Abstract
Recent high-precision mass measurements of and , performed with the TITAN Penning trap at the TRIUMF ISAC facility, are analyzed in light of state-of-the-art shell model calculations. We find an explanation for the anomalous isobaric mass multiplet equation behavior for the two quartets. The presence of a cubic term for the quartet and the vanishing cubic term for the excited multiplet depend upon the presence of a nearby state in and that induces isospin mixing. This is contrary to previous hypotheses involving purely Coulomb and charge-dependent effects. states have been observed near the calculated energy, above the state. However, an experimental confirmation of their is needed.
- Received 12 March 2012
DOI:https://doi.org/10.1103/PhysRevLett.108.212501
© 2012 American Physical Society