Precise branching ratio measurement for the superallowed β+ decay of Si26: Completion of a second mirror pair Academic Article uri icon


  • © 2019 American Physical Society. As part of a continuing effort to test the unitarity of the Cabbibo-Kobayashi-Maskawa matrix, we have measured the branching ratio for the superallowed 0+→0+β+-decay transition from Si26 to be 0.7569(14), a result with 0.18% relative precision. With this result, the ft value for the transition is now established with comparable precision to the well-known superallowed transitions currently used in the determination of Vud. It also completes a second pair of mirror superallowed transitions, Si26 → Al26m and Al26m → Mg26, the ratio of whose measured ft values provides a sensitive test of the method used to calculate the isospin-symmetry-breaking correction δC needed to determine Vud. Like the previously measured ratio for the mass-38 mirror pair, the new result agrees well with the calculation based on Woods-Saxon radial wave functions and strengthens the case for rejecting the calculation that uses Hartree-Fock radial functions.

altmetric score

  • 0.25

author list (cited authors)

  • Bencomo, M., Hardy, J. C., Iacob, V. E., Park, H. I., Chen, L., Horvat, V., ... Towner, I. S.

citation count

  • 3

publication date

  • July 2019