In an energy-dependent phase-shift analysis of all low-energy $\mathrm{np}$ scattering data below $T_{\mathrm{lab}}=30\mathrm{}$ MeV we reach $\frac{{\chi }^2}{N_{\mathrm{DF}}}=1.1\mathrm{}$, where $N_{\mathrm{DF}}$ is the number of degrees of freedom. In our fit we determine the $S$ matrix elements in the coupled ${}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}+{}_{}{}^3{}_{}{}^{}D_1^{}{}_{}{}^{}$ channels, which allows us to compute the residue at the deuteron pole. Expressed in terms of the deuteron parameters, we find for the asymptotic normalization of the ${}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}$ state $A_S=0.8838\mathrm{}\left(4\right)\mathrm{}$ ${\mathrm{fm}}^{-1/2\mathrm{}}$ and for the asymptotic $\frac{D}{S}$ ratio $\eta =0.02712\mathrm{}\left(22\right)\mathrm{}$. Compared with other determinations, there seems to be some indication for the presence of closed isobar channels and/or energy-dependent potentials in the deuteron system.

Cross sections ascribed to a multifragmentation process have been obtained from the measured fragment yields ($3\le Z_f\le 14$) in proton-xenon interactions ($1\le E_p\le 20$ GeV). The variation of the yields with both mass and bombarding energy can be understood by use of the droplet model of the liquid-gas phase transition. With increasing energy, this model indicates that multifragmentation occurs first in the mechanical-instability region, next in the supersaturated vapor, and finally in the critical region.

The first measurements of the transverse momenta ($p_T$) of heavy projectile fragments produced by fragmentation of 1.2-GeV/nucleon La are presented. The momentum distributions of the fragments (Z≃26–56) are Gaussians and broader than predicted by models based on internal momenta of the projectile nucleons. The larger $p_T$ observed do not appear to be due solely to Coulomb effects, but are consistent with a simple model whereby nucleons from the (hot) overlap region recoil collectively into the (colder) projectile fragments. Thus, $p_T$ and the fragment mass may provide a good indication of the vector impact parameter b.

Electron-scattering cross sections for the reaction ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(e,e’p) have been measured for recoil momenta between 300 and 600 MeV/c and for missing energies up to 90 MeV. Proton momentum distributions in ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, corrected for final-state–interaction and meson-exchange effects, have been obtained from 318 to 600 MeV/c for the pd channel and from 290 to 515 MeV/c for the ppn channel. Explicit evidence for nucleon-nucleon correlations is presented.

The elastic magnetic form factor of ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ has been measured for effective momentum transfers 2.47≤${\mathrm{q}}_{\mathrm{eff}}$≤3.65 ${\mathrm{fm}}^{\mathrm{-}1}$ by electron scattering. The form factor drops by almost three decades in this range. The data follow an extreme single-particle Woods-Saxon shell-model calculation. Many-body effects such as meson-exchange currents or core polarization do not seem to play a significant role in the q range of this experiment.

A discrete superdeformed band was found in ${}_{}{}^{148}{}_{}{}^{}\mathrm{Gd}$, and was produced both in Ca- and Si-induced compound-nucleus reactions. It is the third band found in the mass-150 region and its properties provide the clearest indication that ${}_{}{}^{152}{}_{}{}^{}\mathrm{Dy}$ is a ‘‘magic’’ superdeformed nucleus.

Photons with energies from 2 to 60 MeV have been measured in coincidence with binary fragments in the reaction ${}_{}{}^{92}{}_{}{}^{}$Mo${+}^{92}$Mo at an incident energy of 19.5A MeV. The rapid change of the γ-ray spectrum and multiplicity with the fragment total kinetic energy in the exit channel indicates that the γ rays are emitted statistically by the highly excited fragments. Temperatures as high as 6 MeV are inferred.

The E1 capture cross section for the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(α,γ${)}^{16}$O to the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ground state has been measured for $E_{\mathrm{c}.\mathrm{m}.\mathrm{}=1.29\mathrm{}–}$3.00 MeV. A γ-ray–recoil-particle coincidence technique has been used to obtain essentially background-free reaction yields. A three-level R-matrix analysis of the E1 S factor leads to an allowed range for $S_{E1}$ at 300 keV of 0.00–0.14 MeV b. A model-dependent R-matrix analysis and a hybrid R-matrix analysis result in values of 0.14 and 0.08 MeV b, respectively, for $S_{E1}$(300).

The sign of the emission angle for nonequilibrium intermediate-mass fragments was determined from the circular polarization of coincident γ rays for ${}_{}{}^{14}{}_{}{}^{}\mathrm{induced}$ reactions on ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$ at E/A=35 MeV. Positive polarizations, $P_{\gamma }$≤0.3–0.4, are observed for fragments with 3≤Z≤6, consistent with fragment emission after deflection by the attractive nuclear mean field to negative emission angles. These polarizations are small compared to the trends established for nonequilibrium light particles and the expectations of simple dynamical production mechanisms.

Double-charge-exchange reactions induced by pions furnish a direct means of detecting nucleon-nucleon correlations in nuclei. For the particular case of double isobaric analog transitions the effect of correlations is easily isolated and quite strong. We show that the magnitudes of the double-charge-exchange cross sections for the isotopes ${}_{}{}^{42}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ca}$, and ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$, recently measured at low energies, can be explained well by our taking account of the position correlations of the valence neutrons in the respective ground states.

Experiments to determine the characteristics of electromagnetic dissociation (ED) has been extended to high projectile charge and ultrarelativistic energies using ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}$ and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ projectiles on ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ targets. The gross features are reproduced in a Weizsäcker-Williams calculation but significant systematic deviations appear. The results are used as a guide in extending the calculations to the regime of energies and projectiles expected for planned heavy-ion colliders where Ed effects should comprise a major fraction of the total cross section.

Transverse form factors have been measured for elastic electron scattering from ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$ and ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$, as well as for the electroexcitation of the 1.74-MeV ($J^{\pi }$=$O^{+}$, T=1) and 5.17-MeV ($2^{+}$, 1) levels of ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$. These results were utilized to determine the radial shape of the 1$p_{3/2}$ single-particle wave function within the nuclear interior.

The Schwinger representation of the SO(8) fermion-pair algebra in terms of d and quasispin vector s bosons is used in derivation of a microscopic boson coherent state having both particle-hole and pair excitations. The coherent state is the exact boson image of the Hartree-Fock-Bogolyubov variational solution. One can go beyond the mean field and introduce an intrinsic Hamiltonian having the boson condensate as an eigenstate.

Longitudinal and transverse structure functions for the quasielastic reaction ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(e,e’p${)}^{39}$${\mathrm{K}}^{\mathrm{*}}$ have been obtained. Their q dependences appear like those for free nucleons. However, the ratio of the longitudinal to transverse structure functions is found reduced by 30% relative to theoretical calculations.

The intensity interferometry method has been used to measure pion-source parameters in the reaction 1.70A-GeV ${}_{}{}^{56}{}_{}{}^{}$Fe+Fe→2${\pi }^{\mathrm{-}}$+X. The parameters show an oblate source for a narrow-acceptance spectrometer near either 0° or 90° with respect to the beam axis in the center-of-mass frame. Intranuclear-cascade–model predictions show similar behavior and are compared to the experimental results.

Shallow imaginary potentials ($W_0$≊18–25 MeV) are found to be essential to describe various sets of elastic-scattering data for ${}_{}{}^{12}{}_{}{}^{}\mathrm{-}_{}^{12}{}_{}{}^{}$C and ${}_{}{}^{16}{}_{}{}^{}\mathrm{-}_{}^{12}{}_{}{}^{}$C at intermediate energies. This result does not show a continuous ambiguity. An energy-dependent Woods-Saxon–shaped optical-model potential is presented for 60 MeV≲$E_{\mathrm{c}.\mathrm{m}.\mathrm{}\lesssim 650}$ MeV.

The lack of systematic band crossings at high spin in ${}_{}{}^{159}{}_{}{}^{}$,160Er and the selectivity of the single observed neutron band crossing at ħω>0.37 MeV in ${}_{}{}^{159}{}_{}{}^{}\mathrm{Er}$ (i) indicate that static neutron-pair correlations are too weak for the excitation of a pair of quasineutrons, and (ii) can be explained in terms of the expected spectrum of single-neutron states in the absence of static pair correlations.

The process of nuclear fission induced by nonlinear radiative coupling to atomic electrons is considered. For 248-nm radiation at an intensity of ≃${10}^{21}$ W/${\mathrm{cm}}^2$, highly relativistic currents are produced which can couple to the fission mode of nuclear decay. With irradiation for a time of ≃100 fs the results indicate a fission probability of ≃${10}^{\mathrm{-}5}$ for ${}_{{\mathrm{}}^2{\mathrm{}}_{92}^{38}}{}^{}{}_{}{}^{}\mathrm{U}$ nuclei located at the surface of a solid target, a value several orders of magnitude above the limit of detection.

A remeasurement of the β-decay asymmetry parameter for ${}_{}{}^{35}{}_{}{}^{}\mathrm{Ar}$ decay to the ground state of ${}_{}{}^{35}{}_{}{}^{}\mathrm{Cl}$ has been performed. The result, $A_0$=0.49±0.10, leads to a value for the quark mixing angle ${\theta }_C$=0.28±0.08 rad, in agreement with the accepted value 0.23±0.01 and in strong disagreement with the anomalous result ${\theta }_C$<0.10 (95% confidence level) determined from previous measurements of this asymmetry parameter.

A rotational band of nineteen transitions, extending to spin∼(127/2ħ and with an average moment of inertia ${\mathrm{scrI}}^{\mathrm{}\left(2\right)\mathrm{}}$ of 77 ${ħ}^2$ ${\mathrm{MeV}}^{\mathrm{-}1}$, has been observed in ${}_{}{}^{149}{}_{}{}^{}\mathrm{Gd}$. Its intensity accounts for approximately (1/2% of the total fusion cross section. Lifetime measurements yielded an average quadrupole moment of 17±2 e-b, in excellent agreement with the value calculated microscopically for a superdeformed shape. The trends in ${\mathrm{scrI}}^{\mathrm{}\left(1\right)\mathrm{}}$ and ${\mathrm{scrI}}^{\mathrm{}\left(2\right)\mathrm{}}$ are consistent with very weak pairing effects. The data also suggest that to populate superdeformed bands significantly one must form cold residual nuclei.