Title: Inclusive dileptonic rare<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>B</mml:mi></mml:math>decays with an extra generation of vectorlike quarks
Abstract: We investigate the leading effects of extending the standard model of electroweak interactions by an extra isosinglet up- and down-type quark pair on various distributions and total branching ratio of the inclusive $\stackrel{\ensuremath{\rightarrow}}{B}{X}_{s}{l}^{+}{l}^{\ensuremath{-}}$ $(l=e,\ensuremath{\mu})$ rare B decays. The presence of the extra vectorlike down quark D results in the nonunitarity of the extended quark mixing matrix V, which in turn leads to $\stackrel{\ensuremath{\rightarrow}}{b}s$ flavor changing neutral currents at the tree level proportional to ${(V}^{\ifmmode\dagger\else\textdagger\fi{}}{V)}_{\mathrm{sb}}.$ On the other hand, the effective penguin and box vertex functions are sensitive to the mass of the extra isosinglet up quark ${m}_{U}.$ The experimental upper bound on $BR(\stackrel{\ensuremath{\rightarrow}}{B}{X}_{s}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})$ is used to constrain the parameters of the model. It is shown that the shapes of the differential branching ratio and forward-backward asymmetry distribution are very sensitive to the value of the model parameters. We also calculate the $\mathrm{CP}$ aymmetry distribution of the dileptonic decay in the vectorlike quark model. It is shown that, for a typical choice of the model parameters, asymmetries up to around 10% can be achieved for certain values of the dilepton invariant mass.