An exclusive study of the interaction of 1A GeV Au with C shows a separability into two stages: a prompt stage involving emission of most $Z=1\mathrm{}$ and some $Z=2\mathrm{}$ particles and a second stage involving the decay of an equilibrated remnant, which typically undergoes multifragmentation. The mean mass, charge, excitation energy, and the initial temperature $T_i$ of the remnant have been determined as a function of the total charge multiplicity, $m$, as has the freeze-out temperature $T_f$. Both $T_i$ and $T_f$ increase linearly with $m$ and their values at the critical point have been determined. $T_f$ rises monotonically with excitation energy as expected for a continuous phase transition.

The decay out of the yrast and excited highly deformed (HD) bands in ${}^{134}$Nd has been investigated via the ${}^{28}\mathrm{Si}{+}^{110}\mathrm{Pd}$ reaction at 130 MeV using the GASP array. Several deexcitation pathways have been established for both the yrast and excited HD bands. The resulting spins remove previous ambiguities in the assignment of the excited HD band and confirm the structure assigned to the yrast HD band. The decay out is understood in terms of mixing between the normal-deformed and HD states, which is triggered by the crossing between the $\nu i_{13/2}$ and $\nu d_{5/2}$ orbitals.

The single-particle self-energy is calculated in semi-infinite nuclear matter with use of an effective interaction of strength determined self-consistently. The resulting damping width of a particle at a Fermi energy displays a linear dependence with temperature as a result of the coupling to surface excitations, while the effective mass shows an exponential decay. The results are in overall agreement with detailed calculations carried in finite nuclei and with experimental findings.

We study a new type of collective motion with $\alpha$-particle type of correlations and show that it may be relevant for $N\sim Z$ nuclei.

From $\gamma$-ray coincidence studies following spontaneous fission of ${}^{252}\mathrm{Cf}$, direct measurements of yields and neutron multiplicities were made for Sr-Nd, Zr-Ce, Mo-Ba, Ru-Xe, and Pd-Te correlated pairs. A strong enhancement of the 7-10 neutron channels for Mo-Ba pairs is observed. A new fission mode associated with the enhanced neutron yields is identified. These data can be interpreted in terms of one or more of ${}^{144,145,146}\mathrm{Ba}$ being hyperdeformed at scission. Mean field calculations predict a hyperdeformed third minimum in ${}^{252}\mathrm{Cf}$ and an extremely deformed ${}^{146}\mathrm{Ba}$ fragment at scission.

$\alpha$ decay through a deformed potential barrier produces significant mixing of angular momenta when mapped from the nuclear interior to the outside. Using experimental branching ratios and either semiclassical or coupled-channels transmission matrices, we have found that there is a set of internal amplitudes which is essentially constant for all even-even actinide nuclei. These same amplitudes also give good results for the known anisotropic $\alpha$-particle emission of the favored decays of odd nuclei in the same mass region.

The fluctuation properties of nuclear giant resonance spectra are studied in the presence of continuum decay. The subspace of quasibound states is specified by one-particle–one-hole and two-particle–two-hole excitations, and the continuum coupling is generated by a scattering ensemble. It is found that, with an increasing number of open channels, the real parts of the complex eigenvalues quickly decorrelate. This appears to be related to the transition from power-law to exponential time decay of the survival probability of an initially nonstationary state.

Formation and decay of hot nuclei have been studied in ${}^{64}\mathrm{Zn}{+}^{\mathrm{nat}}\mathrm{Ti}$ collisions between 35 and 79 MeV/nucleon. The mass and excitation energy of excited quasiprojectiles are reconstructed from the kinematical characteristics of their decay products. In central collisions, excitation energies larger than 10 MeV/nucleon are reached. Comparisons with theoretical predictions indicate that a fraction of the excitation energy is associated with an isotropic radial flow.

A test of parity-conserving, time-reversal noninvariance (PC TRNI) has been performed in 5.9 MeV polarized neutron transmission through nuclear spin aligned holmium. The experiment searches for the T-violating fivefold correlation via a double modulation technique—flipping the neutron spin while rotating the alignment axis of the holmium. Relative cross sections for spin-up and spin-down neutrons are found to be equal to within $1.2\times {10}^{-5\mathrm{}}$ (80% confidence). This is a 2 orders of magnitude improvement compared to traditional detailed balance studies of time reversal, and represents the most precise test of PC TRNI in a dynamical process.

Some improvements in the final state spectrum of ${\mathrm{T}}_2$ $\beta$ decay are discussed. Their importance for neutrino mass determination has been estimated through numerical experiments. Results depend most strongly on the length of the energy interval of the experimental spectrum used in the fit to the theoretical spectrum. For a Gaussian resolution function and fit intervals to 1.1 keV below the end point energy physically plausible changes in the final state distribution could contribute as much as $-30\mathrm{}{\mathrm{eV}}^2$ to the systematic error in $m_{\nu }^2$. A wider resolution function can increase this error by a factor of 2 or 3. An improved final state spectrum for neutrino mass determination is presented.

Precise level lifetimes have been measured for various superdeformed bands in ${}^{148,149}\mathrm{Gd}$ and ${}^{152}\mathrm{Dy}$ with the Doppler-shift attenuation method. From the derived quadrupole moments, $Q_0$, we find large differences in deformation between the yrast bands and some excited bands in the gadolinium isotopes. Moreover, two of the excited Gd bands and the ${}^{152}\mathrm{Dy}$ yrast band, which have identical moments of inertia, have different elongations, supporting the picture that alignment and deformation effects cancel in identical bands.

The $\gamma$ decay of the excited rotating ${}^{168}$Yb nucleus has been simulated considering the competition between $E1\mathrm{}$ and $E2\mathrm{}$ transitions, using microscopically calculated rotational bands. The simulations were made for two different cases: (i) pure rotating mean field bands and (ii) rotational bands mixed by a residual interaction. Simulated $\gamma -\gamma$ spectra were analyzed in the typical rotational ridge-valley region. The fluctuation analysis method, sensitive to the effective number of $\gamma$-decay paths, was also applied. An overall agreement between experimental and simulated data is found for the case of mixed rotational bands.

The first $(p,n)$ polarization-transfer measurements for delta production on a nuclear target are presented for the ${}^{12}\mathrm{C}(\overrightarrow{p},\overrightarrow{n})$ reaction at 0° and 795 MeV. Polarization observables are used to extract the spin-longitudinal, spin-transverse, and spin-independent partial cross sections. In the spin-longitudinal channel, fair agreement is found between experiment and a model which includes a strongly attractive residual interaction. A large unexpected enhancement in the spin-transverse cross section is observed.

Within the framework of an isospin-dependent Boltzmann-Uehling-Uhlenbeck model using initial proton and neutron densities calculated from the nonlinear relativistic mean-field theory, we compare the strength of transverse collective flow in reactions ${}^{48}\mathrm{Ca}{+}^{58}\mathrm{Fe}$ and ${}^{48}\mathrm{Cr}{+}^{58}\mathrm{Ni}$, which have the same mass number but different neutron/proton ratios. The neutron-rich system ( ${}^{48}\mathrm{Ca}{+}^{58}\mathrm{Fe}$) is found to show significantly stronger negative deflection and consequently has a higher balance energy, especially in peripheral collisions.

Parity and time invariance violating forces produce collective P- and T-odd moments in nuclei with static octupole deformation. Collective Schiff moment, electric octupole and dipole, and also magnetic quadrupole appear due to the mixing of rotational levels of opposite parity and can exceed single-particle moments by more than a factor of 100. This enhancement is due to two factors, the collective nature of the intrinsic moments and the small energy separation between members of parity doublets. The above moments induce T- and P-odd effects in atoms and molecules. Experiments with such systems may improve substantially the limits on time reversal violation.

The quantity R in a new expression $E_I=A[\sqrt{\mathrm{BI}(I+R)+1\mathrm{}}-1\mathrm{}]$, which is introduced on the basis of the Bohr Hamiltonian and which can describe universally the yrast lines of even-even nuclei over the entire nuclear chart in very high precision, is regarded as a fingerprint to identify the nuclear γ shape as shown by both the theory and the survey of experimental data. This fingerprint shows that some of the observed superdeformed bands have axial asymmetry if the previous spin assignments are valid.

We reexamine the matter radii of diffuse halo nuclei, as deduced from reaction cross section measurements at high energy. Careful consideration is given to the intrinsic few-body structure of these projectiles and the adiabatic nature of the projectile-target interaction. Using ${}^{11}$Li, ${}^{11}$Be, and ${}^8$B as examples we show that data require significantly larger matter radii than previously reported. The revised value for ${}^{11}$Li of 3.55 fm is consistent with three-body models with significant $1s$-intruder state components, which reproduce experimental ${}^9$Li momentum distributions following ${}^{11}$Li breakup, but were hitherto thought to be at variance with cross section data.

The NA52 experiment searches for long-lived massive strange quark matter particles, so-called ${\mathit{s}\mathit{t}\mathit{r}\mathit{a}\mathit{n}\mathit{g}\mathit{e}\mathit{l}\mathit{e}\mathit{t}\mathit{s},\mathrm{p}\mathrm{r}\mathrm{o}\mathrm{d}\mathrm{u}\mathrm{c}\mathrm{e}\mathrm{d}\mathrm{i}\mathrm{n}\mathrm{P}\mathrm{b}-\mathrm{P}\mathrm{b}\mathrm{c}\mathrm{o}\mathrm{l}\mathrm{l}\mathrm{i}\mathrm{s}\mathrm{i}\mathrm{o}\mathrm{n}\mathrm{s}\mathrm{a}\mathrm{t}\mathrm{a}\mathrm{b}\mathrm{e}\mathrm{a}\mathrm{m}\mathrm{m}\mathrm{o}\mathrm{m}\mathrm{e}\mathrm{n}\mathrm{t}\mathrm{u}\mathrm{m}\mathrm{o}\mathrm{f}{p}_{\mathrm{lab}}=158\mathrm{}\mathrm{A}\mathrm{}\mathrm{GeV}\mathrm{/}\mathit{c}.\mathrm{U}\mathrm{p}\mathrm{p}\mathrm{e}\mathrm{r}\mathrm{l}\mathrm{i}\mathrm{m}\mathrm{i}\mathrm{t}\mathrm{s}\mathrm{f}\mathrm{o}\mathrm{r}\mathrm{t}\mathrm{h}\mathrm{e}\mathrm{p}\mathrm{r}\mathrm{o}\mathrm{d}\mathrm{u}\mathrm{c}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}\mathrm{o}\mathrm{f}\mathrm{s}\mathrm{t}\mathrm{r}\mathrm{a}\mathrm{n}\mathrm{g}\mathrm{e}\mathrm{l}\mathrm{e}\mathrm{t}\mathrm{s}\mathrm{a}\mathrm{t}\mathrm{z}\mathrm{e}\mathrm{r}\mathrm{o}\mathrm{d}\mathrm{e}\mathrm{g}\mathrm{r}\mathrm{e}\mathrm{e}\mathrm{p}\mathrm{r}\mathrm{o}\mathrm{d}\mathrm{u}\mathrm{c}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}\mathrm{a}\mathrm{n}\mathrm{g}\mathrm{l}\mathrm{e}\mathrm{c}\mathrm{o}\mathrm{v}\mathrm{e}\mathrm{r}\mathrm{i}\mathrm{n}\mathrm{g}\mathrm{a}\mathrm{m}\mathrm{a}\mathrm{s}\mathrm{s}\mathrm{t}\mathrm{o}\mathrm{c}\mathrm{h}\mathrm{a}\mathrm{r}\mathrm{g}\mathrm{e}\mathrm{r}\mathrm{a}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{u}\mathrm{p}\mathrm{t}\mathrm{o}120\mathrm{GeV}\mathrm{/}\mathit{c}}^2$ and lifetimes $t_{\mathrm{lab}}\gtrsim 1.2$ μs are given. The data presented here were taken during the 1994 lead beam running period at CERN.

Using charged-particle-exclusive measurements of $\mathrm{Au}+\mathrm{Au}$ collisions in the Bevalac's EOS time projection chamber, we demonstrate the advantages of an alternative representation of the squeeze-out phenomenon where the speed of collective expansion is slowest in the plane of the reaction, and is modulated sinusoidally according to fragment azimuth relative to this plane. This simpler representation facilitates a highly comprehensive description of light fragment spectra and the three main categories of collective motion: sideward flow, squeeze-out, and radial expansion.

Asymmetries for ${\pi }^{+}$ elastic scattering from polarized ${}^3\mathrm{He}$ were measured across the $\Delta$(1232) $\pi$-nucleon resonance region at incident energies $T_{\pi }=142\mathrm{}$, 180, and 256 MeV. Large discrepancies were found between the data and calculations that use the multiple scattering formalism and Faddeev wave functions. Inclusion of a $\Delta$-neutron spin-spin interaction term in the calculations gives a greatly improved representation of the data.