JOURNAL OF HIGH ENERGY PHYSICS, no.7, 2007 (SCI-Expanded)
This study investigates the influence of the fourth generation quarks on the total branching ratio and the single lepton polarizations in Lambda(b) -> Lambda l(+)l(-) decay. Taking vertical bar Vt ' sVt ' b vertical bar similar to {0.01-0.03} with phase just below 90 degrees, which is consistent with the b -> sl(+)l(-) rate and the B-s mixing parameter Delta(mBs), we obtain that the total branching ratio and the single lepton (mu,tau) polarizations are quite sensitive to the existence of fourth generation. It can serve as a good tool to search for new physics effects, precisely, to search for the fourth generation quarks (t ',b ').