  We discuss the universal behaviour of scattering cross sections in the limit
of infinite rapidity separation between all produced particles, and illustrate
the behaviour explicitly for the production of n jets, W+n jets, Z+n jets for
n=2,3,4, and for H+2,3 jets. We give a set of rules for constructing scattering
cross sections, which are exact in the given limit, and order-by-order
reproduce well the full fixed order results when applied to LHC phenomenology.
The approximation includes both real and virtual corrections, and is
sufficiently simple to allow for the regulated all-order perturbative sum to be
explicitly constructed. We test the expected accuracy by comparing results
order-by-order with full fixed-order perturbation theory for the processes
mentioned above.
