Electric Quadrupole Excitation of the First Excited State of 11B

Abstract

The Coulomb excitation of backscattered llB projectiles has been used to measure the reduced E2 transition probability B(E2; 3/2--+ 1/2-) between the 3/2- ground state and the 1/2- first excited state of llB. It is found that B(E2;3/2--+1/2-) = 2·1±0·4 e2 fm4, which agrees with shell model predictions but is a factor of 10 larger than the prediction of the core-excitation model.