Measurements have been made of the branching ratio for the reactions ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(d,γ${)}^5$He${/}^3$H(d,n) ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ for several incident deuteron energy ranges between 0 and 0.72 MeV. A stopping length tritium gas target bombarded by a pulsed deuteron beam was used to obtain a high reaction rate as well as provide neutron-gamma ray separation by time of flight. The branching ratio was determined to be 5.6±0.6×${10}^{\mathrm{-}5}$ integrated over the resonance from 0 to 275 keV.

A new calculational approach is described which reproduces the Watson multiple scattering series, simplified by neglecting the terms describing the repeated scatterings of a projectile on the same target nucleon. The approach involves solving sets of uncoupled wave equations (Schrödinger or Dirac) with effective optical potentials of the analogous form as the first order optical potential used in the standard impulse approximation optical models. Our approach is particularly suitable in multiple scattering calculations for elastic scattering of hadrons from light nuclei. As an example of the application of the proposed method we evaluated multiple scattering series for the elastic scattering of protons from ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ with the purpose of assessing the importance of relativistic effects in this reaction.

Cross sections for the (p,n) reaction to analog states have been measured for the five stable isotopes of titanium at energies between 11.5 and 26 MeV. In addition to the ground-state analogs, cross sections to the $2_1^{+}$ analog states for the even A isotopes have been determined. A two-channel analysis of the ground-state analog data, searching on the charge-exchange parameters, did not yield a satisfactory globally consistent description of the $0_1^{+}$ analog cross sections. However, in a full coupled-channel description of the $0_1^{+}$ analog angular distributions the N-Z dependence and the strength of the $2_1^{+}$ analog cross sections for ${}_{}{}^{46}{}_{}{}^{}$,48,50Ti are explained by strong inelastic couplings and by rather different charge-exchange couplings among the three isotopes. The isovector deformation parameters used in the charge-exchange couplings were determined from electromagnetic and (p,p’) values, which were obtained from experiment. The experimental energy dependence of the cross section shows a resonance behavior which is not explained by the channel coupling but which can be adequately accounted for by an energy dependent $V_1$.

Two recent works on the structure of medium spin states in ${}_{}{}^{83}{}_{}{}^{}\mathrm{Kr}$, while yielding almost identical results for the level scheme, disagreed on the spins of several important states. The spins of these states are remeasured here and compared to the results of these previous works.

The connection between the electron scattering electric dipole coincidence cross section (e,e’X) and the inclusive electric dipole (e,X) cross section, differential in the angle of the outgoing X particle, is derived. Unlike the (e,e’) inclusive cross section which contains contributions from only two of the four terms of the (e,e’X) cross section, the (e,X) cross section contains contributions from all four terms of the (e,e’X) cross section. Data from a previous experiment have been used to obtain the magnitude and sign of the interference term between the transverse and Coulomb reduced matrix elements (form factors) in the limit as q→ω, from the relationship commonly referred to as Siegert’s theorem in the context of inclusive (e,e’) scattering.

Recent experiments have indicated that there is a large suppression of the M3 as well as the M5 elastic magnetic form factor in ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$. We examine the modification of the form factors due to various configurational admixtures arising from the realistic effective interactions. It turns out that the polarization of the ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$ core plays an important role vis-á-vis the observed anomalous magnetic octupole scattering.

Calculations of the neutrino capture cross sections for ${}_{}{}^{69}{}_{}{}^{}$,71Ga based on a microscopic treatment of the Gamow-Teller matrix elements are presented. A strong enhancement of the cross section for highly energetic neutrinos is found compared to previous phenomenological estimates. As a consequence, the present assumptions on the signal from ${}_{}{}^8{}_{}{}^{}\mathrm{B}$ neutrinos in ${}_{}{}^{71}{}_{}{}^{}\mathrm{Ga}$ have to be revised. A non-negligible solar model dependent background of ${}_{}{}^8{}_{}{}^{}\mathrm{B}$ neutrinos has to be expected in a gallium solar neutrino experiment together with the pp signal. The calculations yield a larger sensitivity of the gallium detector than assumed previously for galactic neutrinos.

The (p,p’)-type singles cross sections are calculated. The knockout of the target nucleons, reabsorption of the knocked-out particle, and particle-hole excitations into bound orbits are taken into account. The sum of cross sections for these three excitation modes is shown to describe nicely the observed continuum cross section data for the ${}_{}{}^{54}{}_{}{}^{}$Fe(p,p’) and ${}_{}{}^{27}{}_{}{}^{}$Al(p,p’) reactions at 62 MeV.

Binary channels of the ${}_{}{}^{12}{}_{}{}^{}$C${+\mathrm{}}^{17}$O reaction have been studied using a kinematic coincidence technique in the $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}$ range 16.5 to 29.0 MeV. Angular distributions have been determined for the elastic, the inelastic to the first excited states of ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, and the transfer channel to the ground states of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$. The angular distributions for the inelastic scattering to the first excited state of ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$, which show strong oscillatory patterns over the whole energy range, could not be reproduced by distorted-wave Born approximation calculations. Structure is observed in the excitation functions of several channels. In particular the structure observed for the inelastic excitation of ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ is similar to that observed in previous γ-ray experiments.

Recent data from C+O collisions are analyzed in terms of the Landau-Zener promotion in nuclei. Evidence for the presence of this mechanism in nuclear collisions is of considerable interest, since it provides a signature of single-particle orbitals in molecular-type potentials and, at the same time, paves the way to a microscopic understanding of the collision dynamics, in particular of the energy dissipation rate. The analyzed data are of two types: integrated cross sections and angular distributions of inelastically scattered particles. The first set of data shows structure qualitatively consistent with recent calculations of the Landau-Zener effect; for this set of data no other reasonable explanation is presently available. The second set of data, while consistent with the presence of the Landau-Zener promotion, is examined in terms of other possible explanations too. The combined data show evidence favoring the presence of the Landau-Zener promotion in nucleus-nucleus collisions.

Nuclear matter equations of state are constructed which incorporate explicitly the pion and delta degrees of freedom. These are used in relativistic one-dimensional and three-dimensional hydrodynamical models of central nucleus-nucleus collisions to determine the influence of the compressional energy on the observed pion multiplicity. We find a modest dependence on the compressional energy but a significant difference between slab-slab and sphere-sphere collisions having to do with curved shock waves. Thus one-dimensional hydrodynamic models do not appear to be suitable for interpreting pion production at energies of 100 MeV–2 GeV.

At a bombarding energy of 32 MeV, angular distributions have been measured for seven states populated in the reaction ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$${(}^6$Li,α${)}^{29}$Si. Angular distributions and angle-integrated cross sections have been compared with results of distorted-wave Born-approximation and statistical compound-nucleus calculations, in order to assess the relative importance of direct and compound processes.

The equation of state of nuclear matter at finite temperature and density is calculated in a relativistic field theory of interacting baryons and mesons. At subnuclear densities there exists a liquid-gas phase transition with a critical point at $T_c$=17.3 MeV, $n_c$=0.052 ${\mathrm{fm}}^{\mathrm{-}3}$. We estimate the critical beam energy in symmetric headon nucleus-nucleus collisions for which the exploding nuclear matter passes through the critical point. The dynamics of phase separation is studied in the extreme limits of no dissipation and maximum dissipation.

The equivalence of the thermal model and the conventional zero lifetime Hanbury-Brown/Twiss descriptions of the two-particle momentum-space correlation function is demonstrated. A simplified expression for the correlation function is presented and tested against recent composite particle correlation measurements. The expression allows a more direct analysis of the measurements and predicts novel behavior for certain interaction potentials.

The mechanism responsible for fusion cross section limitations in light heavy-ion systems has been the focus of numerous experimental and theoretical studies. Many of the experimental investigations have involved a study of the heavy residues emitted following the interaction of light heavy ions. One difficulty encountered in such studies is separating events from competing reaction mechanisms, such as direct transfer and incomplete fusion, from fusion-evaporation events. In the present work, direct and reverse reaction kinematics are exploited in an effort to determine the magnitude of the nonfusion strength in the heavy residue spectra for the interaction of ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$. It is particularly important that the ${}_{}{}^{11}{}_{}{}^{}$B${+\mathrm{}}^{12}$C fusion strength be properly identified, as it is the measured fusion strength in this entrance channel which in earlier studies clearly ruled out a fusion cross section limitation based upon having reached a critical density of compound nuclear states. In agreement with the earlier investigations, the present study reveals no significant nonfusion component in the heavy residue spectra for the ${}_{}{}^{11}{}_{}{}^{}$B${+\mathrm{}}^{12}$C reaction.

Transfer reactions of heavy ions with ${}_{}{}^{248}{}_{}{}^{}$Cm targets are evaluated for their usefulness in producing unknown neutron-rich actinide nuclides. Cross sections for the production of nuclides in the region 91≤Z≤100 were determined radiochemically from bombardments with ${}_{}{}^{18}{}_{}{}^{}$O, ${\mathrm{}}^{86}$Kr, and ${}_{}{}^{136}{}_{}{}^{}$Xe ions. The systematic trends in the cross sections for these reactions can be understood in terms of the Coulomb potential and the stabilizing effect of the reaction Q values, which tend to favor the production of nuclei with Z>$Z_{\mathrm{target}}$ with low excitation energies. Extrapolation of the product yields into unknown regions of charge and mass indicates that the use of heavy-ion transfer reactions to produce new neutron-rich above-target species is limited. Substantial production of unknown neutron-rich below-target species is expected in reactions with heavy projectiles like ${}_{}{}^{136}{}_{}{}^{}$Xe and ${}_{}{}^{238}{}_{}{}^{}$U.

Elastic, inelastic, and single-nucleon transfer data are reported for ${}_{}{}^{28}{}_{}{}^{}$Si${+\mathrm{}}^{40}$Ca at $E_{\mathrm{lab}=225\mathrm{}}$ MeV. Standard optical model and distorted-wave Born approximation analyses of the elastic and inelastic scattering angular distributions have been performed resulting in good descriptions of the data. In the inelastic scattering analysis, the nuclear deformation lengths were found to be consistent with the Coulomb deformation lengths obtained from electron scattering. The data for one-nucleon transfers were analyzed using the distorted-wave Born approximation with the optical potential fitted to the elastic scattering and the spectroscopic factors taken from light-ion studies. With the exception of small shifts in angle, the distorted-wave Born approximation correctly predicts the shapes of the angular distributions and the relative intensities of transitions to different states populated in the same reaction. The magnitudes of the single-particle transfer cross sections are reproduced to within a factor of 1.5. However, the distorted-wave Born approximation fails to predict the nearly 40% difference in the magnitudes of the cross sections observed for the ${(}^{28}$Si, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Si}$) and ${(}^{28}$Si, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$) reactions, which populate mirror states.

The heavy-ion charge exchange reaction ${}_{}{}^{12}{}_{}{}^{}$C${(}^{12}$C,${}_{}{}^{12}{}_{}{}^{}$N${)}^{12}$ B has been studied at E${(}^{12}$C)=35 MeV/nucleon. Angular distributions in the range 3.7–12.1° (c.m.) have been measured for the $1^{+}$ (0.0 MeV), $2^{+}$ (0.95 MeV), $2^{\mathrm{-}}$ (1.67 MeV), and $4^{\mathrm{-}}$,$2^{\mathrm{-}}$ (4.5 MeV) states in ${}_{}{}^{12}{}_{}{}^{}$B. A broad peak at 7.8 MeV excitation was also observed. Microscopic one-step distorted-wave Born approximation calculations yield $V_{\sigma \tau }$ strengths ≥2 times those obtained in (p,n) reactions at similar energies per nucleon. Although this is significantly smaller than $V_{\sigma \tau }$ values obtained in other heavy-ion charge exchange studies, mostly carried out at energies less than 10 MeV/nucleon, it is concluded that the reaction mechanism is still dominated by sequential transfer (two-step) processes at 35 MeV/nucleon. A rough estimate indicates that one-step processes will dominate at bombarding energies above about 50 MeV/nucleon.

We examine the space-time dynamics of the baryons in nucleus-nucleus collisions and estimate the energy density reached in the central rapidity region. It is found that with an incident laboratory energy of 15 GeV per projectile nucleon, a headon collision of Au on Au will leave a substantial spatial region with an energy density of 1.5–3 GeV/${\mathrm{fm}}^3$ which may exceed the energy density for a quark-gluon plasma formation.

The structure of the nucleus ${}_{}{}^{219}{}_{}{}^{}\mathrm{Ac}$(Z=89,N=130) has been studied via the ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$${(}^{13}$C,3n${)}^{219}$Ac reaction. In-beam γ-ray spectroscopic techniques, including γ-ray and α-particle excitation functions, α-γ coincidence, γ-γ coincidence, and γ-ray angular distribution measurements were used in the construction of a level scheme up to a spin of J=(31/2)ħ at an excitation energy of 2245 keV. A total of five bands have been constructed and a series of parity doublets has been observed. For four of the bands the states have been labeled in terms of the simplex quantum number, which should be an appropriate quantum number even for octupole deformed nuclei. However, considerable simplex splitting is observed. The level scheme of ${}_{}{}^{219}{}_{}{}^{}\mathrm{Ac}$ indicates that the nucleus lies in the boundary region between the single-particle shell structure seen in the nuclei immediately surrounding ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ and the collective rotational structure prevalent in the heavier actinides. However, no detailed model predictions are, as yet, available to describe the observed structure, which may require quadrupole, octupole, and nonaxial degrees of freedom.