The level structure of odd-proton ${}_{}{}^{187}{}_{}{}^{}\mathrm{Au}$ was studied using the ${}_{}{}^{172}{}_{}{}^{}\mathrm{Yb}$${(}^{19}$F,4n) reaction. Gamma-gamma coincidence, angular distributions and γ-γ-time measurements were used to establish the energies, spins, parities, and lifetimes for the states in the decay scheme of ${}_{}{}^{187}{}_{}{}^{}\mathrm{Au}$. Both prolate and oblate structures have been established. The prolate bands are built on the π$h_{9/2}$ (α=±(1/2) and the π$i_{13/2}$ (α=(1/2) particle states. An oblate, strongly coupled band built on a 90±10 ns isomeric state is reported for the first time. A second oblate structure built on the $h_{11/2}$ proton-hole state was established to much higher spin than before. The backbend present in the π$i_{13/2}$ band has been interpreted as the alignment of a pair of $h_{9/2}$ protons.

We discuss the production of antiprotons, kaons, and the ${\Omega }^{\mathrm{-}}$ in nuclear collisions at relativistic energies in the framework of a simplified hadrochemical model. We point out the importance of Δ resonances for p¯ as well as $K^{\mathrm{-}}$ production at 1–2 GeV/nucleon, particularly in the region below the threshold for their production in individual NN collisions. Quark matter formation may enhance ${\Omega }^{\mathrm{-}}$ production to a measurable level at 15 GeV/nucleon.

Collective band structures have been observed in the neutron-deficient ${}_{}{}^{137}{}_{}{}^{}\mathrm{Sm}$ nucleus by means of the ${}_{}{}^{104}{}_{}{}^{}\mathrm{Pd}$${(}^{37}$Cl,p3nγ) reaction. At low spins, the yrast band, built on the ν$h_{11/2}$ [514]${(9/2\mathrm{}}^{\mathrm{-}}$ Nilsson orbital, exhibits a large signature splitting (∼100 keV) consistent with a significant triaxial shape (γ∼-20°). At higher spins, two sidebands were observed which are characterized by strong ΔI=1 transitions and a lack of signature splitting. These band structures contain rotationally aligned lower-midshell $h_{11/2}$ protons which drive the nucleus towards the prolate (γ=0°) shape. In addition, a decoupled band was observed built on an $I^{\pi }$= ${\left(\right(17/2\mathrm{}}^{+}$) state. This band reveals a 50% increase in the dynamic moment of inertia consistent with an enhanced quadrupole deformation (β∼0.35), and is believed to be built on the β-driving ν$i_{13/2}$ [660]${(1/2\mathrm{}}^{+}$ single-quasiparticle state, intruding from two harmonic oscillator shells above. The β-driving properties of this orbital represent an important mechanism in the evolution of enhanced nuclear deformation in this region. The results are compared to those of the N=75 ${}_{}{}^{133}{}_{}{}^{}\mathrm{Ce}$, ${}_{}{}^{135}{}_{}{}^{}\mathrm{Nd}$, and ${}_{}{}^{139}{}_{}{}^{}\mathrm{Gd}$ isotones.

Measurement of the ratio of deuterons to excited deuterons is prescribed as a method for determining temperatures and breakup criteria in intermediate-energy heavy-ion collisions. The sudden coalescence model is contrasted with a thermal breakup picture where ratios are determined by Boltzmann factors.

We have studied the ${}_{}{}^{28}{}_{}{}^{}$Si${+}^{24}$Mg system leading to the three-body final states α${+}^{24}$Mg${+}^{24}$Mg and α${+}^{20}$Ne${+}^{28}$Si. Full momentum reconstruction on an event by event basis allows us to obtain all kinematic quantities, and perform a comparison of competing reaction mechanisms. A search reveals very little evidence for the population of high-spin states in ${}_{}{}^{48}{}_{}{}^{}\mathrm{Cr}$ corresponding to resonances observed in the ${}_{}{}^{24}{}_{}{}^{}$Mg${+}^{24}$Mg system, via the ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$${(}^{28}$Si,α${)}^{48}$${\mathrm{Cr}}^{\mathrm{*}}$${(}^{24}$Mg) and ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$${(}^{28}$Si,α${)}^{48}$Cr*${(}^{20}$Ne) reactions. Instead, we find that the dominant processes that occur involve inelastic heavy-ion scattering to α-particle unbound states in ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ and ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$.

The ${}_{}{}^2{}_{}{}^{}\mathrm{H}$${(}^7$Li, αα)n reaction was studied in a kinematically complete experiment at energies between 28 and 48 MeV. Coincidence spectra show the contribution from the quasifree p${+}^7$Li→α+α reaction. The excitation function of the quasifree reaction cross section at small neutron momenta was extracted and compared with the behavior of the free reaction cross section.

The emission of complex fragments was studied for ${}_{}{}^{32}{}_{}{}^{}\mathrm{induced}$ reactions on ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Ag}$ at E/A=22.3 MeV for angles back of the grazing angle, ${\theta }_{\mathrm{IMF}=20\mathrm{}\mathrm{°}–50\mathrm{°}}$. The measured fragment kinetic energy spectra peak at energies near the exit channel Coulomb barriers and decrease exponentially at higher energies. The angular distributions are forward peaked, indicating emission prior to the attainment of full statistical equilibrium of the composite system. The relative populations of a large number of particle stable states of these fragments were measured with a spin spectrometer. Comparisons with statistical calculations which include feeding from known discrete particle unbound states and high-lying continuum states indicate emission temperatures of about 3–4 MeV.

Differential cross section measurements have been made for the giant resonance region (13.2–40 MeV) in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ using 500 MeV protons with an experimental energy resolution of 70 keV. Fine structure was observed in this energy region. After fixing the energy weighted sum rule depletion for the isovector giant dipole resonance at 70%, energy weighted sum rules of 70±14 % for the isoscalar giant quadrupole resonance and 15±3 % for the isoscalar giant hexadecapole resonance were deduced. All of these energy weighted sum rule depletions agree well with theoretical predictions and results from other experiments.

At 200, 300, and 400 MeV bombarding energies, we measured cross section angular distributions for the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$(p,n${)}^7$Be(g.s.+0.43 MeV) reaction and 0° cross sections for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(p,n${)}^{12}$N(g.s.) reaction. Systematics of these reactions are presented. The center-of-mass cross section for the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$(p,n${)}^7$Be(g.s.+0.43 MeV) reaction, when plotted as a function of momentum transfer, is nearly independent of energy. The laboratory cross section for this reaction at 0° in the energy range from 60 to 400 MeV is also independent of energy, having a constant value, to within experimental errors, of 35.5 mb/sr with an estimated uncertainty of ±1.5 mb/sr.

We present the details and results of a Faddeev calculation of πN scattering in the $P_{11}$ channel in the region of the Roper resonance. Our equations respect two- and three-body unitarity, treat the nucleon and delta on an equal footing, and have a pole with correct residue at the nucleon mass. The input is from the cloudy bag model. Resonance behavior is exhibited without the inclusion of a bare Roper bag, although not in detailed agreement with experiment. If a bare Roper bag is included, the phase shifts vary far too rapidly in the resonance region, implying that identifying the lowest radial bag excitations with the Roper leads to a physical Roper that is much too narrow.

It was recently shown that analyzing power data for 500 MeV (p,n) charge exchange from ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$ could not be adequately explained by either relativistic or nonrelativistic distorted wave impulse approximation models. In general, reaction models which incorporate relativistic dynamics provide a successful description of proton-nucleus elastic scattering at intermediate energies. It is therefore important to understand the reasons for the apparent failure of the theoretical models with respect to the description of (p,n) charge exchange data from odd targets. In this work a method of analyzing intermediate energy (p,n) reaction data from odd target nuclei is presented which focuses attention on specific dynamical elements of the relativistic distorted wave impulse approximation model. Included in these elements are the different pieces of the Lorentz invariant nucleon-nucleon isovector effective interaction and the aspects of nuclear structure associated with the valence nucleon. The analysis utilizes certain linear combinations of the (p→,n→) polarization transfer observables, the important quantities being the transverse and longitudinal spin-flip cross sections and the projectile no-spin-flip cross section. The method is illustrated with relativistic distorted wave impulse approximation calculations for the ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$(p→,n→${)}^{13}$N(g.s.) reaction at 500 MeV. It is intended that analyses of this type will provide an important tool for diagnosing the apparent inadequacies with the theoretical description of intermediate energy (p,n) charge exchange from odd nuclei.

New ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$(p,p’) measurements at 400 MeV are reported and analyzed using new approaches to the continuum in the giant resonance region. These approaches include a phenomenological procedure, and calculations based on the free surface response function of semi-infinite nuclear matter. These methods are found to lead to giant resonance parameters which are consistent and in agreement with established results. We interpret this to mean that both approaches provide empirically consistent representations of the continuum underlying the giant resonances. In addition to the well-known resonances, evidence of possible 3ħω L=5 resonance strength is observed at 18-MeV excitation accounting for 10±3 % of the energy-weighted sum rule.

We have performed an experiment in which we have detected three protons in coincidence, following the absorption of positive pions in carbon. Data were collected with twelve plastic scintillator detectors, covering a fairly large region of the available phase space, at three incident pion kinetic energies: $T_{\pi }$=130, 180, and 228 MeV. Comparisons are made with phase space calculations which simulate quasifree three-nucleon and four-nucleon absorption mechanisms. The first of these provides an excellent description of the bulk of the data. Some of the observed events appear to come from quasideuteron absorption, followed by a final-state interaction of one of the outgoing protons. There is no evidence for absorption mechanisms involving more than three nucleons. Estimates are made for the contributions of the three-nucleon absorption mechanisms to the total pion absorption cross section. These are relatively small.

We show that the semiclassical positive and negative angle scattering contributions to the cross section can be obtained via integral angular-momentum summation using the exact phase shifts.

The angular distributions of the inclusive (${\pi }^{+}$,p) and (${\pi }^{+}$,pp) cross sections have been measured for ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, and C at $T_{\pi }$=70, 130, and 165 MeV. The results are compared with the predictions of the intranuclear cascade model in which pion absorption is involved only through the ΔN-NN dynamics. Discrepancy between the intranuclear cascade and experimental results for the (${\pi }^{+}$,pp) reaction is larger than that for the (${\pi }^{+}$,p) reaction. Effective numbers of quasideuteron are deduced from both single-arm and coincidence data, and compared with results of the two-nucleon photoabsorption reaction.

A phenomenological analysis of the ground-state binding energy $B_{\Lambda }$ of a Λ is made based on the Dirac equation with a rectangular scalar potential and fourth component of a vector potential of the same radius. Analytic expressions are obtained for the small and large component of the radial wave function and the eigenvalue equation for $B_{\Lambda }$ is also given. The latter leads to approximate ‘‘semiempirical mass formulas’’ $B_{\Lambda }$=$B_{\Lambda }$(A) for sufficiently large values of the mass number. Estimates are made of $B_{\Lambda }$ and also of the (average) effective mass of the Λ and for the depth of the Schrödinger-equivalent potential by fitting to the experimental values of $B_{\Lambda }$.

A simple Monte Carlo cascade model which gives the exclusive description of the hadron-nucleus collisions is described. Comparison with the data on pAr, pXe collisions at 200 GeV suggests that at this energy all secondary particles are produced basically by the multiple collisions of a projectile and by the cascading of the recoiled nucleons inside the nucleus, while the cascading of the secondary pions is rather negligible.

The first comprehensive study of the full set of 18 response functions relevant to the (e→,e’p→) reaction is presented. Benchmark analytical features and limiting cases of the response functions are described. Numerical predictions contrasting nonrelativistic and relativistic (Dirac) dynamics and on- and off-shell final-state interaction effects are presented. Basic physical characteristics and dependences of the response functions are identified. The outlook for future experimental studies of the (e→,e’p→) polarization response functions is discussed.

A new method, the operator expansion method, is derived and discussed. Using this method, the ββ decay of ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$ is recalculated. It is shown that by employing the Paris forces our method yields a matrix element suppressed by a factor of about 2–6 for the 2νββ mode, while for the 0νββ mode our calculation confirms the results obtained with the conventional closure approximation.

The possibility of performing weak interaction experiments using spectroscopic techniques is discussed. In such an experiment, a laser is tuned to an electronic transition of the daughter, and a signal whose strength is proportional to the number of recoil atoms is monitored, such as fluorescence, absorption, or anisotropy induced in radiation emitted in a subsequent nuclear decay. As a specific example of this technique, we consider measuring the angular correlation between the momenta of the electron and the antineutrino emitted in the decay ${}_{}{}^{85}{}_{}{}^{}\to _{}^{85}{}_{}{}^{}$${\mathrm{Rb}}^{\mathrm{m}}$+${\mathrm{\beta }}^{\mathrm{-}}$+ν¯ using the laser-induced nuclear orientation technique. Such an experiment is currently under way.