The composite particle representation theory (CPRT) proposed by Wu and Feng is examined by comparing its results to the shell-model calculations of Wildenthal and Chung for the s-d shell nuclei ${}_{}{}^{20}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{20}{}_{}{}^{}\mathrm{F}$, and ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$. Each identical nucleon pair is treated in the CPRT as a boson. In all cases, the CPRT results are identical to the shell model. It was found that by evaluating the normalizations and the error sums of the CPRT wave functions, the spurious states, a subject of vital importance for any mapping theory, can be and are correctly removed. This shows that the composite particle representation is equivalent to the conventional representation in quantum mechanics. Thus the CPRT can provide an exact theoretical framework to treat particle clusters as ideal bosons (or fermions, depending on the nature of the clusters) in a many-body system, and is particularly useful for any quantum systems where clusterization dominates.

An approximate analytic formula for calculating B(E2;$2_1^{+}$→$0_1^{+}$) transition probabilities is proposed. We show that this formula reproduces quite accurately numerical calculations based on the interacting-boson model (IBM), and experimental data for a large number of nuclei from Zn to Pt, and in the actinide region, the largest discrepancies being of the order of 40%. The analytic relation is based on an IBM Hamiltonian, whose four parameters can be estimated using expressions given in the text. Since these expressions are based on a microscopic shell-model description, the formula only requires knowledge of the (N,Z) values of the isotope in question.

The ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(n,p${)}^{12}$B reaction has been studied at 60 and 65 MeV. Cross sections for the $1^{+}$ ground state, the $2^{+}$ first excited state at 0.95 MeV, an unresolved pair of $2^{\mathrm{-}}$ and $4^{\mathrm{-}}$ states at 4.4 MeV, and the analogs of the giant electric dipole and spin-dipole resonances around 7.7 MeV have been extracted and compared with previous data at 56 MeV and with microscopic distorted-wave Born approximation calculations. The shapes of angular distributions out to q∼2 ${\mathrm{fm}}^{\mathrm{-}1}$ are well reproduced by the calculations. A comparison of (n,p), (p,n), and (p,p’) cross sections near 60 MeV is made, and a value for ‖${\mathit{J}}_{\mathrm{\sigma }\mathrm{\tau }}$‖ (the volume integral of the central, spin-isospin part of the effective nucleon-nucleon interaction) is extracted. The magnitudes of cross sections for negative-parity states can be qualitatively understood when the loose binding of the sd-shell neutron in the final state and the effect of ground-state correlations on the dipole and spin-dipole strengths are taken into account.

Possible effects of hexadecapole nuclear deformations on subbarrier fusion cross sections are investigated. The ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ on ${}_{}{}^{166}{}_{}{}^{}\mathrm{Er}$ and ${}_{}{}^{176}{}_{}{}^{}\mathrm{Yb}$ reactions have been measured at beam energies ranging from 64 to 100 MeV. The ${}_{}{}^{166}{}_{}{}^{}\mathrm{Er}$ and ${}_{}{}^{176}{}_{}{}^{}\mathrm{Yb}$ data and already existing ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$ data were analyzed in terms of a model including both quadrupole and hexadecapole deformations. Theoretical predictions follow qualitatively the trend of the experimental data.

Differential cross sections for elastic and inelastic α scattering on ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$, ${}_{}{}^{20,22}{}_{}{}^{}\mathrm{Ne}$, and ${}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$ have been measured at 50 MeV. The data have been analyzed in the coupled-channel approach considering the model of a symmetric rotor together with the double-folding model for the optical potential. As an alternative also a Woods-Saxon parametrization for the radial shape of the real part of the optical potential has been considered. Both parametrizations yield similar results for the quadrupole and hexadecapole moments. These isoscalar multipole moments are consistent with those obtained from electromagnetic probes and with the predictions of microscopic shell-model calculations. Large deformations are needed to describe the enhancement of the elastic-scattering cross section at backward angles for ${}_{}{}^{20,22}{}_{}{}^{}\mathrm{Ne}$.

The populations of neutron-unbound states and of bound states in intermediate-mass fragments have been measured at 15°, 31°, and 64° from the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$+Ag reaction at E/A=35 MeV. We did this for eleven neutron-unbound states in seven isotopes whose bound-state populations we were also able to measure. The data are identified in terms of the reaction mechanism producing them, which is either a deep-inelastic mechanism or a quasielastic mechanism. In order to test the assumption that the deep-inelastic data are produced from a thermal source, the unbound-state–bound-state population ratios of deep-inelastic fragments are compared to the predictions of a thermal sequential decay model. Most, but not all, of the deep-inelastic population ratios are fitted with model calculations that assume a source temperature between 2.5 and 3.5 MeV. In the case of ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ we were able to measure four deep-inelastic populations, and in the case of ${}_{}{}^{12}{}_{}{}^{}\mathrm{B}$ we were able to measure three such populations. To further test the assumption of emission from a thermal source, attempts were made to fit all of the populations from each of these two isotopes with the sequential decay model using a single temperature.

The deep-inelastic populations of ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ were fitted with a single temperature between 2.5 and 5.0 MeV. The deep-inelastic populations of ${}_{}{}^{12}{}_{}{}^{}\mathrm{B}$ were not fitted with any temperature. There is enough of the deep-inelastic data that is not fitted with the predictions of a thermal model that the assumption of a thermal source for the production of deep-inelastic fragments may be incorrect, or there may be other effects present which alter the thermal properties of the data. The quasielastic populations in each ${}_{}{}^{12}{}_{}{}^{}\mathrm{B}$ and ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ were also measured and could not be fitted with the model using a single temperature, which is consistent with the assumption of a nonthermal source of production for quasielastic fragments. The dependence of the unbound-state–bound-state population ratio on the fragment kinetic energy shows a difference between the quasielastic and deep-inelastic data. For quasielastic fragments whose mass is near the mass of the beam, the ratio decreases towards zero as the fragment velocity approaches the beam velocity. In contrast, the ratio for half-beam mass quasielastic fragments is constant or only slightly decreasing as the kinetic energy increases. The ratio for deep-inelastic fragments is approximately constant as a function of kinetic energy, independent of fragment mass. The amount of feeding from several neutron-unbound channels into bound states is measured and compared to the sequential decay model. The model successfully predicts the amount of feeding from most of the channels using a source temperature of 2.5 to 4.0 MeV. The effect of feeding both on spectral temperatures and on population temperatures is investigated. We conclude that the effect of feeding on both temperatures, as determined by model calculations, cannot account for the discrepancy in the values between the two.

Differential cross sections and analyzing powers for neutron elastic scattering from ${}_{}{}^{93}{}_{}{}^{}\mathrm{Nb}$ have been measured at energies from 8 to 17 MeV using pulsed-beam time-of-flight methods. These data plus total cross-section data from 1 to 20 MeV are interpreted in terms of the spherical optical model. Several sets of optical potential parameters with systematic energy dependences have been derived in searches that used different initial parameter sets. In addition, comparisons of the data to calculations based on previously reported optical potentials are presented. It is concluded that the data favor the inclusion of a small imaginary spin-orbit term.

Elastic and inelastic scattering of ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$ ions have been observed on targets of C and Au at a beam energy of 14 MeV, using the University of Notre Dame–University of Michigan radioactive nuclear beam facility. The elastic scattering shows that, in most respects, ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$ behaves similarly to ${}_{}{}^{6,7}{}_{}{}^{}\mathrm{Li}$. However, a large probability for populating the first excited state of ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$ via inelastic scattering is observed. Data analysis using a deformed optical-model potential obtained from fits to the elastic scattering yields a reduced transition strength B(E2↑)=30±15 ${\mathit{e}}^2$ ${\mathrm{fm}}^4$.

Nuclear transport models are important tools for interpretation of many heavy-ion experiments and are essential in efforts to probe the nuclear equation of state. In order to fulfill these roles, the model predictions should at least agree with observed single-particle-inclusive momentum spectra; however, this agreement has recently been questioned. The present work compares the Vlasov-Uehling-Uhlenbeck model to data for mass-symmetric systems ranging from ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${+}^{12}$C to ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}$${+}^{139}$La, and we find good agreement within experimental uncertainties at 0.4A and 0.8A GeV. For currently available data, these uncertainties are too large to permit effective nucleon-nucleon scattering cross sections in the nuclear medium to be extracted at a useful level of precision.

By using a two-state approximation, a time-dependent semiclassical theory is developed for the sub-Coulomb transfer of a neutron between two deformed and arbitrarily oriented nuclei. This theory yields the transfer probability as a function of the energy splitting of molecular single-particle states which are degenerate for large internuclear separations. We apply this theory schematically to central collisions of ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ on ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ using a two-center shell model and considering only the three low-lying states 1${\mathit{s}}_{1/2}$, 1${\mathit{p}}_{3/2}$(Ω=1/2), and 1${\mathit{p}}_{3/2}$(Ω=3/2) of the deformed ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ nucleus. Transfer probabilities are calculated as a function of the orientation of the deformed ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ nuclei with respect to the internuclear axis and compared with phenomenological probabilities depending exponentially on the minimum center-to-center and surface-to-surface distances. The transfer probabilities from the 1${\mathit{s}}_{1/2}$ and 1${\mathit{p}}_{3/2}$(Ω=1/2) states seem to support the exponential dependence on the minimal surface-to-surface distance.

A semiclassical distorted wave model is presented for one-step nucleon inelastic-scattering process leading to the continuous states of residual nucleus. The model is based on semiclassical approximations for the distorted waves and the Thomas-Fermi model of the nuclear states. The squared modulus of the matrix elements of nucleon-nucleon (N-N) interaction is substituted by the corresponding N-N scattering cross section in the free space. The model gives a closed-form expression with no adjustable free parameter for the double-differential cross section. We apply the model to the proton inelastic scattering from ${}_{}{}^{120}{}_{}{}^{}\mathrm{Sn}$, ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$, and ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ at 62 MeV, and ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ at 100 and 164 MeV. Experimental data are reproduced very well at high emission energies except in small- and large-angle regions. The cross sections of the neutron inelastic scattering from ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$${,}^{120}$Sn, and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ at 60 and 160 MeV, for which no experimental data are available, are predicted to be quite similar to the cross sections of the proton inelastic scattering. Calculations are also compared with the exciton model and the multistep direct reaction theory.

We present numerical solutions of recently proposed relativistic transport equations for fluctuating hadronic fields with simplified model Lagrangians containing a spin-1/2 nucleon and a light scalar or pseudoscalar meson. We introduce and implement a method for regularizing tadpoles and vector loops which is consistent with the previously proposed regularization of the scalar loops. The resulting solutions in vacuum are well behaved, exhibiting the expected differences between the scalar and pseudoscalar cases without apparent pathologies.

Off-shell effects due to momentum dependence of the optical potential are calculated for the relativistic and no-pair approaches to proton elastic scattering by ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ at 200 and 500 MeV. Optical potentials are based on the optimally factorized impulse approximation using Lorentz-invariant NN amplitudes calculated from the Utrecht meson-exchange model. A momentum-space solution of the Dirac equation is developed based on helicity amplitudes for nucleon-nucleus scattering. A new algorithm for regulating the Coulomb interaction in momentum-space calculations is developed and it is used in the calculations to determine accurately the Coulomb-corrected phase shifts. Off-shell effects due to momentum dependence of the NN interaction are found to be of minor importance in the relativistic analysis based on the factorized (tρ) form of the impulse approximation.

The Glauber S-matrix operator for nucleus-nucleus scattering is expressed as a finite series of matrix elements involving Bell’s polynomials. Analyzing ${\mathrm{\alpha }}^4$He elastic-scattering data at the incident momentum of 4.32 GeV/c, we infer that our expansion is appreciably converging. Further, by applying closure over target and projectile states and neglecting a certain class of terms involving intermediate excitations, we arrive at a recurrence relation for nucleus-nucleus multiple scattering series terms, which invites further study as it seems to provide a simple method for calculating the nucleus-nucleus elastic-scattering cross section.

We report the measurements on partial production cross sections of the multiple helium fragments emitted in the interactions of ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ ions at 14.5A GeV in nuclear emulsion. Interaction mean free paths of the helium fragments have been investigated on the basis of helium multiplicity and size of the target nucleus as a function of the distance from their production points. Multiplicity scaling in the produced helium fragments is also observed.

Cross sections for the incoherent production of the Higgs boson in ultrarelativistic heavy-ion collisions through two-photon processes are calculated by the direct Monte Carlo integration of Feynman diagrams incorporating nuclear-structure functions.

Distribution of the formation lengths of a multihadron system is calculated in the framework of the string model of particle production. The general formula and the particular solution for a simple fragmentation function of the Lund model are given. The distribution is used to calculate nuclear attenuation of a two-hadron system.

Isotope yield ratios produced in collisions of 35 MeV/nucleon ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ with targets of C, Ni, Ag, and Ho have an exponential dependence on total neutron-to-proton ratio. A statistical multifragmentation model including particle emission from excited fragments predicted such behavior for yield ratios measured earlier at the higher energy of 84 MeV/nucleon.

Pre- and post-scission neutron spectra have been calculated by an evaporation code and analyzed using a multiple-source-fitting procedure. It is shown that recoil effects of evaporated particles have to be taken into account to deduce the correct total kinetic energy dependence of pre- and post-scission neutron multiplicities. These effects are less important for the corresponding fragment-mass dependence.

We address some misconceptions concerning the low values of πNN coupling constant recently extracted from pp and πN scattering data. We discuss the effect of this lower coupling on other systems. Suggestions are made for future investigations.