We study the superdeformed (SD) states and corresponding SD hypernuclei of Ar isotopes with the multidimensionally constrained relativistic mean field (MDC-RMF) models, which can accommodate various shape degree of freedom. We found that the density profiles of SD states in Ar isotopes show a strong localization with a ring structure near the surface, while the central part of the density is dilute, showing a hole structure. This localization of SD density induces an appreciable deformation in the hyperon wave function and results in a large overlap between the core and the hyperon in the SD hypernuclei of Ar isotopes. Then the $\Lambda$ separation energy of the SD state becomes larger than that of a normally deformed or spherical ground state. This feature is different from that found in other nuclei such as ${}^{32}$S, ${}^{56}$Ni, and ${}^{60}$Zn in which the $\Lambda$ separation energy of larger deformed state is smaller. In this context, the measurement of the $\Lambda$ separation energy may provide important information on the localization of the density profile of SD states.

High-spin level structures of the near-spherical nuclei ${}^{91,92}$Zr have been reinvestigated via the ${}^{82}$Se(${}^{13}$C, $xn$) $(x=4,3)$ reactions at a beam energy of 44 MeV. By the use of in-beam spectroscopic methods, 13 new transitions belonging to ${}^{91}$Zr and 19 to ${}^{92}$Zr have been observed and the level schemes of ${}^{91,92}$Zr have been extended up to $E_x\approx$ 11 MeV excitation energy. The newly constructed level schemes are characterized by the ${}^{88}$Sr core breaking, and the proton $p_{3/2}\text{−}{p}_{1/2}$ energy gap in ${}^{92}$Zr is obviously reduced compared with ${}^{91}$Zr when one more neutron goes into the $(d_{5/2}/g_{7/2})$ orbital.

This paper reports NMR measurements of the magnetic dipole moments of two high-$K$ isomers, the 37/2${}^{-}$, 51.4 m, 2740 keV state in ${}^{177}\mathrm{Hf}$ and the $8^{-}$, 5.5 h, 1142 keV state in ${}^{180}\mathrm{Hf}$ by the method of on-line nuclear orientation. Also included are results on the angular distributions of $\gamma$ transitions in the decay of the ${}^{177}\mathrm{Hf}$ isotope. These yield high precision $E2/M1$ multipole mixing ratios for transitions in bands built on the 23/2${}^{+}$, 1.1 s, isomer at 1315 keV and on the 9/2${}^{+}$, 0.663 ns, isomer at 321 keV. The new results are discussed in the light of the recently reported finding of systematic dependence of the behavior of the $g_R$ parameter upon the quasiproton and quasineutron make up of high-$K$ isomeric states in this region.

I analyze the pion femtoscopy correlations in noncentral Au-Au and Pb-Pb collisions. The azimuthally sensitive Hanbury-Brown-Twiss (HBT) method is used to extract the interferometry radii depending on the azimuthal angle with respect to the second- and third-order event plane. The results are in semiquantitative agreement with the STAR collaboration data on the HBT radii with respect to the second-order reaction plane, with the preliminary PHENIX collaboration data on the HBT radii with respect to the third-order reaction plane in Au-Au collisions at 200 GeV, and with the preliminary ALICE collaboration data for the HBT radii with respect to the second-order event plane for Pb-Pb collisions at $2.76$ TeV.

Inelastic $\alpha$-scattering excitation cross sections are calculated for electric-dipole excitations in ${}^{124}\mathrm{Sn}$ based on the transition densities obtained from the relativistic quasiparticle time-blocking approximation (RQTBA) in the framework of a semiclassical model. The calculation provides the missing link to directly compare the results from the microscopic RQTBA calculations to recent experimental data measured via the $(\alpha ,{\alpha }^{\prime }\gamma )$ reaction, which show a structural splitting of the low-lying $E1$ strength often denoted as pygmy dipole resonance (PDR). The experimentally observed splitting is reproduced by the cross-section calculations, which allows us to draw conclusion on the structure of the PDR.

We study the one-body momentum distribution at different densities in nuclear matter, with special emphasis on its components at high momentum. Explicit calculations for finite neutron-proton asymmetry, based on the ladder self-consistent Green's function approach, allow us to access the isospin dependence of momentum distributions and elucidate their role in neutron-rich systems. Comparisons with the deuteron momentum distribution indicate that a substantial proportion of high-momentum components are dominated by tensor correlations. We identify the density dependence of these tensor correlations in the momentum distributions. Further, we find that high-momentum components are determined by the density of each subspecies and we provide a new isospin-asymmetry scaling of these components. We use different realistic nucleon-nucleon interactions to quantify the model dependence of our results.

Configuration-constrained potential-energy-surface calculations are performed including ${\beta }_6$ deformation to investigate high-$K$ isomeric states in nuclei around ${}^{254}$No and ${}^{270}$Ds, the heaviest nuclei where there have been some observations of two-quasiparticle isomers, while data for four-quasiparticle isomers are scarce. We predict the prevalent occurrence of four-quasiparticle isomeric states in these nuclei, together with their favored configurations. The most notable examples, among others, are $K^{\pi }={20}^{+}$ states in ${}^{266,268}$Ds and ${}^{268,270}$Cn having very high $K$ value, relatively low excitation energy, and well-deformed axially symmetric shape. The predicted isomeric states, with hindered spontaneous fission and $\alpha$ decay, could play a significant role in the future study of superheavy nuclei.

This article generalizes the notion of the local density of a many-body system to introduce collective coordinates as explicit degrees of freedom. It is shown that the energy of the system can be expressed as a functional of this object. The latter can in turn be factorized as the product of the square modulus of a collective wave function and a normalized collective-coordinate-dependent density. Energy minimization translates into a set of coupled equations, i.e., a local Schrödinger equation for the collective wave function and a set of Kohn-Sham equations for optimizing the normalized density at each point in the collective space. These equations reformulate the many-body problem exactly provided one is able to determine density- and collective-wave-function-dependent terms of the collective mass and potential which play a similar role to the exchange-correlation term in electronic Kohn-Sham density functional theory.

Using the color evaporation model, the cross section for charmonium production in $\text{p}+\text{p}$ collision is calculated in quark-gluon plasma. The threshold energy for open charms is given by the free-energy potential from lattice calculations, the initial charm quark pairs by the pythia simulations, and their time evolution by solving the Langevin equation. It is found that the threshold energy, which decreases with temperature, reduces the cross section while the invariant mass of charm pairs which decreases by collisions enhances it. As a result, charmonium production is suppressed by $20\%\sim 50\%$ depending on temperature and charm diffusion constant while $J/\psi$ production is similar or enhanced compared with in vacuum.

The tilted axis cranking model based on covariant density functional theory is used to investigate the negative-parity yrast sequence in ${}^{109}\mathrm{Cd}$. The energy spectra, the relation between spin and rotational frequency, deformation parameters, and reduced $E2$ transition probabilities are calculated, which are in good agreement with available data. The orientation of angular momentum is also extracted and discussed in detail. By investigating microscopically the orientation of angular momentum and the contributions of antimagnetic rotation and core rotation to the total angular momentum, we find that ${}^{109}\mathrm{Cd}$ should be a critical transitional nucleus between the antimagnetic and core rotations.

We study the energy of an impurity (polaron) that interacts strongly in a sea of fermions when the effective range of the impurity-fermion interaction becomes important, thereby mapping the Fermi polaron of condensed matter physics and ultracold atoms to strongly interacting neutrons. We present quantum Monte Carlo results for this neutron polaron, and compare these with effective field theory calculations that also include contributions beyond the effective range. We show that state-of-the-art nuclear density functionals vary substantially and generally underestimate the neutron polaron energy. Our results thus provide constraints for adjusting the time-odd components of nuclear density functionals to better characterize polarized systems.

The effect of $\delta$- and $\omega \text{−}\rho$-meson cross couplings on asymmetry nuclear systems are analyzed in the framework of an effective field theory motivated relativistic mean field formalism. The calculations are done on top of the G2 parameter set, where these contributions are absent. To show the effect of $\delta$ meson on the nuclear system, we split the isospin coupling into two parts: (i) $g_{\rho }$ due to $\rho$ meson and (ii) $g_{\delta }$ for $\delta$ meson. Thus, our investigation is based on varying the coupling strengths of the $\delta$ and $\rho$ mesons to reproduce the binding energies of the nuclei ${}^{48}\mathrm{Ca}$ and ${}^{208}\mathrm{Pb}$. We calculate the root mean square radius, binding energy, single particle energy, density, and spin-orbit interaction potential for some selected nuclei and evaluate the $L_{\mathrm{sym}}$ and $E_{\mathrm{sym}}$ coefficients for nuclear matter as function of $\delta$- and $\omega \text{−}\rho$-meson coupling strengths. As expected, the influence of these effects are negligible for the symmetric nuclear system, but substantial for the contribution with large isospin asymmetry.

The formalism of linear response theory for a Skyrme functional including spin-orbit and tensor terms is generalized to the case of infinite nuclear matter with arbitrary isospin asymmetry. Response functions are obtained by solving an algebraic system of equations, which is explicitly given. Spin-isospin strength functions are analyzed varying the conditions of density, momentum transfer, asymmetry, and temperature. The presence of instabilities, including the spinodal one, is studied by means of the static susceptibility.

The treatment of angular momentum in the event-by-event fission model Fission Reaction Event Yield Algorithm (freya) has been refined to ensure conservation of angular momentum both at scission and during neutron evaporation. While the effect on previously calculated quantities is relatively minor, as expected, the refined model gives a more consistent description of directional correlations.

The total charge-changing, charge pick-up, and partial charge-changing cross sections of very neutron-rich nuclei (${}^{30}\mathrm{Ne}$, ${}^{32,33}\mathrm{Na}$) with a proton target have been measured at ∼240$A$ MeV for the first time. We introduced the phenomenological correction factor in Glauber-model calculations for the total charge-changing cross sections with the proton target, and applied it to deduce the proton radii of these nuclei. For ${}^{30}\mathrm{Ne}$ and ${}^{32}\mathrm{Na}$, the neutron skin thicknesses of the nuclei were deduced by comparing the proton radii with the matter radii deduced from the interaction cross-section measurements. A significant thick neutron-skin has been observed for the nuclei. We also found that the charge pick-up cross sections are much larger than those in the systematics of stable nuclei.

Within the newly updated version of the ultrarelativistic quantum molecular dynamics (UrQMD) model, the transverse-velocity dependence of the elliptic flow of free nucleons from ${}^{197}\mathrm{Au}$+${}^{197}\mathrm{Au}$ collisions at the incident energy 400 MeV$/$nucleon is studied within different windows of the normalized c.m. rapidity $y_0$. It is found that the elliptic flow difference $v_2^n-v_2^p$ and ratio $v_2^n$/$v_2^p$ of neutrons versus protons are sensitive to the density dependence of the symmetry energy, especially the ratio $v_2^n$/$v_2^p$ at small transverse velocity in the intermediate rapidity intervals $0.4<|y_0|<0.6$. By comparing either transverse-momentum-dependent or integrated FOPI/LAND elliptic flow data of nucleons and hydrogen isotopes with calculations using various Skyrme interactions, all exhibiting similar values of isoscalar incompressibility but very different density dependences of the symmetry energy, a moderately soft to linear symmetry energy is extracted, in good agreement with previous UrQMD or Tübingen QMD model calculations but contrast with results obtained with ${\pi }^{-}/{\pi }^{+}$ yield ratios in the literature.

We study elliptic and triangular flow in the collisions of deuteron-gold nuclei at $\sqrt{s_{NN}}=200$ GeV at RHIC and of proton-lead nuclei at $\sqrt{s_{NN}}=5.02$ TeV at the LHC, utilizing (3+1)-dimensional ideal hydrodynamics for the dynamic evolution of the fireball and a Monte Carlo Glauber based energy deposition model for simulating the fluctuating initial conditions. Sizable values of elliptic and triangular flow are obtained for both colliding systems, and the results are consistent with PHENIX, ALICE, ATLAS, and CMS measurements. For these studied centralities, we find that the elliptic flow in proton-lead collisions is smaller than deuteron-gold collisions, while the triangular flows are comparable in both colliding systems. Our results indicate that the observed collective anisotropic flow in deuteron-gold and proton-lead collisions may be obtained from relativistic hydrodynamic evolution of the fireball with initial-state fluctuations.