  The rare decay $B^+ \to D_s^+ \phi $ can occur only via annihilation type
diagram in the standard model. The small branching ratio predicted in the
standard model makes this channel sensitive to new physics contributions. We
analyze this decay mode, both in the standard model and in several extensions
of it. The models considered are minimal supersymmetric model with R-parity
violation and two Higgs doublet model. The experimental verification of our
findings of large branching ratio and/or nonzero CP asymmetry may signal the
presence of new physics.
