The average resonance capture (ARC) data measured at different filter beam facilities are re-analyzed. They include all measurements made between 1970 and 1990, but only partially exploited. Updated spectroscopic information on the states of interest as well as on $s$-wave resonance spacing are used to extract the $E1$ and $M1$ photon strength function. This re-evaluation aims at providing experimental information on the $E1$ and $M1$ strength function around the neutron binding energy and in doing so provides also constraints for existing models used in statistical reaction codes. The revised data are compared to the photon strength function extracted from other experimental methods, such as photoneutron data and Oslo-method data. We also compare the ARC data with recent quasiparticle random phase approximation calculations based on the D1M Gogny force. The ratio of the $E1$ to $M1$ strength functions is also analyzed and proposed as a new stringent test for the future elaboration of theoretical models for the dipole strength function.

The relativistic mean field theory with the Green's function method is extended to study $\mathrm{\Lambda }$ hypernuclei. Taking the hypernucleus ${}_{\mathrm{\Lambda }}{}^{61}\mathrm{Ca}$ as an example, the single-particle resonant states for $\mathrm{\Lambda }$ hyperons are investigated by analyzing the density of states, and the corresponding energies and widths are given. Different behaviors are observed for the resonant states, i.e., the distributions of the very narrow $1f_{5/2}$ and $1f_{7/2}$ states are very similar to bound states while those of the wide $1g_{7/2}$ and $1g_{9/2}$ states are like scattering states. Besides, the impurity effect of $\mathrm{\Lambda }$ hyperons on the single-neutron resonant states is investigated. For most of the resonant states, both the energies and widths decrease with adding more $\mathrm{\Lambda }$ hyperons due to the attractive $\mathrm{\Lambda }N$ interaction. Finally, the energy level structure of $\mathrm{\Lambda }$ hyperons in the Ca hypernucleus isotopes with mass number $A=53-73$ are studied; obvious shell structure and small spin-orbit splitting are found for the single-$\mathrm{\Lambda }$ spectrum.

Background: One important ingredient for many applications of nuclear physics to astrophysics, nuclear energy, and stockpile stewardship is cross sections for reactions of neutrons with rare isotopes. Since direct measurements are often not feasible, indirect methods, e.g., ($d,p$) reactions, should be used. Those ($d,p$) reactions may be viewed as three-body reactions and described with Faddeev techniques.

Purpose: Faddeev equations in momentum space have a long tradition of utilizing separable interactions in order to arrive at sets of coupled integral equations in one variable. Optical potentials representing the effective interactions in the neutron (proton) nucleus subsystem are usually non-Hermitian as well as energy dependent. Including excitations of the nucleus in the calculation requires a multichannel optical potential. The purpose of this paper is to introduce a separable, energy-dependent multichannel representation of complex, energy-dependent optical potentials that contain excitations of the nucleus and that fulfill reciprocity exactly.

Methods: Momentum space Lippmann-Schwinger integral equations are solved with standard techniques to obtain the form factors for the separable representation.

Results: Starting from energy-dependent multichannel optical potentials for neutron and proton scattering from ${}^{12}\mathrm{C}$, separable representations based on a generalization of the Ernst-Shakin-Thaler (EST) scheme are constructed which fulfill reciprocity exactly. Applications to $n+{}^{12}\mathrm{C}$ and $p+{}^{12}\mathrm{C}$ scattering are investigated for energies from 0 to 50 MeV.

Conclusions: We find that the energy-dependent separable representation of complex, energy-dependent phenomenological multichannel optical potentials describes scattering data with the same quality as the original potential.

In 2+1 dimensions, the evolution of flow under the influence of an external electromagnetic field is simulated. The external electromagnetic field is exponentially decaying with time. Under the same initial conditions, flow evolution with and without the external electromagnetic field is compared. It was found that the production of particles was enhanced when the external electromagnetic field was present. As the strength of the electromagnetic field increased, more particles were produced. Enhancement is greater at the high transverse momentum than at the low transverse momentum. In addition, the electromagnetic field also modifies the elliptic flow and the modification is related to the mass and charge of the particles.

Even though the fission of nuclei in the mass region 200 with excitation energy near 50 MeV has been studied extensively, a unique description of the fission probability and prefission neutron multiplicity (${\nu }_{\mathrm{pre}}$) data remains elusive. In the present work, a reexamination of the relevant data along with a new estimate of ${\nu }_{\mathrm{pre}}$ and fission chance distributions, obtained from the experimental fission excitation functions of neighboring Po isotopes, has been carried out. The ${\nu }_{\mathrm{pre}}$ from the above-mentioned method, sensitive to only the presaddle part, is significantly lower than the value obtained from neutron spectra measurements. Further, ${\nu }_{\mathrm{pre}}$ from the fission chance data is in good agreement with the statistical model predictions, which also accounts for the light-ion induced fission probability data up to low excitation energy ($\sim 30$ MeV). From this observation, it is concluded that the presaddle dynamical effects are not significant over this excitation energy range, and the ${\nu }_{\mathrm{pre}}$ data determined from the neutron spectra might have a significant contribution from the near-scission emission.

In hydrodynamical modeling of ultrarelativistic heavy-ion collisions, the freeze-out is typically assumed to take place at a surface of constant temperature or energy density. A more physical approach is to assume that freeze-out takes place at a surface of constant Knudsen number. We evaluate the Knudsen number as a ratio of the expansion rate of the system to the pion-scattering rate and apply the constant Knudsen number freeze-out criterion to the ideal hydrodynamical description of heavy-ion collisions at the Relativistic Heavy Ion Collider at BNL ($\sqrt{s_{\mathrm{NN}}}=200$ GeV) and the Large Hadron Collider ($\sqrt{s_{\mathrm{NN}}}=2760$ GeV) energies. We see that once the numerical values of freeze-out temperature and freeze-out Knudsen number are chosen to produce similar $p_T$ distributions, the elliptic and triangular anisotropies are similar too, in both event-by-event and averaged initial state calculations.

The low-lying energy levels of proton-rich ${}^{56}\mathrm{Cu}$ have been extracted using in-beam $\gamma$-ray spectroscopy with the state-of-the-art $\gamma$-ray tracking array GRETINA in conjunction with the S800 spectrograph at the National Superconducting Cyclotron Laboratory at Michigan State University. Excited states in ${}^{56}\mathrm{Cu}$ serve as resonances in the ${}^{55}\mathrm{Ni}(p,\gamma ){}^{56}\mathrm{Cu}$ reaction, which is a part of the $\mathit{rp}$ process in type-I x-ray bursts. To resolve existing ambiguities in the reaction $Q$ value, a more localized isobaric multiplet mass equation (IMME) fit is used, resulting in $Q=639\pm 82$ keV. We derive the first experimentally constrained thermonuclear reaction rate for ${}^{55}\mathrm{Ni}(p,\gamma ){}^{56}\mathrm{Cu}$. We find that, with this new rate, the $\mathit{rp}$ process may bypass the ${}^{56}\mathrm{Ni}$ waiting point via the ${}^{55}\mathrm{Ni}(p,\gamma )$ reaction for typical x-ray burst conditions with a branching of up to $\sim 40\%$. We also identify additional nuclear physics uncertainties that need to be addressed before drawing final conclusions about the $\mathit{rp}$-process reaction flow in the ${}^{56}\mathrm{Ni}$ region.

In this work, the low-density regions of nuclear and neutron star matter are studied. The search for the existence of nuclear pasta phases in this region is performed within the context of the quark-meson coupling (QMC) model, which incorporates quark degrees of freedom. Fixed proton fractions are considered, as well as nuclear matter in $\beta$ equilibrium at zero temperature. We discuss the recent attempts to better understand the surface energy in the coexistence phases regime and we present results that show the existence of the pasta phases subject to some choices of the surface energy coefficient. We also analyze the influence of the nuclear pasta on some neutron star properties. The equation of state containing the pasta phase will be part of a complete grid for future use in supernova simulations.

Exclusive breakup measurements have been performed for the ${}^6\mathrm{Li}+p$ system in inverse kinematics at ${}^6\mathrm{Li}$ incident energies of 25 and 29 MeV. The results are considered in the Continuum Discretized Coupled-Channels framework, together with elastic scattering data at 16, 20, 25, and 29 MeV, obtained simultaneously in the same experiment and reported previously. Good agreement between data and theory is observed, interpreted as evidence for strong coupling to the continuum. The direct and sequential (via the ${}^6\mathrm{Li}{3}_1{}^{+}$ resonance) breakup cross sections are found to be equally large at the higher incident energies but the dominant effect on the elastic scattering is due to coupling to the sequential breakup. This effect remains dominant even at the lowest energy of 16 MeV, despite the negligible cross section for excitation of the resonance at this low incident energy.

The deformation evolution of giant dipole resonance (GDR), in the chains of Sm and Nd isotopes, are investigated in the framework of an extended quantum molecular dynamics (EQMD) model. The mass number dependence of resonance peak position $\left(E_m\right)$ in the major and minor axis directions of deformed nuclei as well as the difference $\mathrm{\Delta }{E}_m$ between them are described in detail. The correlation between the splitting ($\mathrm{\Delta }{E}_m/{\overline{E}}_m$) of the GDR spectra and the deformation (${\beta }_2$) is further studied. The results confirm that $\mathrm{\Delta }{E}_m/{\overline{E}}_m$ is proportional to ${\beta }_2$. By comparing the calculation with the experimental data on photon absorption cross section ${\sigma }_{\gamma }$, it shows that the EQMD model can quite well reproduce the shape of GDR spectra from spherical to prolate shape. The GDR shapes in ${}^{134}\mathrm{Sm}, {}^{136}\mathrm{Sm}, {}^{138}\mathrm{Sm}, {}^{130}\mathrm{Nd}, {}^{132}\mathrm{Nd}$, and ${}^{134}\mathrm{Nd}$ are also predicted. In addition, the symmetry energy coefficient $\left(E_{\text{sym}}\right)$ dependence of GDR spectra of ${}^{150}\mathrm{Nd}$ is also discussed. It is found that the calculated GDR spectrum in the EQMD model is perfectly consistent with the experimental results when $E_{\text{sym}}$ equals 32 MeV.

Exploring a variety of closing schemes to the infinite hierarchy of momentum moments of the exactly solvable Boltzmann equation for systems undergoing Gubser flow, we study the precision with which the resulting hydrodynamic equations reproduce the exact evolution of hydrodynamic moments of the distribution function. We find that anisotropic hydrodynamics, obtained by expanding the distribution function around a dynamically evolving locally anisotropic background whose evolution is matched to exactly reproduce the macroscopic pressure anisotropy caused by the different longitudinal and transverse expansion rates in Gubser flow, provides the most accurate macroscopic description of the microscopic kinetic evolution. This confirms a similar earlier finding for Bjorken flow [Molnár et al., Phys. Rev. D 94, 125003 (2016)]. We explain the physics behind this optimal matching procedure and show that one can efficiently correct for a nonoptimized matching choice by adding a residual shear stress to the energy-momentum tensor whose evolution is again determined by the Boltzmann equation.

A systematic analysis of correlations between different orders of $p_T$-differential flow is presented, including mode coupling effects in flow vectors, correlations between flow angles (a.k.a. event-plane correlations), and correlations between flow magnitudes, all of which were previously studied with integrated flows. We find that the mode coupling effects among differential flows largely mirror those among the corresponding integrated flows, except at small transverse momenta where mode coupling contributions are small. For the fourth- and fifth-order flow vectors $V_4$ and $V_5$ we argue that the event plane correlations can be understood as the ratio between the mode-coupling contributions to these flows and the flow magnitudes. We also find that, for $V_4$ and $V_5$, the linear-response contribution scales linearly with the corresponding cumulant-defined eccentricities but not with the standard eccentricities.

A temperature-dependent bulk viscosity coefficient is used in $3+1$-dimensional hydrodynamic simulations. I study the effect of the increase of bulk viscosity around the critical temperature on the system dynamics in central $\mathrm{Pb}+\mathrm{Pb}$ collisions at $\sqrt{s_{NN}}=2760$ GeV. With increasing bulk viscosity the lifetime of the system increases slightly. Also the shape of the freeze-out hypersurface changes; the outer layers of the fireball live longer. This effect causes a small reduction of the ratio of two interferometry radii, $R_{\mathrm{out}}/R_{\mathrm{side}}$, improving the agreement with experimental data.

Elliptic flow, $v_2$, and triangular flow, $v_3$, are to a good approximation linearly proportional to the corresponding spatial anisotropies of the initial density profile, ${\varepsilon }_2$ and ${\varepsilon }_3$. Using event-by-event hydrodynamic simulations, we point out when deviations from this linear scaling are to be expected. When these deviations are negligible, relative $v_n$ fluctuations are equal to relative ${\varepsilon }_n$ fluctuations, and one can directly probe models of initial conditions using ratios of cumulants, for instance $v_n\left\{4\right\}/v_n\left\{2\right\}$. We argue that existing models of initial conditions tend to overestimate flow fluctuations in central Pb + Pb collisions, and to underestimate them in peripheral collisions. We make predictions for $v_3\left\{6\right\}$ in noncentral Pb + Pb collisions, and for $v_3\left\{4\right\}$ and $v_3\left\{6\right\}$ in high-multiplicity $p+\text{Pb}$ collisions.

We give a precision analysis of the correlation coefficients of the electron energy spectrum and angular distribution of the ${\beta }^{-}$ decay and radiative ${\beta }^{-}$ decay of the neutron with polarized neutron and electron to order ${10}^{-3}$. The calculation of correlation coefficients is carried out within the standard model, with contributions of order ${10}^{-3}$ caused by the weak magnetism and proton recoil taken to next-to-leading order in the large proton mass expansion, and with radiative corrections of order $\alpha /\pi \sim {10}^{-3}$ calculated to leading order in the large proton mass expansion. The obtained results can be used for the planning of experiments on the search for contributions of order ${10}^{-4}$ of interactions beyond the standard model.

I have performed a reanalysis of mixing between the first two $0^{+}$ and $2^{+}$ states in ${}^{96}\mathrm{Zr}$. My mixing amplitude for the $0^{+}$ states is about three times a recent value, although both are small. My mixing is consistent with the $E0$ strength connecting the two $0^{+}$ states, whereas the earlier mixing gives an $E0$ strength that is too small by an order of magnitude.

Starting from the quasiparticle random phase approximation based on the Skyrme interaction SLy5, we study the effects of phonon-phonon coupling (PPC) on the low-energy electric dipole response in ${}^{40-58}\mathrm{Ca}$. Using the same set of parameters we describe available experimental data for ${}^{40,44,48}\mathrm{Ca}$ and give the prediction for ${}^{50-58}\mathrm{Ca}$. The inclusion of the PPC results in the formation of low-energy $1^{-}$ states. There is an impact of the PPC effect on low-energy $E1$ strength of ${}^{40,44,48}\mathrm{Ca}$. The PPC effect on the electric dipole polarizability is discussed. We predict a strong increase of the summed $E1$ strength below 10 MeV, with increasing neutron number from ${}^{48}\mathrm{Ca}$ until ${}^{58}\mathrm{Ca}$.

The instability of hot asymmetric nuclear matter with respect to bulk density distortions is considered. The equation of state of the extended Thomas-Fermi approximation is used. The origin of the anomalous dispersion and the influence of the Fermi-surface distortion effects on the bulk and isospin instabilities in homogenous nuclear matter are investigated. It is shown that the development of both instabilities is reduced significantly due to the Fermi-surface distortion effects. The dependence of the bulk instability on the temperature and on the multipolarity of the particle density distortions are shown for the nucleus of ${}^{208}\mathrm{Pb}$. The dependence of the formation of the decay modes (fission or multifragmentation) of the nuclei on the temperature and the Fermi-surface distortion effects are demonstrated. It is shown that in the case of low temperatures the preferable mode for the bulk instability is binary fission. For higher temperatures, the preferred modes are the multifragmentations for small clusters. The number of clusters increases with increasing temperature.

Excitation energy, reduced transition rates, and $g$ factors of the lowest $2^{+}$ and $3^{-}$ states of even-even $N=82$ and $N=126$ isotones are studied in relativistic QRPA formalism. These values are compared to available experimental data and some of the recent theoretical results. In the following the obtained results are presented first for $N=82$ isotones with $Z=36–72$, that is very neutron-rich to neutron-deficient nuclei with $N/Z$ varying from 2.28 to 1.14 and then for $N=126$ isotones with $Z=76–92$. These calculations are performed employing NL3, as well as its recently revised version $\mathrm{NL}{3}^{*}$ set of the RMF Lagrangian parameters. It is found that both the interaction sets produce almost similar results. The agreement with available data is rather satisfactory in view of such a wide range of nuclei considered here, though there are serious disagreements like in the case of ${}^{140}\mathrm{Ce}$ and properties of $3^{-}$ states of $N=126$ isotones.

Properties of $\mathrm{\Lambda }$ and ${\mathrm{\Xi }}^0$ hypernuclei and neutron stars are investigated in a quark mean field model with pion and gluon corrections. First, $u, d$, and $s$ quarks are confined by relativistic harmonic oscillator potentials to generate baryons, such as nucleons and $\mathrm{\Lambda }, \mathrm{\Sigma }$, and $\mathrm{\Xi }$ hyperons. The effects of pion-quark coupling and one-gluon exchange are considered perturbatively. Then, the baryons interact with each other through exchanging $\sigma , \omega$, and $\rho$ mesons between quarks in hypernuclei and nuclear matter. The strengths of confinement potentials for $u, d$, and $s$ quarks are determined by the masses and radii of free baryons. The coupling constants between the quarks and mesons are fixed by the ground-state properties of several nuclei and single-hyperon potentials at nuclear saturation density, which yields three parameter sets for the coupling constants between mesons and quarks, named QMF-NK1S, QMF-NK2S, and QMF-NK3S. Compared to the results of the previous quark mean field model without pion and gluon corrections, it is found that properties of $\mathrm{\Lambda }$ hypernuclei, i.e., the single-$\mathrm{\Lambda }$ energies, are more consistent with the experimental observables. Properties of ${\mathrm{\Xi }}^0$ hypernuclei are also calculated and compared with the results in the previous quark mean field model. With these three parameter sets, the neutron stars containing hyperons are investigated through solving the Tolman-Oppenheimer-Volkoff equation. Maximum masses of neutron stars approach $2.1M_{\odot }$ with hyperons, and corresponding radii are around 13 km.