[en] Total reaction cross sections, σ_R, for ⁸B, ¹²C, and ¹⁴N on ^natSi were measured from about 20 to 60 MeV/A. The σ_R for ¹²C and ¹⁴N compared reasonably well with conventional strong absorption and microscopic calculations. Measured σ_R for ⁸B were slightly larger than those for the two heavier nuclei, and notably larger than the conventional calculations. The ⁸B data were well reproduced by microscopic calculations using the same matter distribution used to explain the ⁸B guadrupole moment data, and therefore provide new evidence for the existence of a proton halo in ⁸B

No abstract available

[en] Recent double coincidence data for the ⁶Li + ⁶Li → 2α + 2d reaction show double spectator pole (DSP) peaks much sharper than those predicted from realistic ⁶Li cluster wave functions. The PWBA correctly predicts the centers and approximate amplitudes of these peaks. However, their widths remain much too large even when all obvious straightforward improvements - symmetry under boson exchange, Coulomb cluster wave functions, a finite-range participant interaction potential, and deuteron structure - are added to the model. (orig.)

[en] Recent extensive measurements of total reaction cross sections (σ_R) for 38, 65, and 97 MeV deuterons on targets from ⁹Be to ²⁰⁸Pb were fitted with microscopic model calculations. Using accepted two- and three-parameter Fermi matter distributions for the targets, zero-range nucleon-nucleon forces, and eikonal orbits for the projectile, reasonable fits were obtained when the impact parameter was corrected for Coulomb force effects. Correcting the orbit for nuclear force effects worsened the fits somewhat, as did the use of finite-range nuclear forces; we argue however that it is redundant to make both of these corrections. The results were nearly independent of whether a Hulthacute en, Gartenhaus, or Gaussian form factor was used for the deuteron matter distribution. An attempt to fit older d+Pb σ_R measurements near 25 MeV indicated either a failure of the model at low energies or a need for remeasurement of those data. copyright 1997 The American Physical Society

[en] Simple theoretical estimates of the cross sections for 2n removal from ⁶He and for combined 2n and 4n removal from ⁸He are compared with new measurements on Si targets at 0 endash 55 MeV/nucleon. Nuclear effects, described by a microscopic theory of Esbensen and Bertsch, account for nearly all of the observed cross sections. The electric dipole response function for ⁶He obtained by Danilin et al., whose calculations include valence n-n correlations, is used to predict a Coulomb dissociation cross section about 10% as large as that for nuclear dissociation. A smaller upper limit for ⁸He Coulomb dissociation is found by applying the non-energy-weighted sum rule. Equally good fits to the 800-MeV/nucleon ^6,8He+C fragmentation data are obtained. copyright 1997 The American Physical Society

[en] The differential cross sections for ²H(⁶Li,α) α* (20.08 MeV) and ²H(⁶Li,α) α were measured at 30⁰ c.m. from E/sub Li/ = 10 to 31 MeV. Possible evidence is presented for ⁸Be states decaying by α* emission, near the 3^- and 4⁺ levels of an αα* rotational band in ⁸Be predicted by resonating group calculations

No abstract available

[en] Microscopic calculations of nuclear reaction cross sections and total reaction probabilities are compared with measurements for the d+Si, ^3,4He+Si, and d+Ge systems at energies ranging from 2 to 53 MeV/nucleon. Good agreement is obtained, except for ³He+Si at the very lowest energies, when zero-range nucleon-nucleon forces are assumed and realistic nuclear density distributions are used in the tail regions, where the models are most sensitive. The agreement is less good for finite-range forces. A strong absorption model gives much poorer agreement with the recent ⁴He+Si measurements than do the microscopic models

[en] The internal momentum spectrum of p+n pairs produced in the /sup 6/Li(/alpha/,2/alpha/)pn reaction at 118 MeV was measured for those pairs whose c.m. was at rest after the reaction. This spectrum was calculated with a plane wave impulse approximation model, having no free parameters, for two p/sub 3/2/ nucleons initially bound in a harmonic oscillator potential. The calculation gave reasonable agreement with measured values of both the normalization of the spectrum and its dependence upon the p+n internal energy, when the final nucleons were described by Yamaguchi, Paris, or Reid wave functions and the data were reduced by the final-state energy prescription. Less satisfactory fits were obtained with p+n plane waves and/or the initial-state energy prescription

No abstract available