Abstract
<p>Since the nuclear interaction is, to first order, isospin independent, simple relationships can be derived for E2 strengths across isobaric analog states within an isobaric triplet. At the same time, there is a well-known relationship between the 2+ excitation energy and the B(E 2; 2+ -> 0+) transition strength in deformed even-even nuclei. Here, we highlight a tension between these two trends in the A = 78 isobaric triplet. Recent level-energy determinations indicate that the proton-rich member of the triplet, 78Zr, is strongly deformed while recent lifetime measurements in 78Sr and 78Y, as extrapolated into 78Zr, would imply that 78Zr is weakly deformed. Here, we explore the implications of this apparent contradiction and explore potential solutions.</p>