Differential neutron elastic- and inelastic-scattering cross sections of elemental zirconium were measured from ≊1.5 to 10 MeV. Below 3 MeV the measurements were made at incident-neutron energy intervals of ≊100 keV, from 3 to 4 MeV in steps of ≊200 keV, and in ≊500 keV increments at higher energies. The angular range of the measurements is ≊18° to 160°, with up to more than 100 differential values per distribution. This comprehensive database, augmented with a 24 MeV elastic-scattering distribution from the literature, is used to develop two phenomenological optical-statistical models, both of which describe the data very well. First, the parameters of the conventional spherical optical model (SOM) are deduced. Second, the model in which the dispersion relationship, linking real and imaginary interactions (DOM), is considered. The SOM parameters are consistent with systematics previously reported from this laboratory, and the volume integral per nucleon of the real potential strength, ${\mathit{J}}_{\mathit{V}}$, and the radius, ${\mathit{r}}_{\mathit{V}}$, are energy dependent. Although the energy dependence of ${\mathit{J}}_{\mathit{V}}$ is reduced by about 30% in going from the SOM to the DOM, there is little change in the E variation of ${\mathit{r}}_{\mathit{V}}$ between the two models. Both models are extrapolated to the bound-state regime where they have modest success in predicting the binding energies of the single-particle and single-hole states in ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$.

Differential cross sections for the neutral pion production reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(p,${\mathrm{\pi }}^0$${)}^{13}$${\mathrm{N}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}$ have been measured at 153.5, 166.1, 186.0, and 204.0 MeV bombarding energy using recoil detection. The shape of the angular distribution agrees well with that of the mirror reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(p,${\mathrm{\pi }}^{+}$${)}^{13}$${\mathrm{C}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}$. Isospin invariance predicts for the ratio of the cross sections σ(p,${\mathrm{\pi }}^{+}$)/σ(p,${\mathrm{\pi }}^0$)=2. At 153.5, 166.1, and 186.0, MeV, where (p,${\mathrm{\pi }}^{+}$) cross sections have been reported previously by other groups at the same reduced pion momentum η=${\mathit{p}}_{\mathrm{\pi }}$/${\mathit{m}}_{\mathrm{\pi }}$c=0.34,0.55,0.78, the ratio of the total cross sections is 2.02±0.14, 3.14±0.12, and 2.12±0.16, respectively. The (p,${\mathrm{\pi }}^0$) cross sections at 166 MeV is therefore 1.57±0.06 times larger than expected. For ${\mathit{T}}_{\mathit{p}}$<160 MeV, the experimental cross sections are larger than predicted by a phase space and Coulomb barrier penetration calculation that fits the higher-energy data. Differential cross sections were also obtained for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(p,${\mathrm{\pi }}^{\mathrm{-}}$${)}^{13}$O reaction, and upper limits set for differential cross sections for radiative capture to the ground state of ${}_{}{}^{13}{}_{}{}^{}\mathrm{N}$.

Partition functions for a canonical and microcanonical ensemble are developed which are then used to describe various properties of excited hadronic systems. Relating multinomial coefficients to a generating function of these partition functions, it is shown that the average value of various moments of cluster sizes are of a quite simple form in terms of canonical partition functions. Specific applications of the results are to partitioning problems as in the partitioning of nucleons into clusters arising from a nuclear collision and to branching processes as in Furry branching. The underlying dynamical evolution of a system is studied by parametrizing the multinomial variables of the theory. A Fokker-Planck equation can be obtained from these evolutionary equations. By relating the parameters and variables of the theory to thermodynamic variables, the thermal properties of excited hadronic systems are studied.

We describe a calculation for the electron Coulomb distortion effects in (e,e’p) in the quasielastic region from medium and heavy nuclei. The bound nucleons are described by single-particle Dirac wave functions in the presence of scalar and vector potentials which are parametrized fits to relativistic Hartree potentials, while the wave function of the knocked-out nucleon is a solution to the Dirac equation with the relativistic optical potential. The electron wave functions are solutions to the Dirac equation in the presence of the Coulomb potential of the nucleus and the interaction with the selected nucleon is treated to first order. We examine the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(e,e’p) reaction in both parallel and ω-q constant kinematics. We find that electron Coulomb distortion has a smaller effect in ω-q constant kinematics than in parallel kinematics. The principal effect in parallel kinematics is to shift the maximum and minimum of the reduced cross section which is consistent with the experimental data. Occupation numbers of about 70% to 80% are needed to normalize the distorted-wave Born approximation calculation to the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(e,e’p) experimental data. We also calculate the reduced cross section for the 3${\mathit{s}}_{1/2}$ state in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ and compare our results to experimental data and previous calculations. We find no significant difference in using relativistic, as compared with nonrelativistic, nuclear wave functions. We do find significant corrections to earlier methods of treating Coulomb distortion which, in turn, affect the occupation number extracted from experiment. We find an occupation number for this state of 71.4%.

The feasibility of general generator coordinate method calculations with monopolar specific distortion is investigated on α+α scattering. A triple integral transform of matrix elements calculated with Slater determinants eliminates spurious center-of-mass components and uniformizes the basis functions of the relative motion. Besides the α-particle ground state, the ${\mathrm{\alpha }}^{\mathrm{*}}$ breathing mode and two pseudostates are included in the calculation. Collision matrices are determined up to 400 MeV with the microscopic R-matrix method. Different types of resonances and the α+${\mathrm{\alpha }}^{\mathrm{*}}$ inelastic cross section are discussed. The nature of Pauli resonances, i.e., resonances related to almost forbidden states and their relation with the Levinson theorem are investigated in a single-channel approximation.

We report a calculation of inclusive electron scattering from ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ in the quasielastic region where we use relativistic Hartree bound-state wave functions for the nucleons and use the same real potential for the final-state interaction which guarantees orthogonality of initial and final states, current conservation, and, hence, gauge invariance. This potential gives quite good agreement with the measured cross sections, especially for energy transfer above the quasielastic peak approaching the dip region; however, it still does not successfully reproduce the experimentally separated longitudinal and transverse structure functions. We use this simple model which gives a reasonable fit to the cross-section data to discuss possible problems involved in the experimental separation procedure, which might distort the extraction of the longitudinal structure function.

The effect of a quadrupole force on a set of degenerate states of a rotational band with arbitrary spin projection along the symmetry axis K is studied. Analytic expressions for the eigenvalues and eigenvectors are obtained in terms of a set of orthogonal polynomials. This is applied to the collision of a spherical nucleus with a deformed one in which the coupling to a given set of rotational states is allowed, ignoring excitation energies. The elastic S-matrix, transition amplitudes, and the fusion cross sections are obtained as a weighted average of the magnitudes corresponding to a set of definite orientations of the axis of the deformed nucleus with respect to the relative coordinate. That weighted average corresponds to approximate the extreme sudden result, consisting of an integral over all the orientations, by a generalized Gaussian quadrature.

Dynamical properties of the ${}_{}{}^{238}{}_{}{}^{}\mathrm{-}_{}^{238}{}_{}{}^{}$U system at the classical turning point, specifically the distance of closest approach, the relative orientations of the nuclei, and deformations have been studied at the sub-Coulomb energy of ${\mathit{E}}_{\mathrm{lab}}$=6.07 MeV/nucleon using a classical dynamical model with a variable moment of inertia. Probability of favorable alignment for anomalous positron-electron pair emission through vacuum decay is calculated. The calculated small favorable alignment probability value of 0.116 is found to be enhanced by about 16% in comparison with the results of a similar study using a fixed moment of inertia as well as the results from a semiquantal calculation reported earlier.

We discuss, in a collective framework, single-step and coupled-channels distorted-wave calculations for inelastic scattering of pions from nuclei. Two frequently used codes are compared and contrasted.

The wounded projectile nucleon model is applied to the zero-degree energy distributions in ultrarelativistic nuclear collisions. The zero-degree energy distribution of the wounded projectile nucleon can be obtained from the transverse energy distribution, if a linear relation of anticorrelation between zero-degree energy and transverse energy is assumed. Agreement with the experimental data is satisfactory.

We use the toy model of baryon bag formation to study the changes in the structure of a nucleon when it is placed in nuclear matter. Several interesting qualitative results have been found. We find that ${\mathit{M}}^{\mathrm{*}}$, the nucleon mass in nuclear matter, does not scale with ${\mathit{F}}_{\mathrm{\pi }}^{\mathrm{*}}$, the latter being the value of the σ field in nuclear matter. The product ${\mathit{M}}^{\mathrm{*}}$〈${\mathit{r}}^2$${\mathrm{〉}}^{1/2\mathrm{*}}$ is nearly independent of nuclear density. The coupling constant ${\mathit{g}}_{\mathrm{\sigma }\mathit{N}\mathit{N}}^{\mathrm{*}}$ decreases with density. The coupling constant ${\mathit{g}}_{\mathrm{\pi }\mathit{N}\mathit{N}}^{\mathrm{*}}$/2${\mathit{M}}^{\mathrm{*}}$ and the rho-nucleon tensor coupling constant, ${\mathit{f}}_{\mathrm{\rho }\mathit{N}\mathit{N}}^{\mathrm{*}}$/2${\mathit{M}}^{\mathrm{*}}$, increase with density at the same rate. The coupling constants ${\mathit{g}}_{\mathrm{\omega }\mathit{N}\mathit{N}}^{\mathrm{*}}$ and ${\mathit{g}}_{\mathrm{\rho }}^{\mathrm{*}}$ also increase at the same rate, but the rate itself is low. We find that ${\mathit{M}}^{\mathrm{*}}$+${\mathit{g}}_{\mathrm{\sigma }\mathit{N}\mathit{N}}^{\mathrm{*}}$(${\mathit{F}}_{\mathrm{\pi }}$-${\mathit{F}}_{\mathrm{\pi }}^{\mathrm{*}}$) is approximately independent of the nuclear density. The magnetic moments increase, while ${\mathit{g}}_{\mathit{A}}^{\mathrm{*}}$(0) decreases. At half the normal density these changes are in the range 3–7 % depending on the parameters used. We discuss briefly the implications of these results on the properties of nuclear matter.

We present a new derivation of the convolution formula for the contributions of nuclear binding to the structure functions measured in the deep inelastic scattering of leptons from nuclei. The derivation, which is manifestly covariant, gives a new binding correction. This new correction, which depends on the mass of the recoiling nucleon fragments, gives corrections that are numerically significant, and that improve the agreement between theory and experiment at large x. We conclude that nuclear binding effects may be sufficient to explain the European-Muon-Collaboration effect at large x.

The ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$(d,n) and ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$(d,n) cross sections have been measured for 0.2≤${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$≤2.1 MeV and 0.2≤${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$≤1.3 MeV, respectively, using a 4π neutron detector. The cross sections are used to calculate the thermonuclear reaction rates for temperatures below 10 GK. The implications of these and other new nuclear-physics results for inhomogeneous primordial nucleosynthesis are discussed.

Thick-target recoil ranges and forward-to-backward ratios of some thirty target fragments from the interaction of Ag with 218 GeV ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ions have been measured. The results were analyzed by means of the two-step model and compared with similar data for 18.5 GeV ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ ions and 400 GeV protons in order to test the applicability of factorization and limiting fragmentation.

The few odd-A nuclides known to exhibit cluster radioactivity decay at rates hindered with respect to their even-even neighbors. For ${}_{}{}^{237}{}_{}{}^{}\mathrm{Np}$, the most likely clusters are predicted to be ${}_{}{}^{30}{}_{}{}^{}\mathrm{Mg}$ and ${}_{}{}^{32}{}_{}{}^{}\mathrm{Si}$. We have completed a rigorous search for cluster emission from ${}_{}{}^{237}{}_{}{}^{}\mathrm{Np}$, with a null result. Our 90% confidence limit on the branching ratio with respect to alpha emission, B (cluster/α) <1.8×${10}^{\mathrm{-}14}$, is a factor 4.3 lower than the limit obtained by Tretyakova et al. The two experiments together place an upper limit of 1.5×${10}^{\mathrm{-}14}$ on the branching ratio for emission of clusters with 10≤Z≤14 from ${}_{}{}^{237}{}_{}{}^{}\mathrm{Np}$.

Nonrelativistic distorted-wave Born approximation predictions for polarized proton elastic scattering from polarized ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ are discussed and compared with data. Effects due to Pauli blocking, binding potentials in intermediate states, and shell-model configuration mixing are studied. The changes in the predicted polarized target spin observables are small at forward angles but can be significant at larger scattering angles.

We have shown the predictions of the constituent quark model for nuclei are consistent with the New Muon Collaboration data in the x, ${\mathit{Q}}^2$, and A dependences of the European Muon Collaboration effect.

The effect of the kaon loop correction to the property of a phi meson in dense matter is studied in the vector dominance model. Using the density-dependent kaon effective mass determined from the linear chiral perturbation theory, we find that with increasing baryon density the phi meson mass is reduced slightly while its width is broadened drastically.

Using a new technique to solve the kinetic equation including Bose statistics, we show that the shape of the pion transverse momentum spectrum is sensitive to the hadronization time in ultrarelativistic heavy ion collisions. For a pure pion gas, the magnitude of the soft pion component observed in central 200 GeV/nucleon O+Au collisions is reproduced by an effective pionization time of about 7 fm/c. This explanation implies that the hadrons are produced out of chemical equilibrium.