  We discuss diffractive dissociation of gluons into heavy quark pairs. The
particular mechanism is similar to the diffractive dissociation of virtual
photons into quarks. The amplitude for the $g p \to Q \bar Q p$ is derived in
the impact parameter and momentum space. The cross section for single
diffractive $p p \to Q \bar Q p X$ is calculated as a convolution of the
elementary cross section and gluon distribution in the proton. Integrated cross
section and differential distributions in transverse momentum and rapidity of
the charm and bottom quark and antiquark, etc. are calculated for the nominal
LHC energy for different unintegrated gluon distributions from the literature.
The ratio of the bottom-to-charm cross sections are shown and discussed as a
function of several kinematical variables.
