JOURNAL OF HIGH ENERGY PHYSICS, no.5, 2005 (SCI-Expanded)
The exclusive Lambda(b)->Lambda l(+)l(-) decay is analyzed in the fourth generation model. We studied the sensitivity of the physical observables such as the branching ratio and the forward-backward asymmetry of this process to the model parameters, namely, the mass of the fourth generation up-type quark t' and the fourth generation CKM matrix element V-t's*V-t'b by using two possible solutions of the latter and the experimental results on branching ratios for B-s -> X-s gamma and Bs -> X(c)l nu overbar. It has been found that these observables are almost the same as the SM predictions when V-t's*V-t'b is positive. However, when it is negative, they are essentially very sensitive to the fourth generation model and can serve as efficient tools in search of the fourth generation.