A Test of the Unitarity of the CKM Matrix
The most precise experimental values of the effective weak vector coupling constant Gv come from measurement of the 0+ - 0+ superallowed Fermi beta decay. We are currently measuring the lifetime of Oxygen-14 to determine the Vud element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix relating the mass and weak eigenstates for quarks. Previous measurements of Vud , Vus, and Vub have suggested that the CKM matrix is not unitary.
