Precise branching ratio measurement for the superallowed + 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++-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 C 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.

published proceedings

  • Physical Review C

author list (cited authors)

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

complete list of authors

  • Bencomo, M||Hardy, JC||Iacob, VE||Park, HI||Chen, L||Horvat, V||Nica, N||Roeder, BT||Saastamoinen, A||Towner, IS

publication date

  • January 1, 2019 11:11 AM