Analysis of the semileptonic Bc→Bu*ℓ+ℓ- decay from QCD sum rules

We analyze the semileptonic Bc→Bu*ℓ+ℓ- decay in the framework of the Standard Model. We calculate the Bc to Bu* transition form factors in QCD sum rules. Analytical expressions for the spectral densities and gluon condensates are presented. The branching ratio of the Bc→Bu*ℓ+ℓ- decay is calculated, and it is obtained that this decay can be detectable at forthcoming LHC machines.