New results on the halo structure of "8B

The longitudinal momentum distribution of "7Be fragments after fragmentation of "8B and the one-proton removal cross section (#sigma#_-_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, #sigma#_-_1_p=98#+-#6 mb. Both these results support the interpretation of a spatially extended proton orbit forming a halo in the "8B ground state. The momentum distribution and the one-proton removal cross section are shown to be reproduced with a three-body wave function for "8B where the target is treated as a black disc in the breakup process. (orig.)Available from TIB Hannover: RO 801(99-09) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman