We investigate the properties of equation of state, the quark fraction, the isospin chemical potential, and the entropy per baryon of strange quark matter at finite temperature under constant magnetic field within the quasiparticle model. We find that both the effects of temperature and magnetic field can significantly influence the thermodynamical properties of quark matter. Our result also indicates that the maximum mass of protoquark stars (PQSs) increases with the heating process along the star evolution, and the core temperature of the maximum mass of PQSs depends on the different snapshots by considering the isentropic stages along the star evolution line.

The article of Pastore et al., whereas proposing an interesting and potentially useful approach for the generalization of quantum Monte Carlo techniques to the treatment of the nuclear electromagnetic response, features an incorrect and misleading discussion of $y$ scaling. The response to interactions with transversely polarized virtual photons receives sizable contributions from nonscaling processes in which the momentum transfer is shared between two nucleons. It follows that, contrary to what is stated by the the authors, $y$ scaling in the transverse channel is accidental.

We briefly review the concept of scaling and how it occurs in quasielastic electron and neutrino scattering from nuclei, and then the particular approach to scaling in the short-time approximation. We show that, whereas two-nucleon currents do significantly enhance the transverse electromagnetic response, they do not spoil scaling, but, in fact, enhance it. We provide scaling results obtained in the short-time approximation that verify this claim. The enhanced scaling, although obtained empirically, is not “accidental”—as claimed in [O. Benhar, Phys. Rev. C 105, 049801 (2022)]—but rather reflects quasielastic kinematics and the dominant role played by pion-exchange interactions and currents in the quasielastic regime.

Three new negative-parity bands have been identified in ${}^{120}\mathrm{Ba}$, two of them forming a strongly coupled band. The previously known negative-parity band is significantly extended to high spin, while the lower part of the yrare positive-parity band has been modified. From the analysis of the band properties and comparison with the neighboring nuclei a coherent description of all bands is achieved. In particular, a simple explanation of the evolution of the positive-parity bands at high spin is proposed, including the possible occupation of the $\nu f_{7/2}\left[541\right]1/2^{-}$ intruder orbital. Cranked Nilsson-Strutinsky calculations reveal similar quadrupole deformations but different triaxiality of the bands, while particle number conserving cranked shell model calculations qualitatively reproduce the experimental data and support the assigned configurations. The new measured ratios of reduced transition probabilities $B\left(E1\right)/B\left(E2\right)$ complete the systematics in the ${}^{118–124}\mathrm{Ba}$ nuclei, exhibiting a decrease with decreasing neutron number, and are compared with the known values in the ${}^{116–120}\mathrm{Xe}$ nuclei, which are larger. Extended calculations with the quadrupole and octupole collective Hamiltonian based on the relativistic Hartree-Bogoliubov model employing the relativistic DD-PC1 density functional nicely reproduce the decreasing trend towards lower neutron numbers for Ba and Xe nuclei, as well as the larger values in Xe nuclei, but are much larger in amplitude than the experimental values. On the other hand, particle number conserving cranked shell model calculations without octupole deformation overestimate the low-spin values, while those with octupole deformation included reproduce the experimental values in ${}^{120}\mathrm{Ba}$, suggesting the possible existence of moderate octupole collectivity in the negative-parity bands of nuclei in this mass region.

Realistic nuclear level densities (NLDs) obtained within the spectral distribution method (SDM) are employed to study nuclear processes of astrophysical interest. The merit of SDM lies in the fact that the NLDs corresponding to many-body shell-model Hamiltonians consisting of residual interaction can be obtained for the full configurational space without recourse to the exact diagnolization of huge matrices. We calculate NLDs and $s$-wave neutron resonance spacings which agree reasonably well with the available experimental data. By employing these NLDs, we compute reaction cross sections and astrophysical reaction rates for radiative neutron capture in few Fe-group nuclei and compare them with experimental data as well as with those obtained with NLDs from phenomenological and microscopic mean-field models. The results obtained for the NLDs from SDM are able to explain the experimental data quite well. These results are of particular importance since the configuration mixing through the residual interaction naturally accounts for the collective excitations. In the mean-field models, the collective effects are included through the vibrational and rotational enhancement factors, and their NLDs are further normalized at low energies with neutron resonance data.

The characterization of fission-driven nuclear systems primarily relies on calculations of neutron-induced chain reactions, and these calculations require evaluated nuclear data as input. Calculation accuracy heavily depends on input nuclear data evaluation accuracy, and thus high precision on the experimental input to the nuclear data evaluation is essential for fundamental quantities like the energy spectrum of neutrons emitted from neutron-induced fission (i.e., the prompt fission neutron spectrum, PFNS). Despite decades of measurement efforts, prior to the measurements described in this work there were only three literature data sets for the ${}^{235}\mathrm{U}(n,f)$ PFNS at incident neutron energies above 1.0 MeV considered reliable for inclusion in nuclear data evaluations and no reliable data sets above 3.0 MeV incident neutron energy. In this work we report on new measurements of the ${}^{235}\mathrm{U}(n,f)$ PFNS spanning a grid of 1.0–20.0 MeV in incident neutron energy and 0.01–10.0 MeV in outgoing (PFNS) neutron energy. These measurements were carried out at the Weapons Neutron Research facility at the Los Alamos Neutron Science Center and used a multifoil parallel-plate avalanche counter target with both a Li-glass and a liquid scintillator detector array in separate experiments to span the quoted outgoing neutron energy ranges. The PFNS results are shown in terms of the energy spectra themselves as well as the average PFNS energy ($\langle E\rangle$) and ratios of $\langle E\rangle$ at forward and backward angles. The results are compared with literature data and selected nuclear data evaluations. Generally, the data agree with the ENDF/B-VIII.0 evaluation below 5.0-MeV incident neutron energy and more closely with the JEFF-3.3 evaluation above 5.0 MeV, though no evaluations considered for comparison in this work agree with the data across all of the incident and outgoing neutron energies shown, especially in regions where the third-chance fission process becomes available. Additionally, we show a ratio of the present PFNS results for ${}^{235}\mathrm{U}(n,f)$ with a recent and highly correlated experiment to measure the ${}^{239}\mathrm{Pu}(n,f)$ PFNS at the same experimental facility and with nearly identical equipment and analysis procedures. Many observations reported in this work are the first of their kind and represent significant advancements for knowledge of the ${}^{235}\mathrm{U}(n,f)$ PFNS.

A recently developed formalism is used to carry out generator coordinate method calculations using a set of Hartree-Fock-Bogoliubov wave functions, where each of the members of the set can be expanded in an arbitrary basis. In this paper it is assumed that the HFB wave functions are expanded in harmonic oscillator (HO) bases with different oscillator lengths. General expressions to compute the required matrix elements of arbitrary operators are given. The application of the present formalism to the case of fission is illustrated with an example.

Self-consistent solutions for the chiral rotation in the rhodium isotopes ${}^{102–107}\mathrm{Rh}$ are obtained within the three-dimensional tilted axis cranking covariant density functional theory. The orientation of angular momenta is determined self-consistently by minimizing the total Routhian surface calculations with respect to the azimuth angle $\phi$ and polar angle $\theta$ for a given rotational frequency. It is found that when neutrons are added the critical rotational frequency ${\omega }_{\text{crit}}$ of the appearance of chiral aplanar rotation decreases, which can be attributed to the neutrons in $\left(gd\right)$ shells having smaller and larger angular momentum components along the short and medium axes, respectively. The theoretical results agree well with the experimental energy spectra, electromagnetic transition probabilities, as well as the kinetic and dynamic moments of inertia.

Background: Shell effects have been found to influence both the compound nuclear fission (CNF) and quasifission processes. Besides quasifission processes, which fission modes remain active at excitation energy ($E^{*}$) as high as 56 MeV should be investigated.

Purpose: We investigate the signatures of fission modes in ${}^{254}\mathrm{Fm}$ populated by ${}^{16}\mathrm{O}+{}^{238}\mathrm{U}$ through the mass distribution (MD) and total kinetic energy distribution (TKED).

Method: The mass–total kinetic energy distributions (M-TKED) of fission fragments of the reaction ${}^{16}\mathrm{O}+{}^{238}\mathrm{U}$ have been measured at two laboratory energies $E_{\text{lab}}=89$ and 101 MeV. The spontaneous fission (SF) of ${}^{254}\mathrm{Fm}$, one-dimensional (1D) fragment MD, and two-dimensional (2D) M-TKEDs of ${}^{16}\mathrm{O}+{}^{238}\mathrm{U}$ have been described by the multimodal random neck rupture (MM-RNR) model.

Results: Channel probabilities and the characteristics of different fission modes are obtained and discussed in detail. The enhancement observed in the mass yield ($\approx {10}^{-2}\%$) in the region 60–70 u for the light fragments at $E^{*}\approx 45$ MeV goes away at the higher $E^{*}\approx 56$ MeV. The heavy fragments of S1 and S2 modes are found to be associated with $Z\approx 53$ and $Z\approx 56$ shells, respectively. The slope of asymmetric to symmetric fission yields (when plotted against $E^{*}$) of ${}^{16}\mathrm{O}+{}^{238}\mathrm{U}$ is found to be similar to that of previously reported ${}^{18}\mathrm{O}+{}^{208}\mathrm{Pb}$.

Conclusions: Analysis of 2D M-TKED data by the MM-RNR model reveals the possible presence of fission modes in ${}^{16}\mathrm{O}+{}^{238}\mathrm{U}$. The liquid-drop-like broad symmetric SL mode is found to peak at a lower energy than predicted by the Viola systematic, which matches mostly with that of Standard 2 mode. No signature of asymmetric quasifission is observed. The MD widths show a linear dependence with the measured energies.

Background: In our earlier work [Phys. Rev. C 104, 055804 (2021)], we studied the surface properties of a neutron star, assuming it as a huge finite nucleus containing protons, neutrons, electrons, and muons. For the first time, we reported these results of a neutron star for a few representative masses.

Purpose: The purpose of the present work is to calculate the domain of numerical values for the surface properties of neutron stars based on the theoretical analogy of finite nuclei. In the present paper, we systematically calculate incompressibility, symmetry energy, slope parameter, etc. for a certain range of neutron star's mass to draw some definite conclusions.

Method: To carry forward our earlier idea, the energy density functional of the momentum space of neutron star matter is converted to the coordinate space in a local density approximation. This functional is again used to derive the neutron star surface properties within the coherent density fluctuation model using the weight function obtained from the density profile of the neutron star using the recently developed G3 and widely used NL3 and IU-FSU parameter sets in the context of relativistic mean-field formalism.

Results: The systematic surface properties of the neutron star, such as incompressibility, symmetry energy, slope parameter, and curvature coefficient is calculated. The volume and surface components of the total symmetry energy are decomposed with the help of the $\kappa$ factor obtained from the volume to surface ratio of the symmetry energies in the liquid drop limit of Danielewicz. The magnitude of the computed surface quantities increases with the neutron star's mass.

Conclusion: The incompressibility $K^{\mathrm{star}}$, symmetry energy $S^{\mathrm{star}}$, slope parameter $L_{\mathrm{sym}}^{\mathrm{star}}$, and curvature coefficient $K_{\mathrm{sym}}^{\mathrm{star}}$ of the neutron stars with different mass are analyzed and found to be model dependent. NL3 is the stiffest equation of state and endues us with the higher magnitude of surface quantities as compared to the G3 and IU-FSU forces.

The dynamics of low-energy-induced fission is explored using a consistent microscopic framework that combines the time-dependent generator coordinate method (TDGCM) and time-dependent nuclear density functional theory (TDDFT). While the former presents a fully quantum mechanical approach that describes the entire fission process as an adiabatic evolution of collective degrees of freedom, the latter models the dissipative dynamics of the final stage of fission by propagating the nucleons independently toward scission and beyond. The two methods, based on the same nuclear energy density functional and pairing interaction, are employed in an illustrative study of the charge distribution of yields and total kinetic energy for induced fission of ${}^{240}\mathrm{Pu}$. For the saddle-to-scission phase a set of initial points for the TDDFT evolution is selected along an isoenergy curve beyond the outer fission barrier on the deformation energy surface, and the TDGCM is used to calculate the probability that the collective wave function reaches these points at different times. Fission observables are computed using both methods and compared with available data.

Two-neutrino double-beta $\left(2\nu \beta \beta \right)$ decay has been used to constrain the neutron-proton part of effective interactions, which in turn is used to compute the nuclear matrix elements for neutrinoless double-beta decay, the observation of which would have important consequences for fundamental physics. We carefully examine $2\nu \beta \beta$ matrix elements within the proton-neutron quasiparticle random-phase approximation with nuclear energy density functionals. We work with functionals that are fit globally to single-beta-decay half-lives and charge-exchange giant-resonance energies, but not to $2\nu \beta \beta$ half-lives themselves, to evaluate the $2\nu \beta \beta$ nuclear matrix elements for all important nuclei, including those whose half-lives have not yet been measured. Such a comprehensive evaluation in large model spaces without configuration truncation requires an efficient computational scheme; we employ a double contour integration within the finite amplitude method. The results generally reproduce the nuclear matrix element extracted from half-lives well, without the use of any of those half-lives in the fitting procedure. We present predictions of the matrix elements in a total of 27 nuclei with half-lives that are still unmeasured.

An extensive study of the level structure of ${}^{62}\mathrm{Co}$ has been performed following a complex multinucleon transfer reaction, ${}^{26}\mathrm{Mg}({}^{48}\mathrm{Ca}, 2\alpha 3np\gamma ){}^{62}\mathrm{Co}$, at beam energies of 275, 290, and 320 MeV. The combination of the Gammasphere array, the fragment mass analyzer, and a focal-plane ionization chamber was used to identify and delineate excited levels in ${}^{62}\mathrm{Co}$. A considerable extension to the ${}^{62}\mathrm{Co}$ level scheme is proposed with firm spin-parity values assigned on the basis of angular distribution and correlation analyses. Various level sequences built upon states of single-particle character have been observed, and an interpretation of these structures in the framework of the spherical shell model is presented. At moderate spins, two dipole bands have been observed and, based on their phenomenological study, a possible magnetic rotation character is suggested. However, theoretical calculations performed using the particle rotor model support magnetic rotation for only one of these dipole bands.

The recently observed positive and negative parity bands in ${}^{73}\mathrm{Br}$ are investigated by the reflection-asymmetric triaxial particle rotor model. The experimental energy spectra as well as the electric transition probabilities $B\left(E1\right), B\left(E2\right)$, and the ratio $B\left(E1\right)/B\left(E2\right)$ are well reproduced by the theoretical calculations. It is found that the enhanced interband $E1$ transitions between the opposite-parity bands, a crucial evidence for octupole correlations, are mainly contributed by the intrinsic single-particle electric dipole matrix elements.

Background: Multinucleon transfer reactions at energies around the Coulomb barrier offer a vital opportunity to study the rich physics of nuclear structure and dynamics, e.g., single-particle level structure and quantum shells, mass and charge equilibration processes, energy dissipation, as well as secondary decays via particle emission or fission. Despite the continuous development in the field, we still have limited knowledge about how deformation—one of the representative nuclear structures—affects multinucleon transfer reactions.

Purpose: To develop our understanding of the reaction mechanism and to shed light on the effect of deformation in multinucleon transfer processes, we study the ${}^{16}\mathrm{O}+{}^{154}\mathrm{Sm}$ reaction at $E_{\mathrm{lab}}=85$ MeV (near the Coulomb barrier) and 134 MeV (substantially above the Coulomb barrier), where the target nucleus ${}^{154}\mathrm{Sm}$ is a well-established, deformed nucleus.

Methods: We have performed experiments on the ${}^{16}\mathrm{O}+{}^{154}\mathrm{Sm}$ reaction at the BARC-TIFR pelletron-Linac accelerator facility, Mumbai, India, measuring angular distributions and $Q$-value spectra for various transfer products. The measured cross sections have been analyzed along with theoretical calculations based on the time-dependent Hartree-Fock (TDHF) theory, together with a statistical model for secondary deexcitation processes, $\mathrm{GEMINI}++$.

Results: Angular distributions for elastic scattering and for various transfer channels were measured over a wide angular range. The $Q$-value- and angle-integrated isotope production cross sections have been extracted from the measured angular distributions. We obtained production cross sections for various isotopes for $E_{\mathrm{lab}}=85$ MeV, while only for four isotopes could be deduced for $E_{\mathrm{lab}}=134$ MeV due to present experimental limitations. For the lower incident energy case, we find a reasonable agreement between the measurements and the TDHF calculations for a-few-nucleon transfer channels; whereas TDHF underestimates cross sections for many-nucleon transfers, consistent with earlier works. On the other side, we find that calculated cross sections for secondary reaction products for the higher incident energy case qualitatively explains the measured trends of isotopic distributions observed for the lower energy. The latter observation indicates possible underestimation of excitation energies in the present TDHF $+$ GEMINI analysis. Although certain orientation effects were observed in TDHF results, it turns out to be difficult to disentangle them from the $Q$-value- and angle-integrated production cross sections.

Conclusions: The present analysis highlights the deep-inelastic character of multinucleon transfer processes and importance of secondary deexcitation processes. We show that the orientation effect in multinucleon transfer processes in the ${}^{16}\mathrm{O}+{}^{154}\mathrm{Sm}$ reaction is rather weak and hard to disentangle from the present measured data. Further systematic investigations, especially in the subbarrier energy regime, where the data would be more sensitive to single-particle properties, would be required to uncover effects of nuclear deformation on multinucleon transfer processes in low-energy heavy-ion reactions.

The complete-fusion excitation functions of $xn$-evaporation channels for the reactions ${}^{144}\mathrm{Sm}\left({}^{40}\mathrm{Ar},xn\right){}^{184-x}\mathrm{Hg}$, ${}^{148}\mathrm{Sm}\left({}^{36}\mathrm{Ar},xn\right){}^{184-x}\mathrm{Hg}$, ${}^{144}\mathrm{Nd}\left({}^{40}\mathrm{Ca},xn\right){}^{184-x}\mathrm{Hg}$, ${}^{142}\mathrm{Nd}\left({}^{48}\mathrm{Ca},xn\right){}^{190-x}\mathrm{Hg}$, and ${}^{166}\mathrm{Er}\left({}^{40}\mathrm{Ar},xn\right){}^{206-x}\mathrm{Rn}$ have been measured by using the catcher foil technique. Its modified version as well as a corresponding software of data processing, including a deconvolution procedure to take into account effects caused by spreading the energy of the beam at its passing through absorbing foils, have been described. The measured excitation functions have been compared with ones theoretically calculated with the coupled-channel model.

The present study, carried out for the first time, contributes to the multidisciplinary work in reactor design and nuclear astrophysics. Cadmium has been chosen for the present study for its significant importance in the development of nuclear reactors and for the astrophysical $p$ process. A stacked foil activation technique followed by offline $\gamma$-ray spectroscopy were used to carry out the present work. Cross sections were measured for the ${}^{114}\mathrm{Cd}{(p,\gamma )}^{115m}$ reaction due to the scarcity of data observed in the literature. The $S$ factor was calculated from the cross-section data. The ${}^{114}\mathrm{Cd}(p,n){}^{114m}\mathrm{In}$ reaction was also investigated using the same spectra. Statistical model calculations were performed using the Hauser-Feshbach (HF) code of the latest version of talys and were compared with the measured data and the previously measured experimental data available in the literature. A good agreement between theoretical and experimental data was found. The present data follow the trend of theoretical predictions and are in good agreement with the EXFOR database.