We present a scenario in heavy-ion collisions where different modes of collective motions are noninterdependent, driven by factorized actions in the created nuclear medium. Such physics mechanisms could each dominate at a distinct evolution stage, or coexist simultaneously. If the probability of particle emission is modulated by each nondependent collective motion with a single-harmonic Fourier expansion, the particle azimuthal distribution should be the product of all these expansions. Consequently, nonleading cross terms between collectivity modes appear, and their contributions to experimental observables could be significant. In particular, we argue that the chiral magnetic effect (CME) and elliptic flow can develop separately, with their convolution affecting the observable that is sensitive to the shear-induced CME. We will use the event-by-event anomalous-viscous fluid dynamics model to illustrate the effects of this scenario. Besides giving insights into searches for the CME, we also propose feasible experimental tests based on conventional flow harmonics, and demonstrate the emergence of nonleading cross terms with a multiphase transport model.

In this paper, we study ground-state properties of weakly bound neutron-rich nuclei nuclei to investigate effects of three-body interactions in neutron-rich nuclei. We treat the nuclei as two-neutron halo systems where the cores have different atomic masses and different degrees of stability. We observe that the strength of the three-body potential, required to keep the halo nucleus bound, appears to decrease with the increase in atomic mass. We conjecture that effects of three-body interactions may be insignificant when the core is weakly bound.

From the data on baryon production in heavy-ion collisions it is shown that a set of measurable functions exist, one for each baryon type, that depends exponentially on transverse momenta up to the maximum values detected for all collision energies ranging from the low end of the BNL Relativistic Heavy Ion Collider Beam Energy Scan to the high end of the CERN Large Hadron Collider. The implied temperatures satisfy a scaling law in collision energy with a universal exponent for all baryon types which is the novel discovery. A self-similar thermal source is implied. Furthermore, it is shown how the scaling behavior depends on centralities. Those features in the data are related to simple properties of light and strange quarks by use of the recombination model. Prediction of $\varphi$ meson production is made and then verified by existing data.

For quantum many-body systems with short-range correlations (SRCs), the intimate relationship between their magnitude, the behavior of the single-particle occupation probabilities at momenta larger than the Fermi momentum, and the entanglement entropy is a new qualitative aspect not studied and exploited yet. A large body of recent condensed matter studies indicates that the time evolution of the entanglement entropy describes the nonequilibrium dynamics of isolated and strongly interacting many-body systems, in a manner similar to the Boltzmann entropy, which is strictly defined for dilute and weakly interacting many-body systems. Both theoretical and experimental studies in nuclei and cold atomic gases have shown that the fermion momentum distribution has a generic behavior $n\left(k\right)=C/k^4$ at momenta larger than the Fermi momentum, due to the presence of SRCs, with approximately 20% of the particles having momenta larger than the Fermi momentum. The presence of the long momentum tails in the presence of SRCs changes the textbook relation between the single-particle kinetic energy and occupation probabilities, $n_{\text{mf}}\left(k\right)=1/\{1+exp\beta [\epsilon \left(k\right)-\mu ]\}$ for momenta very different form the Fermi momentum, particularly for dynamics processes. SRCs induced high-momentum tails of the single-particle occupation probabilities increase the entanglement entropy of fermionic systems, which in its turn affects the dynamics of many nuclear reactions, such as heavy-ion collisions and nuclear fission.

Reported small-angle differential cross sections of proton elastic scattering off ${}^{20,22}\mathrm{Ne}$ and ${}^{24,26}\mathrm{Mg}$ at 0.8 GeV were analyzed with the Glauber model. Matter density distributions of ${}^{20,22}\mathrm{Ne}$ and ${}^{24,26}\mathrm{Mg}$ were determined based on the two-parameter Fermi density model, and the corresponding root-mean-square point-matter radii are 2.891(52) fm, 2.895(104) fm, 2.935(20) fm, and 2.946(21) fm. The occupation number effects of the $2s$ orbital on inner density were probed by the matter density difference between ${}^{22}\mathrm{Ne}$ and ${}^{24}\mathrm{Mg}$. Combined with the experimental occupation numbers, the relativistic Hartree-Bogoliubov calculations with the DD-ME2 and PC-PK1 interactions describe the obtained density difference trend, and indicate that there may be a bubble structure in ${}^{24}\mathrm{Mg}$.

Information on the ${}^{38}\mathrm{S}$ level scheme was expanded through experimental work utilizing a fusion-evaporation reaction and in-beam $\gamma$-ray spectroscopy. Prompt $\gamma$-ray transitions were detected by the Gamma-Ray Energy Tracking Array (GRETINA) and recoiling ${}^{38}\mathrm{S}$ residues were selected by the Fragment Mass Analyzer (FMA). Tools based on machine-learning techniques were developed and deployed for the first time in order to enhance the unique selection of ${}^{38}\mathrm{S}$ residues and identify any associated $\gamma$-ray transitions. The new level information, including the extension of the even-spin yrast sequence through $J^{\pi }=8^{(+)}$, was interpreted in terms of a basic single-particle picture as well shell-model calculations which incorporated the empirically derived FSU interaction. A comparison between the properties of the yrast states in the even-$Z, N=22$ isotones from $Z=14$ to 20, and for ${}^{36}\mathrm{Si}–{}^{38}\mathrm{S}$ in particular, was also presented with an emphasis on the role and influence of the neutron $1p_{3/2}$ orbital on the structure in the region.

The $\alpha$ decay of a new isotope ${}^{190}\mathrm{At}$ has been studied via the ${}^{109}\mathrm{Ag}({}^{84}\mathrm{Sr},3\mathrm{n}){}^{190}\mathrm{At}$ fusion-evaporation reaction by employing a gas-filled recoil separator. An $\alpha$-particle energy of 7750(20) keV and a half-life of $1.0_{-0.4}^{+1.4}$ ms were measured. The measured decay properties correspond to an unhindered $\alpha$ decay, suggesting the same spin and parity of (${10}^{-}$) as those of the final state of the decay. The systematics of the nearby nuclei and the predictions of selected atomic mass models were compared with the measured decay properties.

In this study, the number of virtual photons obtained through general, relativistic, nonrelativistic, and intermediate methods was investigated, which is an important factor in obtaining the Coulomb dipole strength distribution. The number of virtual photons was studied according to the incident energy $E_{\text{lab}}$ using five methods. The general method, which has two different forms (integral and differential), is valid for all energy regions, whereas the relativistic method is effective for regions with high $\beta$ values. In addition, the validity of the nonrelativistic approximation was tested by comparing it with the general method in the low-incident-energy region, and the intermediate method was shown to be not effective in the high-excitation-energy region. Further, an investigation was conducted on the dependence of the number of virtual photons on the charges of the projectile and target nuclei. Using the same $R$ value, target nuclei, and incident energy, it was found that the number of virtual photons does not depend on the charge number of the projectile in the relativistic method. With the same $R$ value, projectile, and incident energy, in contrast it can be seen that the number of virtual photon depends on the square of the charge number of target nuclei.

We analyze the relative yields of different bottomonia and charmonia states produced in Pb-Pb, $p\text{−}\mathrm{Pb}$, and high multiplicity $p\text{−}p$ collisions at the CERN Large Hadron Collider, within a semiclassical grand canonical ensemble approach. The underlying assumption is the early thermalization and subsequent freeze-out of these heavy hadrons resulting in their chemical freeze-out at a temperature of approximately $230\mathrm{MeV}$, significantly higher than that of light and strange hadrons. The systematic dependence of the freeze-out temperature on the collision centrality is also investigated in detail.

Classical novae are one of the most frequent explosive nucleosynthesis events in our universe but are still not sufficiently understood. To this day, nuclear astrophysics cannot explain the endpoint of the nucleosynthesis networks that drive them. This is mainly due to a scarce experimental database of nuclear reaction rates for proton induced reactions in the mass region above silicon at temperatures between 0.1 and 0.4 GK. Because some nova ejecta hint at the production of elements in the calcium range (Centauri V1065), and some possibly even up to the iron region (Cygni V1974), it is of utmost interest to investigate possible paths towards heavier elements. Here we report on new measurements of resonance strengths for the ${}^{39}\mathrm{K}(p,\gamma ){}^{40}\mathrm{Ca}$ reaction below 900 keV. Measurements were performed at the 5U accelerator at the University of Notre Dame. The implications of these new strengths for the ${}^{39}\mathrm{K}(p,\gamma ){}^{40}\mathrm{Ca}$ reaction rate are discussed.

Near-threshold resonances play an important role in nucleosynthesis and applied nuclear science. The study of nuclei removed from stability has greatly extended the list of resonances close to decay thresholds. The no core shell model with continuum (NCSMC) recently predicted an $s$-wave resonance just above the proton-decay threshold of ${}^7\mathrm{Li}$ at an excitation energy of 10.2 MeV. This potential case of a near-threshold resonance is dependent on the quantum mechanics of the $p+{}^6\mathrm{He}$ fragments extended into the continuum. The ${}^6\mathrm{He}(d,n){}^7\mathrm{Li}^{*}$ reaction was employed in an attempt to populate this resonance and search for its proton decay via the invariant-mass method. No evidence of this resonance was found. However, the data collected in this search led to better constraints on the energy and width of the isobaric analog state (IAS) with $(J^{\pi },T)=(3/2^{-},3/2)$ and revealed a new weak resonance just above the IAS in energy, predicted by the NCSMC as a $(J^{\pi },T)=(3/2^{-},1/2)$ state and potentially a part of the antianalog structure.

Mass distributions of fission fragments produced from the ${}^{249}\mathrm{Bk}$ compound nucleus (CN), populated by complete fusion of ${}^{11}\mathrm{B}$ with ${}^{238}\mathrm{U}$, were measured for the excitation energies in the range of $E_{\mathrm{cn}}^{*}\approx 36.7–69.7$ MeV. Nearly flat tops observed for these distributions indicate the presence of asymmetric fission, contrary to the pure Gaussian mass distributions expected at such high excitation energies. A fit to the mass distribution using three Gaussian functions provides an estimate of individual contributions from symmetric and asymmetric modes of fission. A significant contribution of the asymmetric component observed at CN excitation energies above 40 MeV can be understood only by invoking “multichance fission” in the calculations using the semiempirical model code gef. A systematic analysis of the mass distributions for several heavy transuranic nuclei reveals that the manifestation of the fragment shell effect in the integral mass distributions are visible even up to an initial compound nucleus excitation of $E_{\mathrm{cn}}^{*}\approx 70$ MeV due to their influence on the distributions of higher chance fissions.

We formulate a microscopic theory to calculate cross section of the radiative neutron capture reaction on neutron-rich nuclei using the continuum random-phase approximation (cRPA) to the time-dependent density functional theory (TDDFT). With an intention of applying to the $r$ process, for which the statistical reaction model may not be appropriate, we describe the transition between a initial state of incident neutron and a final state of the $\gamma$ decay by means of a single many-body framework of the cRPA-TDDFT. With the cRPA approach, it is possible to describe various excitation modes present in the $(n,\gamma )$ reaction, including soft dipole excitation, the giant resonances, as well as noncollective excitations and the single-particle resonances. Furthermore, it enables us to describe the $(n,\gamma )$ reaction where the the final states of the $\gamma$ transition are low-lying surface vibrational states. We demonstrate the theory by performing numerical calculation for the reaction ${}^{139}\mathrm{Sn}(n,\gamma ){}^{140}\mathrm{Sn}$. We discuss various new features which are beyond the single-particle model: the presence of narrow and wide resonances originating from noncollective and collective excitations and roles of low-lying quadrupole and octupole vibrational states.

The generator coordinate method of a microscopic cluster model is developed to treat the resonance and scattering of nuclear clusters with complex scaling. We consistently derive the formulation of the complex scaling for the microscopic cluster model, in which only the relative motions between clusters are transformed in the generator coordinate wave function. We also reveal the applicability of this method to the cluster wave function. Furthermore, we demonstrate this framework in the $2\alpha$ system of ${}^8\mathrm{Be}$ and obtain the solutions of resonance and nonresonant continuum states. Using these solutions, we calculate the level density, which brings the phase shifts of the cluster-cluster scattering. This work becomes the foundation in the description of the multicluster scattering states of nuclei in a microscopic framework with complex scaling.

Background: Detailed spectroscopy of neutron-rich, heavy, deformed nuclei is of broad interest for nuclear astrophysics and nuclear structure. Nuclei in the $r$-process path and following freeze-out region impact the resulting $r$-process abundance distribution, and the structure of nuclei midshell in both proton and neutron number helps to understand the evolution of subshell gaps and large deformation in these nuclei.

Purpose: We aim to improve the understanding of the nuclear structure of ${}^{160}\mathrm{Gd}$, specifically the $K^{\pi }=4^{+}$ bands, as well as study the $\beta$ decay of ${}^{160}\mathrm{Eu}$ into ${}^{160}\mathrm{Gd}$.

Methods: High-statistics decay spectroscopy of ${}^{160}\mathrm{Gd}$ resulting from the $\beta$-decay of ${}^{160}\mathrm{Eu}$ was collected using the GRIFFIN spectrometer at the TRIUMF-ISAC facility.

Results: Two new excited states and ten new transitions were observed in ${}^{160}\mathrm{Gd}$. The $\beta$-decaying half-lives of the low- and high-spin isomers in ${}^{160}\mathrm{Eu}$ were determined, and the low-spin state's half-life was measured to be $t_{1/2}=26.0\left(8\right)$ s, $\approx 16\%$ shorter than previous measurements. Lifetimes of the two $K^{\pi }=4^{+}$ bandheads in ${}^{160}\mathrm{Gd}$ were measured for the first time, as well as $\gamma \text{−}\gamma$ angular correlations and mixing ratios of intense transitions out of those bandheads.

Conclusions: Lifetimes and mixing ratios suggest that the hexadecapole phonon model of the $K^{\pi }=4^{+}$ bandheads in ${}^{160}\mathrm{Gd}$ is preferred over a simple two-state strong mixing scenario, although further theoretical calculations are needed to fully understand these states. Additionally, the 1999.0-keV state in ${}^{160}\mathrm{Gd}$ heavily populated in $\beta$ decay is shown to have positive parity, which raises questions regarding the structure of the high-spin $\beta$-decaying state in ${}^{160}\mathrm{Eu}$.

${}^{90}\mathrm{Zr}$ is a double-magic spherical nucleus. Nucleon scattering on such a nucleus can be well described by spherical optical model potentials. Nucleon scattering data including neutron total cross section, elastic scattering angular distributions and analyzing powers, and low-energy scattering observables are used to derive a new Lane-consistent spherical optical model potential that obeys dispersive constraints, features nonlocality of the real part, and considers the shell gap in the potential. It is shown that the derived dispersive optical potential gives a good description of the energies of the bound single-particle states of the target nucleus ${}^{90}\mathrm{Zr}$.

We present a systematic analysis of the nuclear two- and three-body short-range correlations and their relations to the zero-energy eigenstates of the Schrödinger equation. To this end we analyze the doublet and triplet coupled-cluster amplitudes in the high momentum limit, and show that they obey universal equations independent of the number of nucleons and their state. Furthermore, we find that these coupled-cluster amplitudes coincide with the zero-energy Bloch-Horowitz operator. These results illuminate the relations between the nuclear many-body theory and the generalized contact formalism, introduced to describe the nuclear two-body short range correlations, and they might also be helpful for general coupled-cluster computations as the asymptotic part of the amplitudes is given and shown to be universal.

We explore the effects on nuclear bulk properties of using regularization cutoffs larger than the nucleon mass within the chiral effective field theory with a power counting that ensures order-by-order renormalization in the two-nucleon system. To do so we calculate ground-state properties of the ${}^{16}\mathrm{O}$ nucleus in the Hartree-Fock approach in a basis made up of plane waves confined in a cube. We find that regularization cutoff effects manifest themselves in two distinct ways: a strong sensitivity to the counterterms in attractive singular partial waves (related to the sign of the corresponding low-energy constant) and to the correction for spurious deeply bound states (for high enough cutoffs). In fact the latter happens to deprive the Hartree-Fock approximation of yielding bound solutions in nuclei. We conclude that, when using a leading-order chiral potential in the Nogga–Timmermans–van Kolck power counting (with a regularization cutoff higher than the nucleon mass), one cannot produce a self-consistent mean field free of spurious bound-state effects that can serve as a reference state for beyond-mean-field methods. For high regularization cutoffs which yield an attractive ${}^3{S}_1$ contact potential, one can at best incorporate in the mean-field solution a partial correction for spurious bound states. Then the remaining correction has to be added to the residual interaction in a treatment beyond the Hartree-Fock approximation. However a “full” correction in the ${}^3{D}_2$ channel, with energy shifts of the order of or somewhat larger than those recommended by Yang et al. [Phys. Rev. C 103, 054304 (2021)], is possible in the Hartree-Fock solution.