Double-Lepton Polarization Asymmetries and Branching Ratio of the $B\rar   \gamma l^+ l^- $ transition in Universal Extra Dimension
  We study the radiative dileptonic $B \rar \gamma l^+ l^- $ transition in the presence of a universal extra dimension in the Applequist-Cheng-Dobrescu model. In particular, using the corresponding form factors calculated via light cone QCD sum rules, we analyze the branching ratio and double lepton polarization asymmetries related to this channel and compare the results with the predictions of the standard model. We show how the results deviate from predictions of the standard model at lower values of the compactification factor ($1/R $) of extra dimension. 
K. Azizi, N. K. Pak, B. B. Sirvanli
hep-ph