He-8-He-6: a comparative study of nuclear fragmentation reactions

• Published in: Nuclear physics. A Vol. 679; no. 3-4; p. 462
• Main Authors: Markenroth, Karin, Meister, Mikael, Eberlein, B., Aleksandrov, D., Aumann, T., Axelsson, Leif, Baumann, T., Borge, M. J. G., Chulkov, L. V., Dostal, W., Elze, T. W., Emling, H., Geissel, H., Grunschloss, A., Hellstrom, M., Holeczek, J., Jonson, Björn, Kratz, J. V., Kulessa, R., Leistenschneider, A., Mukha, I., Munzenberg, G., Nickel, F., Nilsson, Thomas, Nyman, Göran Hugo, Pfutzner, M., Pribora, V., Richter, A., Riisager, K., Scheidenberger, C., Schrieder, G., Simon, H., Stroth, J., Tengblad, O., Zhukov, Mikhail
• Format: Journal Article
• Language: English
• Published: 2001
• Subjects: halo nuclei; he-isotopes; inelastic-scattering; interaction cross-sections; isospin; light-nuclei; momentum distributions; orbital shell-model; parameters; states
• ISSN: 0375-9474
• DOI: 10.1016/S0375-9474(00)00372-9

Dissociation of 227 MeV/u He-8 in a carbon target has been studied in kinematically complete experiments. The data include the relative energy spectrum, angular distributions in the neutron knock-out channel (He-6 + n) as well as diffractive dissociation and inelastic scattering into the (He-6 + 2n) channel. The data are compared with corresponding results from the well-known halo nucleus He-6. In both cases it is found that neutron knock-out is the: dominating reaction channel. The relative energy spectrum (He-6 + n) shows a structure, which is interpreted as being due to the I-pi = 3/2(-) resonance in the He-7 ground state with about equal contribution from its I-pi = 1/2(-) spin-orbit partner. The He-7 resonance shows a spin alignment similar to that observed in He-5, but with a smaller anisotropy indicating that the structure of the He-8 ground state is more complicated than that of He-6. The data in the (He-6 + 2n) channel were used to identify resonances in the excitation energy spectrum of He-8. If the spectrum is interpreted as two overlapping resonances, the spin-parity assignment for these is found to be 2(+) and 1(-), respectively.