The three-body system inside the unitary window is studied for three equal bosons and three equal fermions having $1/2$ spin-isospin symmetry. We perform a Gaussian characterization of the window using a Gaussian potential to define trajectories for low-energy quantities as binding energies and phase shifts. On top of this trajectories experimental values are placed or, when not available, quantities calculated using realistic potentials that are known to reproduce experimental values. The intention is to show that the Gaussian characterization of the window, thought as a contact interaction plus range corrections, captures the main low-energy properties of real systems as for example three helium atoms or three nucleons. The mapping of real systems on the Gaussian trajectories is taken as indication of universal behavior. The trajectories continuously link the physical points to the unitary limit allowing for the explanation of strong correlations between observables appearing in real systems and which are known to exist in that limit. In the present study we focus on low-energy bound, scattering, and virtual states.

We propose a new two-dimensional (2D) plotting method of isoscalar-isovector (IS-IV) densities of ${}^{48}\mathrm{Ca}$ and ${}^{208}\mathrm{Pb}$ to extract not only empirical symmetry energy coefficients $J, L$, and $K_{\mathrm{sym}}$ but also the asymmetric isospin term $K_{\tau }$ in the nuclear incompressibility. We adopted several modern relativistic and nonrelativistic energy density functional (EDF) for the theoretical calculations of IS and IV densities to compare with experimental neutron and proton density distributions determined by recent proton elastic scatterings. We found very strong correlations between the trajectory of the 2D density at the density $\rho =0.1{\mathrm{fm}}^{-3}$ and the symmetry energy coefficients $J, L$, and also $K_{\tau }$. For $K_{\mathrm{sym}}$, the Skyrme EDF SAMi-J family shows a strong correlation in the trajectory of 2D density, while the RMF Lagrangian DDME-J family shows a peculiar quadratic curve and does not provide the experimental value. The symmetry energy term $K_{\tau }$ of nuclear incompressibility is also discussed in term of the slope of 2D trajectory.

The multinucleon transfer reaction is treated as a diffusion process by solving four-variable master equations within the dinuclear system (DNS) concept. The reaction systems ${}^{136}\mathrm{Xe}+{}^{208}\mathrm{Pb}$ and ${}^{136}\mathrm{Xe}+{}^{198}\mathrm{Pt}$ are investigated and compared to the experimental data. The calculated results correctly describe the magnitude and maxima of the observed transfer cross sections for a wide range of transfers. One finds that the neutron richness of the reaction products is strongly dependent on the projectile energy near the Coulomb barrier. By comparing the obtained results for the above two reaction systems, the absolute cross sections from the ${}^{208}\mathrm{Pb}$ target predict smaller production cross sections for neutron-deficient nuclei and moderately neutron-rich nuclei as compared to ${}^{198}\mathrm{Pt}$.

${}^{208}\mathrm{Pb}$ is a doubly magic nucleus which has been studied extensively by many experiments and nuclear models. Its properties, such as excitation energies, spins, and parities of the ground and excited states are well known. However, some $\gamma$ transitions with $E_{\gamma }>3$ MeV from the excited states to the ground state in ${}^{208}\mathrm{Pb}$ have never been observed. The intensities of these $\gamma$ transitions are important issues for $0\nu \beta \beta$ decay searches because these transitions can make non-negligible background signals depending on their intensities. We conducted a measurement to search for the 3197.7, 3475.1, and 3708.4 keV transitions, which are emitted from the second, third, and fourth excited states in ${}^{208}\mathrm{Pb}$, respectively. A 2 kg ${\mathrm{ThO}}_2$ sample was measured using a 100% relative efficiency high-purity germanium detector for 39.5 days at Y2L, an underground laboratory in Yangyang, Korea. We improved upper limits for intensities of the 3197.7, 3475.1, and 3708.4 keV $\gamma$ transitions as $<1.2\times {10}^{-4}\%, <1.4\times {10}^{-4}\%$, and $<1.2\times {10}^{-4}\%$, respectively. These upper limits are at least a factor of 19 better than the previous results.

We introduce an improved form for the anisotropic hydrodynamics distribution function which explicitly takes into account the free-streaming and equilibrating contributions separately. We demonstrate that with this improvement one can better reproduce exact results available in the literature for the evolution of moments of the distribution function, in particular, for moments which contain no powers of the longitudinal momentum in their definition ($m=0$ moments). Using the resulting dynamical equations, we extract the non-equilibrium attractor associated with our improved anisotropic hydrodynamics ansatz and demonstrate that the improvement also allows one to better reproduce the exact dynamical attractor obtained using kinetic theory in the relaxation time approximation, particularly at early rescaled times and for $m=0$ moments.

The PHENIX experiment at the Relativistic Heavy Ion Collider measured ${\pi }^0$ and $\eta$ mesons at midrapidity in $\mathrm{U}+\mathrm{U}$ collisions at $\sqrt{s_{{}_{NN}}}=192$ GeV in a wide transverse momentum range. Measurements were performed in the ${\pi }^0\left(\eta \right)\to \gamma \gamma$ decay modes. A strong suppression of ${\pi }^0$ and $\eta$ meson production at high transverse momentum was observed in central $\mathrm{U}+\mathrm{U}$ collisions relative to binary scaled $p+p$ results. Yields of ${\pi }^0$ and $\eta$ mesons measured in $\mathrm{U}+\mathrm{U}$ collisions show similar suppression pattern to those measured in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV for similar numbers of participant nucleons. The $\eta /{\pi }^0$ ratios do not show dependence on centrality or transverse momentum and are consistent with previously measured values in hadron-hadron, hadron-nucleus, nucleus-nucleus, and $e^{+}{e}^{-}$ collisions.

We calculate cross sections for inclusive dijet photoproduction in electron-nucleus scattering in the kinematics of the future EIC and the possible LHeC, HE-LHeC, and FCC using next-to-leading order (NLO) perturbative QCD and nCTEQ15 and EPPS16 nuclear parton density functions (nPDFs). We make predictions for distributions in the dijet average transverse momentum ${\overline{p}}_T$, the average rapidity $\overline{\eta }$, the observed nuclear momentum fraction $x_A^{\mathrm{obs}}$, and the observed photon momentum fraction $x_{\gamma }^{\mathrm{obs}}$. Comparing the kinematic reaches of the four colliders, we find that an increase of the collision energy from the EIC to the LHeC and beyond extends the coverage in all four considered variables. Notably, the LHeC and HE-LHeC will allow one to probe the dijet cross section down to $x_A^{\mathrm{obs}}\sim {10}^{-4}$ (down to $x_A^{\mathrm{obs}}\sim {10}^{-5}$ at the FCC). The ratio of the dijet cross sections on a nucleus and the proton, ${\sigma }_A/\left(A{\sigma }_p\right)$, depends on $x_A^{\mathrm{obs}}$ in a similar way as the ratio of gluon densities, $g_A(x_A,{\mu }^2)/\left[A{g}_p(x_A,{\mu }^2)\right]$, for which current nPDFs predict a strong suppression due to nuclear shadowing in the region $x_A^{\mathrm{obs}}<0.01$. Dijet photoproduction at future lepton-nucleus colliders can therefore be used to test this prediction and considerably reduce the current uncertainties of nPDFs.

We extend the excluded-volume model of isospin symmetric two-flavor dense quarkyonic matter [Phys. Rev. C 101, 035201 (2020)] including strange particles and address its implications for neutron stars. The effective sizes of baryons are defined from the diverging hard-core potentials in the short interdistance regime. Around the hard-core density, the repulsive core between baryons at short distances leads to a saturation in the number density of baryons and generates perturbative quarks from the lower phase space, which leads to the shell-like distribution of baryons by the Pauli exclusion principle. The strange-quark Fermi sea always appears at high densities but the $\mathrm{\Lambda }$ hyperon shell only appears when the effective size of the $\mathrm{\Lambda }$ hyperon is smaller than the effective size of nucleons. We find that the pressure of strange quarkyonic matter can be large enough to support neutron stars with two times solar mass and can have a large sound speed, $c_s^2\simeq 0.7$. The fraction of the baryon number carried by perturbative quarks is about 30% at the inner core of most massive neutron stars.

We develop a manifestly microscopic method to deal with strongly interacting nuclear systems that have different interactions in spin-singlet and spin-triplet states. In a first step we analyze variational wave functions that have been suggested to describe such systems and demonstrate that the so-called commutator contributions can have important effects whenever the interactions in the spin-singlet and the spin-triplet states are very different. We then identify these contributions as terms that correspond, in the language of perturbation theory, to non-parquet diagrams. We include these diagrams in a way that is suggested by the Jastrow-Feenberg approach and show that the corrections from non-parquet contributions are, at short distances, larger than all other many-body effects.

The ground state binary and ternary decays of the ${}^{253}\mathrm{Es}$ radioactive nucleus are investigated using the quantum mechanical fragmentation theory (QMFT) based cluster decay models. First, the relative fragmentation of ${}^{253}\mathrm{Es}$ is analyzed within the framework of the preformed cluster model (PCM). The PCM-calculated binary fragmentation structure is explored for two types of nuclear potential, i.e., Yukawa plus exponential and proximity potentials. The structure of the fragmentation potential and the location of potential minima are found to be independent of the choice of nuclear potential. It is observed from binary fragmentation structures that $\alpha$ $\left({}^4\mathrm{He}\right)$ decay, cluster $\left({}^{46}\mathrm{Ar}\right)$ emission, heavy particle $\left({}^{82}\mathrm{Ge}\right)$ radioactivity, and spontaneous fission fragmentation $\left({}^{125}\mathrm{In}\right)$ are the possible ground state decay modes of the ${}^{253}\mathrm{Es}$ nucleus. The competitive emergence of these decay channels is explored by studying the preformation probability $P_0$, penetrability $P$, and half-lives $T_{1/2}$. The calculated half-lives of $\alpha$ and spontaneous fission match nicely with the experimental measurements. Also, the half-lives are predicted for cluster and heavy particle radioactivity, for which experimental verification would be of further interest. Further, an effort is made to explore the possibility of ternary fission (particle accompanied fission) for the decay of the ${}^{253}\mathrm{Es}$ nucleus using the three-cluster model (TCM), where ${}^4\mathrm{He}$ is observed to be the third fragment along with two binary fission fragments. A comparison of relative yields of binary and ternary fission confirm that the probability of the binary fission decay mode is larger than that of ternary fission. Moreover, closed shell effects play a significant role in the symmetric and asymmetric fission of binary and ternary fission, respectively.

We investigate effects of thermal and quantum fluctuations of the superfluid order parameter in ${}^{1}S_0$ superfluids in neutron stars. We construct a separable potential to reproduce the ${}^{1}S_0$ phase shift reconstructed by using the partial wave analysis from nucleon scattering data. We include superfluid fluctuations within a strong-coupling approximation developed by Nozières and Schmitt-Rink and determine self-consistently the superfluid order parameter as well as the chemical potential. We show that the quantum depletion, which gives a fraction of noncondensed neutrons at zero temperature due to quantum pairing fluctuations, plays an important role not only near the critical temperature from superfluid states to normal states but also at zero temperature. We derive the dispersion relation of Anderson-Bogoliubov modes associated with phase fluctuations and show also that there is a nonzero fraction of noncondensed components in the neutron number as a result of the strong-coupling effect. Our results indicate that superfluid fluctuations are important for thermodynamic properties in neutron stars.

In $\beta$-decay studies the determination of the decay probability to the ground state (g.s.) of the daughter nucleus often suffers from large systematic errors. The difficulty of the measurement is related to the absence of associated delayed $\gamma$-ray emission. In this work we revisit the $4\pi \gamma -\beta$ method proposed by Greenwood and collaborators in the 1990s, which has the potential to overcome some of the experimental difficulties. Our interest is driven by the need to determine accurately the $\beta$-intensity distributions of fission products that contribute significantly to the reactor decay heat and to the antineutrinos emitted by reactors. A number of such decays have large g.s. branches. The method is relevant for nuclear structure studies as well. Pertinent formulas are revised and extended to the special case of $\beta$-delayed neutron emitters, and the robustness of the method is demonstrated with synthetic data. We apply it to a number of measured decays that serve as test cases and discuss the features of the method. Finally, we obtain g.s. feeding intensities with reduced uncertainty for four relevant decays that will allow future improvements in antineutrino spectrum and decay heat calculations using the summation method.

A search for production of the superheavy elements with atomic numbers 119 and 120 was performed in the ${}^{50}\mathrm{Ti}+{}^{249}\mathrm{Bk}$ and ${}^{50}\mathrm{Ti}+{}^{249}\mathrm{Cf}$ fusion-evaporation reactions, respectively, at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. Over four months of irradiation, the ${}^{249}\mathrm{Bk}$ target partially decayed into ${}^{249}\mathrm{Cf}$, which allowed for a simultaneous search for both elements. Neither was detected at cross-section sensitivity levels of 65 and 200 fb for the ${}^{50}\mathrm{Ti}+{}^{249}\mathrm{Bk}$ and ${}^{50}\mathrm{Ti}+{}^{249}\mathrm{Cf}$ reactions, respectively, at a midtarget beam energy of $E_{\mathrm{lab}}=281.5$ MeV. The nonobservation of elements 119 and 120 is discussed within the concept of fusion-evaporation reactions including various theoretical predictions on the fission-barrier heights of superheavy nuclei in the region of the island of stability.

We investigate the effect of hydrodynamic fluctuations on the rapidity decorrelations of anisotropic flow in high-energy nuclear collisions using a $(3+1)$-dimensional integrated dynamical model. The integrated dynamical model consists of twisted initial conditions, fluctuating hydrodynamics, and hadronic cascades on an event-by-event basis. We consider several choices of the cutoff which is the free parameter of fluctuating hydrodynamics within the current modeling. To understand the rapidity decorrelation, we analyze the factorization ratio in the longitudinal direction. Comparing the factorization ratios between fluctuating hydrodynamics and ordinary viscous hydrodynamics, we find a sizable effect of hydrodynamic fluctuations on rapidity decorrelations. We qualitatively describe the experimental data of the factorization ratios. We also propose to calculate the Legendre coefficients of the flow magnitude and the event-plane angle to understand the decorrelation of anisotropic flow in the longitudinal direction.

The outer crust properties of cold nonaccreting neutron stars are studied within the framework of the quark-meson coupling (QMC) model, which includes the effects of modifications of the quark structure inside individual nucleons when they are within a high-density nuclear medium. With a unique set of five well-constrained adjustable parameters, which have a clear physical basis, the QMC model gives predictions for the ground state observables of even-even nuclei which agree with experiment as well as traditional models. Furthermore, it gives improved theoretical values for nuclei thought to play a role in the outer crusts of neutron stars but for which experimental data are not available. Using the latest experimental data tables wherever possible but otherwise the predictions from the QMC model, we construct an equation of state for the outer crust, which is then used within stellar model calculations to obtain an equilibrium sequence of crustal layers, each characterized by a particular neutron-rich nucleus. Various properties of the layers are calculated for a range of neutron-star masses and comparisons are made with alternative equations of state from the literature. This leads to the conclusion that the QMC model successfully predicts the outer crust properties and is fully comparable with the more traditional mass models, which all depend on a larger number of parameters.

Background: The region of the neutron-rich calcium isotopes chain of the nuclei chart is, nowadays, of great activity. The experimental assessment of the limit of stability is of interest to confirm or improve microscopic theoretical models.

Purpose: The goal of this work is to provide the drip line of the calcium isotopes from the exact solution of the pairing Hamiltonian which incorporates explicitly the correlations with the continuum spectrum of energy.

Method: The modified Richardson equations, which include correlations with the continuum spectrum of energy modeled by the continuum single particle level density, is used to solve the many-body system. Three models are used, two isospin independent models with core ${}^{40}\mathrm{Ca}$ and ${}^{48}\mathrm{Ca}$, and one isospin dependent model.

Results: One- and two-neutron separation energies and occupation probabilities for bound and continuum states are calculated from the solution of the Richardson equations.

Conclusions: The one particle drip line is found at the nucleus ${}^{57}\mathrm{Ca}$, while the two neutron drip line is found at the nucleus ${}^{60}\mathrm{Ca}$ from the isospin independent model and at ${}^{66}\mathrm{Ca}$ from the isospin dependent one.

The level structure of ${}^{25}\mathrm{Na}$ and ${}^{22}\mathrm{Ne}$ in the high excitation energy/high spin regime was studied using $\gamma$-ray spectroscopy and Doppler shift lifetime measurements following ${}^{12}\mathrm{C}({}^{18}\mathrm{O},\alpha p){}^{25}\mathrm{Na}$ and ${}^{12}\mathrm{C}({}^{18}\mathrm{O},2\alpha ){}^{22}\mathrm{Ne}$ reactions. Multiple new levels and transitions were identified in both nuclides based on $\gamma \text{−}\gamma$ coincidence data. In ${}^{25}\mathrm{Na}$, evidence was found for higher-spin negative-parity states up to $I^{\pi }=13/2^{-}$ resulting from neutron excitation into the $pf$ shell, in good agreement with shell model calculations using the SDPF-MU and FSU interactions. Candidates for the yrast $7^{+}$ and $8^{+}$ levels in ${}^{22}\mathrm{Ne}$, consistent with calculations using the USDB interaction, were also identified.

A formula to evaluate the effects of a general deformation on the Coulomb direct contribution to the energy of the isobaric analog state (IAS) is presented and studied via a simple yet physical model. The toy model gives a reasonable account of microscopic deformed Hartree-Fock-Bogoliubov (HFB) calculations in a test case, and provides a guidance when predicting unknown IAS energies. Thus, deformed HFB calculations, to predict the IAS energies, are performed for several neutron-deficient medium-mass and heavy nuclei which are now planned to be studied experimentally.