Anisotropy scaling functions derived from comprehensive measurements of transverse momentum- and centrality-dependent anisotropy coefficients $v_2(p_T,\text{cent})$ and $v_3(p_T,\text{cent})$ in $\mathrm{Pb}+\mathrm{Pb}$ collisions at 5.02 and 2.76 TeV, $\mathrm{Xe}+\mathrm{Xe}$ collisions at 5.44 TeV, and $\mathrm{Au}+\mathrm{Au}$ collisions at 0.2 TeV offer new insights into the ultracentral flow puzzle. These functions integrate diverse measurements into a single curve, clarifying anisotropy attenuation throughout the entire $p_T$ and centrality range. They reveal the influence of initial-state eccentricities (${\varepsilon }_n$), dimensionless size ($\mathbb{R}$), radial flow, viscous correction to the thermal distribution function (${\delta }_f$), the medium's stopping power ($\widehat{q}$), and specific shear viscosity ($\eta /s$) on the observed anisotropies. This analysis not only enhances understanding of transport coefficients but also provides crucial constraints on nuclear deformation.

Observed rotational bands that terminate or appear to terminate at very high spin are analyzed within the configuration constrained cranked Nilsson-Strutinsky (unpaired CNS or CNSB with pairing) formalism. Spin values for the nuclei discussed reach or come close to the maximum spin that can be built within the $Z,N=50–82$ shells. Configurations are distinguished not only by the number of particles in high-$j$ and low-$j$ shells within each $\mathcal{N}$ shell but, in some cases, also by the number of particles in pseudospin partners like $d_{5/2}{g}_{7/2}$ and $s_{1/2}{d}_{3/2}$. Configurations in ${}^{156}\mathrm{Dy}$ and ${}^{164}\mathrm{Hf}$, which terminate at $I\approx 60$, are well understood in terms of their occupation of open $j$ shells or groups of $j$ shells. The bands in ${}^{156}\mathrm{Dy}$ are tentatively observed up to termination while the bands in ${}^{164}\mathrm{Hf}$ are still a few spin units away. These terminating states are built with up to 18 aligned particles or 18 $\text{particles}+\text{holes}$ outside a core. The core is built from nucleons in filled $j$ shells, which gives no contribution to the spin. Analysis of the high-spin bands in ${}^{125,126}\mathrm{Xe}$ and ${}^{131,132}\mathrm{Ce}$ suggests that bands in ${}^{126}\mathrm{Xe}$ and ${}^{132}\mathrm{Ce}$ are observed to terminate at similar spin values, where terminating bands in ${}^{126}\mathrm{Xe}$ are observed high above yrast. It is remarkable that the deformed mean field, plus single-particle configurations, is able to provide such a comprehensive description of known experimental levels in nuclei up to spin $60\hslash$ and beyond. It is also impressive that the model can relate alignments of single-particle spin vectors to changes in shape with the nuclear spin.

The ${}^8\mathrm{Li}+{}^{120}\mathrm{Sn}$ collision has been investigated at laboratory energies of 21.7 and 25.8 MeV ($V_{\mathrm{CB}}^{\mathrm{lab}}=20.5$ MeV). The ${}^8\mathrm{Li}+{}^{120}\mathrm{Sn}$ elastic scattering and the ${}^7\mathrm{Li}$ fragment angular and energy distributions from the ${}^{120}\mathrm{Sn}({}^8\mathrm{Li},{}^7\mathrm{Li})X$ reaction have been measured. The elastic scattering angular distributions were analyzed by optical model and coupled reaction channels (CRC) calculations considering the coupling with the neutron stripping channel. The effect of the projectile breakup on the elastic scattering distributions has been studied via continuum-discretized coupled-channels (CDCC) calculations. The experimental ${}^7\mathrm{Li}$ energy distribution presents characteristics similar to a neutron transfer reaction populating a wide range of excited states in the recoil system, from the ground state up to states above the neutron threshold, with a maximum in the excitation energy predicted by $Q$-optimum arguments. These energy distributions, as well as the corresponding ${}^7\mathrm{Li}$ angular distributions, are well described using the Ichimura, Austern, and Vincent (IAV) model, which includes the neutron transfer to bound and unbound states of the target nucleus. The total reaction cross sections from the elastic scattering angular distributions and total breakup cross sections have been obtained from the IAV plus CDCC and CRC calculations. A comparison with previous measurements of the ${}^8\mathrm{Li}$ scattering on ${}^9\mathrm{Be}$ and ${}^{58}\mathrm{Ni}$ targets is presented. A dominance of the transfer to bound states over the breakup channel is seen in the present case.

Nuclear reactions present an interesting case for studies of the time evolution of entanglement between complex quantum systems. In this work, the time-dependent nuclear density-functional theory is employed to explore entanglement in multinucleon transfer reactions. As an illustrative example, for the reaction ${}^{40}\mathrm{Ca}+{}^{208}\mathrm{Pb}$ at $E_{\mathrm{lab}}=249\mathrm{MeV}$, in the interval of impact parameters $4.65–7.40\mathrm{fm}$, and the relativistic density-functional PC-PK1, we compute the von Neumann entropies, entanglement between fragments, nucleon-number fluctuations, and Shannon entropy for the nucleon-number observable. A simple linear correlation is established between the entanglement and nucleon-number fluctuation of the final fragments. The entanglement between the fragments can be related to the corresponding excitation energies and angular momenta. The relationship between the von Neumann entropy and the Shannon entropy for the nucleon-number observable is analyzed, as well as the time evolution of the entanglement (nucleon-number fluctuation). The entanglement is also calculated for a range of incident energies and it is shown how, depending on the impact parameter, the entanglement increases with the collision energy.

Background: Knowledge of the neutron-induced ${}^{35}\mathrm{Cl}(n,x)$ cross sections is vital to the design and certification of molten chloride fast reactors (MCFRs) since the ${}^{35}\mathrm{Cl}(n,p_0){}^{35}\mathrm{S}$ reaction is believed to be a significant reactor poison. However, recently published measurements are inconsistent with each other and with evaluation.

Purpose: The goal of this work is to measure the ${}^{35}\mathrm{Cl}(n,p_0)$ reaction cross section using a technique that is different from recent measurements.

Methods: The experiment was conducted at Lawrence Berkeley National Laboratory's (LBNL) 88-Inch Cyclotron using thick target deuteron breakup from a 14 MeV deuteron beam. Energy-differential ${}^{35}\mathrm{Cl}(n,p_0){}^{35}\mathrm{S}$ cross sections were obtained via ratio with the ${}^6\mathrm{Li}(n,\alpha ){}^3\mathrm{H}$ reaction using an active target experiment with a ${\mathrm{Cs}}_2{\mathrm{LiYCl}}_6$ (CLYC) scintillator.

Results: The ${}^{35}\mathrm{Cl}(n,p_0)$ reaction cross section was measured from 2.02 to 7.46 MeV. The results are consistent with Kuvin et al., confirming a roughly 50% reduction in magnitude relative to the ENDF/B-VIII.0 evaluation.

Conclusions: These data provide new insight into the role of natural Cl as an MCFR poison. The reduction of the ${}^{35}\mathrm{Cl}(n,p_0)$ reaction cross section compared to evaluation suggests that MCFR criticality is less sensitive to Cl enrichment. This may in turn reduce building and operating costs since isotope separation may not be needed.

Background: The established Gaseous Detector with Germanium Tagging (GADGET) detection system is used to measure weak, low-energy $\beta$-delayed proton decays. It consists of the Gaseous Proton Detector equipped with a MICROMEGAS (MM) readout to detect protons and other charged particles calorimetrically, surrounded by the Segmented Germanium Array (SeGA) for high-resolution detection of prompt $\gamma$ rays.

Purpose: To upgrade GADGET's Proton Detector to operate as a compact time projection chamber (TPC) for the detection, three-dimensional imaging and identification of low-energy $\beta$-delayed single- and multiparticle emissions mainly of interest to astrophysical studies.

Method: A new high granularity MM board with 1024 pads has been designed, fabricated, installed, and tested. A high-density data acquisition system based on generic electronics for TPCs (GET) has been installed and optimized to record and process the gas avalanche signals collected on the readout pads. The TPC's performance has been tested using a ${}^{220}\mathrm{Rn}\alpha$-particle source and cosmic-ray muons. In addition, decay events in the TPC have been simulated by adapting the attpcroot data analysis framework. Furthermore, a novel application of two-dimensional convolutional neural networks for GADGET II event classification is introduced. The optimization of data throughput is also addressed.

Results: The GADGET II TPC is capable of detecting and identifying $\alpha$ particles as well as measuring their track direction, range, and energy. The extracted energy resolution of the GADGET II TPC using P10 gas is about 5.4% at 6.288 MeV (${}^{220}\mathrm{Rn}\alpha$ events), computed using charge integration. Based on a systematic simulation study, we estimated the detection efficiency of the GADGET II TPC for protons and $\alpha$ particles, respectively. It has also been demonstrated that the GADGET II TPC is capable of tracking minimum-ionizing particles (i.e., cosmic-ray muons). From these measurements, the electron drift velocity was measured under typical operating conditions. In addition to being one of the first generation of micropattern gaseous detectors (MPGDs) to utilize a resistive anode applied to low-energy nuclear physics, the GADGET II TPC will also be the first TPC surrounded by a high-efficiency array of high-purity germanium $\gamma$-ray detectors.

Conclusions: The TPC of GADGET II has been designed, fabricated, and tested and is ready for operation at the Facility for Rare Isotope Beams for radioactive-beam-line experiments.

A fast secondary beam of ${}^{37}\mathrm{Ca}$ impinged on a ${}^9\mathrm{Be}$ target resulting in a set of reactions populating proton-rich nuclei including ${}^{35}\mathrm{Ca}$ and the first observations of ${}^{37,38}\mathrm{Sc}$ and ${}^{34}\mathrm{K}$. Invariant-mass spectroscopy, used to reconstruct proton decays for these nuclei, yielded three new ground-state masses and information on their low-lying structures. The newly measured mass excesses are: $\mathrm{\Delta }\mathrm{M}\left({}^{37}\mathrm{Sc}\right)=3500\left(410\right)\mathrm{keV}, \mathrm{\Delta }\mathrm{M}\left({}^{38}\mathrm{Sc}\right)=-4656\left(14\right)\mathrm{keV}$, and $\mathrm{\Delta }\mathrm{M}\left({}^{34}\mathrm{K}\right)=-1487\left(17\right)\mathrm{keV}$. These nuclei straddle the well-known $Z=20$ shell closure as well as the $N=16$ subshell closure. Trends in separation energies help elucidate how nuclear structure evolves showing a fading of the $Z=20$ shell gap for $N\le 18$ and indications of a $N=16$ subshell gap.

Nuclear-structure calculations for the description of low-energy neutral-current neutrino scattering off the stable ${}^{203,205}\mathrm{Tl}$ isotopes are performed in the context of the nuclear shell model using the model space jj56pn. Cross-section and event-rate calculations focusing on inelastic solar-neutrino scattering off ${}^{203,205}\mathrm{Tl}$ are performed. The individual contributions of the various nuclear responses are presented and discussed, and the results are also illustrated in terms of the nuclear recoil energy. Analytical expressions entering the cross sections are given in order to achieve a direct connection with experimental observables.

Binary tree states (BTSs) are states whose decomposition on a quantum register basis formed by a set of qubits can be made sequentially. Such states sometimes appear naturally in many-body systems treated in Fock space when a global symmetry is imposed, such as the total spin or particle number symmetries. Examples are the Dicke states, the eigenstates of the total spin for a set of particles having individual spin $1/2$, or states obtained by projecting a BCS states onto particle number, also called projected BCS in small superfluid systems. Starting from a BTS described on the set of $n$ qubits or orbitals, the entanglement entropy of any subset of $k$ qubits is analyzed. Specifically, a practical method is developed to access the $k$-qubit or $k$-particle von Neumann entanglement entropy of the subsystem of interest. Properties of these entropies are discussed, including scaling properties, upper bounds, or how these entropies correlate with fluctuations. Illustrations are given for the Dicke state and the projected BCS states.

The first in-beam $\gamma$-ray spectroscopic study of the neutron-deficient actinium isotopes ${}^{211,213}\mathrm{Ac}$ has been carried out at the Accelerator Laboratory of the University of Jyväskylä using a highly selective recoil-decay tagging method with the jurogam 3 germanium-detector array and MARA separator. The nuclei of interest were produced using the ${}^{175}\mathrm{Lu}({}^{40}\mathrm{Ar},4n){}^{211}\mathrm{Ac}$ and ${}^{180}\mathrm{Hf}({}^{37}\mathrm{Cl},4n){}^{213}\mathrm{Ac}$ fusion-evaporation reactions. Excited states in ${}^{211}\mathrm{Ac}$ were observed for the first time. In ${}^{211}\mathrm{Ac}$ and ${}^{213}\mathrm{Ac}$ low-lying core-excited states whose excitation energies follow the systematic trends of their respective core states in even-even isotones ${}^{210}\mathrm{Ra}$ and ${}^{212}\mathrm{Ra}$ were identified. Additionally, we were able to extend the level scheme of ${}^{211}\mathrm{Ra}$, which was also produced in the ${}^{40}\mathrm{Ar}+{}^{175}\mathrm{Lu}$ reaction. We also remeasured the half-lives of the ground states of these nuclei and also that of the (${{}^{13}{/}_2}^{+}$) isomeric state of ${}^{211}\mathrm{Ra}$.

The correlation between the spin-orbit strength and effective mass at saturation density is demonstrated for various Skyrme energy-density functionals without tensor force. This correlation can be used to reduce the number of parameters in these functionals. The role of the spin-orbit interaction is considered together with the tensor force, which has a similar effect on the observable nuclear characteristics. The use of the relation obtained between the spin-orbit strength and the effective mass in the calculations of binding energies, spin-orbit splitting, and charge radii does not spoil the description of experimental data.

The synthesis of superheavy elements represents the forefront of exploring the properties of unknown nuclear matter. Theoretically, significant uncertainties in predicting the fission barriers of superheavy nuclei make accurate calculations of the survival probabilities of compound nuclei extremely challenging. This study utilizes a machine learning methodology to predict the fission barriers of nuclides with $93<Z\le 120$ and $135<N\le 184$. We have estimated the fission barriers for a total of 660 nuclides, and leveraged these fission barriers to calculate the crucial survival probabilities in the synthesis of superheavy elements. Based on this, we calculated the reaction cross sections for the ${}^{48}\mathrm{Ca}+{}^{243}\mathrm{Am}$ reaction within the framework of the dinuclear system model, and compared the results with experimental data measured using the new gas-filled separator DGFRS-2. The calculations successfully reproduced the experimental data within an acceptable range of error. Additionally, we explored the optimal synthesis conditions for synthesizing the new elements $Z=119$ and $Z=120$, including projectile-target combinations, incident energies, and maximum reaction cross sections.

The angular distributions of neutron elastic scattering on natural carbon were studied in the fast neutron energy region between 1 and 8 MeV. The experiments were carried out at the white neutron source of the Geel Electron Linear Accelerator (GELINA) facility by using thin and thick natural carbon samples. This work demonstrates the need for using thin samples to avoid strong multiple scattering effects. Neutrons and $\gamma$ rays from scattering were detected using the ELastic and Inelastic Scattering Array (ELISA), a setup consisting of 32 liquid organic scintillators. The $n\text{−}\gamma$ separation was achieved via pulse-shape analysis. For each sample a different approach in methodology is studied, one based on a global response function model and another one based on a per-detector model. The detectors are placed at eight different detection angles between ${16}^{\circ }$ and ${164}^{\circ }$ with respect to the neutron beam direction, allowing the simultaneous calculation of both the differential and the integral cross section by implementing the Gauss-Legendre quadrature rule. The neutron flux was measured with a ${}^{235}\mathrm{U}$ ionization chamber. The angular distributions were extracted relative to the ${}^{235}\mathrm{U}(n,f)$ cross section. The results are compared with other experimental data available in the EXFOR library, along with the most recent nuclear data evaluations. The angle-integrated cross sections are in excellent agreement with the nuclear data evaluations and for the angular distributions, ENDF/B-VIII.0 is better reproducing the experimental data in all eight detection angles.

Proxies for cumulants of baryon number $B$, electric charge $Q$, and strangeness $S$ are usually measured in heavy-ion collisions via moments of net-number distribution of given hadronic species. Since these cumulants of conserved charges are expected to be sensitive to the existence of a critical point in the phase diagram of nuclear matter, it is crucial to ensure that the proxies used as substitutes are as close to them as possible. Hence, we use the epos4 framework to generate $\text{Au}+\text{Au}$ collisions at several collision energies of the BNL Relativistic Heavy Ion Collider beam energy scan. We compute second-order net cumulants of $\pi$, $K$, and $p$, for which experimental data have been published as well as the corresponding conserved charge cumulants. We then compare them with proxies, defined in previous lattice QCD and hadron resonance gas model studies, which are shown to reproduce more accurately their associated conserved charge cumulants. We investigate the impact of hadronic rescatterings occurring in the late evolution of the system on these quantities, as well as the amount of signal actually originating from the bulk medium which endures a phase transition.

The pairing model with configuration mixing has been applied to the odd-$A{}^{133}\mathrm{Cs}$ nucleus to study band mixing. Then, a simple two-state mixing model has been utilized for the two lowest ground and excited bands. Unique solutions were identified for the $3/2^{+}$ and $5/2^{+}$ mixing in both bands, as well as for the $E2$ matrix elements connecting the basis states. The excited band exhibited greater collectivity compared to the ground-state band. The use of a quasispin pairing operator with configuration mixing significantly improves the model's accuracy, especially in replicating experimental data for positive parity states and $E2$ transition rates.

Based on our previous work about Coulomb corrections in the trap method [H. Zhang et al. Phys. Lett. B 850, 138490 (2024)], we extend the Coulomb-corrected Busch-Englert-Rzażewski-Wilkens formula in coupled-channels nuclear reactions and examine the reliability by taking ${}^4\mathrm{He}=[{}^3\mathrm{H}+p]+[{}^3\mathrm{He}+n]$ as an example. The obtained numerical results are generally well consistent with conventional methods. Our work lays some groundwork for analyzing the coupled-channel reactions involving light charged particles within the trap method.

$\alpha$ decay is one of the prominent decay modes in the nucleosynthesis of heavy and superheavy elements synthesized at temperatures of the order of gigakelvin. To facilitate the investigation of the role played by the $\alpha$ decay half-lives of thermally excited nuclei in nucleosynthesis calculations, an empirical formula based on a model for the $\alpha$ decay of nuclei in their ground and excited states to daughter nuclei in their ground or excited states is presented. Constants appearing in the analytical expression for the $\alpha$ decay half-life obtained within the model are treated as adjustable parameters and fitted to experimental data on 342 $\alpha$ decays in the range of 82 $\le Z_p\le$ 94, to obtain an excitation energy-dependent decay law. Under the assumption that thermal equilibrium has been reached between nuclear states, temperature ($T$) dependent half-lives, $t_{1/2}\left(T\right)$, for several of the experimentally studied $\alpha$ emitters with 65 $\le Z_p\le$ 94 are presented using available data on the half-lives of excited nuclei. Though the general trend is a decrease in $t_{1/2}\left(T\right)$ at elevated temperatures, exceptional cases with increased half-lives are found in the case of some isomeric states. A list of such isomers provided in this paper motivates future work involving considerations of their thermal equilibration and role in shaping kilonova light curves.

The nonrelativistic model of nuclear matter with Brussels extended Skyrme interactions is employed in order to build, within a Bayesian approach, models for the dense matter equation of state. In addition to a minimal set of constraints on nuclear empirical parameters, the density behavior of the energy per particle in pure neutron matter (PNM), and a lower limit on the maximum neutron star (NS) mass, we require that the Fermi velocity of neutrons ($v_{F;n}$) in PNM and symmetric nuclear matter (SNM) with densities up to $0.8{\mathrm{fm}}^{-3}$ (arbitrary) does not exceed the speed of light. The latter condition is imposed in order to cure a deficiency present in many Skyrme interactions [Duan and Urban, Phys. Rev. C 108, 025813 (2023)]. We illustrate the importance of this constraint for the posterior distributions. Some of our models are subjected to constraints on the density dependence of neutron (nucleon) Landau effective mass in PNM (SNM), too. The impact of various sets of constraints on the behaviors of nuclear matter and NSs is discussed in detail. Systematic comparison with results previously obtained by employing Skyrme interactions is done for posteriors of both nuclear matter (NM) and NS parameters. Special attention is given to the model and constraints dependence of correlations among various quantities.

We determine cross sections and astrophysical $S$ factors of the reactions generated in collisions between ${}^6\mathrm{Li}$ and ${}^3\mathrm{H}$ and between ${}^6\mathrm{Li}$ and ${}^3\mathrm{He}$. A microscopic three-cluster model is employed to study the dynamics of reactions occurring in the mirror nuclei ${}^9\mathrm{Be}$ and ${}^9\mathrm{B}$. In a previous study [Phys. Rev. C 109, 045803 (2024)], this model was successfully applied to investigate the resonance structure of ${}^9\mathrm{Be}$ and ${}^9\mathrm{B}$, as well as reactions induced by the interaction of deuterons with ${}^7\mathrm{Li}$ and ${}^7\mathrm{Be}$. A fairly good agreement between theoretical results and available experimental data was achieved. To the best of our knowledge, appropriate experimental data for the astrophysical $S$ factors of the reactions generated by the interaction of ${}^6\mathrm{Li}$ with ${}^3\mathrm{H}$ and with ${}^3\mathrm{He}$ are currently unavailable. Thus, our results can serve as a guideline for future experimental efforts.

We present new microscopic effective shell-model interactions in the valence $sd$ shell, obtained from the modern Daejeon16 nucleon-nucleon potential using no-core shell-model (NCSM) wave functions of ${}^{18}\mathrm{F}$ at $N_{\max }=6$ (total oscillator quanta of excitation) model space and the Okubo-Lee-Suzuki transformation. First, we explore the convergence properties of our calculations and show that the excitation energies of states in ${}^{18}\mathrm{F}$, characterized by the largest valence-like configurations, are reasonably converged and the lowest states are in sensible agreement with experiment. Then, we investigate the monopole properties of that interaction in comparison with the phenomenological universal $sd$-shell interaction, USDB, and with the previously derived interaction at $N_{\max }=4$. Theoretical binding energies and low-energy spectra of the O isotopes, as well as low-energy spectra of a selection of $sd$-shell nuclei, are presented. We conclude that the use of larger-space NCSM wave functions leads to a noticeable improvement in the quality of the derived effective interaction. We propose monopole modifications of the Daejeon16 centroids which further improve the agreement with experiment throughout the $sd$ shell, as demonstrated by a compilation of spectra contained in Supplemental Material.