Within a relativistic mean-field theory (RMFT) experimental data on the single-particle spectra of lambda hypernuclei are well reproduced. It is shown that the coupling constants cannot be fixed unambiguously from the single-particle spectra. The stability and structure of multi-lambda hypernuclei is explored on the basis of the RMFT using the coupling constants as determined from the observed single lambda hypernuclear levels. It is predicted that multistrange nuclei exhibit an enhanced interaction radius, which further increases in the case of finite temperatures. We suggest that multi-lambda hypernuclei could be produced in high-energy heavy ions and observed in secondary noncharge-changing reactions. The equation of state of lambda matter and the possibility of pure lambda droplets are also discussed.

The effect of two-particle–two-hole ground-state correlations on spin-dipole transitions and the similar first-forbidden β-decay transitions is studied for nuclei in the lead region with realistic shell-model interactions. Transitions are considered between states for which one is a particle-hole excitation of the other. It is found that the tensor component of the residual interaction is quite important for the $0^{\mathrm{-}}$ and $1^{\mathrm{-}}$ spin-dipole transitions and the analogous β-decay matrix elements. It is destructive for $0^{\mathrm{-}}$ and constructive for $1^{\mathrm{-}}$ so that the quenching of the two modes is quite different. The atypical 1${\mathit{g}}_{9/2}$→0${\mathit{h}}_{9/2}$ transition is described. The results are compared to previous determinations.

Neutron elastic-scattering cross sections of indium are measured from 4.5 to 10 MeV at intervals of ≊500 keV. Seventy or more differential values are obtained at each incident energy, distributed between ≊18° and 160°. These are combined with lower-energy data previously obtained at this laboratory, and with 11- and 14-MeV results from the literature, to form a comprehensive elastic-scattering database extending from ≊1.5 to 14 MeV. These data are interpreted in terms of a conventional spherical optical model. The resulting potential is extrapolated to the bound-state regime. It is shown that in the middle of the 50–82 neutron shell, the potential derived from the scattering results adequately describes the binding energies of particle states, but does not do well for hole states. The latter shortcoming is attributed to hole states having occupational probabilities sufficiently different from unity so that the exclusion principle becomes a factor, to rearrangement of the neutron core, and to the fact that the shell-model potential was assumed to have an energy-independent geometry. The systematic behavior of the real optical potential is discussed, and it is shown that the isovector strength deduced from neutron scattering is consistent with the nucleon-nucleon scattering data when a mass dependence of the radius is used.

Few-nucleon transfer reactions have been measured for the systems ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$${+}^{208}$Pb and ${}_{}{}^{80}{}_{}{}^{}\mathrm{Se}$${+}^{208}$Pb at energies slightly above the Coulomb barrier. Together with previous data, heavy-ion-induced transfer reactions on ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ have now been studied with projectiles in the mass range A=12–86. The experimental total reaction cross sections and the yields for quasielastic processes are compared with various theoretical predictions. For the one- and two-nucleon transfer reactions a systematic behavior of the energy- and angle-integrated cross sections is observed. This behavior can be understood within a simple semiclassical model. A comparison of the cross-section ratios between one- and two-neutron and the one- and the two-proton transfer reactions indicates that the two-proton-transfer process shows an enhancement with respect to the one-proton transfer reaction.

Relativistic iron, lanthanum, holmium, and gold projectile nuclei with several different energies have been fragmented in targets of polyethylene, carbon, aluminum, copper, and lead. Our detectors cleanly resolve the individual charges of the heaviest of these fragments and provide some limited information on the masses. We have measured 1256 elemental partial cross sections for the production of fragments from interactions in these target materials. Values have been derived for another 417 cross sections in a hydrogen medium. These cross sections depend on the energy and mass of the projectile nuclei as well as on the nature of the target. Total charge-changing cross sections were also found, but only in a composite target, and have been shown to be weakly dependent on energy. The mean mass losses observed for fragments that have lost a few protons show that typically many neutrons are lost with each proton, producing fragment nuclei that must be highly proton rich, and consequently very unstable. The cross sections for charge pickup on heavy targets show a rapid increase with decreasing energy, particularly for the heaviest targets. The systematics of the dependencies of the partial cross sections will be discussed in a companion paper.

Measurements of the partial charge-changing cross sections for the fragmentation of relativistic iron, lanthanum, holmium, and gold nuclei of several different energies incident on targets of polyethylene, carbon, aluminum, and copper have been reported in an accompanying paper. This paper describes the systematics of the variations of these cross sections with energy, projectile, target, and fragment. We have been able to generate a seven-parameter global fit to 795 measured cross sections for the heavy targets which fits the data with a standard deviation of 7%. We have also generated a similar global fit to 303 measured cross sections for a hydrogen target which fits the data with a standard deviation of 10%. These representations imply that the hypothesis of limiting fragmentation is only accurate to some 20–30 %. Weak factorization can apply, but fits that are marginally better, and more physically plausible, can be obtained without factorization. We have identified, and discussed, a number of caveats to the applicability of these fits outside, and inside, the range of energies and masses covered. Excessively large cross sections for the loss of a single proton from the projectile nuclei suggest electromagnetic dissociation. The cross sections for fragments that experience large charge changes appear to become independent of the size of the charge change. Very heavy projectiles have a significant probability of experiencing fission.

Target residues from the reaction of 2.6 GeV protons with gold and thorium nuclei have been studied with radiochemical techniques. Chemical separations were used to enhance the sensitivity for detecting target residues in the near-target region. These data are compared to a new empirical parametrization of the mass and charge yields of fragmentation, or spallation, products based on a comprehensive analysis of data in the literature. Data include results from both projectile and target fragmentation studies. The new near-target residues provide significant new insight into the variation of the cross sections of products near in mass to the target (or projectile). The results of this study and the empirical description are compared to the internuclear-cascade model of these reactions.

Measurements of the spin dependence of large l, j=l-1/2, transfer reactions at medium energies provide a stringent test of three-body reaction models. We report measurements of the cross section (dσ/dΩ), vector (${\mathit{A}}_{\mathit{y}}$) and tensor (${\mathit{A}}_{\mathit{y}\mathit{y}}$) analyzing powers, and outgoing proton polarization (p) angular distributions (${\mathrm{\theta }}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$=6.9°–82.3°) for the l=3, ${\mathit{j}}^{\mathrm{\pi }}$=5/$2^{\mathrm{-}}$ ground-state transition in ${}_{}{}^{66}{}_{}{}^{}\mathrm{Zn}$(d,p${)}^{67}$Zn measured with 88.2-MeV deuterons. Adiabatic model calculations fail to describe either interference oscillations in the data or departures from the simple theoretical relationships, 1+3p+2${\mathit{A}}_{\mathit{y}\mathit{y}}$=0 and 2+${\mathit{A}}_{\mathit{y}\mathit{y}}$+3${\mathit{A}}_{\mathit{y}}$=0, that are expected to hold for a far-side–dominated reaction. The quasiadiabatic model, in which the center-of-mass energy in breakup configurations is not constrained to be degenerate with the elastic channel, is able to reproduce qualitatively these features of the data.

We study momentum-dependent or nonlocal couplings and off-shell effects in the internucleon force arising from antisymmetrization for inclusive nucleon scattering over a wide range of momentum transfer and energy loss to the target. Our results illustrate that spin observables are more sensitive to these couplings than are unpolarized cross sections. The experimental results can be understood in terms of the nuclear response function with an uncertainty of ∼10% for incident nucleons above 300 MeV. At incident energies near ∼100 MeV and below, the nonlocal couplings are much more important and cannot reliably be neglected. The sensitivity of inclusive nucleon scattering to the choice of effective nucleon-nucleon interaction is also found to be generally non-negligible.

Calculations have been performed for the photoproduction of eta mesons on nuclear targets to selected discrete states. A recent fit to the ${}_{}{}^1{}_{}{}^{}\mathrm{H}$(γ,η${)}^1$H elementary amplitude was employed in an impulse approximation. Transition densities were determined by comparison with inelastic electron scattering data. Stretched state excitations yield cross sections on the order of tenths of microbarns in the region of the ${\mathit{S}}_{11}$(1535). Calculations for photoproduction to selected states demonstrate how experiments can provide the isospin structure of the elementary amplitude. The same experiments can also test models of the ηN interaction by comparing measured and calculated distortion effects.

Double-differential cross section for the in-flight ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$(${\mathit{K}}^{\mathrm{-}}$,${\mathrm{\pi }}^{+}$) reaction is investigated theoretically in the framework of the distorted-wave impulse approximation by using the Green’s-function method. The difference in the reaction cross sections is clearly seen between a phenomenological nucleus-${\mathrm{\Sigma }}^{\mathrm{-}}$ potential which reproduces ${\mathrm{\Sigma }}^{\mathrm{-}}$ atom data and a folding potential with a repulsive bump near the nuclear surface which is constructed from the realistic ΣN interaction.

One-nucleon knockout calculations have been performed for the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(γ,p${)}^{11}$B at incident photon energies of 60, 80, and 100 MeV. Both two-step processes and high-momentum components in the single-nucleon wave function due to short-range correlations have been included. It is shown that direct knockout leading to the ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ ground state followed by inelastic excitation of the 7/$2^{\mathrm{-}}$ state at 6.743 MeV in ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ exceeds the direct excitation of this state by 1 to 2 orders of magnitude. For the ground-state transition the influence of high-momentum components becomes increasingly important going from ${\mathit{E}}_{\gamma }$=60 to 100 MeV. Constraining the parameters entering the calculation by recently measured quasielastic ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(e,e’p${)}^{11}$B data a discrepancy is found between the calculations and the data, particularly at low photon energies, which is attributed to exchange currents and random-phase approximation correlations.

Pole expansions of the Green function (Berggren and Mittag-Leffler) are used to calculate single-particle and particle-hole response functions for a square well plus Coulomb potential and the results are compared with the corresponding exact ones. The approximate and exact response functions agree well with each other in the resonant energy region. The Mittag-Leffler expansion is shown to be valid even for the long-range Coulomb potential. The computation time needed for the calculation of the particle-hole response function can be reduced considerably by using the pole expansions.

We investigate nuclear fragmentation in a supersaturated system using classical nucleation theory. This allows us to go outside the normally applied constraint of chemical equilibrium. The system is governed by a virial equation of state, which we use to find an expression for the density as a function of pressure and temperature. The evolution of the system is discussed in terms of the phase diagram. Corrections are included to account for the droplet surface and all charges contained in the system. Using this model we investigate and discuss the effects of temperature and saturation, and compare the results to those of other models of fragmentation. We also discuss the limiting temperatures of the system for the cases with and without chemical equilibrium. We find that large nuclei will be formed in saturated systems, even above the limiting temperature as previously defined. We also find that saturation and temperature dominate surface and Coulomb effects. The effects are quite large, thus even a qualitative inspection of the yields may give an indication of the conditions during fragmentation.

The multistep α-transfer treatment of Aleixo et al. is employed in a detailed investigation of the anomalous back angle scattering of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$${+}^{28}$Si. We have improved the calculation of the propagator in the transfer channel and taken into account the coupling to elastic transfer. This way, we have obtained a good description of the experimental back scattering cross section from the barrier energy to ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$∼50 MeV. It is shown that the rise of the cross section at ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$∼45 MeV can be explained by parity-dependent terms in the S matrix, arising from the coupling to the elastic transfer channel. A study of the conditions for the coupling with an α-transfer channel to produce dynamical Regge poles indicates that pickup channels can be left out.

The angular distribution of electrons and positrons emitted in internal pair conversion is calculated. Coulomb-distorted waves are used as electron wave functions. Nuclear transitions of various multipolarities L>0 and of magnetic (ML) and of electric (EL) type are considered as well as E0 conversion. Analytical expressions for the angular correlation are derived, which are evaluated numerically assuming a finite extension of the nucleus and, for the EL and ML conversion, also in the point-nucleus approximation. The calculated angular correlations are compared with results obtained within the Born approximation and, for the E0 case, with experimental data.

We calculate two-pion correlation functions from a dynamical string model situation and from a Bjorken-scaling solution. The effects of hadronic decays and final-state Coulomb and strong interactions are included. Correlation functions are shown to depend strongly on both the total transverse momenta and the direction of the relative momentum of the pairs.

Relativistic quasifree approximations for inclusive scattering on a bound system are investigated. The system is described by means of the Bethe-Salpeter equation. It is shown that final state interaction (FSI) corrections to the relativistic West approximation (on-shell quasifree kinematics for the struck nucleon) are of the same order of magnitude as the quasifree term in the asymptotic limit q→∞. Therefore the on-shell approximation cannot be applied to data analysis. A consistent relativistic extension is proposed for the West approximation and for the FSI term. The response function given by this approximation depends on a new scaling variable ỹ which differs from that obtained from on-shell kinematics. The analysis of inclusive ${\mathit{e}}^2$H→e’X experimental data using the new quasifree approximation shows an agreement with the calculated asymptotic limit in the scaling region.

The magnitude of the effect of meson exchange currents on low-energy pion nucleus double charge exchange is reexamined. In particular, the role of chiral symmetry in limiting the size of the effect is studied, using the method of effective Lagrangians. The equivalence of two commonly used versions of the theory is shown, which resolves some of the disagreements in the literature. The effect is calculated for the case of ${}_{}{}^{42}{}_{}{}^{}\mathrm{Ca}$, and found to be smaller than that of ordinary multiple scattering.

Nuclear magnetic moments are investigated in the relativistic quark shell model. The importance of clustering effects, induced by configuration mixing in the j-j coupling quark shell model, is pointed out.