Precision ground state mass of (12)Be and an isobaric multiplet mass equation (IMME) extrapolation for 2(+) and 0(2)(+) states in the T=2, A=12 multiplet
Résumé
We report the mass measurement of the short-lived (12)Be nuclide (T(1/2) = 21.5 ms) performed using the Penning trap mass spectrometer TITAN at TRIUMF. Our mass excess value of 25 078.0(2.1) keV is in agreement with previous measurements, but is a factor of 7 more precise than the Atomic Mass Evaluation of 2003. To address an unresolved discussion on the spin assignment of isospin T = 2 states in (12)C and (12)O, we reevaluate the isobaric mass multiplet equation for the lowest lying T = 2 multiplet in the A = 12 system and use the extracted parameters to extrapolate from the known excited 2(+) and 0(+) states in (12)Be. Though this analysis favors the second known T = 2 state in (12)C to be 2(+), 0(+) cannot be excluded.