Regarded as important for applications and theoretical studies, the differential cross sections of the emitted triton for the neutron-induced ${}^6\mathrm{Li}$ reaction at low incident energies were calculated, based on the zero-range distorted-wave Born approximation theory with the assumption of ${}^6\mathrm{Li}$ nucleus consisting of $t{+}^3\mathrm{He}$ or $d+\alpha$. As a function of widths and excited energies of the discrete energy levels, an effective excited energy formula was proposed to describe their partial contributions. In addition, the optical model potential parameters, which had been successfully used to reproduce the double-differential cross sections of the emitted neutrons in our previous works in incident energy range from 5.0 to 20.0 MeV were extended in a low-energy range from 1.0 eV to 3.0 MeV in this paper. The calculated results agreed well with the measured differential cross sections recently published in 2020 and were further consistent with the measured angle-integrated cross sections. This indicates that the knock-out process and heavy-particle knockout process were dominant in an energy range from 1.0 eV to 3.0 MeV, whereas the shapes of the measured angular distributions in incident energy range from 0.1 to 1.0 MeV could be successfully explained by the Hauser-Feshbach model.

We present an update of the event generator based on the three-fluid dynamics (3fd), complemented by Ultrarelativistic Quantum Molecular Dynamics (urqmd) for the late stage of the nuclear collision—the Three-fluid Hydrodynamics-based Event Simulator Extended by urqmd final State interactions (theseus). Two modifications are introduced. The theseus table of hadronic resonances is made consistent with that of the underlying 3fd model. The main modification is that the generator is extended to simulate the light-nuclei production in relativistic heavy-ion collisions, on an equal basis with hadrons. These modifications are illustrated by applications to the description of available experimental data. The first run of the updated generator revealed a good reproduction of the NA49 data on the light nuclei. The reproduction is achieved without any extra parameters, while the coalescence approach in 3fd requires special tuning of the coalescence coefficients for each light nucleus separately.

In this paper, we start with chiral kinetic theory and construct the spin hydrodynamic framework for a chiral spinor system. Using the 14-moment expansion formalism, we obtain the equations of motion of second-order dissipative relativistic fluid dynamics with nontrivial spin-polarization density. In a chiral spinor system, the spin-alignment effect could be treated in the same framework as the chiral vortical effect (CVE). However, the quantum corrections due to fluid vorticity induce not only CVE terms in the vector/axial charge currents, but also corrections to the stress tensor. In this framework, viscous corrections to the hadron spin polarization are self-consistently obtained, which will be important for precise prediction of the polarization rate for the observed hadrons, e.g., $\mathrm{\Lambda }$ hyperon.

Isotopic cross sections measured in many different fragmentation and spallation reactions display a universal odd-even staggering (OES). On the basis of this universality, four OES relations are proposed for the first time to accurately calculate fragmentation and spallation cross sections. Comparison with extensive experimental data measured in various reaction systems reveals that cross sections calculated by two OES relations agree excellently with 95% measured data within a factor smaller than 1.2, while another two OES relations also show a similar good agreement (within a factor around 1.5). These remarkable agreements, which can hardly be reached by other existing models, strongly support that these simple OES relations open new paths for very accurate and fast calculations of fragmentation as well as spallation cross sections. As an application of these relations, significant discrepancies between some measured cross sections are scrutinized and well resolved by using the OES magnitudes and accurate OES relations first proposed in this work. Finally, based on recent experimental data, small cross sections (down to ${10}^{-13}$ mb) of some new isotopes near the drip-lines are accurately extrapolated or interpolated with these OES relations, which will be very useful for exploring undiscovered isotopes.

We study stable spheroidal configurations of magnetized strange stars using an axially symmetric metric in spherical coordinates that uses a gamma parameter to link the anisotropy in the equation of state due to the magnetic field with the deformation of the star. The stars are composed by magnetized strange quark matter described within the framework of the MIT bag model. Their masses, radii, eccentricity, redshift and mass quadrupole moment are computed. Results are compared with spherical strange star solutions obtained with Tolman-Oppenheimer-Volkoff equations and observational data of strange star candidates. In the spheroidal model the observables depend directly on the deformation of the star, and, even though it is small, the observables strongly deviate from the corresponding spherical configurations. Thus, the highest values of the mass quadrupole moment correspond to the intermediate mass regime. These differences might allow us to discriminate between models with and without magnetic field when compared with observations.

The production cross sections of superheavy nuclei with charge numbers 114–117 are predicted in the (5–9)$n$ evaporation channels of the ${}^{48}\mathrm{Ca}$-induced complete fusion reactions for future experiments. The estimates of synthesis capabilities are based on a uniform and consistent set of input nuclear data provided by the multidimensional microscopic-macroscopic approach. The contributions of various factors to the final production cross section are discussed. As shown, the specific interplay between survival and fusion probabilities unexpectedly leads to a relatively slow decline of the total cross sections with increasing excitation energy. This effect is supported by a favorable arrangement of fission barriers protecting the compound nucleus against splitting concerning energetic thresholds for the emission of successive neutrons. In particular, the probabilities of the formation of superheavy nuclei in the $5n, 6n$, and in some cases even $7n$ evaporation channels are still promising. This may offer a new opportunity for the future synthesis of unknown neutron-deficient superheavy isotopes.

Background: Nuclei in the $sd$ shell demonstrate a remarkable interplay of cluster and mean-field phenomena. The $N=Z$ nuclei, such as ${}^{24}\mathrm{Mg}$ and ${}^{28}\mathrm{Si}$, have been the focus of the theoretical study of both phenomena in the past. A variety of different cluster structures in these nuclei are predicted, characterized by isoscalar dipole and monopole transitions. For example, low-energy isoscalar vortical dipole states were predicted in ${}^{24}\mathrm{Mg}$. The cluster and vortical mean-field phenomena can be probed by excitation of isoscalar monopole and dipole states in scattering of isoscalar particles such as deuterons or $\alpha$ particles.

Purpose: We investigate, both experimentally and theoretically, the isoscalar dipole $IS1$ and monopole $IS0$ strengths in three essentially different light nuclei with different properties: stiff prolate ${}^{24}\mathrm{Mg}$, soft prolate ${}^{26}\mathrm{Mg}$, and soft oblate ${}^{28}\mathrm{Si}$. We analyze possible manifestations of clustering and vorticity in these nuclei.

Methods: Inelastically scattered $\alpha$ particles were momentum analyzed in the K600 magnetic spectrometer at iThemba LABS, Cape Town, South Africa. The scattered particles were detected in two multiwire drift chambers and two plastic scintillators placed at the focal plane of the K600. In the theoretical discussion, the Skyrme quasiparticle random-phase approximation (QRPA) and antisymmetrized molecular dynamics $+$ generator coordinate method ($\mathrm{AMD}+\mathrm{GCM}$) were used.

Results: A number of isoscalar monopole and dipole transitions were observed in the nuclei studied. Using this information, suggested structural assignments have been made for the various excited states. $IS1$ and $IS0$ strengths obtained within QRPA and $\mathrm{AMD}+\mathrm{GCM}$ are compared with the experimental data. The QRPA calculations lead us to conclude that (i) the mean-field vorticity appears mainly in dipole states with $K=1$, (ii) the dipole (monopole) states should have strong deformation-induced octupole (quadrupole) admixtures, and (iii) near the $\alpha$-particle threshold there should exist a collective state with $K=0$ for prolate nuclei and $K=1$ for oblate nuclei, with an impressive octupole strength. The results of the $\mathrm{AMD}+\mathrm{GCM}$ calculations suggest that some observed states may have a mixed (mean-field $+$ cluster) character or correspond to particular cluster configurations.

Conclusion: A tentative correspondence between observed states and theoretical states from QRPA and $\mathrm{AMD}+\mathrm{GCM}$ was established. The QRPA and $\mathrm{AMD}+\mathrm{GCM}$ analysis shows that low-energy isoscalar dipole states combine cluster and mean-field properties. The QRPA calculations show that the low-energy vorticity is well localized in ${}^{24}\mathrm{Mg}$, fragmented in ${}^{26}\mathrm{Mg}$, and absent in ${}^{28}\mathrm{Si}$.

$\alpha$-cluster structures above double shell closures are among the cornerstones for nuclear $\alpha$-cluster physics. Semimicroscopic cluster models (SMCMs) are important theoretical models to study their properties. A crucial ingredient of SMCMs is the effective potential between the alpha cluster and the doubly magic nucleus. We derive new double-folding potentials between $\alpha$ clusters and doubly magic nuclei from soft local chiral nucleon-nucleon potentials given by chiral effective field theory ($\chi \mathrm{EFT}$) at the next-to-next-to-leading order. The $\alpha$-cluster structures in ${}^8\mathrm{Be}, {}^{20}\mathrm{Ne}, {}^{44,52}\mathrm{Ti}$, and ${}^{212}\mathrm{Po}$ are explored to validate these new double-folding potentials. The $\alpha$ decay of ${}^{104}\mathrm{Te}$ is also studied in the light of recent experimental results. Our study shows that double-folding potentials from $\chi \mathrm{EFT}$ are the new reliable effective potentials for the SMCM approach to $\alpha$-cluster structures above double shell closures, with both conceptual and phenomenological merits.

Heavy-ion collisions at low beam energies explore the high density regime of strongly interacting matter. The dynamical evolution of these collisions can be successfully described by hadronic transport approaches. In March 2019, the HADES Collaboration took data for AgAg collisions at $E_{\mathrm{Kin}}=1.58A\mathrm{GeV}$, and in this work we provide predictions for particle production and spectra within the Simulating Many Accelerated Strongly interacting Hadrons (smash) approach. The multiplicities and spectra of strange and nonstrange particles follow the expected trends as a function of system size. In particular, in ArKCl (and $p\mathrm{Nb}$) collisions, much higher yields of double-strange baryons were observed experimentally than expected from a thermal model. Therefore, we incorporate a previously suggested mechanism to produce $\mathrm{\Xi }$ baryons via rare decays of high mass $N^{*}$ resonances and predict the multiplicities. In addition, we predict the invariant mass spectrum for dilepton emission and explore the most important sources of dileptons above 1 GeV, that are expected to indicate the temperature of the medium. Interestingly, the overall dilepton emission is very similar to the one in AuAu collisions at $1.23A\mathrm{GeV}$, a hint that the smaller system at a higher energy behaves very similarly to the larger system at lower beam energy.

Recent astronomical data have provided the primordial deuterium abundance with percent precision. As a result, big bang nucleosynthesis may provide a constraint on the universal baryon to photon ratio that is as precise as, but independent from, analyses of the cosmic microwave background. However, such a constraint requires that the nuclear reaction rates governing the production and destruction of primordial deuterium are sufficiently well known. Here, a new measurement of the ${}^2\mathrm{H}{(p,\gamma )}^3\mathrm{He}$ cross-section is reported. This nuclear reaction dominates the error on the predicted big bang deuterium abundance. A proton beam of 400–1650 keV beam energy was incident on solid titanium deuteride targets, and the emitted $\gamma$ rays were detected in two high-purity germanium detectors at angles of ${55}^{\circ }$ and ${90}^{\circ }$, respectively. The deuterium content of the targets has been obtained in situ by the ${}^2\mathrm{H}({}^3\mathrm{He},p){}^4\mathrm{He}$ reaction and offline using the elastic recoil detection method. The astrophysical $S$ factor has been determined at center of mass energies between 265 and 1094 keV, addressing the uppermost part of the relevant energy range for big bang nucleosynthesis and complementary to ongoing work at lower energies. The new data support a higher $S$ factor at big bang temperatures than previously assumed, reducing the predicted deuterium abundance.

Background: Astrophysical models studying the origin of the neutron-deficient $p$ nuclides require knowledge of the reaction rates of neutron, proton and $\alpha$-proton photodisintegrations of pre-existing neutron-rich $s$ and $r$ nuclei and of proton capture reaction rates. Since experimental data at astrophysically relevant interaction energies are limited, reaction rate calculations rely on the predictions of the Hauser-Feshbach (HF) theory. The HF theory requires nuclear physics input such as masses, level densities, $\gamma$-ray strength functions, and proton-nucleus optical potentials (OMP) describing the average interaction between the $p$ and the nucleus. The proton OMP plays an important role in the description of proton photodisintegrations and radiative capture reactions at low energies relevant to the $p$-process nucleosynthesis.

Purpose: The scope of this work is to improve a global semimicroscopic optical potential for protons at low energies relevant to the $p$-process nucleosynthesis. This is achieved by adjusting the normalization parameters of the OMP to all available radiative proton-capture cross sections measured at energies of astrophysical interest. By establishing the systematic behavior of these parameters, one expects to enhance the predictive power of the proton OMP when expanding to mass regions where no data exist.

Method: The Hauser-Feshbach calculations were obtained using the talys nuclear reaction code. The normalization parameters for the real and imaginary central potentials (${\lambda }_V$ and ${\lambda }_W$) were adjusted to fit the proton data in the energy range where the cross-section calculations are independent of other input parameters, i.e., neutron optical potential, nuclear level density and $\gamma$-ray strength function. As a consequence, the optimization of the proton OMP was done at energies below the opening of the ($p,n$) reaction threshold. The goodness of the fit is based on the $\chi$-square method as well as on visual comparisons.

Results: The results show that the normalization parameter ${\lambda }_V$ of the real part of the proton OMP has a strong mass dependence that can be described by a second degree polynomial function for $A\le 100$ (low mass range) and an exponential increase for $100<A<162$ (intermediate mass range). Though variations of the normalization parameter of the imaginary part ${\lambda }_W$ have a smaller effect on the calculations, a global increase by $50\%$ improves the results for certain nuclei without affecting the rest of the cases.

Conclusions: The resulting adjustment functions were obtained by fitting all suitable proton cross-section data at low energies and can be used with reasonable confidence to generate the global semimicroscopic proton optical potential for nuclei in the medium to heavy mass region. For better statistics, more low-energy proton-capture cross section data are needed for heavier nuclei with mass $A>100$.

The isomeric state in ${}^{213}\mathrm{Th}$ was re-investigated via the reaction ${}^{40}\mathrm{Ar} + {}^{176}\mathrm{Hf}$ at the gas-filled recoil separator Spectrometer for Heavy Atoms and Nuclear Structure. The digital pulse readout technique was employed to record the signals, which enables the feature of dead-time-less data acquisition. Based on the $\mathrm{evaporation}\mathrm{residue}\text{−}\gamma \text{−}\alpha$ correlation analysis, the half-life of $13/2^{+}$ isomer in ${}^{213}\mathrm{Th}$ was measured to be $T_{1/2}=8.30\left(82\right)\mu \mathrm{s}$. The half-life fits in with the systematics of $N=123$ isotones.

We construct an equation of state (EOS) for neutron stars by interpolating hadronic EOS at low density and quark EOS at high density. A hadronic model based on the parity doublet structure is used for hadronic matter and a quark model of Nambu–Jona-Lasinio type is for quark matter. We assume crossover between hadronic matter and quark matter in the color-flavor locked phase. The nucleon mass of the parity doublet model has a mass associated with the chiral symmetry breaking, and a chiral invariant mass $m_0$ which is insensitive to the chiral condensate. The value of $m_0$ affects the nuclear EOSs at low density, and has strong correlations with the radii of neutron stars. Using the constraint to the radius obtained by LIGO-Virgo and NICER, we find that $m_0$ is restricted as $600\mathrm{MeV}\lesssim m_0\lesssim 900\mathrm{MeV}$.

The ${}^{169}\mathrm{Tm}(n,2n){}^{168}\mathrm{Tm}$ and ${}^{169}\mathrm{Tm}(n,3n){}^{167}\mathrm{Tm}$ cross sections have been measured in the neutron energy range between 15 and 21 MeV using the ${}^3\mathrm{H}(d,n){}^4\mathrm{He}$ neutron source reaction. The ${}^{169}\mathrm{Tm}(n,3n){}^{167}\mathrm{Tm}$ data are intended to provide an accurate database for interpreting so-called reaction-in-flight neutron yields, which provide a sensitive tool for studying properties of the deuterium-tritium plasma created in inertial confinement fusion laser shots at the National Ignition Facility at Lawrence Livermore National Laboratory. The data are compared to previous data and evaluations for the reaction studied and are found to be in good agreement with the ENDF/B-VIII.0 evaluation, although small adjustments are necessary for the ${}^{169}\mathrm{Tm}(n,3n){}^{167}\mathrm{Tm}$ reaction. For the first time in any $(n,2n)$ cross-section measurements to date, a comprehensive data set ranging from threshold to 21 MeV has been obtained by the same group.

We calculate the leading-twist helicity-dependent generalized parton distributions (GPDs) of the proton at finite skewness in the Nambu–Jona-Lasinio (NJL) model of quantum chromodynamics (QCD). From these (and previously calculated helicity-independent GPDs) we obtain the spin decomposition of the proton, including predictions for quark intrinsic spin and orbital angular momentum. The inclusion of multiple species of diquarks is found to have a significant effect on the flavor decomposition, and resolving the internal structure of these dynamical diquark correlations proves essential for the mechanical stability of the proton. At a scale of $Q^2=4$ ${\mathrm{GeV}}^2$ we find that the up and down quarks carry an intrinsic spin and orbital angular momentum of $S_u=0.534$, $S_d=-0.214$, $L_u=-0.189$, and $L_d=0.210$, whereas the gluons have a total angular momentum of $J_g=0.151$. The down quark is therefore found to carry almost no total angular momentum due to cancellations between spin and orbital contributions. Comparisons are made between these spin decomposition results and lattice QCD calculations.

The possible conditions for hadron-quark phase transition in hybrid star cores are investigated in the present work. For the hadronic matter part the effective chiral model is adopted. Exotic baryonic degrees like hyperons and the $\mathrm{\Delta }$ baryons are also taken into account. As $\mathrm{\Delta }\mathrm{s}$ possess Breit-Wigner mass distribution ($1232\pm 120$ MeV), the hadronic equation of state is obtained by varying the mass of the $\mathrm{\Delta }$ baryons in this range. For the quark phase the MIT Bag model is chosen with repulsive effects of the unpaired quarks. Phase transition is achieved using Gibbs construction and the gross properties of the resultant hybrid star are calculated in both static and rotating conditions and compared with the various constraints on them from different observational and empirical perspectives. The work presents a thorough study of the phase transition properties like the critical density of the appearance of quarks, the density range for the persistence of the mixed phase, and the population of different hadrons and quarks in hybrid star matter. The hybrid star properties, calculated in both static and rotating conditions, are found to be consistent with the bounds on them from different perspectives.

The extremely neutron-rich system ${}^7\mathrm{H}$ was studied in the direct ${}^2\mathrm{H}({}^8\mathrm{He},{}^3\mathrm{He}){}^7\mathrm{H}$ transfer reaction with a 26 $A\mathrm{MeV}$ secondary ${}^8\mathrm{He}$ beam [Bezbakh et al., Phys. Rev. Lett. 124, 022502 (2020)]. The missing mass spectrum and center-of-mass angular distributions of ${}^7\mathrm{H}$, as well as the momentum distribution of the ${}^3\mathrm{H}$ fragment in the ${}^7\mathrm{H}$ frame, were constructed. In addition, we carried out another experiment with the same beam but a modified setup, which was cross-checked by the study of the ${}^2\mathrm{H}({}^{10}\mathrm{Be},{}^3\mathrm{He}){}^9\mathrm{Li}$ reaction. A solid experimental evidence is provided that two resonant states of ${}^7\mathrm{H}$ are located in its spectrum at 2.2(5) and $5.5\left(3\right)\mathrm{MeV}$ relative to the ${}^3\mathrm{H}+4n$ decay threshold. Also, there are indications that the resonant states at 7.5(3) and $11.0\left(3\right)\mathrm{MeV}$ are present in the measured ${}^7\mathrm{H}$ spectrum. Based on the energy and angular distributions, obtained for the studied ${}^2\mathrm{H}({}^8\mathrm{He},{}^3\mathrm{He}){}^7\mathrm{H}$ reaction, the weakly populated 2.2(5)-MeV peak is ascribed to the ${}^7\mathrm{H}$ ground state. It is highly plausible that the firmly ascertained 5.5(3)-MeV state is the $5/2^{+}$ member of the ${}^7\mathrm{H}$ excitation $5/2^{+}\text{–}3/2^{+}$ doublet, built on the $2^{+}$ configuration of valence neutrons. The supposed 7.5-MeV state can be another member of this doublet, which could not be resolved in Bezbakh et al. [Phys. Rev. Lett. 124, 022502 (2020)]. Consequently, the two doublet members appeared in the spectrum of ${}^7\mathrm{H}$ in the work mentioned above as a single broad 6.5-MeV peak.

A simple universal parametrization of nucleon-induced nonelastic cross sections is presented for a wide range of targets that is valid for the entire energy range from zero to a few gigaelectronvolts. We review several early studies by Letaw et al., Pearlstein, Shen, Niita et al., and Tripathi et al., and our proposed approach differs completely from the formulas therein. The present formula is constructed based on recently discovered physical effects involving Coulomb repulsion and the discrete-level constraint and is based on the assumption that cross sections are continuous in both incident energies and targets. Our formula is given by a set of smooth functions of the mass number, which differs from the best formula to date by Tripathi et al. To compare our formula precisely with that by Tripathi et al., we proposed the relative error index, which indicates the relative error between experimental data and predicted values. For the ${}^{12}\mathrm{C}, {}^{27}\mathrm{Al}, {}^{56}\mathrm{Fe}, {}^{\mathrm{nat}}\mathrm{Ag}, {}^{\mathrm{nat}}\mathrm{Cd}, {}^{\mathrm{nat}}\mathrm{Sn}, {}^{197}\mathrm{Au}$, and ${}^{208}\mathrm{Pb}$ targets used in this paper, the corresponding relative error indices show clearly that our formula is superior to that by Tripathi et al.

We present a calculation of radiative pion photoproduction in the framework of covariant chiral perturbation theory with explicit $\mathrm{\Delta }\left(1232\right)$ degrees of freedom. The analysis is performed employing the small-scale expansion scheme adjusted for the $\mathrm{\Delta }$ region. Depending on the channel, we include contributions up to next-to-next-to-leading order. We fit the available experimental data for the reaction $\gamma p\to \gamma p{\pi }^0$ and extract the value of the ${\mathrm{\Delta }}^{+}$ magnetic moment. Errors from the truncation of the small-scale expansion are estimated using the Bayesian approach. We compare our results both with the previous studies within the $\delta$-expansion scheme and with the $\mathrm{\Delta }$-less theory. We also give predictions for radiative charged-pion photoproduction.