I have examined the $B$($E$2)'s in ${}^{12}$Be connecting the first 2${}^{+}$ state to the first two 0${}^{+}$ states. I find that they can be understood in the simple model that has been successful for a variety of other observables in this nucleus, but only if the 2${}^{+}$ state has an excited-core component.

• Received 7 February 2012

DOI:https://doi.org/10.1103/PhysRevC.85.044309