  We consider the central exclusive production of $q\bar{q}$ pairs and Higgs
boson at proton-proton collisions at LHC. The amplitude for the process is
derived within the $k_{\perp}$-factorization approach and considered in
different kinematical asymptotics, in particular, in the important high quark
transverse momenta and massless quark limits. Quark helicity and
spin-projection amplitudes in two different frames are shown in extenso.
Rapidity distributions, quark jet $p_{\perp}$ distributions, invariant
$q\bar{q}$ mass distributions, angular azimuthal correlations between outgoing
protons and jets are presented. Irreducible $b{\bar b}$ background to the
central exclusive Higgs boson production is analyzed in detail, in particular
how to impose cut to maximize signal-to-background ratio.
