Effects of a Single Universal Extra Dimension in $B_c \rightarrow   (D_{s},D) \,\ell^+ \ell^-$ Decays
  The rare semileptonic $B_c \rightarrow D_{s,d}\, \ell^+ \ell^-$ decays are studied in the universal extra dimension with a single extra dimension scenario. The sensitivity of differential and total branching ratios, polarization asymmetries of final state leptons to the compactification parameter is presented, both for muon and tau decay channels. Comparing with the standard model, the obtained results indicate that there are new contributions to the physical observables. Considering the ability of available experiments, it would be useful to study these effects. 
U. O. Yilmaz and E. Danapinar
hep-ph