New results on the halo structure of [formula omitted]B

• Published in: Physics letters. B Vol. 452; no. 1; pp. 1 - 7
• Main Authors: Smedberg, M.H., Baumann, T., Aumann, T., Axelsson, L., Bergmann, U., Borge, M.J.G., Cortina-Gil, D., Fraile, L.M., Geissel, H., Grigorenko, L., Hellström, M., Ivanov, M., Iwasa, N., Janik, R., Jonson, B., Lenske, H., Markenroth, K., Münzenberg, G., Nilsson, T., Richter, A., Riisager, K., Scheidenberger, C., Schrieder, G., Schwab, W., Simon, H., Sitar, B., Strmen, P., Sümmerer, K., Winkler, M., Zhukov, M.V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1999
• Subjects: Breakup reactions; Momentum distributions; Nuclear structure; One-proton removal cross section; Unstable nuclei; Momentum distributions; Nuclear structure; 25.60.Gc; Unstable nuclei; 27.20.+n; One-proton removal cross section; Breakup reactions
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/S0370-2693(99)00245-2

The longitudinal momentum distribution of
7
Be fragments after fragmentation of
8
B and the one-proton removal cross section (
σ
−1
p
) in a carbon target were measured at 1440 MeV/u with the fragment separator FRS used as an energy-loss spectrometer. The results show a narrow momentum distribution with a FWHM value of 91±5 MeV/c and a large cross-section,
σ
−1
p
= 98±6 mb. Both these results support the interpretation of a spatially extended proton orbit forming a halo in the
8
B ground state. The momentum distribution and the one-proton removal cross section are shown to be reproduced with a three-body wave function for
8
B where the target is treated as a black disc in the breakup process.