates reproduce the data for ${}^{150}\mathrm{Nd}(n,2n){}^{149}\mathrm{Nd}$ reaction quite well with specific level density models. Most of the model calculations failed to reproduce the cross sections for the ${}^{86}\mathrm{Sr}(n,2n){}^{85m}\mathrm{Sr}$ reaction, except by the TALYS model.

Conclusions: The cross section of the ${}^{150}\mathrm{Nd}(n,2n){}^{149}\mathrm{Nd}$ and ${}^{86}\mathrm{Sr}(n,2n){}^{85m}\mathrm{Sr}$ reactions were measured at three different neutron energies ranging from 12 to 19 MeV using the neutron activation method. Most of the theoretical models reproduce the cross sections for the ${}^{150}\mathrm{Nd}(n,2n){}^{149}\mathrm{Nd}$ reaction. The cross sections for the ${}^{86}\mathrm{Sr}(n,2n){}^{85m}\mathrm{Sr}$ reaction were higher than those predicted by most models but showed good agreement with TALYS calculations and previously reported experimental values. The results suggest that the existing theoretical models need further improvements.

The distorted-wave impulse approximation (DWIA) formalism for computing the cross sections in electroproduction of hypernuclei, used before for lighter ($p$-shell and $sd$-shell) systems, is utilized in studying electroproduction on heavier targets such as ${}^{52}\mathrm{Cr}$, and ${}^{208}\mathrm{Pb}$. First, the effects from kaon distortion and kinematics are reexamined and then results for the heavy targets are discussed in view of various forms of the $\mathrm{\Lambda }N$ effective interaction, the elementary amplitude, and kinematics. Apparent sensitivity of the hypernucleus excitation spectra to various forms of the $\mathrm{\Lambda }N$ effective interaction is shown. Predictions of the excitation spectrum in electroproduction of ${}_{\mathrm{\Lambda }}{}^{208}\mathrm{Tl}$ are also given in kinematics of the experiment E12-20-013 in preparation at Jefferson Lab.

The evaporation residue (ER) cross sections for ${}^{50}\mathrm{Ti}$-induced fusion reactions are calculated in the framework of the dinuclear system (DNS) model. The theoretical results demonstrate reasonable agreement with available experimental data. The primary goal of these calculations is to explore the potential of ${}^{50}\mathrm{Ti}$ as the projectile in the synthesis of superheavy new nuclides and elements. Subsequently, ER cross sections for ${}^{50}\mathrm{Ti}$ projectiles interacting with actinide targets, including isotopes of U, Np, Pu, Am, and Cm, were predicted. The predicted maximum ER cross sections approximately fall within the range of 0.01–0.1 pb, which may fill gaps in the existing nuclide chart. Furthermore, the reactions ${}^{50}\mathrm{Ti}+\mathrm{Bk}$ and ${}^{50}\mathrm{Ti}+\mathrm{Cf}$ as isotope targets, which lead to new superheavy nuclei with atomic numbers $Z=119$ and 120, were also studied. However, the ER cross sections for these systems drop to the femtobarn level.

The fluid-dynamical modeling of a nuclear collision at high energy usually starts shortly after the collision. A major source of uncertainty comes from the detailed modeling of the initial state. While the collision itself likely involves far-from-equilibrium dynamics, it is not excluded that a fluid theory of second order can reasonably well describe its soft features. Here we explore this possibility and discuss how the state before the collision can be described in that setup, what are the requirements from relativistic causality to the form of the equations of motion, how much entropy production can result from shear and bulk viscous dissipation during the initial longitudinal dynamics, and how one can thus obtain sensible initial conditions for the subsequent transverse expansion. While we do here only first steps, we outline a larger program. If the latter could be successfully completed, then it could lead to a dynamical description of heavy-ion collisions where the only uncertainty lies in the thermodynamic and transport properties of quantum chromodynamics.

The systematics are investigated for the charge radii of the even-$Z$ nuclei with $8⩽Z⩽120$ calculated by the deformed relativistic Hartree-Bogoliubov theory in continuum with the functional PC-PK1, and their deformation correlation is explored. The available data of the charge radius are reproduced with a root-mean-square deviation $\sigma =0.033$ fm. In particular, for the nuclei between the closed shells, the descriptions of the charge radii are remarkably improved by including the deformation. Taking molybdenum isotopes as examples, both the evolutions of the charge radius and deformation are well reproduced. It is found that while the charge radius typically increases with the deformation, there also exist different cases. For example, in ${}^{346}\mathrm{Sg}$, the charge radius of the deformed ground state is smaller than the one of the spherical state, and the largest binding energy does not necessarily correspond to the smallest charge radius. The increase or decrease of the charge radii with deformation is related to specific shell structures, particularly the key single-particle levels near the Fermi energy.

This study evaluates the accuracy of nuclear fragmentation simulations using a quantum molecular dynamics (QMD) model based on relativistic mean field (RMF) theory for an energy range of 50–400 MeV/u, relevant to hadron therapy. A total of 10 parameter sets within the RMF framework are assessed based on their ability to reproduce ground-state properties such as the mean squared radius and binding energy, as obtained in QMD simulations. Among these, the NS2 parameter set is identified as the most suitable for describing stable nuclei over a wide mass range, with the use of an adaptive Gaussian wave packet width. Fragmentation cross sections of carbon ion projectiles on light-nucleus targets (H, C, O, Al, Ti, and Cu) are simulated at incident energies of 50, 95, 290, and 400 MeV/u and compared with experimental data. The results indicate that the RQMD.RMF model provides superior reproductions for fragmentation at lower energies (50 and 95 MeV/u) compared with the light ion QMD (LIQMD) model implemented in Geant4 version 11.2. At higher energies (290 and 400 MeV/u), the RQMD.RMF model performs comparably to the LIQMD. This study demonstrates that the RQMD.RMF model provides a reliable framework for analyzing nuclear fragmentation and holds potential for applications in the planning and quality assurance of hadron therapy.

High-spin states in the ${}_{68}^{165,166,167}\mathrm{Er}$ nuclei were populated in the incomplete fusion of 55-MeV ${}^7\mathrm{Li}$ ions with a ${}^{164}\mathrm{Dy}$ target. Previously known rotational sequences in ${}^{165,166,167}\mathrm{Er}$ have been extended, in some cases beyond the $i_{13/2}$ two-quasineutron crossing region. In ${}^{165}\mathrm{Er}$, four rotational sequences were observed up to a maximum $I^{\pi }$ of ($45/2^{+}$); in ${}^{166}\mathrm{Er}$, five decay sequences were observed to $I^{\pi }=({28}^{+}$); and in ${}^{167}\mathrm{Er}$, four decay sequences were populated to $I^{\pi }=(53/2^{-}$). Comparisons of the experimental data with the results of Cranked Shell Model calculations provide insight into the configuration dependence of the first two-quasineutron crossing frequencies and the blocking effects of the odd quasineutron in ${}^{165}\mathrm{Er}$ and ${}^{167}\mathrm{Er}$. The experimental high-spin decay sequences in ${}^{165}\mathrm{Er}$ and ${}^{167}\mathrm{Er}$ have also been compared with the results of Projected Shell Model (PSM) calculations; the overall agreement between experiment and theory is very good over the complete range of spins for all high-spin rotational sequences. In particular, the observed signature splitting in the $5/2^{+}\left[642\right]$ band in ${}^{165}\mathrm{Er}$ and in the $7/2^{+}\left[633\right]$ and $1/2^{-}\left[521\right]$ bands in ${}^{167}\mathrm{Er}$ together with the absence of signature splitting in the high-$K$ $11/2^{-}\left[505\right]$ band in ${}^{165}\mathrm{Er}$ are reproduced in the PSM calculations. For ${}^{166}\mathrm{Er}$, the Triaxial Projected Shell Model calculations yield satisfactory results for both the ground and $\gamma$-vibrational band. For the latter band, there is a one-to-one correspondence between the theoretical results and experimental data for all states with $I^{\pi }$ in the range from the $2^{+}$ bandhead to the ${21}^{+}$ state.

High-spin states of odd-odd nucleus ${}^{138}\mathrm{Pm}$ are populated using the fusion-evaporation reaction ${}^{124}\mathrm{Te}({}^{19}\mathrm{F},5\mathrm{n}){}^{138}\mathrm{Pm}$. The previously known level scheme of ${}^{138}\mathrm{Pm}$ is extended and modified with the addition of nearly 40 new $\gamma$ transitions. One negative-parity band is newly established, and several new $E1$ transitions between the positive- and negative-parity bands are observed, indicating possible octupole correlations in ${}^{138}\mathrm{Pm}$. Two negative-parity bands before the back bend are assigned $\pi d_{5/2}\left[411\right]3/2^{+}\otimes \nu h_{11/2}\left[514\right]9/2^{-}$ and $\pi g_{7/2}\left[413\right]5/2^{+}\otimes \nu h_{11/2}\left[514\right]9/2^{-}$ configurations, which are interpreted as a pair of pseudospin partner bands, supported by the particle rotor model calculations. Moreover, the back bends observed in the two bands are attributed to the alignment of the first pair of $h_{11/2}$ protons. The previously observed negative-parity $\mathrm{\Delta }I=2$ band is extended to ${18}^{-}$ state, having a two-quasiparticle $\pi h_{11/2}\left[541\right]3/2^{-}\otimes \nu s_{1/2}$ configuration. In addition, a doubly decoupled band is identified and tentatively assigned the $\pi h_{11/2}\otimes \nu f_{7/2}$ configuration.

Employing the isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model, the 500 MeV/nucleon deformed uranium-uranium ultracentral collisions are simulated. The impacts of high-momentum tails caused by short-range correlations and the symmetry energy in high-density regions on geometric effects are discussed under different reaction orientations. The high-momentum tails increase the isotropic average momentum, thereby diminishing the geometric effects on collective flow from coordinate space. Simultaneously, symmetry energy does not significantly impact collective flows. Both higher momentum and softer symmetry energy lead to an increased pion meson yield, with the former reducing the ${\pi }^{-}/{\pi }^{+}$ ratio, while the latter increases it. Finally, we further analyze the mean square elliptic flow ratio of neutrons to protons in the body-body and the nonpolarized collisions, noting that as the symmetry energy softens, this ratio also decreases. The related results will facilitate the study of nuclear properties in deformed nuclei.

Background: In recent years there has been significant experimental effort aimed at studying the impact of ${}^{16}\mathrm{O}$ neutron poisoning on the weak $s$ process in rotating massive stars. Improving the understanding of energy levels in ${}^{21}\mathrm{Ne}$ is crucial to reducing uncertainties in the rates of the $\alpha$-induced reactions on ${}^{17}\mathrm{O}$ that determine the overall efficiency of the weak $s$ process.

Purpose: This paper reports on one such experiment: a study of the ${}^{20}\mathrm{Ne}$$(d,p){}^{21}\mathrm{Ne}$ reaction in inverse kinematics.

Methods: Deduced spin-parity assignments were made based on adiabatic distorted-wave approximation analysis and neutron partial widths were estimated by comparison with a previous experiment.

Results: Of particular significance for nuclear astrophysics is the resulting neutron partial width for the 7820-keV energy level, estimated to be $12200\left(2900\right)\mathrm{eV}$, and an upper limit of $\le 9300\mathrm{eV}$ for that of the 7749-keV energy level.

Conclusions: These results are in tension with previous studies and therefore this paper also discusses the current state of the research into the astrophysically relevant energy levels and highlights both areas of agreement and areas of disagreement between this and various other studies that have investigated this nucleus.

Mean lifetimes of the low-lying positive-parity yrast states up to $J^{\pi }=6^{+}$ in ${}^{116}\mathrm{Te}$ were measured with the recoil distance Doppler shift method, and the corresponding $B$($E2$) values were deduced. Using our values for ${}^{116}\mathrm{Te}$ and the most recent measured transition strengths for the other isotopes in this region, we show that the $B$($E2$) values, especially those of the $2^{+}\to 0^{+}$ transition, show a smooth evolution of quadrupole collectivity, with only a slight asymmetric behavior across the middle of the shell, in contrast to the one found in Sn isotopes. The transition strengths of even-even Te isotopes are then compared with systematic theoretical calculations within the shell model using the realistic pairing plus multipole terms with monopole interaction and the large-scale shell-model configuration-interaction approach with a realistic interaction, while the projected shell model is applied to calculate only the structure of ${}^{116}\mathrm{Te}$. The latter model gives a very good description of the individual $B$($E2$) values in ${}^{116}\mathrm{Te}$, while the first two models predict a stronger asymmetric behavior across the middle of the shell than the one observed experimentally.

The nuclear halo structure is one of the exotic phenomena appearing near the drip line. Due to the Coulomb barrier, proton halo nuclei are rarer than neutron halo ones, with some different properties. However, most previous research on halos only considered the nuclei as spherical or axially deformed. Motivated by previous research on the effect of triaxial deformation on neutron halos, we analyze the effect of triaxial deformation on proton halos, based on the theoretical model including a core plus single proton, using Woods-Saxon potential, the spin-orbit coupling potential, and the Coulomb potential. In our calculation, one can find that the inclusion of triaxiality can increase the $s$-wave component for weakly bound $d$-wave protons, leading to an extra extension of density distribution on some nuclei that were previously excluded from proton halo candidates by traditional models. Additionally, triaxial deformation also affects the rms radius of the $s$-wave proton halo nuclei, increasing the consistency between theory and experiments. Therefore, future experiments on the structure of proton halo nuclei are hoped to help explore the possible triaxial deformation in more nuclides.