A hollow-cathode electric discharge, a well-established source in optical spectroscopy, was used to populate the “3.5-eV isomer” in ${}^{229}\mathrm{Th}$ with use of nuclear excitation by electron transition (NEET). The radiochemically purest ${}^{229}\mathrm{Th}$ sample was loaded into the hollow cathode in which the electric discharge excited the ${}^{229}\mathrm{Th}$ to atomic states some of which could be expected to lie close to the excitation energy of the sought isomer. Although there remain some uncertainties, our experiments indicate that the isomer was populated by NEET and its $\alpha$ decay observed after switching off the electric discharge with a corresponding isomer half-life 1 min $\lesssim T_{1/2}^m\lesssim \hspace{0.5em}3$ min. From the present NEET condition, the isomer appears to lie between 3 eV and 7 eV. The probability of the isomer population by NEET is discussed.

The cross sections of fragments produced in 140 $A$ MeV ${}^{40,48}\mathrm{Ca}+{}^9\mathrm{Be}$ and ${}^{58,64}\mathrm{Ni}+{}^9\mathrm{Be}$ reactions are calculated by the statistical abration-ablation (SAA) model and compared to the experimental results measured at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The fragment isotopic and isotonic cross section distributions of ${}^{40}\mathrm{Ca}$ and ${}^{48}\mathrm{Ca}$, ${}^{58}\mathrm{Ni}$ and ${}^{64}\mathrm{Ni}$, ${}^{40}\mathrm{Ca}$ and ${}^{58}\mathrm{Ni}$, and ${}^{48}\mathrm{Ca}$ and ${}^{64}\mathrm{Ni}$ are compared and the isospin dependence of the projectile fragmentation is studied. It is found that the isospin dependence decreases and disappears in the central collisions. The shapes of the fragment isotopic and isotonic cross section distributions are found to be very similar for symmetric projectile nuclei. The shapes of the fragment isotopic and isotonic distributions of different asymmetric projectiles produced in peripheral reactions are found to be very similar. The similarity of the distributions are related to the similar proton and neutron density distributions inside the nucleus in framework of the SAA model.

We present a reanalysis of single photon production from a relativistic collision of lead nuclei at CERN SPS measured by the WA98 experiment. The refinements include use of isospin and shadowing corrected NLO pQCD treatment for prompt photon production using an optimized scale for factorization, renormalization, and fragmentation and use of hydrodynamics suited for noncentral collisions along with a well tested equation of state admitting a quark-hadron phase transition. A quantitative explanation of the data requires a large initial temperature (at a small formation time of about 0.2 fm/$c$) and a moderate increase in the prompt yield which could perhaps be attributed to the Cronin effect in nuclei. The data can also be explained using a moderate initial temperature (at a formation time of about 1 fm/$c$) with a very large $K$-factor multiplying the prompt yield. We show that different initial times give rise to different values for the elliptic flow parameter $v_2$ for thermal photons. We also argue that a measurement of $v_2$ for thermal photons could also distinguish between the scenarios with or without a phase transition.

In the present paper, we investigate the onset of the “pasta” phase with different parametrizations of the density dependent hadronic model and compare the results with one of the usual parametrizations of the nonlinear Walecka model. The influence of the scalar-isovector virtual $\delta$ meson is shown. At zero temperature, two different methods are used, one based on coexistent phases and the other on the Thomas-Fermi approximation. At finite temperature, only the coexistence phases method is used. $\mathit{npe}$ matter with fixed proton fractions and in $\beta$ equilibrium are studied. We compare our results with restrictions imposed on the values of the density and pressure at the inner edge of the crust, obtained from observations of the Vela pulsar and recent isospin diffusion data from heavy-ion reactions, and with predictions from spinodal calculations.

Based on a dynamical Langevin equation coupled with a statistical decay model, we calculate the excess of the prescission neutron multiplicity of the heavy nuclei ${}^{240}\mathrm{Cf}$, ${}^{246}\mathrm{Cf}$, ${}^{252}\mathrm{Cf}$, and ${}^{240}\mathrm{U}$ over that predicted by the standard statistical model as a function of the postsaddle dissipation strength. We find that with increasing isospin of the system, the sensitivity of the excess to the dissipation strength decreases substantially. Moreover, for ${}^{240}\mathrm{U}$, this excess is no longer sensitive to the nuclear dissipation. These results suggest that, on the experimental side, to accurately obtain information of the postsaddle dissipation strength by measuring the neutron multiplicity evaporated during the fission process of heavy nuclei, it is best to populate those compound systems with low isospin.

The $E1$ strength is systematically analyzed in very neutron-rich Sn nuclei, beyond ${}^{132}\mathrm{Sn}$ until ${}^{166}\mathrm{Sn}$, within the relativistic quasiparticle random phase approximation. The great neutron excess favors the appearance of a deformed ground state for ${}^{142-162}\mathrm{Sn}$. The evolution of the low-lying strength in deformed nuclei is determined by the interplay of two factors, isospin asymmetry and deformation: while greater neutron excess increases the total low-lying strength, deformation hinders and spreads it. Very neutron rich deformed nuclei may not be as good candidates as spherical nuclei like ${}^{132}\mathrm{Sn}$ for the experimental study of low-lying $E1$ strength.

We systematically investigate the possibility that the $s^2$ configuration of the two neutrons in the middle of the nucleus is a characteristic bond of $\alpha$-clusters in light neutron-rich nuclei. The series of cluster states seen in ${}^{10}\mathrm{Be}(2\alpha +2n)$ and ${}^{14}\mathrm{C}(3\alpha +2n)$ is extended to the cases of heavier nuclei, ${}^{18}\mathrm{O}(4\alpha +2n)$ and ${}^{22}\mathrm{Ne}(5\alpha +2n)$, and we show the appearance of cluster structure with the $s^2$ bond in the excited states by using a microscopic $N\alpha +2n$ model, in which the coupling with low-lying states is included.

Space radiation and cosmic ray transport codes require simple and accurate models for hadron production in intermediate energy, nucleus-nucleus collisions. Several arithmetic parametrization models for pion production are compared to laboratory frame data. It is found that models based on high energy parametrizations are unable to describe intermediate energy, differential cross section data. However, simple thermal model parametrizations, when appropriately transformed from the center of momentum to the laboratory frame, are able to account for the data. Heavy ion transport codes that require algebraic cross section formulas can therefore use arithmetic parametrizations at high energy, but should use thermal model parametrizations at intermediate energy.

We present evidence for a new supersymmetric quartet in the $A~190$ region of the nuclear mass table. New experimental information on transfer and neutron capture reactions to the odd-odd nucleus ${}^{194}\mathrm{Ir}$ strongly suggests the existence of a new supersymmetric quartet, consisting of the ${}^{192,193}\mathrm{Os}$ and ${}^{193,194}\mathrm{Ir}$ nuclei. We make explicit predictions for the odd-neutron nucleus ${}^{193}\mathrm{Os}$ and suggest that its spectroscopic properties be measured in dedicated experiments.

Gamma rays de-exciting isomeric states in the neutron-rich nucleus ${}_{76}^{198}$${\mathrm{Os}}_{122}$ have been observed following relativistic projectile fragmentation of a 1 GeV per nucleon ${}^{208}\mathrm{Pb}$ beam. The ground-state band has properties compatible with oblate deformation. The evolution of the structure of Os isotopes characterized by sudden prolate-oblate shape change is discussed and contrasted with the smooth change known in the Pt chain.

The dynamics of the $\eta \to 3{\pi }^0$ decay have been studied with the Crystal Ball multiphoton spectrometer and the TAPS calorimeter. Bremsstrahlung photons produced by the 1.5-GeV electron beam of the Mainz microtron MAMI-C and tagged by the Glasgow photon spectrometer were used for $\eta$-meson production. The analysis of $3\times {10}^6\hspace{0.5em}\gamma p\to \eta p\to 3{\pi }^{0}p\to 6\gamma p$ events yields the value $\alpha =-0.032\pm 0.003$ for the $\eta \to 3{\pi }^0$ slope parameter, which agrees with the majority of recent experimental results and has the smallest uncertainty. The ${\pi }^0{\pi }^0$ invariant-mass spectrum was investigated for the occurrence of a cusplike structure in the vicinity of the ${\pi }^{+}{\pi }^{-}$ threshold. The observed effect is small and does not affect our measured value for the slope parameter.

We propose a new method for extracting neutron structure functions from inclusive structure functions of nuclei, which employs an iterative procedure of solving integral convolution equations. Unlike earlier approaches, the new method is applicable to both spin-averaged and spin-dependent structure functions. We test the reliability of the method on unpolarized $F_2$ and polarized $g_1$ structure functions of the deuteron in both the nucleon resonance and deep inelastic regions. The new method is able to reproduce known input functions of almost arbitrary shape to very good accuracy with only several iterations.

Excited states with $J^{\pi }=1^{+}$ and $1^{-}$ in ${}^{26}\mathrm{Mg}$ were studied in a photon-scattering experiment using bremsstrahlung produced by an electron beam of 13.0 MeV kinetic energy provided by the superconducting electron linear accelerator ELBE. We determined the transition strengths from the $1^{+}$ and $1^{-}$ states to the ground state as well as to low-lying excited states. In addition, we observed a $J=1$ state at 11.154 MeV, above the neutron-separation energy of 11.093 MeV, and determined its partial $\gamma$ decay width for the first time.

A brief description of the novel approach toward solving few-body scattering problems in a finite-dimensional functional space of the $L_2$ type is presented. The method is based on the complete few-body continuum discretization in the basis of stationary wave packets. This basis, being transformed to the momentum representation, leads to the cell-lattice-like discretization of the momentum space. So the initial scattering problem can be formulated on the multidimensional momentum lattice, which makes it possible to reduce the solution of any scattering problem above the breakup threshold (where the integral kernels include, in general, some complicated moving singularities) to convenient simple matrix equations that can be solved on the real energy axis. The phase shifts and inelasticity parameters for the three-body $\mathit{nd}$ elastic scattering with MT I-III $\mathit{NN}$ potential both below and above the three-body breakup threshold calculated with the proposed wave-packet technique are in a very good agreement with the previous accurate benchmark calculation results.

We present a survey of the phenomenological adjustment of the parameters of the Skyrme-Hartree-Fock (SHF) model for a self-consistent description of nuclear structure and low-energy excitations. A large sample of reliable input data from nuclear bulk properties (energy, radii, surface thickness) is selected guided by the criterion that ground-state correlations should remain small. Least-squares fitting techniques are used to determine the SHF parameters that accommodate best the given input data. The question of the predictive value of the adjustment is scrutinized by performing systematic variations with respect to chosen nuclear matter properties (incompressibility, effective mass, symmetry energy, and sum-rule enhancement factor). We find that the ground-state data, although representing a large sample, leave a broad range of choices, i.e., a broad range of nuclear matter properties. Information from giant resonances is added to pin down more precisely the open features. We then apply the set of newly adjusted parametrizations to several more detailed observables such as neutron skin, isotope shifts, and super-heavy elements. The techniques of least-squares fitting provide safe estimates for the uncertainties of such extrapolations. The systematic variation of forces allows to disentangle the various influences on a given observable and to estimate the predictive value of the SHF model. The results depend very much on the observable under consideration.

Short thermalization times of less than $1\hspace{0.5em}\mathrm{fm}/c$ for quark and gluon matter have been suggested by recent experiments at the Relativistic Heavy Ion Collider. It has been difficult to justify this rapid thermalization in first-principle calculations based on perturbation theory or the color glass condensate picture. Here, we address the related question of the decoherence of the gluon field, which is a necessary component of thermalization. We present a simplified leading-order computation of the decoherence time of a gluon ensemble subject to an incoming flux of Weizsäcker-Williams gluons. We also discuss the entropy produced during the decoherence process and its relation to the entropy in the final state that has been measured experimentally.

We formulate a simple model for a gas of extended hadrons at zero chemical potential by taking inspiration from the compressible bag model. We show that a crossover transition qualitatively similar to lattice QCD can be reproduced by such a system by including some appropriate additional dynamics. Under certain conditions, at high temperature, the system consist of a finite number of infinitely extended bags, which occupy the entire space. In this situation the system behaves as an ideal gas of quarks and gluons.

The nuclear physics uncertainty associated with the production of the Galactic $\beta$-delayed $\gamma$-ray emitter ${}^{26}\mathrm{Al}$ in classical novae is currently dominated by the uncertainty in the thermonuclear ${}^{25}\mathrm{Al}(p,\gamma ){}^{26}\mathrm{Si}$ reaction rate. By combining the results of recent experiments with past work, the center-of-mass energy of the key $J^{\pi }=3^{+}$, ${}^{25}\mathrm{Al}(p,\gamma ){}^{26}\mathrm{Si}$ resonance is determined to be $412(2)$ keV, and a lower limit of ${\Gamma }_p/{\Gamma }_{\gamma }>5.6$ is set for this resonance. The resulting large reduction in the ${}^{25}\mathrm{Al}(p,\gamma ){}^{26}\mathrm{Si}$ rate uncertainty is expected to constrain uncertainties in the nova contribution to Galactic ${}^{26}\mathrm{Al}$.

We solve (3$+$1)-dimensional ideal hydrodynamical equations with source terms that describe punch-through and fully stopped jets to compare their final away-side angular correlations in a static medium. For fully stopped jets, the backreaction of the medium is described by a simple Bethe-Bloch-like model that leads to an explosive burst of energy and momentum (Bragg peak) close to the end of the jet's evolution through the medium. Surprisingly enough, we find that the medium's response and the corresponding away-side angular correlations are largely insensitive to whether the jet punches through or stops inside the medium. This result is also independent of whether momentum deposition is longitudinal (as generally occurs in pQCD energy loss models) or transverse (as the Bethe-Bloch formula implies). The existence of the diffusion wake is therefore shown to be universal to all scenarios where momentum as well as energy is deposited into the medium, which can readily be understood in ideal hydrodynamics through vorticity conservation. The particle yield coming from the strong forward moving diffusion wake that is formed in the wake of both punch-through and stopped jets largely overwhelms their weak Mach cone signal after freeze-out.