Gyromagnetic ratios of levels up to ${10}^{+}$ in the ground-state bands and of the $2^{+}$ states in the γ bands of ${}_{}{}^{164}{}_{}{}^{}\mathrm{Dy}$ and ${}_{}{}^{168}{}_{}{}^{}\mathrm{Er}$ were measured by the perturbed angular correlation technique utilizing the transient hyperfine field acting at the nuclei of these ions as they swiftly traversed thin polarized Fe foils. The experimental g factors, together with the results of earlier similar studies for ${}_{}{}^{166}{}_{}{}^{}\mathrm{Er}$, are discussed and compared with several theoretical predictions.

Calculations are carried out for the ${}_{}{}^{40}{}_{}{}^{}{+}^{40}$,44,48Ca fusion reactions, taking into account both the low-lying inelastic excitations and the dominant single-nucleon transfer reactions which couple directly to the entrance channels. The results agree well with the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ fusion data but they underpredict the low-energy ${}_{}{}^{40}{}_{}{}^{}{+}^{44}$,48Ca measurements.

Two statistical approaches to nuclear disassembly are compared. One is based on a sequential chain of binary decays, and the other on the microcanonical treatment of fragment configurations in a fixed freeze-out volume. The two approaches are formulated in a manner to facilitate this comparison. A volume related to the sequential approach is defined. This volume is interpreted in terms of entropy conservation. Effective freeze-out volumes are defined for various yields. From this it is shown how similar predictions can arise from the approaches which are based on mutually incompatible assumptions. Differences in Coulomb effects are explored. A detailed comparison of two sets of predictions is made for a test example, and the reasons behind specific differences are studied. It is suggested that such differences can serve as experimental signatures to distinguish which approach is more appropriate.

Differential cross sections for exciting the low-lying states in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ by heavy-ion inelastic scattering were measured with a new technique that uses a 4π γ-ray detector in coincidence with charged-particle detectors. The resulting data were subjected to a coupled-channels analysis to obtain a set of E2 and E4 matrix elements for exciting the $2_1^{+}$(1.37 MeV), $4_1^{+}$(4.12 MeV), and $2_2^{+}$(4.24 MeV) states of ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ as well as the interconnecting and self-coupling matrix elements for these states. Our results disagree with electron scattering measurements for the charge shape of ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$. The data on the $2_2^{+}$(4.24 MeV) state is not well accounted for by the asymmetric rotor model.

We investigate the low $p_T$ features of the transverse momentum distribution for pions in relativistic heavy-ion collisions from the NA35 collaboration. Contrary to recent claims, we find that collective hydrodynamic flow cannot account for the experimental low $p_T$ shape of the pion transverse momentum distribution.

The production cross sections and angular distributions of high-energy γ rays have been measured for the reactions of ${}_{}{}^{86}{}_{}{}^{}+\mathrm{Z}\mathrm{r}$, ${}_{}{}^{40}{}_{}{}^{}+\mathrm{C}\mathrm{a}$, and ${}_{}{}^{40}{}_{}{}^{}+\mathrm{Z}\mathrm{r}$ at E/A=15 MeV. The high-energy γ-ray cross section and spectral shape are consistent with previous studies. The source velocity of γ-ray emission for the three reactions is close to that of the nucleon-nucleon center-of-mass frame. The multiplicity of low-energy γ rays in coincidence with high-energy γ rays has been measured for the first time.

The ground-state rotational band of ${}_{}{}^{173}{}_{}{}^{}\mathrm{Yb}$ has been investigated through multiple Coulomb excitation with a beam of 250-MeV ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$. γ-ray branchings and E2/M1 mixing ratios were determined up to the ${(23/2\mathrm{}}^{\mathrm{-}}$ state by measurements of γ-ray angular distributions and γ-γ angular correlations. Nuclear lifetimes of levels up to I=(25/2 have been measured using the Doppler-shift recoil-distance method. No significant signature dependence was observed for ΔI=1 M1 and E2 transition probabilities. The data are analyzed in terms of the rotating shell model and the differences between spin-up and spin-down orbitals are discussed.

Fully energy-damped yields from the ${}_{}{}^{32}{}_{}{}^{}\mathrm{Mg}$ reaction have been measured at center-of-mass energies of $E_{\mathrm{c}.\mathrm{m}.\mathrm{}=51.6\mathrm{}}$ and 60.5 MeV with the use of an experimental arrangement where both of the resulting heavy fragments could be detected in coincidence. Energy, velocity, and angular distributions of the reaction fragments have been determined. The cross sections prior to secondary light-particle emission have been deduced for the breakup of the compound system into different mass channels. These data are discussed in terms of two possible reaction mechanisms: fusion followed by fission and deep-inelastic orbiting.

I construct a simple, analytical model for both the longitudinal and transverse expansion of an interacting hadronic system. This model explicitly assumes that the particle rapidity distribution is not boost invariant, and specifically includes an initial transverse dimension. It employs standard assumptions about the delayed formation of produced particles and the correlation between longitudinal position and rapidity. No particular dynamical scenario is assumed for the early stages of the system’s expansion, but rather the last stage, freeze-out, is tied to the particle rapidity distribution. The observed multiplicity and width of the rapidity distribution control the transverse size and time when the system freezes out. The model predicts a transverse radius at freeze-out and its dependences on rapidity and multiplicity, which are very similar to those obtained by pion interferometry. This analysis can be used with different event classes to correlate changes in the multiplicity and width of the rapidity distribution with changes in the size, shape, and lifetime of the system at freeze-out.

An approximation to the Glauber model for heavy-ion scattering has been recently derived and illustrated by a few examples in two previous papers. We present here a more systematic analysis of nucleus-nucleus elastic and inelastic scattering data, which cover a wide range in the projectile energy (E/$A_P$≊30–350 MeV), the mass number of colliding nuclei (4≤$A_P$≤40, 12≤$A_T$≤208), and the multipolarities of the excited states. The only inputs of the model are the densities and transition densities of the nuclei and the elementary nucleon-nucleon scattering amplitudes, which have been taken from the current literature without any adjustment. The results obtained are in overall good agreement with the experimental data.

The conversion of kinetic energy into target-like fragment excitation and orbital angular momentum into fragment spin has been studied in the reaction 333 MeV ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ with ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$. The light charged particles were detected in a small, highly segmented, 4π phoswich detector system placed in the spin spectrometer, a 4π NaI array which served as a neutron and gamma detector. Multiplicities of light charged particles and neutrons detected in coincidence with projectile-like fragments indicate that the excitation energy of the target-like fragment increases as the kinetic energy of the projectile-like fragment decreases through the quasielastic region and tends toward saturation as the kinetic energy of the projectile-like fragment approaches the kinetic energy corresponding to complete damping. Measurement of the γ-ray multiplicity in coincidence with the projectile-like fragments indicates that the angular momentum transferred to the target-like fragment increases with decreasing mass of the projectile-like fragment for the quasielastic energy region in contrast to the energy region corresponding to completely damped processes where the angular momentum of the target-like fragment decreases with increasing mass loss from the projectile. The influence of preequilibrium processes on both excitation energy and angular momentum transfer to the target-like fragment is discussed. These data present further evidence that l waves below the entrance-channel critical angular momentum for fusion must contribute to the nonfusing reaction channels.

In this paper the formula for the mean curvature radius $R_{\mathrm{cu}}$, in a nucleus-nucleus potential $U_n$, was modified and the contribution of $R_{\mathrm{cu}}$ to the derivatives of $U_n$ with respect to the deformation parameters ${\alpha }_{n\lambda \mu }^{\left(i\right)}$ in the Hamilton equations of motion was considered. At the same time, the rotations of the projectile and the target φ${̇}_i$ have been explicitly included in the set of coupled time-dependent differential equations. The numerical solutions of Hamilton equations of motion show that the calculated trajectories of heavy-ion collisions naturally conserve energy and angular momentum. As a result of this work, the picture of heavy-ion reactions has been changed somewhat.

Mass yield curves in low-energy proton-induced fissions of ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{237}{}_{}{}^{}\mathrm{Np}$, ${}_{}{}^{239}{}_{}{}^{}\mathrm{Pu}$, ${}_{}{}^{242}{}_{}{}^{}\mathrm{Pu}$, ${}_{}{}^{244}{}_{}{}^{}\mathrm{Pu}$, ${}_{}{}^{241}{}_{}{}^{}\mathrm{Am}$, and ${}_{}{}^{243}{}_{}{}^{}\mathrm{Am}$ were measured. The full widths at half maximum (FWHM) of the heavier asymmetric peak of the mass yield curves showed a sudden dip in the region of $A_f$=240–245. The correlation between the P/V ratio and the FWHM of the asymmetric mass yield peak was obtained as a function of proton energy. The FWHM values were independent of the incident proton energy as long as the P/V ratio was larger than 10 for all the fissioning systems studied. The excitation energy dependence of the mass yield curves was investigated. It was found that the excitation energy dependence of symmetrically divided fission products was apparently different from that of asymmetrically divided ones. With a simple assumption of the two-mode hypothesis, the observed mass yield curves could be decomposed into two mass yield curves. Asymmetric mass yield peaks could be best represented by the sum of two Gaussians, and their variation could be expressed by the variation of Gaussian parameters. The peak positions of the two Gaussians were always A=133–135 and A=140–142 for all the investigated fissioning nuclides. The preference of those fragment masses is discussed in terms of both the scission-point model and the saddle-point model.

A systematic experimental study of strong interaction shifts, widths, and yields from high-Z kaonic atoms is reported. Strong interaction effects for the $K^{\mathrm{-}}$(8→7) transition were measured in U, Pb, and W, and the $K^{\mathrm{-}}$(7→6) transition in W was also observed. This is the first observation of two measurably broadened and shifted kaonic transitions in a single target and thus permitted the width of the upper state to be determined directly, rather than being inferred from yield data. The results are compared with optical-model calculations.

The proton-proton parity-violating analyzing power is calculated for laboratory energies up to 1200 MeV using relativistic strong and weak potentials derived consistently from meson field theory. We calculate the parity-violating t-matrix elements with strong distortions generated by the static momentum-space one-boson-exchange Bonn potential. The weak, parity-violating potential, which is derived from parity-violating rho and omega exchanges, employs Desplanques-Donoghue-Holstein weak coupling parameters and Bonn-model coupling parameters and form factors. Below 200 MeV, the results differ very little from a nonrelativistic calculation using the r-space Bonn potential, but at 800 MeV, the analyzing power increases by 44 percent. A calculation with nonstatic, energy-dependent potentials is included for energies below pion-production threshold. The result is larger than for the static calculation, by an amount increasing from 3 percent at 15 MeV to 14 percent at 300 MeV.

A recent two amplitude expression for pion double charge exchange from even-even targets to the double isobaric analog, which is valid for a single shell-model orbital, is generalized to many shell-model orbitals.

Calculations for the in-flight production of Σ hypernuclei with the reactions ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$($K^{\mathrm{-}}$,${\pi }^{\mathrm{-}}$${)}_{\Sigma }^{12}$C, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$($K^{\mathrm{-}}$,${\pi }^{+}$${)}_{\Sigma }^{12}$B, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$($K^{\mathrm{-}}$,${\pi }^{+}$${)}_{\Sigma }^{16}$C, and ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$($K^{\mathrm{-}}$,${\pi }^{\mathrm{-}}$${)}_{\Sigma }^9$Be are presented. The framework of the recoil corrected continuum shell model is employed. The calculations can account for the major feature of the data with a modification of the ΣN interaction of Yamamoto and Bando. This provides information on the strength of the central part of the ΣN interaction and on the ΣN→ΛN conversion strength. However, detailed information on the spin components of the ΣN force will be difficult to obtain.

We present a description of the spin-one Kemmer-Duffin-Petiau equations. An effective second-order equation is obtained for various types of interactions. An argument is given for the use of one particular form of interaction for deuteron-nucleus scattering. This provides the basis for a generalization of the standard Watanabe model in which Dirac scalar and vector nucleon-nucleus potentials are used as input. Parameter-free calculations are performed using both phenomenological and microscopic nucleon-nucleus potentials, and results are compared with deuteron-nucleus elastic scattering data at 400 and 700 MeV. Qualitative agreement is generally obtained. A good description of the forward-angle vector analyzing power data is achieved.

We discuss the continuum response of finite nuclei in the giant resonance region in the context of a nonspectral random-phase approximation which straightforwardly includes correct continuum boundary conditions. Strongly collective discrete low-energy excitations of the nucleus are associated with poles with large residues in the random phase approximation particle-hole propagator at real excitation energies. Giant resonances, by comparison, are associated with similar poles at complex excitation energies where the imaginary part of the pole position corresponds to the escape width of the excitation. We illustrate these points with calculations of the isoscalar quadrupole response in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$. Here giant resonances are readily identified as sharp peaks in the particle-hole propagator in the complex excitation energy plane and the relation of the peaks to the continuum response (for real excitation energies) is demonstrated. Our numerical method allows extraction of transition densities for the giant resonances with continuum effects automatically included and these are used to compute (e,e’) and (π,π’) responses; illustrative comparisons with data are made.

Spin correlation parameters $A_{\mathrm{LL}}$, $A_{\mathrm{SL}}$,$A_{\mathrm{NL}}$, $A_{\mathrm{NO}}$, $A_{\mathrm{SO}}$, $A_{\mathrm{LO}}$, and$A_{\mathrm{OL}}$ have been measured for pp→np${\pi }^{+}$ at 492, 576, 643, 729, and 796 MeV over a large part of phase space, using a longitudinally polarized target and a polarized beam. Results rule out broad dibaryons in this mass range in NN ${}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}$ and ${}_{}{}^3{}_{}{}^{}\mathrm{F}_3^{}{}_{}{}^{}$; in ${}_{}{}^1{}_{}{}^{}\mathrm{D}_2^{}{}_{}{}^{}$ some phase variation is observed, resembling that expected of a strong inelastic threshold.