Seven ${}^{271}\mathrm{D}\mathrm{s}$ decay chains were identified in the bombardment of ${}^{208}\mathrm{P}\mathrm{b}$ targets with 311.5 and 314.3 MeV ${}^{64}\mathrm{N}\mathrm{i}$ projectiles using the Berkeley Gas-filled Separator. These data, combined with previous results, provide an excitation function for this reaction. From these results, an optimum energy of 321 MeV was estimated for the production of ${}^{272}111$ in the new reaction ${}^{208}\mathrm{P}\mathrm{b}({}^{65}\mathrm{C}\mathrm{u},n)$. One decay chain was observed, resulting in a cross section of ${1.7}_{-1.4}^{+3.9}\mathrm{p}\mathrm{b}$. This experiment confirms the discovery of element 111 by the Darmstadt Group who used the ${}^{209}\mathrm{B}\mathrm{i}({}^{64}\mathrm{N}\mathrm{i},n){}^{272}111$ reaction.

We study the phase diagram of the proton-neutron interacting boson model with special emphasis on the phase transitions leading to triaxial phases. The existence of a new critical point between spherical and triaxial shapes is reported.

Spallation residues and fission fragments from $1A\mathrm{G}\mathrm{e}\mathrm{V}{}^{238}\mathrm{U}$ projectiles irradiating a liquid hydrogen target were investigated by using the fragment separator at GSI for magnetic selection of reaction products including ray-tracing, energy-loss and time-of-flight techniques. The longitudinal-momentum spectra of identified fragments were analyzed, and evaporation residues and fission fragments could be separated. For 1385 nuclides, production cross sections down to values of $10\mu \mathrm{b}$ with a mean accuracy of 15%, velocities in the uranium rest frame and kinetic energies were determined. In the reaction all elements from uranium to nitrogen were found, each with a large number of isotopes.

An explicit evaluation of the spin asymmetry of the deuteron and the associated Gerasimov-Drell-Hearn sum rule is presented which includes photodisintegration, and single and double pion and eta production as well. Photodisintegration is treated with a realistic retarded potential and a corresponding meson exchange current. For single pion and eta production the elementary operator from MAID is employed, whereas for double pion production, an effective Lagrangian approach is used. A large cancellation between the disintegration and the meson production channels yields for the explicit GDH integral a value of $27.31\mu \mathrm{b}$ to be compared to the sum rule value $0.65\mu \mathrm{b}$.

Highly precise data on the magnetic dipole strength distributions from the Darmstadt electron linear accelerator for the nuclei ${}^{50}\mathrm{T}\mathrm{i}$, ${}^{52}\mathrm{C}\mathrm{r}$, and ${}^{54}\mathrm{F}\mathrm{e}$ are dominated by isovector Gamow-Teller-like contributions and can therefore be translated into inelastic total and differential neutral-current neutrino-nucleus cross sections at supernova neutrino energies. The results agree well with large-scale shell-model calculations, validating this model.

Two-proton correlations at small relative momentum $q$ were studied in the $eA({}^3\mathrm{H}\mathrm{e},{}^4\mathrm{H}\mathrm{e},\mathrm{C},\mathrm{F}\mathrm{e})\to e^{\prime }ppX$ reaction at $E_0=4.46\mathrm{G}\mathrm{e}\mathrm{V}$ using the CLAS detector at Jefferson Lab. The enhancement of the correlation function at small $q$ was found to be in accordance with theoretical expectations. Sizes of the emission region were extracted, and proved to be dependent on $A$ and on the proton momentum. The size of the two-proton emission region for He was measured in $eA$ reactions for the first time.

The electric dipole strength distribution in ${}^{44}\mathrm{C}\mathrm{a}$ has been measured up to 10 MeV in high resolution photon scattering experiments for the first time. The data obtained have been compared to earlier measurements on ${}^{40,48}\mathrm{C}\mathrm{a}$ in order to view the evolution of the electric pygmy dipole resonance (PDR). Calculations that were performed within the framework of the microscopic extended theory of finite Fermi systems, which adds contributions of the quasiparticle-phonon coupling to random phase approximation calculations, give a qualitative agreement with the experimental data for all three isotopes. We have shown that it is necessary to include this coupling to describe the PDR.

Using selective laser extraction technique combined with sensitive ion-counting mass spectrometry, we have analyzed the isotopic structure of fission noble gases in U-free La-Ce-Sr-Ca aluminous hydroxy phosphate associated with the 2 billion yr old Oklo natural nuclear reactor. In addition to elevated abundances of fission-produced Zr, Ce, and Sr, we discovered high (up to $0.03{\mathrm{c}\mathrm{m}}^3\mathrm{S}\mathrm{T}\mathrm{P}/\mathrm{g}$) concentrations of fission Xe and Kr, the largest ever observed in any natural material. The specific isotopic structure of xenon in this mineral defines a cycling operation for the reactor with 30-min active pulses separated by 2.5 h dormant periods. Thus, nature not only created conditions for self-sustained nuclear chain reactions, but also provided clues on how to retain nuclear wastes, including fission Xe and Kr, and prevent uncontrolled runaway chain reaction.

Within the hydrodynamical approach, we study the Bose-Einstein correlation of identical pions by taking into account both event-by-event fluctuating initial conditions and continuous pion emission during the whole development of the hot and dense matter formed in high-energy collisions. Important deviations occur, compared to the usual hydrocalculations with smooth initial conditions and a sudden freeze-out on a well defined hypersurface. Comparison with data at the BNL Relativistic Heavy Ion Collider (RHIC) shows that, despite the rather rough approximation we used here, this description can account for the $m_T$ dependence of $R_L$ and $R_s$, and produces a significant improvement for $R_o$ with respect to the usual version.

We have carried out an $(e,e^{\prime }p)$ experiment at high momentum transfer and in parallel kinematics to measure the strength of the nuclear spectral function $S(k,E)$ at high nucleon momenta $k$ and large removal energies $E$. This strength is related to the presence of short-range and tensor correlations, and was known hitherto only indirectly and with considerable uncertainty from the lack of strength in the independent-particle region. This experiment locates by direct measurement the correlated strength predicted by theory.

A model for a special configuration in triaxial odd-odd nuclei is constructed which exhibits degenerate chiral bands with a sizable rotation, a manifestation of dynamical spontaneous symmetry breaking. A quantum number obtained from the invariance of the model Hamiltonian, which characterizes observable states, is given and selection rules for electromagnetic transition probabilities in chiral bands is derived in terms of this quantum number. The degeneracy of the lowest two bands is indeed obtained in the numerical diagonalization of the Hamiltonian at an intermediate spin range, over which electromagnetic transitions follow exactly the selection rule expected for the chiral geometry.

The decay of ${}^{182}\mathrm{H}\mathrm{f}$, now extinct, into stable ${}^{182}\mathrm{W}$ has developed into an important chronometer for studying early solar system processes such as the accretion and differentiation of planetesimals and the formation of the Earth and the Moon. The only ${}^{182}\mathrm{H}\mathrm{f}$ half-life measurements available were performed 40 years ago and resulted in an imprecise half-life of $(9\pm 2)\times {10}^6\mathrm{y}\mathrm{r}$. We redetermined the half-life by measuring the specific activity of ${}^{182}\mathrm{H}\mathrm{f}$ based on two independent methods, resulting in a value of $t_{1/2}({}^{182}\mathrm{H}\mathrm{f})=(8.90\pm 0.09)\times {10}^6\mathrm{y}\mathrm{r}$, in good agreement with the previous value, but with a 20 times smaller uncertainty. The greatly improved precision of this half-life now permits very precise intercalibration of the ${}^{182}\mathrm{H}\mathrm{f}$–${}^{182}\mathrm{W}$ isotopic system with other chronometers.

We calculate the two-body correlation function of direct photons produced in central $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ collisions at the Relativistic Heavy-Ion Collider. Our calculation includes contributions from the early preequilibrium phase in which photons are produced via hard parton scatterings as well as radiation of photons from a thermalized quark-gluon plasma and the subsequent expanding hadron gas. We find that high energy photon interferometry provides a faithful probe of the details of the space-time evolution and of the early reaction stages of the system.

Evaporation residue cross sections in the ${}^{16}\mathrm{O}+{}^{238}\mathrm{U}$ reaction were measured for the energy range from above- to extreme sub-barrier. The cross sections are reproduced by a statistical model calculation, for which partial cross sections are calculated by a coupled-channel model taking into account the prolate deformation of ${}^{238}\mathrm{U}$. Complete fusion was observed in the collision of the projectile with the tips of the ${}^{238}\mathrm{U}$ target, in the same way as the side collision.

Bose-Einstein correlations of identically charged pion pairs were measured by the PHENIX experiment at midrapidity in $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ collisions at $\sqrt{s_{NN}}=200\mathrm{G}\mathrm{e}\mathrm{V}$. The Bertsch-Pratt radius parameters were determined as a function of the transverse momentum of the pair and as a function of the centrality of the collision. Using the standard core-halo partial Coulomb fits, and a new parametrization which constrains the Coulomb fraction as determined from the unlike-sign pion correlation, the ratio $R_{\mathrm{o}\mathrm{u}\mathrm{t}}/R_{\mathrm{s}\mathrm{i}\mathrm{d}\mathrm{e}}$ is within 0.8–1.1 for $0.25<\langle k_{\mathrm{T}}\rangle <1.2\mathrm{G}\mathrm{e}\mathrm{V}/c$. The centrality dependence of all radii is well described by a linear scaling in $N_{\mathrm{p}\mathrm{a}\mathrm{r}\mathrm{t}}^{1/3}$, and $R_{\mathrm{o}\mathrm{u}\mathrm{t}}/R_{\mathrm{s}\mathrm{i}\mathrm{d}\mathrm{e}}$ for $\langle k_{\mathrm{T}}\rangle \sim 0.45\mathrm{G}\mathrm{e}\mathrm{V}/c$ is approximately constant at unity as a function of centrality.

The generalized forward spin polarizabilities ${\gamma }_0$ and ${\delta }_{LT}$ of the neutron have been extracted for the first time in a $Q^2$ range from 0.1 to $0.9{\mathrm{G}\mathrm{e}\mathrm{V}}^2$. Since ${\gamma }_0$ is sensitive to nucleon resonances and ${\delta }_{LT}$ is insensitive to the $\Delta$ resonance, it is expected that the pair of forward spin polarizabilities should provide benchmark tests of the current understanding of the chiral dynamics of QCD. The new results on ${\delta }_{LT}$ show significant disagreement with chiral perturbation theory calculations, while the data for ${\gamma }_0$ at low $Q^2$ are in good agreement with a next-to-leading-order relativistic baryon chiral perturbation theory calculation. The data show good agreement with the phenomenological MAID model.

The quantum deformation concept is applied to a study of pairing correlations in nuclei with mass $40\le A\le 100$. While the nondeformed limit of the theory provides a reasonable overall description of certain nuclear properties and fine structure effects, the results show that the $q$ deformation plays a significant role in understanding higher-order effects in the many-body interaction.

It is shown that strong $0_2^{+}\to 0_1^{+}$ $E0$ transitions provide a clear signature of phase transitional behavior in finite nuclei. Calculations using the interacting-boson approximation (IBA) show that these transition strengths exhibit a dramatic and robust increase in spherical-deformed shape transition regions, that this rise matches well the existing data, that the predictions of these $E0$ transitions remain large in deformed nuclei, that they arise from the specific $d$-boson coherence in the wave functions, and do not necessarily require the explicit mixing of normal and intruder configurations from different IBA spaces.

We report on the $g$ factor measurement of an isomer in the neutron-rich ${}_{26}{}^{61}\mathrm{F}\mathrm{e}$ ($E^{*}=861\mathrm{k}\mathrm{e}\mathrm{V}$ and $T_{1/2}=239(5)\mathrm{n}\mathrm{s}$). The isomer was produced and spin aligned via a projectile-fragmentation reaction at intermediate energy, the time dependent perturbed angular distribution method being used for the measurement of the $g$ factor. For the first time, due to significant improvements of the experimental technique, an appreciable residual alignment of the nuclear spin ensemble has been observed, allowing a precise determination of its $g$ factor, including the sign: $g=-0.229(2)$. In this way we open the possibility to study moments of very neutron-rich short-lived isomers, not accessible via other production and spin-orientation methods.

We study low-lying multipole strength in neutron-halo nuclei. The strength depends only on a few low-energy constants: the neutron separation energy, the asymptotic normalization coefficient of the bound-state wave function, and the scattering length that contains the information on the interaction in the continuum. The shape of the transition probability shows a characteristic dependence on few scaling parameters and the angular momenta. The total $E1$ strength is related to the root-mean-square radius of the neutron wave function in the ground state and shows corresponding scaling properties. We apply our approach to the $E1$ strength distribution of ${}^{11}\mathrm{B}\mathrm{e}$.