2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/214604We analyze the semileptonic (B_c -> B_u* l+ l-) decay in the frame work of the Standard Model. We calculate the (B_c) to (B_u*) transition form factors in QCD sum rules. Analytical expressions for the spectral densities and gluon condensates are presented. The branching ratio of the (B_c -> B_u* l+ l-) decay is calculated, and it is obtained that this decay can be detectable at forthcoming LHC machines.17 pages, no figures, LaTeX formattedHigh Energy Physics - Phenomenologytext