Background: The central depression of nucleonic density, i.e., a reduction of density in the nuclear interior, has been attributed to many factors. For instance, bubble structures in superheavy nuclei are believed to be due to the electrostatic repulsion. In light nuclei, the mechanism behind the density reduction in the interior has been discussed in terms of shell effects associated with occupations of $s$ orbits.

Purpose: The main objective of this work is to reveal mechanisms behind the formation of central depression in nucleonic densities in light and heavy nuclei. To this end, we introduce several measures of the internal nucleonic density. Through the statistical analysis, we study the information content of these measures with respect to nuclear matter properties.

Method: We apply nuclear density functional theory with Skyrme functionals. Using the statistical tools of linear least square regression, we inspect correlations between various measures of central depression and model parameters, including nuclear matter properties. We study bivariate correlations with selected quantities as well as multiple correlations with groups of parameters. Detailed correlation analysis is carried out for ${}^{34}\mathrm{Si}$ for which a bubble structure has been reported recently, ${}^{48}\mathrm{Ca}$, and $N=82$, 126, and 184 isotonic chains.

Results: We show that the central depression in medium-mass nuclei is very sensitive to shell effects, whereas for superheavy systems it is firmly driven by the electrostatic repulsion. An appreciable semibubble structure in proton density is predicted for ${}^{294}\mathrm{Og}$, which is currently the heaviest nucleus known experimentally.

Conclusion: Our correlation analysis reveals that the central density indicators in nuclei below ${}^{208}\mathrm{Pb}$ carry little information on parameters of nuclear matter; they are predominantly driven by shell structure. On the other hand, in the superheavy nuclei there exists a clear relationship between the central nucleonic density and symmetry energy.

Widths of the rapidity distributions of various identified hadrons generated with the UrQMD-3.4 event generator at all the Super Proton Synchrotron (SPS) energies have been presented and compared with the existing experimental results. An increase in the width of the rapidity distribution of $\mathrm{\Lambda }$ could be seen with both Monte Carlo (MC) and experimental data for the studied energies. Using MC data, the study has been extended to Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies. A similar jump, as observed in the plot of rapidity width versus rest mass at Alternating Gradient Synchrotron (AGS) and all SPS energies, persists even at RHIC and LHC energies, confirming its universal nature from AGS to the highest LHC energies. Such observation indicates that pair production may not be the only mechanism of particle production at the highest LHC energies. However, with MC data, the separate mass scaling for mesons and baryons is found to exist even at the top LHC energy.

We present $\mathit{NN}$ potentials through five orders of chiral effective field theory ranging from leading order (LO) to next-to-next-to-next-to-next-to-leading order (${\mathrm{N}}^4\mathrm{LO}$). The construction may be perceived as consistent in the sense that the same power counting scheme as well as the same cutoff procedures are applied in all orders. Moreover, the long-range parts of these potentials are fixed by the very accurate $\pi N$ low-energy constants (LECs) as determined in the Roy-Steiner equations analysis by Hoferichter, Ruiz de Elvira, and coworkers. In fact, the uncertainties of these LECs are so small that a variation within the errors leads to effects that are essentially negligible, reducing the error budget of predictions considerably. The $\mathit{NN}$ potentials are fit to the world $\mathit{NN}$ data below the pion-production threshold of the year 2016. The potential of the highest order (${\mathrm{N}}^4\mathrm{LO}$) reproduces the world $\mathit{NN}$ data with the outstanding ${\chi }^2$/datum of 1.15, which is the highest precision ever accomplished for any chiral $\mathit{NN}$ potential to date. The $\mathit{NN}$ potentials presented may serve as a solid basis for systematic ab initio calculations of nuclear structure and reactions that allow for a comprehensive error analysis. In particular, the consistent order by order development of the potentials will make possible a reliable determination of the truncation error at each order. Our family of potentials is nonlocal and, generally, of soft character. This feature is reflected in the fact that the predictions for the triton binding energy (from two-body forces only) converges to about 8.1 MeV at the highest orders. This leaves room for three-nucleon-force contributions of moderate size.

Finite-temperature Hartree-Fock-Bogoliubov theory using Skyrme interactions and relativistic Hartree-Fock effective Lagrangians predicts ${}^{48}\mathrm{Ni}$ as being a possible candidate for the finite-temperature pairing re-entrance phenomenon. For this proton-drip-line nucleus, proton resonant states are expected to contribute substantially to pairing correlations and the two predicted critical temperatures are $T_{c1}\sim 0.08–0.2$ MeV and $T_{c2}\sim 0.7–0.9$ MeV. It is also shown that pairing re-entrance modifies the proton single-particle energies around the Fermi level, as well as occupation numbers and quasiparticle levels. The understanding of pairing re-entrance in ${}^{48}\mathrm{Ni}$ presently challenges our understanding of exotic matter under extreme conditions.

We propose to use proton knockout reactions $\left(p,2p\right)$ from a deeply bound orbit as a new probe into three-nucleon-force (3NF) effects. The remarkable advantage of using $\left(p,2p\right)$ reaction is that we can choose an appropriate kinematical condition to probe the 3NF effects. We analyze $\left(p,2p\right)$ reactions on a ${}^{40}\mathrm{Ca}$ target within the framework of distorted-wave impulse approximation with a $g$-matrix interaction based on chiral two- and three-nucleon forces. The chiral 3NF effects significantly change the peak height of the triple differential cross section of $\left(p,2p\right)$ reaction. We also clarify the correspondence between the $\left(p,2p\right)$ cross sections and the in-medium $pp$ cross sections.

The dependence of the evaporation residue cross section (ERCS) to produce superheavy nuclei (SHN) on the entrance channel of colliding nuclei is analyzed within the dinuclear system concept. The ERCS for the hot fusion reactions are investigated systematically and compared with existing experimental data. The capture cross section depends sensitively on the reaction $Q$ value. The fusion probabilities and surviving probabilities depend sensitively on the neutron numbers of the target and projectile nuclei. In most cases more neutron excess in the system can increase the producing cross section of SHN.

The existence of a supernumerary nuclear rainbow in inelastic scattering is reported. This is done by studying inelastic ${}^{16}\mathrm{O}$ scattering from ${}^{12}\mathrm{C}$, exciting the $2^{+}$ (4.44 MeV) state of ${}^{12}\mathrm{C}$ and elastic scattering at the incident energies in the range 124–200 MeV, using the coupled channels method. An extended double folding potential is used. This is derived from realistic wave functions for ${}^{12}\mathrm{C}$ and ${}^{16}\mathrm{O}$ calculated with a microscopic $\alpha$ cluster model and a finite-range density-dependent nucleon-nucleon force. Excitations to the $2^{+}$ (4.44 MeV), $3^{-}$ (9.64 MeV), and $4^{+}$ (14.08 MeV) states of ${}^{12}\mathrm{C}$, and the $3^{-}$ (6.13 MeV) and $2^{+}$ (6.92 MeV) states of ${}^{16}\mathrm{O}$ are included in the coupled channels calculations. The emergence of the supernumerary bow is understood by the properties of both the Luneburg-lens-like potential in the internal region and diffuse attraction in the outer region. The existence of a supernumerary rainbow for inelastic scattering in addition to the existence of a dynamically created secondary rainbow and a dynamically refracted primary rainbow for elastic scattering, which are not observed in meteorological rainbows, further deepens the understanding of nuclear rainbows.

The cross sections of the ${}^{186}\mathrm{W}(n,\gamma ){}^{187}\mathrm{W}, {}^{183}\mathrm{W}\left(n,p\right){}^{183}\mathrm{Ta}$ and ${}^{154}\mathrm{Gd}\left(n,2n\right){}^{153}\mathrm{Gd}, {}^{160}\mathrm{Gd}\left(n,2n\right){}^{159}\mathrm{Gd}$ reactions were measured at the neutron energies $5.08\pm 0.165, 8.96\pm 0.77, 12.47\pm 0.825$, and $16.63\pm 0.95\mathrm{MeV}$. Standard neutron activation analysis technique and off-line $\gamma$ ray spectrometry were used for the measurement and analysis of the data. Measurements were done in the energy range where few or no measured data are available. The results from the present work are compared with the literature data based on the EXFOR compilation. The experimental results are supported by theoretical predictions using nuclear modular codes TALYS 1.8 and EMPIRE 3.2.2. The predictability of different one-dimensional models available in TALYS 1.8 and Levden models in EMPIRE 3.2.2 were tested. A detailed comparison of experimental results with theoretical model calculations is made.

A high-precision half-life measurement for the superallowed ${\beta }^{+}$ transition between the isospin $T=1/2$ mirror nuclei ${}^{21}\mathrm{Na}$ and ${}^{21}\mathrm{Ne}$ has been performed at the TRIUMF-ISAC radioactive ion beam facility yielding $T_{1/2}=22.4506\left(33\right)$ s, a result that is a factor of 4 more precise than the previous world-average half-life for ${}^{21}\mathrm{Na}$ and represents the single most precisely determined half-life for a transition between mirror nuclei to date. The contribution to the uncertainty in the ${}^{21}\mathrm{Na} \mathcal{F}{t}^{\mathrm{mirror}}$ value due to the half-life is now reduced to the level of the nuclear-structure-dependent theoretical corrections, leaving the branching ratio as the dominant experimental uncertainty.

The impact of nonequilibrium effects on the dynamics of heavy-ion collisions is investigated by comparing a nonequilibrium transport approach, the Parton-Hadron-String-Dynamics (PHSD), to a 2D+1 viscous hydrodynamical model, which is based on the assumption of local equilibrium and conservation laws. Starting the hydrodynamical model from the same nonequilibrium initial condition as in the PHSD, using an equivalent lQCD equation of state (EoS), the same transport coefficients, i.e., shear viscosity $\eta$ and the bulk viscosity $\zeta$ in the hydrodynamical model, we compare the time evolution of the system in terms of energy density, Fourier transformed energy density, spatial and momentum eccentricities, and ellipticity to quantify the traces of nonequilibrium phenomena. In addition, we also investigate the role of initial pre-equilibrium flow on the hydrodynamical evolution and demonstrate its importance for final state observables. We find that because of nonequilibrium effects, the event-by-event transport calculations show large fluctuations in the collective properties, while ensemble averaged observables are close to the hydrodynamical results.

The effect of temperature on the evolution of the isovector dipole and isoscalar quadrupole excitations in ${}^{68}\mathrm{Ni}$ and ${}^{120}\mathrm{Sn}$ nuclei is studied within the fully self-consistent finite temperature quasiparticle random phase approximation framework, based on the Skyrme-type SLy5 energy density functional. The new low-energy excitations emerge due to the transitions from thermally occupied states to the discretized continuum at finite temperatures, whereas the isovector giant dipole resonance is not strongly impacted by the increase of temperature. The radiative dipole strength at low energies is also investigated for the ${}^{122}\mathrm{Sn}$ nucleus, becoming compatible with the available experimental data when the temperature is included. In addition, both the isoscalar giant quadrupole resonance and low-energy quadrupole states are sensitive to the temperature effect: while the centroid energies decrease in the case of the isoscalar giant quadrupole resonance, the collectivity of the first $2^{+}$ state is quenched and the opening of new excitation channels fragments the low-energy strength at finite temperatures.

The multinucleon transfer reactions ${}^{124,136,144}\mathrm{Xe}+{}^{238}\mathrm{U}, {}^{136,144}\mathrm{Xe}+{}^{160}\mathrm{Gd}, {}^{136,144}\mathrm{Xe}+{}^{170}\mathrm{Er}$, and ${}^{136,144}\mathrm{Xe}+{}^{186}\mathrm{W}$ are investigated within the framework of the dinuclear system model. The charge equilibration effects on the production cross sections of exotic nuclei are studied. The neutron-deficient projectile ${}^{124}\mathrm{Xe}$ is favorable to produce transtarget neutron-deficient nuclei, while ${}^{136,144}\mathrm{Xe}$ shows great advantages of cross sections for producing neutron-rich nuclei in the proton pick-up channel. Furthermore, the influence of entrance angular momentum on the charge equilibration process is investigated. It is found that in a low angular momentum channel the more profound reconstruction of initial nuclei is noticed rather than peripheral collisions. We predict the production cross sections of several neutron-rich nuclei in the reactions ${}^{136,144}\mathrm{Xe}+{}^{160}\mathrm{Gd}, {}^{136,144}\mathrm{Xe}+{}^{170}\mathrm{Er}$, and ${}^{136,144}\mathrm{Xe}+{}^{186}\mathrm{W}$. It is found that many unknown nuclei can be produced at the level of $\mu \mathrm{b}$ to mb.

The chiral magnetic effect (CME) is a fundamental prediction of QCD, and various observables have been proposed in heavy ion collisions to access this physics. Recently the CMS Collaboration [V. Khachatryan et al., Phys. Rev. Lett. 118, 122301 (2017)] has reported results from $p+\mathrm{Pb}$ collisions at 5.02 TeV on one such observable, the three-point correlator. The results are strikingly similar to those measured at the same particle multiplicity in $\mathrm{Pb}+\mathrm{Pb}$ collisions, which have been attributed to the CME. This similarity, combined with two key assumptions about the magnetic field in $p+\mathrm{Pb}$ collisions, presents a major challenge to the CME picture. These two assumptions as stated in the CMS paper are (i) that the magnetic field in $p+\mathrm{Pb}$ collisions is smaller than that in $\mathrm{Pb}+\mathrm{Pb}$ collisions and (ii) that the magnetic field direction is uncorrelated with the flow angle. We test these two postulates in the Monte Carlo–Glauber framework and find that the magnetic fields are not significantly smaller in central $p+\mathrm{Pb}$ collisions; however the magnetic field direction and the flow angle are indeed uncorrelated. The second finding alone gives strong evidence that the three-point correlator signal in $\mathrm{Pb}+\mathrm{Pb}$ and $p+\mathrm{Pb}$ collisions is not an indication of the CME. Similar measurements in $d+\mathrm{Au}$ over a range of energies accessible at the BNL Relativistic Heavy Ion Collider would be elucidating. In the same calculational framework, we find that even in $\mathrm{Pb}+\mathrm{Pb}$ collisions, where the magnetic field direction and the flow angle are correlated, there exist large inhomogeneities that are on the size scale of topological domains. These inhomogeneities need to be incorporated in any detailed CME calculation.

We employ a set of recent, theoretically motivated fits to nonperturbative unquenched gluon propagators to check on how far double gluon exchange can be used to describe the soft sector of $pp$ scattering data (total and differential cross section). In particular, we use the refined Gribov-Zwanziger gluon propagator (as arising from dealing with the Gribov gauge fixing ambiguity) and the massive Cornwall-type gluon propagator (as motivated from Dyson-Schwinger equations) in conjunction with a perturbative quark-gluon vertex, next to a model based on the nonperturbative quark-gluon Maris-Tandy vertex, popular from Bethe-Salpeter descriptions of hadronic bound states. We compare the cross sections arising from these models with older ISR and more recent TOTEM and ATLAS data. The lower the value of total energy $\sqrt{s}$, the better the results appear to be.

We discuss the pole mass and the width of the $\mathrm{\Delta }\left(1232\right)$ resonance to third order in chiral effective field theory. In our calculation we choose the complex-mass renormalization scheme (CMS) and show that the CMS provides a consistent power-counting scheme. In terms of the pion-mass dependence, we compare the convergence behavior of the CMS with the small-scale expansion.

Harissopulos et al. [Phys. Rev. C 72, 062801(R) (2005)] report a cross section from a measurement that used a moderated neutron detector not capable of measuring the neutron energy and therefore unable to determine the relative contribution from neutrons that populate the ground state or excited ${}^{16}\mathrm{O}$ states in ${}^{13}\mathrm{C}(\alpha ,n){}^{16}\mathrm{O}$ reactions above 5 MeV. Since the energies of ejected neutrons populating the excited states are 6 MeV lower than those populating the ground state, the corresponding efficiency of their neutron detector for these neutrons was a factor of 2 higher than assumed. Therefore, the reported ${}^{13}\mathrm{C}(\alpha ,n){}^{16}\mathrm{O}$ cross sections above 5 MeV may be overcalculated by nearly 50%.

A systematic search for axial octupole deformation in the actinides and superheavy nuclei with proton numbers $Z=88–126$ and neutron numbers from the two-proton drip line up to $N=210$ was performed in covariant density functional theory (DFT) using four state-of-the-art covariant energy density functionals representing different model classes. The nuclei in the $Z\sim 96, N\sim 196$ region of octupole deformation were investigated in detail and the systematic uncertainties in the description of their observables were quantified. A similar region of octupole deformation exists also in Skyrme DFT and microscopic+macroscopic approaches but it is centered at somewhat different particle numbers. Theoretical uncertainties in the predictions of the regions of octupole deformation increase on going to superheavy nuclei with $Z\sim 120, N\sim 190$. There are no octupole deformed nuclei for $Z=112–126$ in covariant DFT calculations. This agrees with Skyrme DFT calculations, but disagrees with Gogny DFT and microscopic+macroscopic calculations which predict an extended $Z\sim 120, N\sim 190$ region of octupole deformation.

Within the improved Weizsäcker-Skyrme (WS)-type nuclear mass formulas, we systematically calculated one-nucleon and two-nucleon separated energy, α-decay and β-decay energies, and the odd-even staggering (OES) of nuclear binding energies. As a result, the root-mean-square (rms) deviations of 2267 nuclei within the new improved WS-type mass formula are dropped from 493 to 167 keV, where 2267 nuclei are extracted from the atomic mass evaluation of 2012. Simultaneously, all the rms deviations of one-nucleon and two-nucleon separation energies and decay energies $Q_{\alpha },Q_{{\beta }^{-}},Q_{{\beta }^{+}}$, and $Q_{\mathrm{EC}}$ for more than 3000 nuclei are cut down by about 100–400 keV. Further, some basic physical observations of 988 boundary nuclei are predicted for providing reference to experiments. Finally, the overall neutron OESs and proton OESs have been systemically investigated and the residual error satisfies a normal distribution. The pairing gaps ${\mathrm{\Delta }}_{\mathrm{n}}$ and ${\mathrm{\Delta }}_{\mathrm{p}}$ of the isotopes of O, Ca, Ni, Zr, Sn, Gd, Qs, Pb, Pa, Ds and the isotonic magic chains of $N=28,50,82,126$ and even-even nuclei are also studied with dramatic improvements obtained. Especially, the rms of ${\mathrm{\Delta }}_{\mathrm{n}}$ and ${\mathrm{\Delta }}_{\mathrm{p}}$ in these nuclei have been reduced by about 200 keV. The above physical quantities show important information for nuclear charts and the features of nuclear structure.

Lifetimes of excited states in the yrast band of the neutron-deficient nuclide ${}^{166}\mathrm{W}$ have been measured utilizing the DPUNS plunger device at the target position of the JUROGAM II $\gamma$-ray spectrometer in conjunction with the RITU gas-filled separator and the GREAT focal-plane spectrometer. Excited states in ${}^{166}\mathrm{W}$ were populated in the ${}^{92}\mathrm{Mo}({}^{78}\mathrm{Kr},4p$) reaction at a bombarding energy of 380 MeV. The measurements reveal a low value for the ratio of reduced transitions probabilities for the lowest-lying transitions $B(E2;4^{+}\to 2^{+})/B(E2;2^{+}\to 0^{+})=0.33\left(5\right)$, compared with the expected ratio for an axially deformed rotor ($B_{4/2}$ = 1.43).