Abstract
Background: The precise determination of the value in mixed mirror decays is an important avenue for testing the standard model of the electroweak interaction through the determination of in nuclear decays. is an interesting case, as its low mass and small value make it particularly sensitive to violations of the conserved vector current hypothesis. The present dominant source of uncertainty in the value is the half-life.
Purpose: A high-precision measurement of the half-life was performed, and a new world average half-life was calculated.
Method: was created by transfer reactions and separated using the TwinSol facility at the Nuclear Science Laboratory at the University of Notre Dame. It was then implanted into a tantalum foil, and counting was used to determine the half-life.
Results: The new half-life, s, is consistent with the previous values but significantly more precise. A new world average was calculated, s, and a new estimate for the Gamow-Teller to Fermi mixing ratio is presented along with standard model correlation parameters.
Conclusions: The new world average half-life allows the calculation of a value that is now the most precise value for all superallowed mixed mirror transitions. This gives a strong impetus for an experimental determination of , to allow for the determination of from this decay.
- Received 28 August 2017
- Revised 18 December 2017
DOI:https://doi.org/10.1103/PhysRevC.97.035503
©2018 American Physical Society