  We present the calculations of collisional and radiative energy loss of $B$
and $D$ mesons in the medium produced in PbPb collisions at $\sqrt{s_{NN}}$ =
2.76 TeV. The nuclear modification factor $R_{AA}$ of $B$ and $D$ mesons
including shadowing and energy loss are calculated and compared with the
measured data. While the $D$ meson $R_{AA}$ can be described in terms of the
radiative energy loss alone, both the collisional as well as radiative energy
loss are required to explain the $B$ meson measurements.
