Background: Among the several inhomogeneities in the composition of globular cluster stars, an overabundance of ${}^{23}\mathrm{Na}$ is interpreted as the signature of the operation of the neon-sodium (NeNa) cycle. One of the hypothesis to explain the observed O-Na anticorrelation invokes massive asymptotic giant branch stars as the main agents. At temperatures relevant for nucleosynthesis in asymptotic giant branch stars the ${}^{22}\mathrm{Ne}(p,\gamma ){}^{23}\mathrm{Na}$ reaction rate has been the most uncertain so far, giving rise to considerable experimental efforts in recent years. While overall there is a good agreement between reported cross section results, some tensions still remain on the branching ratios of resonance $\gamma$-ray modes and direct capture to excited sates.

Purpose: The present paper offers full details and a partial analysis of the high sensitivity study, of both direct capture and low-energy resonances in the ${}^{22}\mathrm{Ne}(p,\gamma ){}^{23}\mathrm{Na}$ reaction, performed at LUNA, and whose results were previously published in abbreviated form [F. Ferraro et al., Phys. Rev. Lett. 121, 172701 (2018)].

Methods: During the LUNA measurement an intense proton beam was delivered to a ${}^{22}\mathrm{Ne}$ gas target. The $\gamma$ rays from the ${}^{22}\mathrm{Ne}(p,\gamma ){}^{23}\mathrm{Na}$ reaction were detected by a high efficiency $4\pi$, sixfold segmented bismuth germanate (BGO) detector. In the present paper the data from individual detector segments were combined with simulated detector responses to obtain cascade branching ratios.

Results: For the three resonances at $E_p=156.2$ and 259.7 keV new $\gamma$-decay branchings are provided. Moreover, partial cross sections for the direct capture to different states of ${}^{23}\mathrm{Na}$ are reported down to $E_p=188\mathrm{keV}$, the lowest energy measured to date.

Conclusions: A revised reaction rate has been calculated based on a new $R$-matrix fit of the recent ${}^{22}\mathrm{Ne}(p,\gamma ){}^{23}\mathrm{Na} S$-factor data and results for the resonances. The thermonuclear reaction rate is provided in tabular form to be used in stellar models.

We present an approach to describe the fusion of two heavy ions in which the colliding system has access to a wide spectrum of shapes through the utilization of an auxiliary reference frame and the employment of a multipole expansion of the nuclear radius with the dipole term treated as an actual and leading shape variable. Access to fusion shapes that would otherwise be unattainable is possible by initially placing the origin of the auxiliary reference frame in the neck region between the colliding nuclei. The fusion process is modeled as an unconstrained biased random walk in a four-dimensional deformation space with step probabilities correlated to the density of available states. Deformation energy is calculated using the macroscopic-microscopic method, incorporating rotational energy. The presented approach successfully describes fusion probabilities for reactions involving ${}^{48}\mathrm{Ca}, {}^{50}\mathrm{Ti}$, and ${}^{54}\mathrm{Cr}$ projectiles with a ${}^{208}\mathrm{Pb}$ target.

The quasielastic barrier distribution ($D_{\mathrm{qe}}$) of the ${}^{20}\mathrm{Ne} +{}^{208}\mathrm{Pb}$ system exhibits a single broad structureless peak, unlike the results of coupled-channels calculations, including the strongest collective states of both projectile and target, which show a pronounced double-peaked structure. Separate measurements of the transfer strength, combined with the relatively small number of weak noncollective states in ${}^{208}\mathrm{Pb}$, suggested that the observed barrier smoothing in this system could be due to the influence of couplings to transfer reactions. The coupled reaction channels (CRC) calculations performed by explicitly coupling to the two strongest transfer partitions, one-neutron pickup and one-proton stripping, suggest that the cumulative effect of coupling to many relatively weak transfer channels is responsible for the barrier smoothing rather than a few strong transfer reactions. In this perspective, the four main transfer channels (one- and two-neutron pickup and one-proton and one-alpha stripping) of the ${}^{20}\mathrm{Ne} +{}^{208}\mathrm{Pb}$ system were coupled to the collective excitations by employing an upgraded ccqel code, where we introduced the dependence of the transfer coupling strength on the transferred particle and experimental $Q$-value distributions. Because of the availability of $Q$ distributions measured at the two beam energies of 96 and 103 MeV, two sets of transfer coupling strength were determined for each transfer channel. The study with the upgraded code indicates transfers with negative ground-to-ground states $Q$ value as the leading cause of the smearing of the barrier distribution. At the beam energy of 103 MeV, the smoothing of $D_{\mathrm{qe}}$ is influenced mainly by the one-neutron pickup. On the other hand, the one-neutron pickup and one-proton stripping transfers are dominant for the beam energy of 96 MeV. These results highlight the importance of the transfer coupling dependence on the experimental $Q$-value distribution and, consequently, on the dissipation of the projectile kinetic energy.

The difference between the spin alignments of $K^{*}$ and those of $\varphi$ at low collision energies is a puzzle raised by the recent experiments. Unlike the $\varphi$ meson, $K^{*}$, carrying a unit strange charge, should react to strange chemical potential ${\mu }_S$. In this paper, I shall first show that ${\mu }_S$ is not small in a baryon-rich medium for keeping strange neutrality, and then derive the spin alignment induced by the gradient of ${\mu }_S$ using linear response theory, with the transport coefficients expressed, without any approximation, in terms of the $K^{*}$'s in-medium spectral properties by employing the Ward-Takahashi identity. It turns out that such an effect applies mainly to the particles whose longitudinal and transverse modes diverge, and induces only the local spin alignment in a static medium. The magnitudes of these coefficients will be further estimated using the quasiparticle approximation.

Modifications of large transverse momentum single-hadron, dihadron, and $\gamma$-hadron spectra in relativistic heavy-ion collisions are direct consequences of parton-medium interactions in the quark-gluon plasma (QGP). The interaction strength and underlying dynamics can be quantified by the jet transport coefficient $\widehat{q}$. We carry out the first global constraint on $\widehat{q}$ using a next-to-leading order pQCD parton model with higher-twist parton energy loss and combining world experimental data on single-hadron, dihadron, and $\gamma$-hadron suppression at both RHIC and LHC energies with a wide range of centralities. The global Bayesian analysis using the information field (IF) priors provides the most stringent constraint on $\widehat{q}\left(T\right)$. We demonstrate in particular the progressive constraining power of the IF Bayesian analysis on the strong temperature dependence of $\widehat{q}$ using data from different centralities and colliding energies. We also discuss the advantage of using both inclusive and correlation observables with different geometric biases. As a verification, the obtained $\widehat{q}\left(T\right)$ is shown to describe data on single-hadron anisotropy at high transverse momentum well. Predictions for future jet quenching measurements in oxygen-oxygen collisions are also provided.

The novel technique of frequency-offset separated oscillatory fields (FOSOF) was originally proposed as a modification to Ramsey's method of separated oscillatory fields. It has recently been employed in precision measurements with atomic beams since it allows for an alternative approach to determine absolute resonance frequencies. We present results from a systematic investigation of the FOSOF technique adapted to a beam of cold neutrons.

We propose a hybrid quantum-classical framework to solve the elastic-scattering phase shift of two well-bound nuclei in an uncoupled channel. Within this framework, we develop a many-body formalism in which the continuum scattering states of the two colliding nuclei are regulated by a weak external harmonic-oscillator potential with varying strength. Based on our formalism, we propose an approach to compute the eigenenergies of the low-lying scattering states of the relative motion of the colliding nuclei as a function of the oscillator strength of the confining potential. Utilizing the modified effective range expansion, we extrapolate the elastic-scattering phase shift of the colliding nuclei from these eigenenergies to the limit when the external potential vanishes. In our hybrid approach, we leverage the advantage of quantum computing to solve for these eigenenergies from a set of many-nucleon Hamiltonian eigenvalue problems. These eigenenergies are inputs to classical computers to obtain the phase shift. We demonstrate our framework with two simple problems, where we implement the rodeo algorithm to solve the relevant eigenenergies with the IBM Qiskit quantum simulator. The results of both the spectra and the elastic-scattering phase shifts agree well with other theoretical results.

Fission processes of the excited compound nuclei ${}^{197}\mathrm{Tl}, {}^{217}\mathrm{Fr}, {}^{224}\mathrm{Th}$, and ${}^{254}\mathrm{Fm}$ in a wide range of mass numbers produced in fusion reactions have been simulated in the framework of the modified statistical model and different observables were reproduced for these nuclei. In the statistical calculations have been considered the effects of the projection of the total spin of the compound nucleus onto the symmetry axis $K$, the temperature dependence of the location and height of fission transition points, and the classical collective motion of the excited compound nuclei about the ground state. Furthermore, in the present research, particle binding energies as a function of deformation of nuclei and subbarrier fission have been considered for more accurate reproduction of the experimental data. The fission cross section, the evaporation residue cross section, the fission probability, the average prescission neutron multiplicity, and the anisotropy of fission fragments’ angular distribution have been calculated for the excited compound nuclei ${}^{197}\mathrm{Tl}, {}^{217}\mathrm{Fr}, {}^{224}\mathrm{Th}$, and ${}^{254}\mathrm{Fm}$. In the statistical simulations, the scaling factor of the fission barrier height, $r_s$, and the temperature coefficient of the effective potential, $k$, were considered as a free parameter. For each reaction the parameters $r_s$ and $k$ were adjusted to reproduce a single fission cross section and a single evaporation residue cross section. It was shown that the results of calculations are in good agreement with the experimental data by using appropriate values for these parameters equal to $k=0.0182\pm 0.0050\mathrm{Me}{\mathrm{V}}^{-2}$ and $r_s=1.0005\pm 0.0020$ for ${}^{197}\mathrm{Tl}$; $k=0.0063\pm 0.0040\mathrm{Me}{\mathrm{V}}^{-2}$ and $r_s=1.0042\pm 0.0015$ for ${}^{217}\mathrm{Fr}$; $k=0.0060\pm 0.0040\mathrm{Me}{\mathrm{V}}^{-2}$ and $r_s=1.0050\pm 0.0020$ for ${}^{224}\mathrm{Th}$; $k=0.0025\pm 0.0015\mathrm{Me}{\mathrm{V}}^{-2}$ and $r_s=1.0100\pm 0.0014$ for ${}^{254}\mathrm{Fm}$. Furthermore, by using appropriate values of parameters $k$ and $r_s$ I have calculated the average prescission neutron multiplicity, the fission probability, and the anisotropy of fission fragments’ angular distribution for the compound nuclei ${}^{197}\mathrm{Tl}, {}^{217}\mathrm{Fr}, {}^{224}\mathrm{Th}$, and ${}^{254}\mathrm{Fm}$. It was shown that the modified statistical model is well able to reproduce different experimental data, although at high excitation energies the results of calculations for the neutron multiplicity and the anisotropy of fission fragments’ angular distribution are slightly lower than the experimental data. It was also shown that, at high excitation energy, for reproducing the neutron multiplicity one needs to increase the nuclear dissipation. Finally, from the comparison of the extracted results of parameters $k$ and $r_s$ for the compound nuclei ${}^{197}\mathrm{Tl}, {}^{217}\mathrm{Fr}, {}^{224}\mathrm{Th}$, and ${}^{254}\mathrm{Fm}$, it was shown that the parameter $k$ decreases and the parameter $r_s$ increases with increasing mass number of the compound nucleus.

Quantum fluctuations plays an essential role in forming the collective flow of hadrons observed in relativistic heavy-ion collisions. Event-by-event fluctuations of the collective flow can arise from various sources, such as the fluctuations in the initial geometry, hydrodynamic expansion, hadronization, and hadronic evolution of the nuclear matter, while the exact contribution from each source is still an open question. Using a ($3+\mathrm{1}$)-dimensional relativistic hydrodynamic model coupled to a Monte Carlo Glauber initial condition, Cooper-Frye particlization and a hadronic transport model, we explore the system-size and shape dependencies of the collective-flow fluctuations in $\mathrm{Au}+\mathrm{Au}, \mathrm{Cu}+\mathrm{Au}$, and $\mathrm{O}+\mathrm{O}$ collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV. The particle yields, mean transverse momenta, two-particle and four-particle cumulant elliptic flows ($v_2\left\{2\right\}$ and $v_2\left\{4\right\}$) from our calculation agree with the currently existing data from RHIC. Different centrality dependencies of the flow fluctuations, quantified by the $v_2\left\{4\right\}/v_2\left\{2\right\}$ ratio, are found for different collision systems due to their different sizes and shapes. By comparing $v_2\left\{4\right\}/v_2\left\{2\right\}$ between different hadron species, and comparing $v_2\left\{4\right\}/v_2\left\{2\right\}$ to the initial state geometric fluctuations quantified by the cumulant eccentricity ratio ${\varepsilon }_2\left\{4\right\}/{\varepsilon }_2\left\{2\right\}$, we find that while the initial state fluctuations are the main source of the $v_2$ fluctuations in large collision systems, other sources like nonlinear hydrodynamic response, hadronization, and hadronic afterburner can significantly affect the $v_2$ fluctuations in small systems.

We examine the possible existence of quadrupole resonances in exotic atoms containing odd-$A$ nuclei. We find that the spin flip of the deexciting exotic particle can induce a resonance, altering the orbital angular momentum of the nucleus by one quantum. This process results in an excited nucleus with a suppression in x-ray photon emissions during the exotic atom cascade. We provide specific cases of antiprotonic atoms of stable elements where this resonance effect is expected to occur. The study of this phenomena may provide insight into the strong interaction of deeply bound antiprotonic states in the proximity of the unpaired nucleon, and serve as a tool for probing short-lived excited nuclear states.

A detailed $\beta$-decay study of the low- and high-spin states in ${}^{216}\mathrm{Bi}$ has been performed at the ISOLDE Decay Station at the CERN-ISOLDE facility. In total, 48 new levels and 83 new transitions in the $\beta$-decay daughter ${}^{216}\mathrm{Po}$ were identified. Shell-model calculations for excited states in ${}^{216}\mathrm{Bi}$ and ${}^{216}\mathrm{Po}$ were performed using the H208 and the modified Kuo-Herling particle effective interactions. Based on the experimental observations and the shell-model calculations, the most likely spin and parity assignments for the $\beta$-decaying states in ${}^{216}\mathrm{Bi}$ are $\left(3^{-}\right)$ and $\left(8^{-}\right)$, respectively.

In this work, I present the first, to my knowledge, theoretical description of two-proton removal reactions with proton target $(p,3p)$ for medium-mass nuclei at intermediate energies and present cross sections for the different bound states of the residual nucleus with two fewer protons. The description of the reaction assumes two sequential “quasifree” collisions between the target and removed protons and considers eikonal propagation in between. The formalism is applied to the reactions ${}^{12}\mathrm{C}(p,3p){}^{10}\mathrm{Be}, {}^{28}\mathrm{Mg}(p,3p){}^{26}\mathrm{Ne}$, and ${}^{54}\mathrm{Ca}(p,3p){}^{52}\mathrm{Ar}$, finding reasonable agreement to experimental data for the ${}^{12}\mathrm{C}$ target and an overestimation of a factor $\approx 3$ for the more neutron-rich and ${}^{54}\mathrm{Ca}$, which is similar to the results found in two-proton knockout experiments with ${}^9\mathrm{Be}$ and ${}^{12}\mathrm{C}$ targets.

High-precision cosmic-ray (CR) data from ongoing and recent past experiments (Voyager, ACE-CRIS, PAMELA, ATIC, CREAM, NUCLEON, AMS-02, CALET, DAMPE) are being released in the tens of the MeV/$n$ to multi-TeV/$n$ energy range. Astrophysical and dark matter interpretations of these data are limited by the precision of nuclear production cross sections. In Paper I [Phys. Rev. C 98, 034611 (2018)], we set up a procedure to rank nuclear reactions whose desired measurements will enable us to fully exploit currently available data on CR Li to N ($Z=3$–7) species. Here we extend these rankings to O up to Si nuclei ($Z=8$–14), also updating our results on the LiBeB species. We also highlight how comprehensive new high-precision nuclear data that could, e.g., be obtained at the Super Proton Synchrotron at CERN would be a game changer for the determination of key astrophysical quantities (diffusion coefficient, halo size of the Galaxy) and indirect searches for dark matter signatures.

The recent discovery of a central compact object (CCO) within the supernova remnant HESS J1731-347, characterized by a mass of approximately $0.{77}_{-0.17}^{+0.20} M_{\odot }$ and a radius of about $10.4_{-0.78}^{+0.86}$ km, has opened up a new window for the study of compact objects. This CCO is particularly intriguing because it is the lightest and smallest compact object ever observed, raising questions and challenging the existing theories. To account for this light compact star, a mean-field model within the framework of the parity doublet structure is applied to describe the hadron matter. Inside the model, part of the nucleon mass is associated with the chiral symmetry breaking while the other part is from the chiral invariant mass $m_0$ which is insensitive to the temperature and density. The value of $m_0$ affects the nuclear equation of state for uniform nuclear matter at low density and exhibits strong correlations with the radii of neutron stars. We point out that HESS J1731-347 can be explained as the lightest neutron star for $m_0\simeq 850$ MeV.

Brillouin-Wigner (BW) perturbation theory is developed for both ground and excited states of open-shell nuclei. We show that with optimal partitioning of the many-body Hamiltonian proposed earlier by the authors [Z. Li and N. A. Smirnova, Phys. Lett. B 854, 138749 (2024)], one can redefine the BW perturbation series for a given state of the effective Hamiltonian in a small $\mathbb{P}$ space to be converging under the condition that the energy of this state is below the lowest eigenvalue of the Hamiltonian matrix block belonging to the complement of the $\mathbb{P}$ space, characterized by the same good quantum numbers as the state under consideration. Specifically, the BW perturbative calculations for the lowest $J^{\pi }$ states are always converging due to the variational principle. This property does hold for both soft and hard internucleon interactions in the harmonic oscillator basis. To illustrate this method and check the convergence behavior, we present numerical studies of low-energy spectra of ${}^{5,6,7}\mathrm{Li}$ using the Daejeon16 and bare ${\mathrm{N}}^3\mathrm{LO}$ potentials.

We investigate the ${\beta }^{-}$-decay properties of $N=125$ and $N=126$ isotones with $Z=52–79$ through large-scale shell model calculations, considering both Gamow-Teller and first-forbidden transitions. We observed that the distributions of GT strength exhibit a prominent peak at lower excitation energies, making a substantial contribution to the resulting half-lives. This peak, dominated by the $\nu 0h_{9/2}\to \pi 0h_{11/2}$ transition, is enhanced on the proton-deficient side because the Pauli-blocking effect caused by the occupying the valence proton $0h_{11/2}$ orbit is weakened. It is also observed that the contributions of first-forbidden transitions are diminished with a decrease in proton number from $Z=82$.

Background: The excitation energy dependence of the fission fragment mass distributions for heavy ion-induced reactions on preactinides targets well above the Coulomb barrier energies has received limited attention due to the lack of data. An extensive study is required to understand the reaction mechanism at high excitation energy as it bridges our understanding of the mechanism of fission and noncompound nuclear reactions.

Purpose: The purpose was to understand the fusion-fission dynamics well above the Coulomb barrier energies, particularly to address if the theoretical models that are valid near the Coulomb barrier can explain the fission data at high excitation energies.

Methods: In the experiment, a pulsed heavy-ion beam from the cyclotron was utilized, and the resulting binary fragments were detected using two position-sensitive multiwire proportional counters. By analyzing the time-of-flight differences and position information ($\theta ,\varphi$) of the binary fragments, mass distributions were obtained for the reactions ${}^{16}\mathrm{O} + {}^{181}\mathrm{Ta}, {}^{197}\mathrm{Au}, {}^{205}\mathrm{Tl}$, and ${}^{208}\mathrm{Pb}$.

Results: The variance of the fission fragment mass distributions exhibits a smooth increase with excitation energy, although values are smaller compared to the predicted values of the semiempirical calculation GEF. The measured variation of the variance of the mass distribution with the fissility showed an exponential increase. The contribution of fast fission have been identified at high energies with mass asymmetry value $\approx 0.22$.

Conclusion: Our systematic measurements over a wide range of excitation energy and target mass indicate that the fission fragment mass distributions are consistent with statistical models up to $\approx 2$ times the Coulomb barrier energies for the pre-actinides target nuclei when bombarded with ${}^{16}\mathrm{O}$. The result provides benchmark data to test the new reaction models at high excitation energies.

The experimental data from quasielastic electron and (anti)neutrino scattering on ${}^{12}\mathrm{C}$ are reanalyzed in terms of a new scaling variable ${\psi }^{*}$ suggested by the interacting relativistic Fermi gas with scalar and vector interactions, which is known to generate a relativistic effective mass for the interacting nucleons. We construct a new scaling function $f^{\text{QE}}\left({\psi }^{*}\right)$ for the inclusive lepton scattering from nuclei within the coherent density fluctuation model (CDFM). The latter is a natural extension of the relativistic Fermi gas model to finite nuclei. In this work, on the basis of the scaling function obtained within CDFM with a relativistic effective mass $m_N^{*}=0.8m_N$, we calculate and compare the theoretical predictions with a large set of experimental data for inclusive ($e,e^{\prime }$) and (anti)neutrino cross sections. The model also includes the contribution of weak two-body currents in the two-particle two-hole sector, evaluated within a fully relativistic Fermi gas. Good agreement with experimental data is found over the whole range of electron and (anti)neutrino energies.

Machine learning methods have recently gained interest in the complexity of nuclear mass prediction. According to previous studies, we propose a continuous Bayesian probability (CBP) classifier combined with Bayesian model averaging (BMA) to refine the descriptions of sophisticated nuclear mass models. In the CBP method, the nuclear masses are considered continuous variables to generate prior and conditional probability density functions (PDFs), and the posterior PDFs are determined by the Bayesian formula. The global optimizations and the extrapolating analyses exhibit impressive improvements. Additionally, we employ the BMA method to consider the predictions of different models by assigning weights based on their predictive effectiveness for seven benchmark nuclei. By presenting predictions of the neutron drip line, we assess the reliability of the refinements of the BMA method. The methods proposed in this paper provide an effective way of predicting the nuclear mass in unknown regions and can be applied to other model-based extrapolations of nuclear properties.