Abstract
We have measured the isospin mixing of the MeV state in nearly doubly magic with the isobaric analog state of . Using the TRIUMF atom trap for decay, we have measured a nonzero asymmetry of the progeny with respect to the initial spin polarization, which together with the asymmetry implies a nonzero ratio of Fermi to Gamow-Teller matrix elements for the transition. Interpreting as mixing between this state and the isobaric analog state implies a Coulomb matrix element magnitude keV. This relatively large matrix element supports a model from the literature of analog-antianalog isospin mixing, which predicts large matrix elements in cases involving excess neutrons over protons occupying more than one major shell. The result supports pursuing a search for time-reversal odd, parity-even, isovector interactions using a correlation in decay.
- Received 4 March 2024
- Accepted 3 May 2024
DOI:https://doi.org/10.1103/PhysRevC.109.L052501
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