The two reactions ${}^{12}\mathrm{C}$(${}^4\mathrm{He}$,${}^4\mathrm{He}$ + ${}^4\mathrm{He}$ + ${}^4\mathrm{He}$)${}^4\mathrm{He}$ and ${}^9\mathrm{Be}$(${}^4\mathrm{He}$, ${}^4\mathrm{He}$ + ${}^4\mathrm{He}$ + ${}^4\mathrm{He}$)$n$ were measured using an array of four double-sided strip detectors. Excited states in ${}^{12}\mathrm{C}$ were reconstructed filtered by the condition that the $\alpha$-decay proceeded via the ${}^8\mathrm{Be}$ ground state. In both measurements, evidence was found for a new state at 13.3(0.2) MeV with a width 1.7(0.2) MeV. Angular correlation measurements from the ${}^{12}\mathrm{C}$(${}^4\mathrm{He}$, ${}^4\mathrm{He}$ + ${}^4\mathrm{He}$ + ${}^4\mathrm{He}$)${}^4\mathrm{He}$ reaction indicates that the state may have $J^{\pi }=4^{+}$.

In this work, we have reviewed the Oslo method, which enables the simultaneous extraction of the level density and $\gamma$-ray transmission coefficient from a set of particle-$\gamma$ coincidence data. Possible errors and uncertainties have been investigated. Typical data sets from various mass regions as well as simulated data have been tested against the assumptions behind the data analysis.

We simulate direct photon production in the evolution of viscous quark-gluon plasma medium. Photons from Compton and annihilation processes are considered. The viscous effect on photon production is very strong and reliable simulation is possible only in a limited $p_T$ range. For minimally viscous fluid ($\eta /s=0.08$), direct photons can be reliably computed only up to $p_T⩽1.3$ GeV. With reduced viscosity ($\eta /s=0.04$), the limit increases to $p_T⩽2$ GeV.

Elliptic flows of charged particles produced in nucleus-nucleus collisions at high energy are studied in the framework of a multisource ideal-gas model. The participant nucleon number at a fixed impact parameter is calculated by a geometrical picture of the participant-spectator model. Then, the dependence of elliptic flow on participant nucleon number is obtained in the combined framework of the two models. Our calculated results are approximately in agreement with the experimental data of the PHENIX Collaboration.

We generate a new complete equation of state (EOS) of nuclear matter for a wide range of temperatures, densities, and proton fractions ready for use in astrophysical simulations of supernovae and neutron star mergers. Our previous two papers tabulated the EOS at over $180\hspace{0.5em}000$ grid points in the temperature range $T=\text{0-80}$ MeV, the density range $n_B={10}^{-8}-1.6$ fm${}^{-3}$, and the proton fraction range $Y_P=\text{0-0.56}$. In this paper we combine these data points using a suitable interpolation scheme to generate a single EOS table on a finer grid. This table is thermodynamically consistent and conserves entropy during adiabatic compression tests. We present various thermodynamic quantities and the composition of matter in the new EOS, along with several comparisons with existing EOS tables. Our EOS table is available for download.

We investigate the presence of spatial localization in nuclei using a method that maps the nucleon same-spin pair probability and is based on the density matrix. The method is used to study spatial localization of light nuclei within the Hartree-Fock approximation. We show that the method provides an alternative tool for studying spatial localization in comparison to the localization observed from maxima in the nuclear mass density.

The liquid drop Hamiltonian is amended with a potential which allows us to separate, in the intrinsic frame, the equations for $\beta$ and $\gamma$ coordinates. The Schrödinger equation for $\beta$ is that for a sextic oscillator plus a centrifugal term, while that for $\gamma$ is just the equation for the Mathieu function. The total energy has a compact form. The operator for the electric quadrupole transitions is considered in the intrinsic frame and involves two parameters accompanying the harmonic and anharmonic components. The parameters determining the energies as well as those defining the transition operator are to be determined by a fitting procedure. Applications refer to five isotopes: ${}^{188}\mathrm{Os}$, ${}^{190}\mathrm{Os}$, ${}^{192}\mathrm{Os}$, ${}^{228}\mathrm{Th}$, and ${}^{230}\mathrm{Th}$. Results are in good agreement with the corresponding experimental data. Results are also compared with those obtained within the coherent state model. A possible connection between the two formalisms is pointed out.

Large discrepancies between quasifree neutron-neutron ($\mathit{nn}$) cross section data from neutron-deuteron ($\mathit{nd}$) breakup and theoretical predictions based on standard nucleon-nucleon ($\mathit{NN}$) and three-nucleon (3$N$) forces are pointed out. The $\mathit{nn}$ ${}^1{S}_0$ interaction is shown to be dominant in that configuration and has to be increased to bring theory and data into agreement. Using the next-to-leading order ${}^1{S}_0$ interaction of chiral perturbation theory, we demonstrate that the $\mathit{nn}$ quasifree scattering cross section depends only slightly on changes of the $\mathit{nn}$ scattering length but is very sensitive to variations of the effective range parameter. In order to account for the reported discrepancies one must decrease the $\mathit{nn}$ effective range parameter by $\approx$$12\%$ from its value implied by charge symmetry and charge independence of nuclear forces.

We investigate the effects of the Coulomb force on the nuclear pairing properties by performing the Gogny Hartree-Fock-Bogolyubov calculations for the $N=20$, $28$, $50$, $82$, and $126$ nuclei. The Coulomb force reduces the proton pair energy and the even-odd mass difference by about $25\%$, except for nuclei at and around the proton shell or subshell closure. We then propose a renormalization scheme via a reduction factor ${\gamma }_p$ for the proton pairing channel. It is found that a single value ${\gamma }_p=0.90$ accounts well for the Coulombic effect for nuclei covering a wide range of the mass number and the neutron excess, including the nuclei around the shell or subshell closure.

The absolute differential cross sections for the ${}^3\mathrm{He}$($\gamma ,n)\mathit{pp}$ reaction were measured as a function of outgoing neutron scattering angle and energy at the incident $\gamma$-ray energies of 12.8, 13.5, and 14.7 MeV to within a precision better than $\pm$6%. Both the absolute cross sections and the neutron energy distributions at each incident $\gamma$-ray energy agree with the state-of-the-art theoretical results when the Coulomb interaction in the final state is included.

We theoretically investigate energy spacings of doublets in ${}_{\Lambda }\mathrm{Li}$ hypernuclear isotopes with $A=7-10$ in shell-model calculations with a $\Lambda N-\Sigma N$ coupling effect. The calculated results show that the energy shifts are $\Delta \epsilon =0.09-0.28\hspace{0.5em}\mathrm{MeV}$ and the $\Sigma$-mixing probabilities are $P_{\Sigma }=0.10\%-0.34\%$ in $\Lambda$ ground states for the isotopes because of the $\Lambda N-\Sigma N$ coupling in the first-order perturbation. It is found that the energy spacing of the doublet is enhanced as a neutron number $N$ increases; the contribution of the $\Lambda N-\Sigma N$ coupling interaction is comparable to that of the $\Lambda N$ interaction in the neutron-rich $\Lambda$ hypernuclei. The coherent mechanism of this doublet-spacing enhancement is also discussed in terms of Fermi-type and Gamow-Teller-type $\Lambda N-\Sigma N$ couplings.

States above the known $K^{\pi }=8^{-}$ 6 $\mu$s isomer in ${}^{138}\mathrm{Gd}$ have been populated with the ${}^{106}\mathrm{Cd}$(${}^{36}\mathrm{Ar}$,$2p2n$) reaction at a beam energy of 180 MeV at the University of Jyväskylä, Finland. The recoil-isomer tagging technique was utilized to correlate delayed $\gamma$-ray decays, detected in the GREAT focal plane spectrometer, with prompt decays measured in the JUROGAM II spectrometer at the target position. The lifetime of the $K^{\pi }=8^{-}$ isomeric state has been remeasured as 6.2(2) $\mu$s. Two high-lying strongly coupled bands have been established with $K^{\pi }⩾{12}^{-}$. Potential-energy surface calculations, in conjunction with $g$ factor measurements, reveal that they are built upon four-quasiparticle structures comprising two-quasineutron plus two-quasiproton configurations. The short half-life or lack of hindrance for the decays from these four-quasiparticle band-head states is reasoned to be a consequence of increased triaxial deformation and mixing due to the high density of states relative to the lower two-quasiparticle 6-$\mu$s isomeric state.

Prompt fission neutron spectra from ${}^{235}\mathrm{U}$ and ${}^{239}\mathrm{Pu}$ were measured for incident neutron energies from 1 to 200 MeV at the Weapons Neutron Research facility (WNR) of the Los Alamos Neutron Science Center, and the experimental data were analyzed with the Los Alamos model for the incident neutron energies of 1–8 MeV. A CEA multiple-foil fission chamber containing deposits of 100 mg ${}^{235}\mathrm{U}$ and 90 mg ${}^{239}\mathrm{Pu}$ detected fission events. Outgoing neutrons were detected by the Fast Neutron-Induced $\gamma$-Ray Observer array of 20 liquid organic scintillators. A double time-of-flight technique was used to deduce the neutron incident energies from the spallation target and the outgoing energies from the fission chamber. These data were used for testing the Los Alamos model, and the total kinetic energy parameters were optimized to obtain a best fit to the data. The prompt fission neutron spectra were also compared with the Evaluated Nuclear Data File (ENDF/B-VII.0). We calculate average energies from both experimental and calculated fission neutron spectra.

The fission fragment mass angle correlations and mass ratio distributions have been investigated for the two systems ${}^{16}\mathrm{O}+{}^{197}\mathrm{Au}$ and ${}^{27}\mathrm{Al}+{}^{186}\mathrm{W}$, leading to the same compound nucleus ${}^{213}\mathrm{Fr}$ around the Coulomb barrier energies. Systematic analysis of the variance of the mass distributions as a function of temperature and angular momentum suggests true compound nuclear fission for both the reactions, indicating the absence of nonequilibrium fission processes.

The multiplicity and elliptic flow of charged particles produced in Pb-Pb collisions at center of mass energy $\sqrt{s_{\mathit{NN}}}=2.76$ TeV from the Large Hadron Collider are studied in a multiphase transport (AMPT) model. With the standard parameters in the HIJING model, which is used as initial conditions for subsequent partonic and hadronic scatterings in the AMPT model, the resulting multiplicity of final charged particles at mid-pseudorapidity is consistent with the experimental data measured by the ALICE Collaboration. This value is, however, increased by about $25\%$ if the final-state partonic and hadronic scatterings are turned off. Because of final-state scatterings, particularly those among partons, the final elliptic flow of charged hadrons is also consistent with the ALICE data if a smaller but more isotropic parton scattering cross section than previously used in the AMPT model for describing the charged hadron elliptic flow in heavy ion collisions at the Relativistic Heavy Ion Collider is used. The resulting transverse momentum spectra of charged particles as well as the centrality dependence of their multiplicity density and the elliptic flow are also in reasonable agreement with the ALICE data. Furthermore, the multiplicities, transverse momentum spectra, and elliptic flows of identified hadrons such as protons, kaons, and pions are predicted.

We investigate the effects of the light vector U boson that couples weakly to nucleons in relativistic mean-field models on the equation of state and subsequently the consequence in neutron stars. It is analyzed that the U boson can lead to a much clearer rise of the neutron star maximum mass in models with the much softer equation of state. The inclusion of the U boson may thus allow the existence of the non-nucleonic degrees of freedom in the interior of large mass neutron stars initiated with the favorably soft EOS of normal nuclear matter. In addition, the sensitive role of the U boson in the neutron star radius and its relation to the test of the non-Newtonian gravity that is herein addressed by the light U boson are discussed.

Following the reports of two pairs of chiral doublet bands observed in ${}^{105}\mathrm{Rh}$, the adiabatic and configuration-fixed constrained triaxial relativistic mean-field calculations are performed to investigate their triaxial deformations with the corresponding configuration and the possible multiple chiral doublet (M$\chi$D) phenomenon. The existence of the $\mathrm{M}\chi$D phenomenon in ${}^{105}\mathrm{Rh}$ is highly expected.

A wide variety of modern instruments allow us to study neutron-deficient nuclei in the $A=130$ mass region. Highly deformed nuclei have been found in this region, providing opportunities to study the deformed rotational bands. The description of the ${}^{125,127,129,131,133}\mathrm{Pr}$ isotopes with the projected shell model is presented in this paper. Good agreement between theory and experiment is obtained and some characteristics are discussed, including the dynamic moment of inertia ${\mathcal{J}}^{(2)}$, kinetic moment of inertia ${\mathcal{J}}^{(1)}$, the crossing of rotational bands, and backbending effects.

Low-energy dipole excitations in neon isotopes and $N=16$ isotones are calculated with a fully consistent axially-symmetric-deformed quasiparticle random phase approximation (QRPA) approach based on Hartree-Fock-Bogolyubov (HFB) states. The same Gogny D1S effective force has been used both in HFB and QRPA calculations. The microscopical structure of these low-lying resonances, as well as the behavior of proton and neutron transition densities, are investigated in order to determine the isoscalar or isovector nature of the excitations. It is found that the $N=16$ isotones ${}^{24}\mathrm{O}$, ${}^{26}\mathrm{Ne}$, ${}^{28}\mathrm{Mg}$, and ${}^{30}\mathrm{Si}$ are characterized by a similar behavior. The occupation of the $2s$${}_{1/2}$ neutron orbit turns out to be crucial, leading to nontrivial transition densities and to small but finite collectivity. Some low-lying dipole excitations of ${}^{28}\mathrm{Ne}$ and ${}^{30}\mathrm{Ne}$, characterized by transitions involving the $\nu 1d$${}_{3/2}$ state, present a more collective behavior and isoscalar transition densities. A collective proton low-lying excitation is identified in the ${}^{18}\mathrm{Ne}$ nucleus.

The 1.9-s isomeric state (${}^{261}\mathrm{Rf}$${}^b$) in ${}^{261}\mathrm{Rf}$ was directly populated in the ${}^{248}\mathrm{Cm}$(${}^{18}\mathrm{O}$,5$n$)${}^{261}\mathrm{Rf}$${}^b$ reaction. Alpha and spontaneous fission (SF) decays of ${}^{261}\mathrm{Rf}$${}^b$, as well as the 68-s state ${}^{261}\mathrm{Rf}$${}^a$, was investigated with a rotating wheel apparatus under low background conditions attained by a gas-jet transport system coupled to the RIKEN gas-filled recoil ion separator. An identification of ${}^{261}\mathrm{Rf}$${}^b$ was based on $\alpha$-$\alpha$ correlations linking $\alpha$ decays of ${}^{261}\mathrm{Rf}$${}^b$ and its daughter ${}^{257}\mathrm{No}$. The $\alpha$-particle energy of ${}^{261}\mathrm{Rf}$${}^b$ was measured to be 8.52 ± 0.05 MeV. The half-life was determined to be 1.9 ± 0.4 s based on both 8.52-MeV $\alpha$ and SF decays. The $\alpha$ and SF branches are 0.27 ± 0.06 and 0.73 ± 0.06, respectively. The cross section for the ${}^{248}\mathrm{Cm}$(${}^{18}\mathrm{O}$,5$n$)${}^{261}\mathrm{Rf}$${}^b$ reaction is σ(${}^{261}\mathrm{Rf}$${}^b$) = 11 ± 2 nb at 95.1 MeV, which gives a cross-section ratio of σ(${}^{261}\mathrm{Rf}$${}^a$)/σ(${}^{261}\mathrm{Rf}$${}^b$) = 1.1 ± 0.2.