Comment on ‘‘E2 contribution to thep8+7Be Coulomb dissociation cross section’’

The E2 cross section calculated by Langanke and Shoppa for the RIKEN experiment on the Coulomb dissociation of ${}_{}{}^8{}_{}{}^{}\mathrm{B}$ uses E2 nuclear matrix element from one specific model. Other nuclear models predict a considerably smaller E2 cross section (by approximately a factor of 3 to 4), and Langanke and Shoppa appear to assume the most optimistic scenario, predicting a large E2 cross section. We also note that Barker has already criticized the nuclear model used by Langanke and Shoppa. A model independent chi-square analysis of the RIKEN data suggest the best fit for the current RIKEN data is obtained with E1 amplitudes only. The upper limit (90% confidence) on the E2 component derived from our chi-square analysis is considerably smaller than that used by Langanke and Shoppa. The model dependent analysis of Langanke and Shoppa should not be considered as a correction to the RIKEN result, as claimed, and their quoted ${\mathit{S}}_{17}$(0) is not substantiated.