W. Satula, J. Dobaczewski, W. Nazarewicz, M. Borucki, and M. Rafalski
We present the isospin- and angular-momentum-projected nuclear density functional theory (DFT) and its applications to the isospin-breaking
corrections to the superallowed

-decay rates
in the vicinity of the

line.
A preliminary value obtained for the Cabbibo-Kobayashi-Maskawa
matrix element,

, agrees well with the
recent estimate by Towner and Hardy [Phys. Rev. C
77, 025501 (2008)].
We also discuss new opportunities to study the symmetry
energy by using the isospin-projected DFT.