We systematically study the symmetry energy effects of the transition density $n_{\mathrm{t}}$ and the transition pressure $P_{\mathrm{t}}$ around the crust-core interface of a neutron star in the framework of the dynamical and the thermodynamical methods respectively. We employ both the parabolic approximation and the full expansion, for the definition of the symmetry energy. We use various theoretical nuclear models, which are suitable for reproducing the bulk properties of nuclear matter at low densities, close to saturation density as well as the maximum observational neutron star mass. First we derive and present an approximation for the transition pressure $P_{\mathrm{t}}$ and crustal mass $M_{\mathrm{crust}}$. Moreover, we derive a model-independent correlation between $P_{\mathrm{t}}$ and the slope parameter $L$ for a fixed value of the symmetry energy at the saturation density. Second, we explore the effects of the equation of state on a few astrophysical applications which are sensitive to the values of $n_{\mathrm{t}}$ and $P_{\mathrm{t}}$ including neutron star oscillation frequencies, thermal relaxation of the crust, crustal fraction of the moment of inertia, and the $r$-mode instability window of a rotating neutron star. In particular, we employ the Tolman VII solution of the TOV equations to derive analytical expressions for the critical frequencies and the relative time scales, for the $r$-mode instability, in comparison with the numerical predictions. In the majority of the applications, we found that the above quantities are sensitive mainly to the applied approximation for the symmetry energy (confirming previous results). There is also a dependence on the used method (dynamical or thermodynamical). The above findings lead us to claim that the determination of $n_{\mathrm{t}}$ and $P_{\mathrm{t}}$ must be reliable and accurate before they are used to constrain relevant neutron star properties.

The neutron capture cross section of ${}^9\mathrm{Be}$ for stellar energies was measured via the activation technique using the Karlsruhe Van de Graaff accelerator in combination with accelerator mass spectrometry at the Vienna Environmental Research Accelerator. To characterize the energy region of interest for astrophysical applications, activations were performed in a quasistellar neutron spectrum of $kT=25$ keV and for a spectrum at ${\mathrm{E}}_n=473\pm 53$ keV. Despite the very small cross section, the method used provided the required sensitivity for obtaining fairly accurate results of $10.4\pm 0.6$ and $8.4\pm 1.0\mu \mathrm{b}$, respectively. With these data it was possible to constrain the cross section shape up to the first resonances at 622 and 812 keV, thus allowing for the determination of Maxwellian-averaged cross sections at thermal energies between $kT=5$ and 100 keV. In addition, we report a new experimental cross section value at thermal energy of ${\sigma }_{\text{th}}=8.31\pm 0.52$ mb.

We derive the formulas of the squeezed back-to-back correlation (SBBC) between a boson and antiboson with different in-medium masses in high-energy heavy-ion collisions. The influence of the in-medium mass difference between a boson and antiboson on the SBBC is investigated. We calculate the SBBC functions of $D$-meson pairs for the hydrodynamic sources described by the vish2+1 code for Au+Au collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$. Our results indicate that the SBBC strengths of $D^{+}{D}^{-}$ and $D^0{\overline{D}}^0$ are different if there are charge-dependent in-medium interactions.

Stimulated by the still puzzling competition between spin-singlet and spin-triplet pairing in nuclei, the ${}^{3}SD_1$ neutron-proton pairing is investigated in the framework of BCS theory of nuclear matter. The medium-polarization effects are included in the single-particle spectrum and also in the pairing interaction starting from the $G$ matrix, calculated in the Brueckner-Hartree-Fock approximation. The vertex corrections due to spin and isospin collective excitations of the medium are determined from the Bethe-Salpeter equation in the random-phase approximation (RPA) limit, taking into account the tensor correlations. It is found that the self-energy corrections confine the superfluid state to very low density, while remarkably quenching the magnitude of the energy gap, whereas the induced interaction has an attractive effect. The interplay between spin-singlet and spin-triplet pairing is discussed in nuclear matter as well as in finite nuclei.

In this work, the Coulomb mixing and the isospin mixing in the ground states of even-even nuclei are evaluated in perturbation theory. The calculation of the isospin mixing is performed by using the connection to isovector monopole resonance properties. The uncertainty in the results that depends on different choices of the Skyrme interactions is shown. While Coulomb mixing turns out to be large in the ground states of heavy nuclei, isospin mixing is very small.

Coherent exclusive vector meson electroproduction is a key physics channel at an electron-ion collider. It probes the gluon structure of nuclei over a wide range of $Q^2$, and can be used to measure nuclear shadowing and to search for gluon saturation and/or the colored glass condensate. In this paper, we present calculations of the kinematic distributions for a variety of exclusive vector meson final states: the $\rho$, $\varphi$, $\mathrm{J}/\psi$, ${\psi }^{\prime }$, and the $\mathrm{{\rm Y}}$ states. The cross sections for light and $c\overline{c}$ mesons are large, while $\mathrm{{\rm Y}}$ states should be produced in moderate numbers at a medium energy electron-ion collider (EIC)—i.e., one corresponding to the proposed U.S. designs—and in large numbers at the CERN Large Hadron Electron Collider (LHeC). We investigate the acceptances for these states, as a function of detector rapidity coverage. A large-acceptance detector is needed to cover the full range photon-nucleon collision energies produced at an EIC; a forward detector is required to observe vector mesons from the most energetic photon interactions, and thereby probe gluons at the lowest possible Bjorken-$x$ values.

In this paper the results of measurements of the total cross sections for the ${}^{11}\mathrm{Li}+{}^{28}\mathrm{Si}$ reaction in the beam energy range $7A$–$25A$ MeV are presented. The experimental cross sections were obtained by registration of the prompt gamma and neutron radiation accompanying the interaction of ${}^{11}\mathrm{Li}$ nuclei with ${}^{28}\mathrm{Si}$ nuclei. The total cross sections for the ${}^{11}\mathrm{Li}+{}^{28}\mathrm{Si}$ reaction are calculated based on a numerical solution of the time-dependent Schrödinger equation for the external weakly bound neutrons of the projectile nucleus ${}^{11}\mathrm{Li}$. The calculated total reaction cross sections are in good agreement with the experimental data.

A detailed study of charged current quasielastic neutrino and antineutrino scattering cross sections on a ${}^{12}\mathrm{C}$ target with no pions in the final state is presented. The initial nucleus is described by means of a realistic spectral function $S(p,\mathcal{E})$ in which nucleon-nucleon correlations are implemented by using natural orbitals through the Jastrow method. The roles played by these correlations and by final-state interactions are analyzed and discussed. 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. The theoretical predictions are compared with a large set of experimental data for double-differential, single-differential, and total integrated cross sections measured by the MiniBooNE, $\mathrm{MINER}\nu \mathrm{A}$, and T2K experiments. Good agreement with experimental data is found over the whole range of neutrino energies. The results are also in global good agreement with the predictions of the superscaling approach, which is based on the analysis of electron-nucleus scattering data, with only a few differences seen at specific kinematics.

Heavy flavor observables provide valuable information on the properties of the hot and dense quark-gluon plasma (QGP) created in ultrarelativistic nucleus-nucleus collisions. Various microscopic models have successfully described many of the observables associated with its formation. Their transport coefficients differ, however, due to different assumptions about the underlying interaction of the heavy quarks with the plasma constituents, different initial geometries and formation times, different hadronization processes, and a different time evolution of the QGP. In this study we present the transport coefficients of these models and investigate systematically how some of these assumptions influence the heavy quark properties at the end of the QGP expansion. For this purpose we impose on these models the same initial condition and the same model for the QGP expansion and show that both have considerable influence on $R_{AA}$ and $v_2$.

Using the general notion of cross section fluctuations in hadron-nucleus scattering at high energies, we derive an expression for the cross section of incoherent $J/\psi$ photoproduction on heavy nuclei $d{\sigma }_{\gamma A\to J/\psi Y}/dt$, which includes both elastic $d{\sigma }_{\gamma p\to J/\psi p}/dt$ and proton-dissociation $d{\sigma }_{\gamma p\to J/\psi Y}/dt$ photoproduction on target nucleons. We find that, with good accuracy, $d{\sigma }_{\gamma A\to J/\psi Y}/dt$ can be expressed as a product of the sum of the $d{\sigma }_{\gamma p\to J/\psi p}/dt$ and $d{\sigma }_{\gamma p\to J/\psi Y}/dt$ cross sections, which have been measured at HERA, and the common nuclear shadowing factor, which is calculated using the leading twist nuclear shadowing model. Our prediction for the cross section of incoherent $J/\psi$ photoproduction in Pb-Pb ultraperipheral collisions at $\sqrt{s_{NN}}=2.76\mathrm{TeV}$ and $y=0,d{\sigma }_{AA\to J/\psi AY}(y=0)/dy=0.59-1.24\mathrm{mb}$ agrees within significant theoretical uncertainties with the data of the ALICE Collaboration.

The charge form factor and weak decay constant of the pion as well as the pion-quark coupling constant in symmetric nuclear matter are explored in the framework of the Nambu–Jona-Lasinio model, where the pion is described as a bound state of a dressed quark-antiquark pair obtained by the Bethe-Salpeter equation. For the in-medium current quark properties, we adopt the quark-meson coupling model, which describes successfully many hadron properties in a nuclear medium. The pion decay constant and the pion-quark coupling constant are found to decrease with increasing density as well as the magnitude of the light quark condensate. But the pion mass is found to be insensitive to density up to 1.25 times the normal nuclear density. The pion charge form factor in the spacelike region is also explored and is found to have a $Q^2$ dependence similar to the form factor in vacuum, showing $1/Q^2$ behavior in the large $Q^2$ region, where $Q^2$ is the negative of the four-momentum transfer squared. The modifications of the charge radius of the charged pion in nuclear matter are then estimated and the root-mean-square radius at the normal nuclear density is predicted to be larger than that in vacuum by about 20%.

$\beta$-decay half-lives of neutron-rich nuclides in the $A=100–110$ mass region have been measured using an implantation station installed inside of the Summing NaI(Tl) (SuN) detector at the National Superconducting Cyclotron Laboratory. Accurate half-lives for these nuclides are important for nuclear astrophysics, nuclear structure, and nuclear technology. The half-lives from the present work are compared with previous measurements, showing overall good agreement.

Excited states of ${}^{202}\mathrm{Hg}$ have been studied via the ${}^{12}\mathrm{C}({}^{202}\mathrm{Hg},{}^{202}\mathrm{Hg}^{*})$ Coulomb excitation reaction at a beam energy of 890 MeV. The $\gamma$-ray transitions from the excited states of ${}^{202}\mathrm{Hg}$ were detected by the Gammasphere array. The intensities of the observed $\gamma$ rays determined the relative populations of the excited states which were used to extract the absolute $M1$ and $E2$ transition strength distributions for excited $2^{+}$ states of ${}^{202}\mathrm{Hg}$ up to 2 MeV. The measured absolute $B(M1;2_7^{+}\to 2_1^{+})$ strength of $0.18\left(8\right){\mu }_{\mathrm{N}}^2$ indicates that the $2_7^{+}$ level of ${}^{202}\mathrm{Hg}$ is the main fragment of the proton-neutron mixed-symmetry $2_{1,\mathrm{ms}}^{+}$ state. Upper limits for the $F$-spin mixing matrix elements of ${}^{202,204}\mathrm{Hg}$ are determined as well.

The $g$ factor of an isomeric state at 2738 keV in ${}^{135}\mathrm{La}$ has been measured by time differential perturbed angular distribution technique. This isomer was populated in the reaction ${}^{128}\mathrm{Te}({}^{11}\mathrm{B}$, $4\mathrm{n}){}^{135}\mathrm{La}$ at beam energy of 52 MeV. We performed the large-scale shell-model (LSSM) calculations which successfully describe the low-lying levels and band structures of ${}^{135}\mathrm{La}$. The measured value of the $g$ factor,$-0.049\left(3\right)$, has been compared with the LSSM result to firmly assign the configuration of the isomeric state. The major configuration of $23/2^{+}$ state is $\pi \left(d_{5/2}\right)\otimes \nu {\left(h_{11/2}\right)}^{-2}$.

The discovery of the halo phenomenon has changed the traditional understanding of nuclear structure and opened up a new frontier in nuclear physics. The resonant states are thought to play a critical role at the formation of a halo. In this paper, we adopt the complex momentum representation method to explore the single-particle resonances for several slightly heavier nuclei than those halo nuclei found in experiment. The single particle bound and resonant levels and their evolution with the quadruple deformation ${\beta }_2$ are obtained and accompanied by a clear shell structure. The configuration occupations and density distributions of valence nucleon support the existence of halo structure. Namely, an $s$-wave halo may be formed in the range of $-0.06\le {\beta }_2\le 0.13$ ($-0.12\le {\beta }_2\le 0.12$) in ${}^{77}\mathrm{Fe}$ (${}^{75}\mathrm{Cr}$), and a $p$-wave halo may be formed in the range of $0.09\le {\beta }_2\le 0.13$ in ${}^{53}\mathrm{Ar}$. This prediction is of referential value for the exploration of heavier halo nuclei in experiment.

Background: The study of precompound emission has attracted considerable attention for testing nuclear models in light-ion-induced reactions at relatively higher energies above 10 MeV/nucleon.

Purpose: Aiming to study the precompound emission and to develop systematics at low energies below 10 MeV/nucleon, where the compound emission process is likely to dominate, the excitation functions of the reaction residues produced in the interaction of $\alpha$ particles with ${}^{141}\mathrm{Pr}$ have been measured in the energy range $\approx 14$–40 MeV. Further, the measured data have been analyzed within the framework of both the semiclassical and quantum mechanical models.

Methods: The off-line $\gamma$-ray spectroscopy based stacked foil activation technique has been used to measure the excitation functions.

Results: The experimentally measured excitation functions have been compared with the theoretical predictions based on both the semiclassical model codes, viz., pace4, talys-1.9, act, and alice91, and the quantum mechanical model code exifon. The analysis of the data shows that the experimental excitation functions could be reproduced only when the contribution of precompound emission, simulated theoretically, is taken into account. Further, the precompound fraction, which gives the relative importance of precompound emission over compound nucleus emission, has been deduced and is found to be energy dependent.

Conclusions: Analysis of data indicates that in $\alpha$-induced reactions, the precompound emission plays an important role, even at the low incident energies, where the pure compound nucleus process is likely to dominate. The precompound fraction is found to strongly depend on the mass of the target nucleus and the excitation energy per surface nucleon of the composite system.

Ultrarelativistic quantum molecular dynamics phase-space coalescence calculations for the production of deuterons are compared with available data for various reactions from the Facility for Antiproton and Ion Research energy regime energy regime over the CERN Super Proton Synchrotron–Relativistic Heavy Ion Collider Beam Energy Scan region up to CERN Large Hadron Collider energies. It is found that the production process of deuterons, as reflected in their rapidity and transverse-momentum distributions in $p+p$, $p+A$, and $A+A$ collisions in the mentioned energy regime, are in good agreement with experimental data. We further explore the energy and centrality dependence of the $d$/$p$ and $\overline{d}/\overline{p}$ ratios and compare with thermal model results. Finally, we discuss antideuteron production for selected systems. Overall, a good description of the experimental data is observed. Most importantly this good description is based only on a single set of coalescence parameters that is independent of energy and system size and can also be applied for antideuterons.

Quantum models of nuclear reactions require an effective way of taking into account the complex coupling of the components of different excited states as well as the nuclear residual interactions of the composite system. This is usually achieved with the use of distributions giving nonuniform weights for each of the modes involved. The response function of the quantum model permits the inclusion of the residual interaction and thus a unified description of collective and single-particle excitations. We analyze the particle-hole nature of the RPA modes of the response function in the context of multistep direct (MSD) nuclear reactions. The energy distribution of the particle-hole states that contribute to the response function is studied. Although many states make small contributions to the low-energy collective states, we show that the energy distribution of the higher-energy states is concentrated around the energies of the noninteracting components. The spreading energy of the strength function is determined for different nuclei, and a general fit accounting for both the collective and noncollective parts of the spectra is proposed. In addition we also test the randomness assumption commonly applied in models of MSD reactions.

Lifetimes are measured for the low-lying states of ${}^{131}\mathrm{I}$ and ${}^{132}\mathrm{Xe}$ nuclei populated from the decay of radio-chemically separated Te fission fragments. The VENTURE array comprised of eight fast ${\mathrm{CeBr}}_3$ detectors is used for the lifetime measurement with $\gamma \text{−}\gamma$ fast timing technique. Large basis shell model calculations have been performed with the “nushellx” code to interpret the low-lying level structure and to calculate level lifetimes in ${}^{131}\mathrm{I}$ and ${}^{132}\mathrm{Xe}$. The measured lifetimes and absolute transition probabilities are discussed in the light of systematics with the neighboring nuclei. Single particle excitation and loss of collectivity is observed with increasing neutron number up to $N=82$, validating the double shell closure at ${}^{132}\mathrm{Sn}$. Enhanced $B\left(E1\right)$ and $B\left(E3\right)$ strengths are found for the 1646-keV, 11/$2^{-}$ level in ${}^{131}\mathrm{I}$.

The band built on the $K^{\pi }=8^{-},T_{1/2}=9.4$ ms isomer of ${}^{130}\mathrm{Ba}$ has been identified, filling the gap in the systematics of the dipole bands built on the $8^{-}$ isomers in the $N=74$ isotones from ${}^{128}\mathrm{Xe}$ to ${}^{138}\mathrm{Gd}$. The use of the GALILEO array in conjunction with its ancillaries EUCLIDES and Neutron Wall, helped to firmly place the newly identified transitions on top of the long-lived isomer. The extracted $g_K$ and $g_R$ gyromagnetic factors are in agreement with the $7/2^{+}\left[404\right]\otimes 9/2^{-}\left[514\right]$ two-neutron Nilsson configuration. Particle-rotor model calculations give an understanding of the limited degree of $K$ mixing. The experimental information on the $K^{\pi }=8^{-}$ isomer of ${}^{130}\mathrm{Ba}$ is now the most complete among the $K$ isomers of the $N=74$ isotones.