Fourth generation effects in rare exclusive B -> K*l(+)l(-) decay

Influence of the fourth generation, if ever exists, on the experimentally m easurable quantities such as invariant dilepton mass distribution, lepton f orward-backward asymmetry, and the ratio Gamma(L)/Gamma(T) of the decay wid ths when K* meson is longitudinally and transversally polarized, is studied . Using the experimental results on the branching ratios for the B --> X(s) gamma and semileptonic B --> X(c)l (v) over bar decays, the two possible so lutions of the 4 x 4 Cabibbo-Kobayashi-Maskawa factor Vt'sVt'b are obtained as a function of the t'-quark mass. It is observed that the results for th e above-mentioned physical quantities are essentially different from the st andard model predictions only for one solution of the CKM factor. in this c ase the above-mentioned physical quantities can serve as efficient tools in search of the fourth generation. The other solution yields almost identica l results with the SM. (C) 2000 Elsevier Science B.V. All rights reserved.