In terms of the participant-spectator model for high-energy heavy-ion collisions, the probability that a hyperon is created from the participants directly in the nuclear single-particle states of the spectator fragment is evaluated. It is found that the magnitude of the cross section for producing a hypernucleus depends on both the lifetime of the hyperon source and the impact parameter of the reaction.

The Hilb formula, an asymptotic continuous approximation in l for the Legendre polynomials that is valid from forward angles to nearly 180°, is tested numerically in semiclassical summations of scattering amplitudes. It works remarkably well even when the amplitude oscillates and falls by many orders of magnitude so long as the S matrix varies slowly with l. We generalize the Hilb formula to the associated Legendre functions.

It is argued that the conclusions drawn from recent distorted-wave impulse approximation calculations of the sup12C(πsup+,2p) reaction should be based on results of calculations which include distortions. Such results support the interpretation given in the paper describing the experimental study of this reaction.

An attempt is made to clarify some of the areas of disagreement concerning recent distorted-wave impulse approximation calculations of the sup12C(πsup+,2p) reaction. In the absence of detailed exclusive data, it is argued that the identification of the broad ‘‘background’’ reported remains uncertain.

Semiclassical mean field techniques are used to describe the M1 scissors mode in the neutron-proton interacting boson model. The resulting expressions for the energy of the mode are as simple as those obtained recently in the classical limit. The mean field approach, however, yields much better agreement with exact neutron-proton interacting boson model results.

Tensor and vector analyzing powers and cross sections have been measured for low-lying levels populated by the sup89Y(d,α) sup87Sr reaction at 9.0, 12.0, and 16.0 MeV. Angular distributions of dσ/dΩ, Asuby, Asubyy, Asubxx, and Asubxz have been analyzed using full finite-range distorted-wave Born approximation calculations including α-particle D-state effects. It is shown that the sign and amplitude of two-nucleon spectroscopic amplitudes corresponding to different L and J transfers can be determined from the angular distributions of the tensor analyzing powers.

The decay of sup149Er was investigated by γ-ray spectroscopy. Based on these measurements the ssub1/2, dsub3/2, and hsub11/2 neutron states in sup149Er and the ssub1/2, dsub3/2, dsub5/2, and gsub7/2 proton states in sup149Ho were identified. A systematic examination of these proton states in N=82 isotones indicates a modest closure at Z=64, rather than a major one as suggested previously. Spherical Hartree-Fock-Bogolyubov calculations for even-Z N=81 and odd-Z N=82 nuclei are compared with experiment.

The novel momentum analysis technique introduced by Danielewicz and Odyniec can be used to detect and exhibit collective flow in the light system Ar(1800 MeV/nucleon) + KCl where the usual kinetic energy flow analysis fails. The microscopic Vlasov-Uehling-Uhlenbeck theory which includes the nuclear mean field, two-body collisions, and Pauli blocking is used to study this phenomenon. The resulting transverse momentum transfers turn out to be quite sensitive to the nuclear equation of state. From a comparison with experimental data, evidence is presented for a rather stiff nuclear equation of state. The cascade model is unable to describe the data.

Numerical results have been obtained for calculations of pion double-charge-exchange arising from Δsub33-mediated processes. Calculations of double-charge-exchange excitation functions and angular distributions are presented for the reaction sup16O(πsup+πsup-) sup16Ne(g.s.). The sensitivity of the calculations to quantities specifying the reaction mechanism is shown.

The differential cross section for sup12C(p,πsup-)sup13Osubg.s. at 613 MeV has been calculated in the framework of a microscopic two-nucleon model including the nucleon resonances Δ(1232), Nsup*(1470), Nsup*’(1520). The good agreement with the experimental cross section both in magnitude and in shape strongly indicates that, in addition to the Δ isobar, the Nsup*’(1520) resonance contributes substantially to the (p,πsup-) reaction at this energy.

The method of continued fractions recently proposed by the authors is generalized to an off-shell t-matrix calculation for any nonlocal nonsymmetric interaction. The efficiency of the method is demonstrated for some examples in nuclear physics. The method is not only very efficient, but yields very accurate results when it is combined with the Romberg extrapolation method. A new separable approximation of a potential and the off-shell t matrix is proposed in connection with the method of continued fractions.

Differential cross sections and analyzing powers of neutrons elastically scattered from ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{59}{}_{}{}^{}\mathrm{Co}$, and Pb were measured using two 183 cm long position sensitive scintillators. A beam of polarized neutrons (P=0.51, $E_{\mathrm{n}=23\mathrm{}}$ MeV) was produced by the ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(d,n${)}^4$He reaction. A superconducting solenoid was used to precess the neutron spin by 180° for the determination of analyzing powers. After correcting for neutron flux attenuation and multiple scattering due to the finite size of the scatterers, the data were analyzed using a conventional optical model potential.

We have calculated the cross sections for both nonradiative and radiative processes in the nuclear excitation during positron-K-electron annihilation. Also their relative contributions are compared and discussed. The radiative process cannot explain the discrepancies between experiment and theory.

A part of the excitation function of the ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$(n,2n) reaction was determined by the foil activation method for neutron energies of 6.745, 6.938, 7.190, 7.448, 7.697, 7.944, 8.457, 8.975, 9.445, 9.934, and 10.450 MeV. Neutron flux density was measured using reactions ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$(n,f), ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$(n,p), and ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$(n,α). Activity of the ${}_{}{}^{231}{}_{}{}^{}\mathrm{Th}$ residual nuclei was determined by their low energy γ transitions detected with a high purity Ge spectrometer. Results of this experiment are compared with renormalized literature data.

Cross sections were measured for the reactions ${}_{}{}^{87}{}_{}{}^{}$Sr+p→${\mathrm{}}^{86}$Sr+pn and ${}_{}{}^{91}{}_{}{}^{}$Zr+p→${\mathrm{}}^{90}$Zr+pn using two time-of-flight neutron detectors located at 65° and 100°, and a charged particle telescope at 135°. Results are presented for several incident energies from 14.0 to 17.6 MeV. They are compared with Hauser-Feshbach calculations, with which they substantially agree.

The effects of specific distortion in the channel spin (3/2) state of the d${+}^3$He system are considered by including in the resonating-group formulation inelastic channels involving deuteron pseudo-states. The result shows that, because of the high compressibility of the deuteron cluster, these effects are quite important in the l=0 configuration. With specific distortion taken into account, it is found that a satisfactory explanation of the experimental data on d${+}^3$He resonance state and scattering angular distributions can be achieved.

We present a unified investigation of the spin-isospin responses of a finite nucleus in both the spin-transverse (σ→×q→) and spin-longitudinal (σ→⋅q→) channels, utilizing the formalism of the polarization propagator, Πμν. The independent particle transverse response (evaluated in a harmonic oscillator basis) fails to reproduce the recent data from deep inelastic (e,e’) scattering, thus pointing to the existence of collective effects. As a preliminary step toward the solution of the random-phase-approximation equations for Πμν, we explore in detail the mixed-coupling propagator, which may produce significant differences between the collective response of infinite nuclear matter and the one of a finite system.

The boundary condition Ernst-Shakin-Thaler method, introduced previously to generate separable expansions of local potentials of finite range, is applied to the study of the triplet s-wave Malfliet-Tjon potential. The effect of varying the radius where the boundary condition is applied on the T matrix is analyzed. Further, we compare the convergence of the n-d scattering cross sections in the quartet state below the breakup threshold for expansions corresponding to two different boundaries.

Different prescriptions for imposing the constraints of current conservation on the Fourier transform of the electromagnetic current operator generate alternative forms for the electric multipole fields. These forms lead to quite different predictions for electromagnetic form factors in nuclear calculations that violate current conservation either by adopting an approximate current operator or by diagonalizing the nuclear Hamiltonian in a truncated Hilbert space. For typical shell model calculations of electron scattering form factors, it appears that no existing prescription for imposing the constraints of current conservation on electric multipole operators is entirely satisfactory. Numerical results are given for electric transitions in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$.

The branching ratio ${\Gamma }_{\gamma }$/${\Gamma }_{\mathrm{p}}$ for the d+d reaction has been measured for deuteron bombarding energies ranging from 50 to 150 keV. The branching ratio is found to be roughly constant over this energy range and the best value is (1.2±0.3)×${10}^{\mathrm{-}7}$. This result, together with previous branching ratio measurements at higher energies, is compared with direct capture calculations.