To investigate the possible X(5) character of ${}^{122}\mathrm{Ba}$, suggested by the ground-state band energy pattern, the lifetimes of the lowest yrast states of ${}^{122}\mathrm{Ba}$ have been measured, via the recoil distance Doppler-shift method. The relevant levels have been populated by using the ${}^{108}\mathrm{Cd}$(${}^{16}\mathrm{O}$,$2n$)${}^{122}\mathrm{Ba}$ and the ${}^{112}\mathrm{Sn}$(${}^{13}\mathrm{C}$,$3n$)${}^{122}\mathrm{Ba}$ reactions. The $B$($E2$) values deduced in the present work are compared to the predictions of the X(5) model and to calculations performed in the framework of the IBA-1 and IBA-2 models.

The mechanism of the ternary breakup of the very heavy system ${}^{197}\mathrm{Au}+{}^{197}\mathrm{Au}$ at an energy of $15A$ MeV has been studied by using the improved quantum molecular dynamics model. The calculation results reproduce the characteristic features in ternary breakup events explored in a series of experiments; i.e., the masses of three fragments are comparable in size and the very fast, nearly collinear breakup of the colliding system is dominant in the ternary breakup events. Further, the evolution of the time scales of different ternary reaction modes and the behavior of mass distributions of three fragments with impact parameters are studied. The time evolution of the configurations of the composite reaction systems is also studied. We find that for most of the ternary breakup events with the features found in the experiments, the configuration of the composite system has two-preformed-neck shape. The study shows that those ternary breakup events having the characteristic features found in the experiments happen at relatively small impact parameter reactions, but not at peripheral reactions. The ternary breakup reaction at peripheral reactions belongs to binary breakup with a neck emission.

Fusion excitation functions have been measured for the first time with rather good accuracy for ${}^{32}\mathrm{S}+{}^{90}\mathrm{Zr}$ and ${}^{32}\mathrm{S}+{}^{96}\mathrm{Zr}$ near and below the Coulomb barrier. The sub-barrier cross sections for ${}^{32}\mathrm{S}+{}^{96}\mathrm{Zr}$ are much larger than for ${}^{32}\mathrm{S}+{}^{90}\mathrm{Zr}$. A coupled-channels calculation considering the inelastic excitations is capable of describing sub-barrier enhancement only for ${}^{32}\mathrm{S}+{}^{90}\mathrm{Zr}$. The unexplained part for ${}^{32}\mathrm{S}+{}^{96}\mathrm{Zr}$ is found to be correlated with the positive-$Q$-value intermediate neutron transfers in this system. The comparison with ${}^{40}\mathrm{Ca}+{}^{96}\mathrm{Zr}$ suggests that couplings to the positive-$Q$-value neutron transfer channels may play a role in the sub-barrier fusion enhancement. Multi-neutron transfers are taken into account in Zagrebaev’s semiclassical model to explain the discrepancies of the sub-barrier fusion cross sections for ${}^{32}\mathrm{S}+{}^{96}\mathrm{Zr}$.

We apply divergence-type theory (DTT) dissipative hydrodynamics to study the $2+1$ space-time evolution of the fireball created in Au$+$Au relativistic heavy-ion collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV. DTTs are exact hydrodynamic theories that do not rely on velocity gradient expansions and therefore go beyond second-order theories. We numerically solve the equations of motion of the DTT for Glauber initial conditions and compare the results with those of second-order theory based on conformal invariance (Baier-Romatschke-Son-Starinets model) and with data. We find that the charged-hadron minimum-bias elliptic flow reaches its maximum value at lower $p_T$ in the DTT, and that the DTT allows for a value of $\eta /s$ slightly larger than that of the BRSS. Our results show that the differences between viscous hydrodynamic formalisms are a significant source of uncertainty in the precise extraction of $\eta /s$ from experiments.

For $\beta$-equilibrated nuclear matter we estimate the contribution to the bulk viscosity from purely leptonic processes, namely the conversion of electrons to and from muons. For oscillation frequencies in the kilohertz range, we find that this process provides the dominant contribution to the bulk viscosity when the temperature is well below the critical temperature for superconductivity or superfluidity of the nuclear matter.

Fission properties of proton-induced fission on ${}^{232}\mathrm{Th}$, ${}^{237}\mathrm{Np}$, ${}^{238}\mathrm{U}$, ${}^{239}\mathrm{Pu}$, and ${}^{241}\mathrm{Am}$ targets, measured at the Louvain-la-Neuve cyclotron facility at proton energies of 26.5 and 62.9 MeV, are compared with the predictions of the state-of-the-art nuclear reaction code talys. The code couples the multimodal random neck-rupture model with the pre-equilibrium exciton and statistical models to predict fission fragment mass yields, pre- and post-scission neutron multiplicities, and total fission cross sections in a consistent approach. The sensitivity of the calculations to the input parameters of the code and possible improvements are discussed in detail.

Based on the Hugenholtz–Van Hove theorem, it is shown that both the symmetry energy $E$${}_{\mathrm{sym}}(\rho )$ and its density slope $L(\rho )$ at normal density ${\rho }_0$ are completely determined by the nucleon global optical potentials. The latter can be extracted directly from nucleon-nucleus scatterings, ($p,n$) charge-exchange reactions, and single-particle energy levels of bound states. Averaging all phenomenological isovector nucleon potentials constrained by world data available in the literature since 1969, the best estimates of $E_{\mathrm{sym}}({\rho }_0)=31.3$ MeV and $L({\rho }_0)=52.7$ MeV are simultaneously obtained. Moreover, the corresponding neutron-proton effective mass splitting in neutron-rich matter of isospin asymmetry $\delta$ is estimated to be $(m_n^{*}-m_p^{*})/m=0.32\delta$.

Using the ($2+1$)-dimensional viscous hydrodynamic code vish2$+$1 [H. Song and U. Heinz, Phys. Lett. B 658, 279 (2008); H. Song and U. Heinz, Phys. Rev. C 77, 064901 (2008); H. Song, Ph. D. thesis, The Ohio State University, 2009], we present systematic studies of the dependence of pion and proton transverse-momentum spectra and their elliptic flow in $200A$ GeV Au$+$Au collisions on the parameters of the hydrodynamic model (thermalization time, initial entropy density distribution, decoupling temperature, equation of state, and specific shear viscosity $\eta /s$). We identify a tension between the slope of the proton spectra, which (within hydrodynamic simulations that assume a constant shear viscosity to entropy density ratio) prefer larger $\eta /s$ values, and the slope of the $p_T$ dependence of charged hadron elliptic flow, which prefers smaller values of $\eta /s$. Changing other model parameters does not appear to permit dissolution of this tension.

The ${}^{15}\mathrm{N}$($p,\gamma ){}^{16}\mathrm{O}$ reaction represents a breakout reaction linking the first and second cycles of the CNO cycles redistributing the carbon and nitrogen abundances into the oxygen range. The reaction is dominated by two broad resonances, at $E_p=338$ and 1028 keV, and a direct capture contribution to the ground state of ${}^{16}\mathrm{O}$. Interference effects between these contributions both in the low-energy region ($E_p<338$ keV) and between the two resonances ($338<E_p<1028$ keV) can dramatically affect the extrapolation to energies of astrophysical interest. To facilitate a reliable extrapolation, the ${}^{15}\mathrm{N}$$(p,\gamma ){}^{16}\mathrm{O}$ reaction has been remeasured covering the energy range from $E_p=1800$ keV down to 130 keV. The results have been analyzed in the framework of a multilevel $R$-matrix theory and an $S(0)$ value of 39.6 keV b has been found.

Collinear laser spectroscopy was performed on the ${}^{80}\mathrm{Ga}$ isotope at ISOLDE, CERN. A low-lying isomeric state with a half-life much greater than $200$ ms was discovered. The nuclear spins and moments of the ground and isomeric states and the isomer shift are discussed. Probable spins and parities are assigned to both long-lived states ($3^{-}$ and $6^{-}$) deduced from a comparison of the measured moments to shell-model calculations.

In a recent series of articles, Gebremariam, Bogner, and Duguet derived a microscopically based nuclear energy density functional by applying the density matrix expansion (DME) to the Hartree-Fock energy obtained from chiral effective field theory two- and three-nucleon interactions. Owing to the structure of the chiral interactions, each coupling in the DME functional is given as the sum of a coupling constant arising from zero-range contact interactions and a coupling function of the density arising from the finite-range pion exchanges. Because the contact contributions have essentially the same structure as those entering empirical Skyrme functionals, a microscopically guided Skyrme phenomenology has been suggested in which the contact terms in the DME functional are released for optimization to finite-density observables to capture short-range correlation energy contributions from beyond Hartree-Fock. The present article is the first attempt to assess the ability of the newly suggested DME functional, which has a much richer set of density dependencies than traditional Skyrme functionals, to generate sensible and stable results for nuclear applications. The results of the first proof-of-principle calculations are given, and numerous practical issues related to the implementation of the new functional in existing Skyrme codes are discussed. Using a restricted singular value decomposition optimization procedure, it is found that the new DME functional gives numerically stable results and exhibits a small but systematic reduction of our test ${\chi }^2$ function compared to standard Skyrme functionals, thus justifying its suitability for future global optimizations and large-scale calculations.

The influence of the projectile neutron number on the evaporation residue cross sections for the reactions ${}^{208}\mathrm{Pb}$(${}^{52,54}\mathrm{Cr}$,$n,2n$)${}^{258–261}\mathrm{Sg}$ and ${}^{208}\mathrm{Pb}$(${}^{48,50}\mathrm{Ti}$,$n,2n$)${}^{254–257}$Rf has been studied within the framework of a fusion-fission statistical model. The results obtained with the kewpie2 code are compared with recent experimental data. The excitation functions represent the experimental results well both in the maximum value and the lactation of the peak. The calculations show that the projectile neutron number greatly influences both the capture cross section and the fusion probability.

In this paper, we discuss alternative means of measuring the possible presence of local parity violation in relativistic heavy ion collisions. We focus on the phenomenon of charge separation and introduce the charged dipole vector ${\mathrm{Q̂}}_1^c$, which will measure the charge separation on an event-by-event basis. Using Monte Carlo events, we demonstrate the method and its discriminating power. In particular we show that such an analysis will reveal the strength of the charge separation effect and its azimuthal correlation with the reaction plane. We further show that our proposed method may be able to distinguish between the actual charge separation effect and effects due to certain two-particle correlations. The connection to present measurements based on particle correlations is discussed.

We show that the “perfect fluid” elliptic flow of the bulk hadrons and the unexpectedly strong quenching of heavy quark jet fragments in Au $+$ Au reactions at $200A$ GeV can be simultaneously accounted for within leading-order anti-de-Sitter space/conformal field theory (AdS/CFT) holography with a common large t’Hooft coupling $\lambda =g_{\mathit{YM}}^2{N}_c~30$. In contrast, weakly coupled quark-gluon plasma models have so far failed to describe the observed correlation between these soft and hard observables even for couplings extrapolated to ${\alpha }_s~0.5$. We show that phenomenological applications of the classical trailing string AdS/CFT holographic solution are furthermore remarkably robust to higher-order curvature corrections $\mathcal{O}(1/{\lambda }^{3/2})$ in type IIB supergravity theories, as well as to worldsheet fluctuation corrections $\mathcal{O}(1/{\lambda }^{1/2})$ that were not considered previously. We emphasize the importance of future measurements at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) of the correlation between identified charm and beauty quark hard ($p_T>10-30$ GeV) jet quenching observables and low transverse momenta ($p_T⩽1$ GeV) bulk elliptic flow observables to further test the limits of the applicability of conformal holography to strongly coupled quark-gluon plasma.

Within the previously developed Dubna-Mainz-Taipei meson-exchange model, the singularity structure of the $\pi N$ scattering amplitudes has been investigated. For all partial waves up to $F$ waves and c.m. energies up to $W~2$ GeV, the $T$-matrix poles have been calculated by three different techniques: analytic continuation into the complex energy plane and speed-plot and regularization method. For all four-star resonances except the $S_{11}(1535)$, we find very good agreement between the analytic continuation and the regularization method. We also find resonance poles for resonances that are not so well established, but in these cases the pole positions and residues obtained by analytic continuation can substantially differ from the results predicted by the speed-plot and regularization methods.

Using as a tool the $s$-wave approximation (sWA), this work demonstrates that the nonmesonic weak decay transition rates ${\Gamma }_n$ and ${\Gamma }_p$ can be expressed in all hypernuclei up to ${}_{\Lambda }^{29}\mathrm{Si}$ (and very likely in heavier ones too) in the same way as in the $s$-shell hypernuclei, i.e., as a linear combination of only three elementary transition rates. This finding leads to the analytic prediction that, independently of the transition mechanism, all hypernuclei that are on the stability line ($\mathsf{N}=Z$), i.e., ${}_{\Lambda }^5\mathrm{He}$, ${}_{\Lambda }^7\mathrm{Li}$, ${}_{\Lambda }^9\mathrm{Be}$, ${}_{\Lambda }^{11}\mathrm{B}$, ${}_{\Lambda }^{13}\mathrm{C}$, ${}_{\Lambda }^{17}\mathrm{O}$, ${}_{\Lambda }^{29}\mathrm{Si}$, etc., should roughly have the same ratio ${\Gamma }_n/{\Gamma }_p$, the magnitude of which rapidly increases when one approaches the neutron drip line ($\mathsf{N}\gg \mathsf{Z}$), and the opposite happens when one goes toward the proton drip line ($\mathsf{N}\ll \mathsf{Z}$).

Flux-averaged and flux-integrated cross sections for quasi-elastic neutrino charged-current scattering on nuclei are analyzed. It is shown that the flux-integrated differential cross sections are less dependent on nuclear models than the flux-averaged ones. We calculate these cross sections using the relativistic distorted-wave impulse approximation and relativistic Fermi gas model with the Booster Neutrino Beamline flux and compare the results with the recent MiniBooNE experimental data. Within these models an axial mass $M_A$ is extracted from a fit of the measured $d\sigma /{\mathit{dQ}}^2$ cross section. The extracted value of $M_A=1.37\pm 0.05$ GeV/c${}^2$ is consistent with the MiniBooNE result. While the measured and calculated double differential cross sections $d\sigma /\mathit{dTd}\cos \theta$ generally agree, the Fermi gas model predictions are typically lower than data at low muon energies and scattering angles.

We investigate the liquid-gas phase transition of hot protoneutron stars shortly after their birth following supernova explosion and the composition and structure of hyperon-rich (proto)neutron stars within a relativistic mean-field model where the nuclear symmetry energy was constrained from the measured neutron skin thickness of finite nuclei. Light clusters are abundantly formed with increasing temperature well inside the neutrino-sphere for a uniform supernova matter. Liquid-gas phase transition is found to suppress the cluster yield within the coexistence phase as well as decrease considerably the neutron-proton asymmetry over a wide density range. We find symmetry energy has a modest effect on the boundaries and the critical temperature for the liquid-gas phase transition, and the composition depends more sensitively on the number of trapped neutrinos and temperature of the protoneutron star. The influence of hyperons in the dense interior of stars makes the overall equation of state soft. However, neutrino trapping distinctly delays the appearance of hyperons because of an abundance of electrons. We also find that a softer symmetry energy further makes the onset of hyperon less favorable. The resulting structures of the (proto)neutron stars with hyperons and with liquid-gas phase transition are discussed.

Nuclear effective interactions are useful tools in astrophysical applications especially if one can guide the extrapolations to the extremes regions of isospin and density that are required to simulate dense, neutron-rich systems. Isospin extrapolations may be constrained in the laboratory by measuring the neutron skin thickness of a heavy nucleus, such as ${}^{208}\mathrm{Pb}$. Similarly, future observations of massive neutron stars will constrain the extrapolations to the high-density domain. In this contribution we introduce a new relativistic effective interaction that is simultaneously constrained by the properties of finite nuclei, their collective excitations, and neutron-star properties. By adjusting two of the empirical parameters of the theory, one can efficiently tune the neutron skin thickness of ${}^{208}\mathrm{Pb}$ and the maximum neutron-star mass. We illustrate this procedure in response to the recent interpretation of x-ray observations by Steiner, Lattimer, and Brown that suggests that the FSUGold effective interaction predicts neutron-star radii that are too large and a maximum stellar mass that is too small. The new effective interaction is fitted to a neutron skin thickness in ${}^{208}\mathrm{Pb}$ of only $R_n-R_p=0.16$ fm and yields a moderately large maximum neutron-star mass of 1.94 $M_{\odot }$.

We solve a singe-particle Dirac equation with Woods-Saxon potentials using an iterative method in the coordinate space representation. By maximizing the expectation value of the inverse of the Dirac Hamiltonian, this method avoids the variational collapse in which an iterative solution dives into the Dirac sea. We demonstrate that this method works efficiently, reproducing the exact solutions of the Dirac equation.