The rare radiative decay $B_s \to \nu \bar{\nu} \gamma$ in beyond   Standard Model scenarios
  In this paper, I study the branching ratio of the rare radiative decay $B_s \to \nu \bar{\nu} \gamma$ in the framework of the Fourth-Generation Standard Model and the Two-Higgs-Doublet Model. It is shown that this quantity is a very effective tool for establishing new physics beyond the Standard Model. It is observed that there is a region in the parameter space in both extensions of the Standard Model for which the branching ratio show considerable departure from the Standard Model. 
Yusuf Dincer