Measurements of the $\beta$ decay correlation coefficients in nuclear decay aim for a precision below $1\%$ and theoretical predictions should follow this trend. In this work, the influence of the two dominant standard model correction terms, i.e., the recoil-order and the radiative correction, are studied for the most commonly measured $\beta$ correlations, i.e., the $\beta$-asymmetry parameter ($A_{\beta }$) and the $\beta \text{−}\nu$ angular correlation ($a_{\beta \nu }$). The recoil-order correction is calculated with the well-known Holstein formalism using the impulse approximation to evaluate experimentally undetermined form factors. For the $\beta \text{−}\nu$ angular correlation previously unpublished, semianalytical radiative correction values are tabulated. Results are presented for the mirror $\beta$ decays up to $A=45$. We examine the effect of both corrections and provide a comparison between different isotopes. This comparison will help planning, analyzing, and comparing future experimental efforts.

To investigate the underlying mechanisms responsible for the enhanced production of new neutron-rich $N\approx 126$ nuclei in the reaction ${}^{238}\mathrm{U}+{}^{198}\mathrm{Pt}$, detailed simulations of the system at an incident energy of 8 MeV/nucleon using the improved quantum molecular dynamics model have been performed. Sequential and massive transfer processes, responsible for the production of targetlike and projectilelike $n$-rich $N\approx 126$ fragments, respectively, have been recognized. Compared to sequential transfer, the contribution from the massive transfer process plays an almost equal role for the production of new nuclei with atomic number $Z\le 76$. The two processes show distinct features in the angular and kinetic energy distributions in the laboratory system and hopefully can be disentangled experimentally.

Systematic examination of fusion for ${}^{39,41,45,47}\mathrm{K}+{}^{28}\mathrm{Si}$ and ${}^{36,44}\mathrm{Ar}+{}^{28}\mathrm{Si}$ provides insight into the impact of neutron and proton exchange on fusion for nuclei at and near the $N=20$ and $N=28$ shells. Comparison of the reduced excitation functions reveals a marked difference between the behavior of open-shell and closed-shell systems. While coupled channels calculations provide a good description for the closed-shell nuclei, they significantly underpredict the fusion cross section for open-shell nuclei. The observed trends are examined in the context of a potential energy surface, including shell effects, and multinucleon exchange with consideration of Pauli blocking.

The $\beta$ decay of ${}^{22,23}\mathrm{Si}$ by emission of delayed charged particles was investigated in an experiment at the Cyclotron Institute of Texas A&M University by means of an optical-readout time-projection chamber. The previously-known decay of the two isotopes by $\beta$-delayed one- and two-proton emission was confirmed. For the first time, a new, rare, decay mode for ${}^{23}\mathrm{Si}$, $\beta$-delayed three-proton emission, was observed and $\beta$-delayed proton-$\alpha$ emission tentatively identified. Moreover, the $\beta$-decay pattern for the ground state of ${}^{23}\mathrm{Si}$ was studied by means of multireference density-functional-rooted calculations.

The $g$ factor of the isomeric $I=9^{+}$ bandhead of the yrast states in ${}^{128}\mathrm{Cs}$ is obtained from the time differential perturbed angular distribution measurement performed with the electromagnet at IPN Orsay. An external magnetic field of 2.146 T at the target position was attained with GAMIPE reaction chamber surrounded by four high-purity germanium detectors, of which two were low-energy photon spectrometer type. The results are in accordance with $\pi h_{11/2}\otimes \nu h_{11/2}^{-1}I=9^{+}$ bandhead assignment and are discussed in the context of chiral interpretation of the ${}^{128}\mathrm{Cs}$ nucleus as a composition of the odd proton, odd neutron, and even-even core with their angular momentum vectors. The obtained $g$-factor value was compared with predictions of the particle-rotor model. The experimental $g$ factor corresponds to the nonchiral geometry of the isomeric bandhead. This observation indicates the existence of the chiral critical frequency in ${}^{128}\mathrm{Cs}$ and may explain the absence of the chiral doublet members for $I<13\hslash$.

The Gamow-Teller (GT) transitions in four magic nuclei, ${}^{48}\mathrm{Ca}, {}^{90}\mathrm{Zr}, {}^{132}\mathrm{Sn}$, and ${}^{208}\mathrm{Pb}$, are studied using a self-consistent Hartree-Fock (HF) plus charge-exchange subtracted second random-phase approximation (SSRPA) model with several Skyrme energy density functions (EDFs). These calculations show that SSRPA improves systematically the description of main GT strength distributions in terms of the excitation energy and the peak height. The quenching factors are evaluated to be 13–20% of the Ikeda sum rule for ${}^{48}\mathrm{Ca}, {}^{90}\mathrm{Zr}$, and ${}^{132}\mathrm{Sn}$, due to the couplings to two-particle–two-hole (2p-2h) configurations. Also examined are the effects of tensor interactions on the excitation energies and the quenching factors of GT strength distributions.

The generation of fission fragment (FF) spins and of their relative orbital angular momentum has been debated for more than six decades, and no consensus has been achieved so far. The interpretation of recent experimental results of Wilson et al., Nature (London) 590, 566 (2021) has been challenged by several recent theoretical studies, which are not in agreement with one another. According to the interpretation by Wilson et al., Nature (London) 590, 566 (2021), the FF spins emerge very long after scission occurrs. Randrup and Vogt Phys. Rev. Lett. 127, 062502 (2021), while agreeing that the FF spins are uncorrelated, conclude on the basis of a phenomenological model that these spins are uncorrelated already before scission. Bulgac et al., Phys. Rev. Lett. 128, 022501 (2022) in a fully microscopic study demonstrate that the primordial FF spin final values are defined before the emission of prompt neutrons and statistical gammas and are strongly correlated with a relative angle between spins close to $2\pi /3$, a result in full agreement with the present independent analysis. The prompt neutrons and statistical gammas carry a significant amount of angular momentum according to the study of Stetcu et al., Phys. Rev. Lett. 127, 222502 (2021), which can lead to a decorrelation of the FF bandhead spins of the yrast lines measured by Wilson et al., Nature (London) 590, 566 (2021), and which also provides arguments why these measured spins are so different from the primordial FF spins evaluated by Bulgac et al., Phys. Rev. Lett. 128, 022501 (2022). Here, I show that the unexpected character of the angular correlation between the primordial FF intrinsic spins, recently evaluated by Bulgac et al., Phys. Rev. Lett. 128, 022501 (2022), which favors FF intrinsic spins pointing predominantly in opposite directions, can be understood by using simple general phase space arguments. The observation by Wilson et al., Nature (London) 590, 566 (2021) that the FF spins are uncorrelated follows from both the results of the microscopic calculation of Bulgac et al., Phys. Rev. Lett. 128, 022501 (2022) and the present analysis of the full correlated probability distribution of the FF spins together with the relative orbital angular momentum of the primordial FFs. These arguments may apply also to heavy-ion collisions and, since there is no use of specifics of the particle interactions, the present results might apply to atomic and molecular systems as well.

Energy dependence of specific heat extracted from temperature fluctuation of Au + Au collisions at $\sqrt{s_{NN}}$ = 7.7 to 200 GeV was investigated by using a multiphase transport (AMPT) model. The results were compared with those from other models and some differences at low $\sqrt{s_{NN}}$ were found. To explain the above differences and describe the properties of the hot dense matter at low $\sqrt{s_{NN}}$, a new quantity $C_v^{*}$ was derived for describing specific heat in heavy-ion collisions. It was found that, by using $C_v^{*}$ together with its high-order moments (skewness and kurtosis), thermal properties of the hot dense matter can be described and different thermal properties with or without parton process can be clearly distinguished. The proposed observable provides a way to learn the property of QCD matter in heavy-ion collisions.

We present a systematic study of $f$-mode oscillations in neutron stars containing hyperons, extending recent results obtained within the Cowling approximation to linearized general relativity. Employing a relativistic mean-field model, we find that the Cowling approximation can overestimate the quadrupolar $f$-mode frequency of neutron stars by up to 30% compared to the frequency obtained in the linearized general relativistic formalism. Imposing current astrophysical constraints, we derive updated empirical relations for gravitational wave asteroseismology. The frequency and damping time of quadrupole $f$-mode oscillations of hyperonic stars are found to be in the range of 1.47–2.45 kHz and 0.13–0.51 s, respectively. Our correlation studies demonstrate that among the various parameters of the nucleonic and hyperonic sectors of the model, the nucleon effective mass shows the strongest correlation with mode characteristics and neutron star observables. Estimates for the detectability of $f$ modes in a transient burst of gravitational waves from isolated hyperonic stars is also provided.

The polarization emerging in the subsequent scattering processes can never exceed 1 which corresponds to the fully polarized pure state. This property is shown to be provided by the addition rule similar to that for relativistic velocities never exceeding the speed of light. The cases of spin ${\displaystyle 1/2}$ and 1 are considered. The photon linear polarization in subsequent Thomson scattering processes is monotonically increasing. This directness is shown to be a consequence of spin measurement procedure and may be the particular example of the anticipated relation between quantum measurement and time irreversibility. The emergent polarization may be considered as a case of the opposing time's arrows corresponding to microscopic (spin) and macroscopic (momentum) degrees of freedom, respectively.

Background: One fascinating frontier in nuclear physics is the study of exotic nuclei. The deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc), which simultaneously includes the nuclear superfluidity, deformation, and continuum effects, can provide proper descriptions for both stable and exotic nuclei. In a previous work [Zhang et al., Phys. Rev. C 102, 024314 (2020)], the DRHBc theory based on the point-coupling density functionals was developed and the DRHBc calculation, previously accessible only for light nuclei, was extended for all even-even nuclei in the nuclear chart. The ground-state properties for the even-even nuclei with $8\le Z\le 120$ from the DRHBc calculations have been summarized [Zhang et al., At. Data Nucl. Data Tables 144, 101488 (2022)].

Purpose: The aim of this paper is to extend the point-coupling DRHBc theory to odd-$A$ and odd-odd nuclei and examine its applicability by taking odd-$A$ Nd isotopes as examples.

Method: In the DRHBc theory, the densities and potentials with axial deformation are expanded in terms of Legendre polynomials, and the relativistic Hartree-Bogoliubov equations are solved in a Dirac Woods-Saxon basis to include the continuum effects. For an odd-$A$ or odd-odd nucleus, the blocking effect of the unpaired nucleon(s) is taken into account with the equal filling approximation. To determine its ground state, an automatic blocking procedure is adopted, in which the orbital with the lowest quasiparticle energy is blocked during the iteration. This procedure is justified by comparing with the results from the orbital-fixed blocking calculations, in which the blocked orbital near the Fermi surface is fixed during the iteration. The ground states for both light and heavy nuclei can be provided by the automatic blocking procedure as the orbital-fixed blocking procedure, but with considerably reduced computational cost.

Results: The numerical details for even-even nuclei, including the convergence on the energy cutoff, angular momentum cutoff, and Legendre expansion, are found to be valid for odd-$A$ and odd-odd nuclei as well. The ground-state properties of odd-$A$ Nd isotopes are calculated with the density functional PC-PK1. The calculated physical observables, such as binding energies, two-neutron and one-neutron separation energies, and charge radii, are in good agreement with the available experimental data for the whole Nd isotopic chain.

Conclusions: The point-coupling DRHBc theory is extended to odd-$A$ and odd-odd nuclei by including the blocking effect. Taking Nd isotopes including both even-even and odd-$A$ ones as examples, the calculated ground-state properties with PC-PK1 are in good agreement with the available experimental data. This paper paves the way to construct the DRHBc mass table including all even-even, odd-$A$, and odd-odd nuclei in the nuclear chart.

When the asymptotic normalization coefficient (ANC) for the ${}^{\mathrm{A}+1}(Z+1)\to {}^{\mathrm{A}}Z+p$ overlap is extracted from data for proton pickup from the ${}^{\mathrm{A}+1}(Z+1)$ nucleus, the value obtained may strongly depend on the degree of completeness of the modeling of the reaction mechanism, particularly when heavy-ion probes are employed. Taking the specific case of the ANC for the ${}^{14}\mathrm{C}\to {}^{13}\mathrm{B}+p$ overlap, an analysis of data for the heavy-ion ${}^{14}\mathrm{C}({}^{11}\mathrm{B},{}^{12}\mathrm{C}){}^{13}\mathrm{B}$ reaction showed that the distorted wave Born approximation (DWBA) yields a significantly larger ANC than the coupled reaction channel (CRC) technique, incorporating multistep reaction paths. In this paper we present an analysis of data from the literature for the light-ion ${}^{14}\mathrm{C}(d,{}^3\mathrm{He}){}^{13}\mathrm{B}$ pickup reaction and show that the ANC extracted from the heavy-ion data using the CRC technique is entirely compatible with the light-ion data when used in either DWBA or more complete coupled discretized continuum channel plus CRC calculations. The present results also show that the ANC extracted from the light-ion reaction is essentially unaffected by multistep reaction paths, in contrast with the heavy-ion case.

We report a measurement of two energy-weighted $\gamma$ cascade angular distributions from polarized slow neutron capture on the ${}^{35}\mathrm{Cl}$ nucleus, one parity-odd correlation proportional to $\overrightarrow{s_n}·\overrightarrow{k_{\gamma }}$ and one parity-even correlation proportional to $\overrightarrow{s_n}·\overrightarrow{k_n}\times \overrightarrow{k_{\gamma }}$. A parity-violating asymmetry can appear in this reaction due to the weak nucleon-nucleon interaction, which mixes opposite parity S- and P-wave levels in the excited compound ${}^{36}\mathrm{Cl}$ nucleus formed upon slow neutron capture. If parity-violating (PV) and parity-conserving (PC) terms both exist, the measured differential cross section can be related to them via $\frac{d\sigma }{d\mathrm{\Omega }}\propto 1+A_{\gamma ,\mathrm{PV}}cos\theta +A_{\gamma ,\mathrm{PC}}sin\theta$. The PV and PC asymmetries for energy-weighted $\gamma$ cascade angular distributions for polarized slow neutron capture on ${}^{35}\mathrm{Cl}$ averaged over the neutron energies from 2.27–9.53 meV were measured to be $A_{\gamma ,\mathrm{PV}}=(-23.9\pm 0.7)\times {10}^{-6}$ and $A_{\gamma ,\mathrm{PC}}=(0.1\pm 0.7)\times {10}^{-6}$. These results are consistent with previous experimental results. Systematic errors were quantified and shown to be small compared to the statistical error. These asymmetries in the angular distributions of the $\gamma$ rays emitted from the capture of polarized neutrons in ${}^{35}\mathrm{Cl}$ were used to verify the operation and data analysis procedures for the NPDGamma experiment, which measured the parity-odd asymmetry in the angular distribution of $\gamma$s from polarized slow neutron capture on protons.

We calculate the deuteron charge, electric quadrupole, and magnetic form factors up to next-to-next-to-leading order in chiral effective field theory, treating subleading corrections, especially that of chiral nuclear forces, in perturbation theory. We examine the power counting based on naive dimensional analysis by investigating the ultraviolet cutoff variation of these form factors. We find that the ${\mathrm{N}}^2\mathrm{LO}$ magnetic form factor shows significant cutoff dependence, suggesting the contact current operator responsible be enhanced. After promotion to ${\mathrm{N}}^2\mathrm{LO}$, it indeed renormalizes the magnetic form factor. This is in agreement with a previous work based on renormalization-group analysis. For the charge and quadrupole moments, perturbative calculation allows us to study how they scale with multiple low-energy parameters such as the pion mass, deuteron binding momentum, and momentum transfer.

Small nuclear collisions are mainly sensitive to cold-nuclear-matter effects; however, the collective behavior observed in these collisions shows a hint of hot-nuclear-matter effects. The identified-particle spectra, especially the $\varphi$ mesons which contain strange and antistrange quarks and have a relatively small hadronic-interaction cross section, are a good tool to study these effects. The PHENIX experiment has measured $\varphi$ mesons in a specific set of small collision systems $p+\mathrm{Al}$, $p+\mathrm{Au}$, and ${}^3\mathrm{He}+\mathrm{Au}$, as well as $d+\mathrm{Au}$ [Adare et al., Phys. Rev. C 83, 024909 (2011)], at $\sqrt{s_{{}_{NN}}}=200$ GeV. The transverse-momentum spectra and nuclear-modification factors are presented and compared to theoretical-model predictions. The comparisons with different calculations suggest that quark-gluon plasma may be formed in these small collision systems at $\sqrt{s_{{}_{NN}}}=200$ GeV. However, the volume and the lifetime of the produced medium may be insufficient for observing strangeness-enhancement and jet-quenching effects. The comparison with calculations suggests that the main production mechanisms of $\varphi$ mesons at midrapidity may be different in $p+\mathrm{Al}$ versus $p/d/{}^3\mathrm{He}+\mathrm{Au}$ collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV. While thermal quark recombination seems to dominate in $p/d/{}^3\mathrm{He}+\mathrm{Au}$ collisions, fragmentation seems to be the main production mechanism in $p+\mathrm{Al}$ collisions.

Lattice QCD simulations have shown unequivocally that the transition from hadrons to quarks and gluons is a crossover when the baryon chemical potential is zero or small. Many model calculations predict the existence of a critical point at a value of the chemical potential where current lattice simulations are unreliable. We show how to embed a critical point in a smooth background equation of state so as to yield the critical exponents and critical amplitude ratios expected of a transition in the same universality class as the liquid-gas phase transition and the three-dimensional Ising model. There are only two independent critical exponents; the relations $\alpha +2\beta +\gamma =2$ and $\beta (\delta -1)=\gamma$ arise automatically, as does a relation between the two critical amplitudes. The resulting equation of state has parameters that may be inferred by hydrodynamic modeling of heavy-ion collisions in the Beam Energy Scan II at the BNL Relativistic Heavy Ion Collider or in experiments at other accelerators.

Experimental data of charged current inclusive neutrino cross sections on argon as a function of different variables have recently appeared. We have compared them to our theoretical approach. Overall we find an agreement in spite of a tendency of underestimation in some specific regions. A new aspect is the availability of data in terms of the energy transfer to the nucleus, which allows a better separation of the different reaction mechanisms. We explain the deterioration of agreement in specific kinematical conditions by the absence in our model of two-pion production and other inelastic channels, more important for MicroBooNE than for T2K.

A method to describe spectra starting from nuclear density functionals is explored. The idea is based on postulating an effective Hamiltonian that reproduces the stiffness associated with collective modes. The method defines a simple form of such an effective Hamiltonian and a mapping to go from a density functional to the corresponding Hamiltonian. In order to test the method, the Hamiltonian is constrained using a Skyrme functional and solved with the generator-coordinate method to describe low-lying levels and electromagnetic transitions in ${}^{48,49,50,52}\mathrm{Cr}$ and ${}^{24}\mathrm{Mg}$.

We use chiral interactions and several ab initio methods to compute the nuclear matrix elements (NMEs) for ground-state-to-ground-state double Gamow-Teller transitions in a range of isotopes and explore the correlation of these NMEs with those for neutrinoless double beta decay produced by the exchange of a light Majorana neutrino. When all the NMEs of both isospin-conserving and isospin-changing transitions from the ab initio calculations are considered, the correlation is strong. For the experimentally relevant isospin-changing transitions by themselves, however, the correlation is weaker and may not be helpful for reducing the uncertainty in the NMEs for neutrinoless double beta decay.