We have recently obtained the optimal core-cluster decompositions for an extensive set of heavy even-even nuclei in the rare-earth region. The core-cluster charge products thus deduced are found to be closely correlated with the corresponding $B(E2)$ values. We investigate here the strong resemblance of these correlations to the corresponding Casten plots, and find that the cluster model also predicts a further correlation between core-cluster charge products and the nuclear excitation energies, suggesting a new form of Casten plot for these energies.

We have studied the quasielastic ${}^3\mathrm{He}(e,e^{\prime }p){}^2\mathrm{H}$ reaction in perpendicular coplanar kinematics, with the energy and the momentum transferred by the electron fixed at 840 MeV and $1502\mathrm{MeV}/c$, respectively. The ${}^3\mathrm{He}(e,e^{\prime }p){}^2\mathrm{H}$ cross section was measured for missing momenta up to $1000\mathrm{MeV}/c$, while the $A_{TL}$ asymmetry was extracted for missing momenta up to $660\mathrm{MeV}/c$. For missing momenta up to $150\mathrm{MeV}/c$, the cross section is described by variational calculations using modern ${}^3\mathrm{He}$ wave functions. For missing momenta from 150 to $750\mathrm{MeV}/c$, strong final-state interaction effects are observed. Near $1000\mathrm{MeV}/c$, the experimental cross section is more than an order of magnitude larger than predicted by available theories. The $A_{TL}$ asymmetry displays characteristic features of broken factorization with a structure that is similar to that generated by available models.

The photoproduction of $\omega$ mesons on nuclei has been investigated using the Crystal Barrel/TAPS experiment at the ELSA tagged photon facility in Bonn. The aim is to study possible in-medium modifications of the $\omega$ meson via the reaction $\gamma +A\to \omega +X\to {\pi }^0\gamma +X^{\prime }$. Results obtained for Nb are compared to a reference measurement on a ${\mathrm{LH}}_2$ target. While for recoiling, long-lived mesons (${\pi }^0$, $\eta$, and ${\eta }^{\prime }$), which decay outside of the nucleus, a difference in the line shape for the two data samples is not observed, we find a significant enhancement towards lower masses for $\omega$ mesons produced on the Nb target. For momenta less than $500\mathrm{MeV}/c$ an in-medium $\omega$ meson mass of $M_{\mathrm{medium}}=[{722}_{-4}^{+4}(\mathrm{stat}{)}_{-5}^{+35}(\mathrm{syst})]\mathrm{MeV}/c^2$ has been deduced at an estimated average nuclear density of $0.6{\rho }_0$.

Following Coulomb excitation of the radioactive ion beam (RIB) ${}^{132}\mathrm{Te}$ at HRIBF we report the first use of the recoil-in-vacuum (RIV) method to determine the $g$ factor of the $2_1^{+}$ state: $g(973.9\mathrm{keV}{2}^{+}{}^{132}\mathrm{Te})=(+)0.35(5)$. The advantages offered by the RIV method in the context of RIBs and modern detector arrays are discussed.

Results are presented on $\Omega$ production in central $\mathrm{Pb}+\mathrm{Pb}$ collisions at 40 and $158A\mathrm{GeV}$ beam energy. For the first time in heavy ion reactions, rapidity distributions and total yields were measured for the sum ${\Omega }^{-}+{\overline{\Omega }}^{+}$ at $40A\mathrm{GeV}$ and for ${\Omega }^{-}$ and ${\overline{\Omega }}^{+}$ separately at $158A\mathrm{GeV}$. The yields are strongly underpredicted by the string-hadronic UrQMD model but agree better with predictions from hadron gas models.

The evolution of the low-lying $E1$ strength in proton-rich nuclei is analyzed in the framework of the self-consistent relativistic Hartree-Bogoliubov model and the relativistic quasiparticle random-phase approximation (RQRPA). Model calculations are performed for a series of $N=20$ isotones and $Z=18$ isotopes. For nuclei close to the proton drip line, the occurrence of pronounced dipole peaks is predicted in the low-energy region below 10 MeV excitation energy. From the analysis of the proton and neutron transition densities and the structure of the RQRPA amplitudes, it is shown that these states correspond to the proton pygmy dipole resonance.

Despite considerable practical success in dealing with the gluon plasma, finite-temperature perturbation theory suffers at the fundamental level from infrared divergences discovered by Linde. However, if gauge or Gribov copies are properly eliminated from the physical state space, infrared modes are strongly suppressed. We describe the gluon plasma in zeroth order as a gas of free quasiparticles with a temperature-independent dispersion relation of Gribov type, $E(k)=\sqrt{k^2+\frac{M^4}{k^2}}$, that results from the reduction of the physical state space. The effective mass $\frac{M^2}{k}$ controls infrared divergences and allows finite calculable corrections. The equation of state of this gas is calculated and compared with numerical lattice data.

We study properties of a gluon plasma above the critical temperature $T_c$ in a generalized quasiparticle approach with a Lorentz spectral function. The model parameters are determined by a fit of the entropy $s$ to lattice QCD data. The effective degrees of freedom are found to be rather heavy and of a sizable width. With the spectral width being closely related to the interaction rate, we find a large effective cross section, which is comparable to the typical distance squared of the quasiparticles. This suggests that the system should be viewed as a liquid as also indicated by an estimate of the plasma parameter $\Gamma$. Furthermore, within the quasiparticle approach we find a very low viscosity to entropy ratio, $\eta /s\sim 0.2$ for $T>1.05T_c$, supporting the recent conjecture of an almost ideal quark-gluon liquid seen at RHIC.

We report on the first radioactive beam experiment performed at the recently commissioned REX-ISOLDE facility at CERN in conjunction with the highly efficient $\gamma$ spectrometer MINIBALL. Using ${}^{30}\mathrm{Mg}$ ions accelerated to an energy of $2.25\mathrm{MeV}/u$ together with a thin ${}^{\mathrm{nat}}\mathrm{Ni}$ target, Coulomb excitation of the first excited $2^{+}$ states of the projectile and target nuclei well below the Coulomb barrier was observed. From the measured relative deexcitation $\gamma$-ray yields the $B(E2;0_{\mathrm{gs}}^{+}\to 2_1^{+})$ value of ${}^{30}\mathrm{Mg}$ was determined to be $241(31)e^2{\mathrm{fm}}^4$. Our result is lower than values obtained at projectile fragmentation facilities using the intermediate-energy Coulomb excitation method, and confirms the theoretical conjecture that the neutron-rich magnesium isotope ${}^{30}\mathrm{Mg}$ resides outside the “island of inversion.”

Predictions are obtained for $T=0$ and $T=1$ deuteron-transfer intensities between self-conjugate $N=Z$ nuclei on the basis of a simplified interacting boson model which considers bosons without orbital angular momentum but with full spin-isospin structure. These transfer predictions can be correlated with nuclear binding energies in specific regions of the mass table.

We have measured rapidity densities $dN/dy$ of ${\pi }^{\pm }$ and $K^{\pm }$ over a broad rapidity range ($-0.1<y<3.5$) for central $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$. These data have significant implications for the chemistry and dynamics of the dense system that is initially created in the collisions. The full phase-space yields are $1660\pm 15\pm 133$ (${\pi }^{+}$), $1683\pm 16\pm 135$ (${\pi }^{-}$), $286\pm 5\pm 23$ ($K^{+}$), and $242\pm 4\pm 19$ ($K^{-}$). The systematics of the strange to nonstrange meson ratios are found to track the variation of the baryochemical potential with rapidity and energy. Landau-Carruthers hydrodynamics is found to describe the bulk transport of the pions in the longitudinal direction.

Isotopic effects in the fragmentation of excited target residues following collisions of ${}^{12}\mathrm{C}$ on ${}^{112,124}\mathrm{Sn}$ at incident energies of 300 and 600 MeV per nucleon were studied with the INDRA $4\pi$ detector. The measured yield ratios for light particles and fragments with atomic number $Z\le 5$ obey the exponential law of isotopic scaling. The deduced scaling parameters decrease strongly with increasing centrality to values smaller than 50% of those obtained for the peripheral event groups. Symmetry-term coefficients, deduced from these data within the statistical description of isotopic scaling, are near $\gamma =25\mathrm{MeV}$ for peripheral and $\gamma <15\mathrm{MeV}$ for central collisions.

The low-energy level structure of the exotic Na isotopes ${}^{28,29}\mathrm{Na}$ has been investigated through $\beta$-delayed $\gamma$ spectroscopy. The $N=20$ isotones for $Z=10–12$ are considered to belong to the “island of inversion” where intruder configurations dominate the ground state wave function. However, it is an open question as to where and how the transition from normal to intruder dominated configurations happens in an isotopic chain. The present work, which presents the first detailed spectroscopy of ${}^{28,29}\mathrm{Na}$, clearly demonstrates that such a transition in the Na isotopes occurs between ${}^{28}\mathrm{Na}$ ($N=17$) and ${}^{29}\mathrm{Na}$ ($N=18$), supporting the smaller $N=20$ shell gap in neutron-rich $sd$ shell nuclei. The evidence for inverted shell structure is found in $\beta$-decay branching ratios, intruder dominated spectroscopy of low-lying states, and shell model analysis.

The spectroscopic strengths of two-nucleon transfer reactions constitute a stringent test for two-nucleon correlations in the nuclear wave functions. A set of closed analytic expressions for ratios of spectroscopic factors is derived in the framework of nuclear supersymmetry. These ratios are parameter independent and provide a direct test of the wave functions. A comparison between the recently measured ${}^{198}\mathrm{Hg}(\overrightarrow{d},\alpha ){}^{196}\mathrm{Au}$ reaction and the predictions from the nuclear quartet supersymmetry lends further support to the validity of supersymmetry in nuclear physics.

We report the results of a new Rosenbluth measurement of the proton electromagnetic form factors at $Q^2$ values of 2.64, 3.20, and $4.10{\mathrm{GeV}}^2$. Cross sections were determined by detecting the recoiling proton, in contrast to previous measurements which detected the scattered electron. Cross sections were determined to 3%, with relative uncertainties below 1%. The ratio ${\mu }_p{G}_E/G_M$ was determined to 4%–8% and showed ${\mu }_p{G}_E/G_M\approx 1$. These results are consistent with, and much more precise than, previous Rosenbluth extractions. They are inconsistent with recent polarization transfer measurements of similar precision, implying a systematic difference between the techniques.

We have set limits on contributions of scalar interactions to nuclear $\beta$ decay. A magneto-optical trap provides a localized source of atoms suspended in space, so the low-energy recoiling nuclei can freely escape and be detected in coincidence with the $\beta$. This allows reconstruction of the neutrino momentum, and the measurement of the $\beta \mathrm{\text{−}}\nu$ correlation, in a more direct fashion than previously possible. The $\beta \mathrm{\text{−}}\nu$ correlation parameter of the $0^{+}\to 0^{+}$ pure Fermi decay of ${}^{38}\mathrm{K}^m$ is $\tilde{a}=0.9981\pm 0.0030\genfrac{}{}{0ex}{}{+0.0032}{-0.0037}$, consistent with the standard model prediction $\tilde{a}=1$.

We show that the well-known linear Langevin equation, modeling the Brownian motion and leading to a Gaussian stationary distribution of the corresponding Fokker-Planck equation, is changed by the smallest multiplicative noise. This leads to a power-law tail of the distribution for sufficiently large momenta. At finite ratio of the correlation strength for the multiplicative and the additive noises the stationary energy distribution becomes exactly the Tsallis distribution.

Excited states in ${}^{20}\mathrm{O}$ were populated in the reaction ${}^{10}\mathrm{Be}({}^{14}\mathrm{C},\alpha )$ at Florida State University (FSU). Charged particles were detected with a particle telescope consisting of 4 annularly segmented Si surface barrier detectors and $\gamma$ radiation was detected with the FSU $\gamma$ detector array. Five new states were observed below 6 MeV from the $\alpha \mathrm{\text{−}}\gamma$ and $\alpha \mathrm{\text{−}}\gamma \mathrm{\text{−}}\gamma$ coincidence data. Shell model calculations suggest that most of the newly observed states are core-excited $1p\mathrm{\text{−}}1h$ excitations across the $N=Z=8$ shell gap. Comparisons between experimental data and calculations for the neutron-rich O and F isotopes imply a steady reduction of the $p\mathrm{\text{−}}sd$ shell gap as neutrons are added.

Full-overlap $\mathrm{U}+\mathrm{U}$ collisions provide significantly larger initial energy densities at comparable spatial deformation, and significantly larger deformation and volume at comparable energy density, than semicentral $\mathrm{Au}+\mathrm{Au}$ collisions. We show quantitatively that this provides a long lever arm for studying the hydrodynamic behavior of elliptic flow in much larger and denser collision systems and the predicted nonlinear path-length dependence of radiative parton energy loss.

The production of deuterons and antideuterons in the transverse momentum range $1.1<p_T<4.3\mathrm{GeV}/c$ at midrapidity in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$ has been studied by the PHENIX experiment at RHIC. A coalescence analysis, comparing the deuteron and antideuteron spectra with that of proton and antiproton, has been performed. The coalescence probability is equal for both deuterons and antideuterons and it increases as a function of $p_T$, which is consistent with an expanding collision zone. Comparing (anti)proton yields, $\overline{p}/p=0.73\pm 0.01$, with (anti)deuteron yields, $\overline{d}/d=0.47\pm 0.03$, we estimate that $\overline{n}/n=0.64\pm 0.04$. The nucleon phase space density is estimated from the coalescence measurement.