The four jet production at LHC and Tevatron in QCD

5 pages, 2 figuresBy exploring the difference in scales between soft and hard QCD processes and space-time struc- ture of Feynman diagrams we derive within the parton model the general formulae for the two dijet production in pp collisions. Cross section resulting from collisions of four partons is calculated in terms of new generalized two-particle parton distributions (GPDs) in proton. We explain why the derived formulae hold modulo simple modifications even when the pQCD corrections are taken into account. Our derivation justifies the intuitive geometrical approach in the impact parameter space used before to describe the four-jet production. Comparison with CDF and D0 data shows that the independent parton approximation to light cone wave function of proton is insufficient to explain the data. We argue that the nonperturbative multi-parton correlations in the light cone wave functions of colliding protons play an important role. We explain kinematics where the discussed process is enhanced as compared to the four jet production in the hard collisions of two partons