The optical potential of 6He in the eikonal approximation
Abstract The new data of the elastic scattering of 6 He+ 12 C at about 40 MeV/nucleon are analyzed in the eikonal approximation. The 6 He+ 12 C phase-shift function is evaluated completely without any ad hoc assumption by a Monte Carlo integration, which makes it possible to use a realistic 6-nucleon wave function for a halo nucleus 6 He. The effect of the breakup of 6 He on the elastic differential cross sections as well as the optical potential is studied at different energies from 40 to 800 MeV/nucleon.
Microscopic optical potential of nucleus–nucleus elastic scattering
Microscopic optical potential of nucleus–nucleus interaction is presented by a folding method with the isospin-dependent complex nucleon–nucleus optical potential, which is calculated in the framework of the Dirac–Bruecker–Hartree–Fock approach. A local density and improved local density approximations are adopted to make the potentials in nuclear matter relevant to finite nuclei. The 4He scattering off 12C at various energies E< 200 MeV are studied first. Then the elastic scattering data of 6He at 229.8 MeV on 12C target are analyzed within the standard optical model. To take account of the breakup effect of 6He in the reaction a phenomenological, large enhancing factor on the imaginary potential is introduced by hand. The calculated 6He+12C elastic scattering differential cross section is in reasonable agreement with the experimental data. Meanwhile comparisons with results in the double-folded model based on M3Y nucleon–nucleon effective interaction and the few body Glauber-model calculations are discussed. Our model should be of value in the description of the nucleus–nucleus scattering, especially unstable nucleus–nucleus systems.
EXACT AND APPROXIMATE ANGULAR MOMENTUM PROJECTION FOR LIGHT NUCLEI.
Abstract The Peierls-Yoccoz angular momentum projection method is applied to axially symmetric Hartree-Fock wave functions for several sd-shell nuclei. Excitation energies, rms radii and B (E2; 2 + → 0 + ) values are calculated and compared with the results of two different approximation methods. This is also done for some 12 C wave functions considered earlier. A discussion of the accuracy of these approximations is given. An approximate formula for the B (E2; 2 + → 0 + ) value is presented, which gives much better agreement with the exact angular momentum projection results than the formula from the Bohr-Mottelson model.