Decays of heavy quarks

The weak decay of heavy b and t quarks is discussed using the mixing angles obtained in Fritzsch's model (1978). The author finds that the decay b to c dominates over b to u for 7<or=m, <or= 15 GeV by at least 2 to 1 and that the semileptonic branching ratio of b is approximately =14%; the b-quark lifetime is approximately 1.6*10/sup -13/ sec. for m /sub t/ approximately=14 GeV. For t quarks of this mass he finds tau /sub t/<or approximately=1.7*10/sup -17/ sec. and B(t to X mu /sup +/ nu /sub mu /)