Huo, WJ (reprint author), China Ctr Adv Sci & Technol, World Lab, POB 8730, Beijing 100080, Peoples R China.
We investigate the mass differences DeltaM(Bd,s) in B-d,s(0)-(B) over bar (0)(d,s), mixing with a new up-like quark t' in d d the sequential fourth generation model. We give the basic formulae for DeltaM(Bd,s) in this model and obtain two kinds of numerical results for DeltaMB(s) as a function of m(t)'. We find that one of our results can satisfy the present experimental lower bound of DeltaMB(s). We also get the constraints of the fourth generation CKM factor (Vt/bVt'd)-V-*, as a function of t', from the experimental measurements of DeltaM(Bd). Thus, DeltaM(Bd,s) provides a possible test of the fourth generation and may give a signal of new physics.