  We discuss four-jet production at the LHC. We calculate cross section for
both single-parton scattering (SPS) using the ALPGEN code as well as for
double-parton scattering (DPS) in leading-order collinear approach. Our results
are compared with experimental data obtained recently by the CMS collaboration.
We show that the ALPGEN code relatively well describes distributions in
transverse momenta and rapidity of each of the four jets ordered by their
transverse momenta (leading, subleading etc.). The SPS mechanism does not
explain the distributions at large rapidity for the leading jet. The DPS
mechanism considerably improves the agreement with the experimental data in
this corner of the phase space. In order to enhance the relative DPS
contribution we propose to impose different cuts. The relative DPS contribution
increases when decreasing the lower cut on the jet transverse momenta as well
as when a low lower cut on the rapidity distance between the most remote jets
is imposed. We predict very flat distribution in azimuthal angle between the
most remote jets with low lower cuts on jets transverse momentum. We identify
phase-space corners where the DPS content is enhanced relatively to the SPS
one.
