Production cross sections for actinide nuclides formed in the reactions of 791–769 MeV ${}_{}{}^{129}{}_{}{}^{}\mathrm{Xe}$ and 817–793 MeV ${}_{}{}^{132}{}_{}{}^{}\mathrm{Xe}$ with ${}_{}{}^{248}{}_{}{}^{}\mathrm{Cm}$ were measured using radiochemical techniques to isolate elements 93 to 100 (Np to Fm). These results were compared with previous results from the reaction of 790–699 MeV ${}_{}{}^{136}{}_{}{}^{}\mathrm{Xe}$ with ${}_{}{}^{248}{}_{}{}^{}\mathrm{Cm}$. The production cross section distributions of target-like nuclides for a given Z appear to shift to smaller A with the use of the more neutron-deficient projectiles. The production of nuclides with Z>$Z_{\mathrm{target}}$ increases at the expense of nuclides with Z<$Z_{\mathrm{target}}$ with use of the more neutron-deficient projectiles. The distribution of product cross sections from each reaction is treated as the sum of distributions of products from two reaction mechanisms, quasi-elastic transfer and deep inelastic transfer. Potential energy surfaces for the three reacting systems under discussion were calculated for touching sphere configurations and can be used to predict the production cross section trends. However, the peak position of the cross section distribution for a given Z is not accurately predicted by the potential energy surfaces, which suggests that deep inelastic transfer reactions may not be the dominant reaction mechanism, leading to the observed final distribution.

We develop a mass formula for finite lumps of strange quark matter near flavor equilibrium. Our Fermi-gas model includes surface tension and Coulomb energy but not quantum-chromodynamic radiative corrections. Assuming strange matter is stable in bulk, we investigate the radioactive decays of finite strangelets (clumps of strange matter with baryon number A≲${10}^7$). We derive conditions governing instability for all decay modes. The regions of baryon number, charge, and hypercharge in which various decays are allowed are illustrated graphically, and flow lines and accumulation lines for decaying strangelets are obtained. Finally, we present typical histories of decaying strangelets.

A covariant version of light front perturbation theory is obtained as a limit of the covariant time-ordered perturbation theory developed recently by the author. The graphical rules for the covariant light front perturbation theory are essentially the same as Weinberg’s infinite momentum frame rules; however, they involve a redefinition of the original Weinberg variables. The new definitions guarantee that the contributions of individual diagrams to the S matrix are invariant. A set of manifestly invariant three-particle integral equations is derived. These equations are obtained from a model field theory which describes the interaction of a charged scalar particle ψ with a neutral scalar particle φ according to the virtual process ψ⇄ψ+φ. The solutions of the integral equations lead to amplitudes for φ+ψ→φ+ψ and φ+ψ→2φ+ψ which satisfy two- and three-particle unitarity. The integral equations are free of the spurious singularity in s, the square of the invariant c.m. energy, which has been an undesirable feature of earlier relativistic three-particle equations. This singularity is known to be responsible for spurious bound state solutions.

The theory of the coupled πNN-NN systems is applied to the unified description of the πd-πd, πd-NN, and NN-NN reactions in the intermediate energy range. Off-shell modifications are introduced in the $P_{33}$ and $P_{11}$ πN channels and the effects of heavy meson exchange are investigated. In general, results for various observables are in agreement with experiments. We have assessed certain aspects upon which future work should improve.

Yields of 24 radioactive nuclides formed by the interaction of bremsstrahlung with maximum end-point energies of 100 MeV–1 GeV with Cu have been measured by direct γ-ray counting of irradiated targets. The yields in the mass range of 42 to 60 (except for ${}_{}{}^{60}{}_{}{}^{}\mathrm{Cu}$) were analyzed by a nonlinear least-squares fit to obtain the mass yield and charge dispersion curves in spallation reactions. From the parameter values obtained, the energy dependence of the slope of the mass yield curve and the relationship between target N/Z and the most probable product N/Z were investigated and compared with the results of proton, α, and heavy-ion-induced spallation of Cu. The characteristics of photon-induced spallation are discussed.

We have analyzed the data on the primary radiative transitions following slow neutron capture by ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, and ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$. We have made estimates of direct capture from optical potential models with physically realistic parameters. These parameters were varied to allow for the effects of a local $s$-wave level on the initial state. We find that the model estimates are in reasonable agreement with the measured cross sections of the 6.810- and 0.854-MeV transitions in ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$, the 1.262-MeV transition in ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, and, possibly, the 8.174-MeV transition in ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$, indicating a major role played by a direct capture mechanism. In all these cases, the estimate of direct capture is greatly affected and reduced by large cancellation effects in the integrand of the radial dipole matrix element. The strengths of the 3.443-MeV transitions in ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ and, to a lesser extent, the 4.945-MeV transition in ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, cannot be explained by our optical model formulations of direct capture, but these strengths are consistent with extrapolations to these light nuclides of generally accepted formulations of compound nucleus capture.

We present an estimate for the cross section for the inclusive reaction p${+\mathrm{}}^{12}$C→${\mu }^{+}$+ν+X, where X is a nuclear state. For an incident proton c.m. energy of 1076 MeV, a cross section of 4.41×${10}^{\mathrm{-}42}$ ${\mathrm{cm}}^2$ is obtained. The possibility of observing anomalous threshold states is also discussed.

A theoretical framework for the description of the (e→,e’p→) reaction is presented. A set of physically motivated, linearly independent four-vectors is employed to construct a complete set of second rank Lorentz tensors in terms of which the nuclear electromagnetic tensor is expressed. The implications of charge and parity conservation, time reversal, restricted spin dependence, and the final state boundary conditions are developed and applied. The azimuthal angular dependence (in the laboratory frame) of the nuclear tensor is made explicit, leading to the definition of a set of 18 independent response functions. The cross section and the polarization vector of the ejected proton are expressed in terms of the 13 new, spin-dependent response functions. The physical significance of these response functions with regard to spin observables is manifest. The separation of the response functions, both theoretically and experimentally, is discussed. Extensions and restrictions to the general (e→,e’X) reaction, to reactions which violate current and/or parity conservation, and to the case of oriented (polarized) targets are evident. Questions of linear dependence, completeness, and alternative representations of the nuclear tensor for both (e→,e’p→) and the general (e→,e’X) reaction are resolved. Preliminary numerical results indicate the sizes and relative importances of the new response functions and demonstrate their experimental accessibility.

Previous work on the general representation of NN scattering amplitudes in the full Dirac space of two nucleons is extended to allow a simple realization of the generalized Pauli principle. New kinematic covariants are found which are linearly independent and which have simple particle exchange symmetries. This permits a representation in which all invariant amplitudes are even or odd with respect to interchange of initial state four-momenta or interchange of final state four-momenta for on-mass-shell kinematics. When parity invariance, charge symmetry, and time-reversal invariance are taken into consideration, it is found that for each isospin state there are 56 independent amplitudes for off-mass-shell kinematics, 50 independent amplitudes for quasipotential kinematics, and 44 independent amplitudes for on-mass-shell kinematics. A relativistic meson exchange model is used to calculate the invariant amplitudes for on-mass-shell kinematics, and the resulting amplitudes are fit by sums of Yukawa terms. The analysis provides complete sets of Feynman invariant amplitudes for 200, 500, and 800 MeV NN scattering.

The longitudinal and transverse response functions for quasielastic electron scattering on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, and ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$ are calculated in the relativistic σωρ model in random-phase approximation. We use space-dependent baryon densities and effective mass of the nucleons, as obtained from mean-field theory of closed-shell nuclei, in local-density approximation. The longitudinal response function agrees with experimental data quite well, while the transverse response function underestimates data. Our results are also compared with other calculations of the response functions in relativistic models.

We have investigated different forms of the Klein-Gordon equation using phenomenological potentials and attempted to fit the measured strong interaction shifts and widths of kaonic hydrogen and all the heavier kaonic atoms, as well as the scattering lengths obtained from the analysis of low energy K¯N scattering data. We find that we can fit all the data except kaonic hydrogen with various forms of the equation, but in order to fit kaonic hydrogen at the same time it is crucial to have a vector strong interaction term and include the interference between this and the Coulomb force. Our results explain the discrepancy in the sign of the strong interaction shift, which has been a puzzle for many years.

Nuclides with A=152 were produced in ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ bombardments of ${}_{}{}^{96}{}_{}{}^{}\mathrm{Ru}$ and their decay properties were investigated following on-line mass separation. The isotope ${}_{}{}^{152}{}_{}{}^{}\mathrm{Lu}$ ($T_{1/2}$=0.7±0.1 s) was identified by γ rays in its β-decay daughter, ${}_{}{}^{152}{}_{}{}^{}\mathrm{Yb}$. Based on its decay characteristics, the parent state has a probable spin and parity assignment of (4,5,$6^{\mathrm{-}}$). Several new transitions were observed to follow the β decays of ${}_{}{}^{152}{}_{}{}^{}\mathrm{Yb}$ and the ${}_{}{}^{152}{}_{}{}^{}\mathrm{Tm}$ low-spin isomer; they established previously unknown levels in both ${}_{}{}^{152}{}_{}{}^{}\mathrm{Tm}$ and ${}_{}{}^{152}{}_{}{}^{}\mathrm{Er}$. The additional γ rays in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Yb}$ decay reduce from 100% to 88% the direct feeding to the one excited state in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Tm}$ that had been known earlier. Nevertheless, the corresponding logft value is calculated to be 3.5, indicating that this is an allowed β transition which connects the $0^{+}$ parent with a $1^{+}$ excited state in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Tm}$. By comparing the β-decay rates of ${}_{}{}^{148}{}_{}{}^{}\mathrm{Dy}$ and ${}_{}{}^{152}{}_{}{}^{}\mathrm{Ho}$, and the α- and β-decay rates of ${}_{}{}^{152}{}_{}{}^{}\mathrm{Er}$, an α branch of 90±4 % was deduced for ${}_{}{}^{152}{}_{}{}^{}\mathrm{Er}$.

The $T_z$=-(3/2), A=4n+1 nuclide ${}_{}{}^{61}{}_{}{}^{}\mathrm{Ge}$ has been produced via the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$${(}^{24}$Mg,3n) reaction and identified by its beta-delayed proton emission. A single proton group at 3.11±0.03 MeV with $t_{1/2}$=40±15 ms has been observed, corresponding to decay of the T=(3/2) isobaric analog state in ${}_{}{}^{61}{}_{}{}^{}\mathrm{Ga}$ to the ground state of ${}_{}{}^{60}{}_{}{}^{}\mathrm{Zn}$. Searches for the beta-delayed proton decay of the next member of this series, ${}_{}{}^{65}{}_{}{}^{}\mathrm{Se}$, to be produced by the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$${(}^{28}$Si,3n) reaction, have proven unsuccessful.

A U(12) multiplet containing six nuclei with fixed boson number N=7 has been described with a single interacting boson model Hamiltonian with fixed parameter values. Both the fitted energies and B(E2) ratios are in reasonable agreement with experimental values.

A microscopic three-boson force is included in a calculation carried out in boson space to obtain the spectra of a six-fermion system confined in a j=(13/2) shell. In this particular case, the effect of antisymmetrization is completely compensated for by one- to three-body interactions among bosons, and we found that the three-boson force is indispensable in obtaining reasonable results.

The shell-model origin of the exchange term in the interacting-boson-fermion Hamiltonian is studied. The quadrupole pairing interaction is shown to be the dominant source in and near spherical regions of the Periodic Table. The strength of this term calculated for the 0$g_{9/2}$ orbit turns out to be in good agreement with the phenomenological fit.

The (α,αp) reactions on ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ targets have been measured in a quasifree geometry using a 139.2 MeV α particle beam. In general, the shape of the experimental distributions are well described by distorted-wave impulse approximation calculations. Relative spectroscopic factors are consistent with (p,2p) studies. However, discrepancies in absolute magnitude exist and are discussed.

The symmetric fission of ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ into ${}_{}{}^{12}{}_{}{}^{}$C${+\mathrm{}}^{12}$C by inelastic proton scattering at $E_{\mathrm{p}=190\mathrm{}}$ MeV and ${\mathrm{theta}}_{\mathrm{p}\left(\mathrm{l}\mathrm{a}\mathrm{b}\right)=15.25\mathrm{}}$° has been observed. A yield curve of events versus excitation energy in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ is given.

The γ decay of energy relaxed fragments has been studied as a function of the mass asymmetry in the exit channel for the ${}_{}{}^{32}{}_{}{}^{}$S${+\mathrm{}}^{58}$Ni reaction at 143 MeV. γ-multiplicity and γ-anisotropy data as well as 〈Q〉 values from fragment inclusive measurements show the differences between the deep-inelastic and the ‘‘fission-like’’ regimes. The role of the deformation in the symmetric splitting is outlined for medium mass (A∼100) composite systems.

The possibility of nuclei being excited during charge nonconservation was investigated. The process studied is analogous to nuclear K capture which does not change a nucleon’s charge state but which does leave the nucleus in an excited state. We searched for γ rays emitted by ${}_{}{}^{127}{}_{}{}^{}\mathrm{I}$ nuclei and detected in a 25.4 cm×20.3 cm diam NaI(Tl) counter. Our most conservative limit for the charge nonconserving lifetime ${\tau }_{\mathrm{CNC}}$ for this mechanism is ${\tau }_{\mathrm{CNC}\ge 1.9\times {10}^{21}}$ yr. The results can be used to place limits on the charge nonconservation mechanism in weak interactions where a neutrino replaces an electron in the (e,e) current, and where a proton replaces a neutron in the (p,n) current.