Experimental evidence for the 8B ground state configuration

The 7Be fragments produced in one-proton removal from relativistic 8B nuclei of 936 MeV<f>/</f>nucleon in a carbon target have been detected in coincidence with <f>γ</f> rays emitted by these fragments at the reaction target. It is found that <f>13±3</f>% of the 7Be fragments are released in the 429 keV excited state, 7Be&ast;, which gives direct experimental information on the ground state configuration of 8B. The longitudinal momentum distributions (<f>p&par;</f>) of the 7Be fragments have been measured, both inclusively and in coincidence with de-excitation <f>γ</f>-rays from 7Be&ast;. The widths and cross sections of the respective <f>p&par;</f> distributions are compared with calculations in a three-body cluster model. [Copyright &y& Elsevier]