Abstract
An unexpected breakdown of the isobaric multiplet mass equation in the quintet was recently reported, presenting a challenge to modern theories of nuclear structure. In the present work, the excitation energy of the lowest state in has been measured to be keV by using the superallowed beta decay of to access it and an array of high-purity germanium detectors to detect its -ray deexcitation. This value differs by 27 keV (1.9 standard deviations) from the recommended value of keV and is a factor of 28 more precise. The isobaric multiplet mass equation is shown to be revalidated when the new value is adopted.
- Received 8 September 2015
DOI:https://doi.org/10.1103/PhysRevC.92.042501
©2015 American Physical Society